Set your regimen once, then each day just tick off what you took.
Tap a name for all six answers. Every answer carries a badge saying how strong the evidence is, and where the marketing does not match the research, it says so plainly.
No supplement matches that.
A vitamin the body makes from sunlight. It behaves more like a hormone than a vitamin, governing calcium absorption and the expression of thousands of genes.
Correcting deficiency and protecting bone in people who are actually deficient — well established. In people already replete, the VITAL trial (25,871 people) found no reduction in fractures.
Testosterone rises only in men who are genuinely deficient; in replete men it does not move. This is the most commonly mislabelled claim in the supplement aisle.
Does not cause weight loss. Low vitamin D in obesity reflects the vitamin being sequestered in fat tissue — the cause and effect run the other way round.
Small studies link low vitamin D to poorer sleep, but there is no good evidence that supplementing improves it.
Bone, immune function and muscle. Best guided by a blood test — the goal is to reach the normal range, not to go as high as possible.
Commonly used: 1,000-5,000 IU per day
4,000 IU/day (100 mcg) — IOM and EFSA agree; counts all sources.
The vitamin that lets certain proteins bind calcium in the right place. MK-7 stays in the blood far longer than MK-4, so once a day is enough.
Blood markers of arterial calcium handling improve clearly, but the two trials that measured actual arterial imaging came out neutral.
No measurable effect on hormones in humans.
Nothing to do with fat loss.
Nothing to do with sleep.
Bone and blood vessels. The marketing line that vitamin D without K2 will calcify your arteries is not supported at the outcome level — NIH itself calls the role unclear.
Commonly used: 45-180 mcg per day
No upper limit set by IOM or EFSA — no toxicity has ever been reported in humans or animals.
A water-soluble antioxidant needed to build collagen and to absorb plant iron. The body cannot make it.
Markedly improves absorption of plant iron — that part is clear. For colds, it shortens duration slightly if taken regularly beforehand, not if started once symptoms appear.
No measurable effect on sex or thyroid hormones.
Nothing to do with fat loss.
Nothing to do with sleep.
Skin, blood vessels and wound healing. Above 1,000 mg absorption falls off sharply and the excess leaves in the urine.
Commonly used: 250-1,000 mg per day
2,000 mg/day — IOM, based on diarrhoea. EFSA sets no limit, citing insufficient data.
A fat-soluble vitamin needed for night vision, skin and immunity. Supplements carry two forms: retinol, which counts against the ceiling, and beta-carotene, which does not.
Correcting deficiency, the leading preventable cause of blindness worldwide. In people eating a full diet, supplementing adds nothing.
No measurable effect on sex hormones in humans. The claim that vitamin A competes with vitamin D is a cell-biology observation, never demonstrated in people.
Nothing to do with fat loss.
Nothing to do with sleep.
Vision, skin, mucous membranes and immunity.
Commonly used: 700-3,000 mcg per day
3,000 mcg RAE/day — IOM and EFSA (reaffirmed 2024). Counts preformed retinol only, not beta-carotene.
A fat-soluble antioxidant that protects cell membranes.
Correcting deficiency, which is rare. Large trials aimed at heart disease and cancer came out neutral to negative.
No measurable hormonal effect.
Nothing to do with fat loss — and in high doses alongside vitamin C around training it may blunt the muscle adaptation you are training for.
Nothing to do with sleep.
Skin and cell membranes. The SELECT trial found 400 IU/day raised prostate cancer risk 17%, so there is no case for taking high doses indefinitely without a reason.
Commonly used: 100-400 IU per day
The official limits are 1,000 mg (IOM) or 300 mg (EFSA), but the level that actually matters is 400 IU/day, where it starts interfering with clotting.
The eight B vitamins in one tablet. They act as coenzymes that turn food into usable energy.
Correcting deficiency — seen in strict vegetarians, heavy drinkers and long-term acid-blocker users. In people eating a full diet it does not give the extra energy the marketing promises.
No direct hormonal effect.
Does not reduce fat. Metabolism needs B vitamins, but adding more than the body needs does not speed anything up.
The belief that B vitamins at night ruin sleep has no evidence behind it.
Nervous system and red blood cell production.
Commonly used: 1 เม็ด per day
No combined limit — read the label per vitamin. The two to watch are B6 and niacin, which many B-complex products carry above their own ceilings.
The B vitamin behind neurotransmitter synthesis and protein handling.
Nausea in pregnancy, and premenstrual symptoms.
Modestly lowers prolactin at high doses. No effect on testosterone.
Nothing to do with fat loss.
People report more vivid dreams; no trial has measured actual sleep quality.
Nervous system and haemoglobin synthesis.
Commonly used: 2-50 mg per day
100 mg/day — IOM. EFSA cut theirs to 12 mg/day in 2023, an eightfold gap. For long-term use, follow the lower number.
A vitamin found only in animal foods, needed to build red blood cells and the sheath around nerves.
Correcting deficiency — common in vegetarians, older people, and long-term users of acid blockers or metformin. In people who are not deficient it gives no extra energy.
No hormonal effect.
Nothing to do with fat loss. B12 injections for weight loss have no evidence behind them.
Nothing to do with sleep.
Blood and nerves. Prolonged deficiency causes permanent spinal cord damage.
Commonly used: 500-1,000 mcg per day
No limit from IOM or EFSA — no adverse effects at any oral dose, and absorption is self-limiting anyway.
The B vitamin needed to build DNA and divide cells. The synthetic form absorbs better than the natural one, which is exactly why it needs a ceiling.
Preventing neural tube defects — one of the strongest findings in all of nutrition. It has to start before conception.
No hormonal effect.
Nothing to do with fat loss.
Nothing to do with sleep.
Blood formation and cell division.
Commonly used: 400-800 mcg per day
1,000 mcg/day — IOM and EFSA agree. Counts synthetic folic acid from supplements and fortified food only, not natural food folate.
A B vitamin in two very different forms. Nicotinic acid causes flushing and lowers blood lipids; nicotinamide does neither.
High doses genuinely lower triglycerides and raise HDL, but outcome trials found no reduction in heart disease, so it has fallen out of use as a primary treatment.
At 1,500 mg and above it causes insulin resistance and raises blood glucose — a clear adverse effect.
Does not reduce body fat, even though it changes the numbers on a lipid panel.
Nothing to do with sleep, though the flush can be disruptive if taken at bedtime.
Energy metabolism and skin.
Commonly used: 16-500 mg per day
35 mg/day — IOM, but that number is set on the skin-flushing threshold, not on toxicity. Liver injury needs 1,000-3,000 mg/day for months. Crossing this ceiling is worth knowing about, not worth panicking over.
A B vitamin the body needs 30 mcg of a day. Hair and nail products commonly contain 5,000-10,000 mcg — 150 to 300 times that.
Genuinely helps only people who are biotin deficient, which is rare. In everyone else there is almost no trial evidence for hair or nails.
No real hormonal effect — but it makes hormone test results wrong, which is not the same thing.
Nothing to do with fat loss.
Nothing to do with sleep.
Hair, skin and nails as advertised, though the evidence is far weaker than the marketing.
Commonly used: 30-10,000 mcg per day
No limit — no toxicity reported. But this one carries a different kind of danger entirely; see the caution.
Many vitamins and minerals in one tablet, each usually around the recommended daily amount.
A safety net for people whose diet has gaps. Large trials find no reduction in heart disease or cancer in people already eating well.
No direct hormonal effect.
Nothing to do with fat loss.
Nothing to do with sleep.
Preventing nutrient gaps, which is its honest purpose — not preventing disease.
Commonly used: 1 เม็ด per day
No combined limit, but this is the single biggest cause of accidentally exceeding one — it overlaps with whatever standalone products you already take.
A mineral over 300 enzymes depend on. The form matters: glycinate, citrate and malate absorb far better than oxide, which is the cheapest and the worst absorbed.
Correcting deficiency, migraine prevention and constipation — the three well-supported uses.
In people who are deficient it improves insulin resistance. In people who are not, there is no measurable hormonal effect.
Does not reduce fat.
Its reputation for sleep runs well ahead of the evidence: the pooled data is three trials in 151 people, rated low to very low quality, finding sleep onset about 17 minutes faster in older adults with insomnia. Not nothing — but far thinner than people assume.
Muscle, heart, bone and nerve conduction.
Commonly used: 200-400 mg per day
350 mg/day — IOM; EFSA says 250 mg. Counts supplemental magnesium only, not food, and is set on diarrhoea rather than toxicity.
A mineral essential to immunity, wound healing and sex hormone production.
Shortening a cold — though the 2024 Cochrane update rates the evidence low to very low certainty, far more cautious than the two-days figure people repeat. The clearest use is correcting deficiency.
Testosterone rises only in men who are genuinely zinc deficient. In men with normal levels it does not move — the most common misunderstanding among people taking it for that reason.
Does not reduce fat.
No good evidence for sleep.
Immunity, skin, taste and wound healing.
Commonly used: 10-30 mg per day
40 mg/day — IOM; EFSA says 25 mg. Counts all sources, and is set on zinc blocking copper absorption.
The mineral that carries oxygen in the blood. It should be taken because a test showed you are low, not just in case.
Correcting iron deficiency anaemia and the chronic fatigue that comes with it — very well established.
No direct hormonal effect, though severe deficiency does impair thyroid function.
Does not reduce fat, but if you are genuinely deficient, fixing it will visibly increase what you can do in training.
In restless legs caused by iron deficiency, replacing it genuinely improves sleep. Outside that group, no effect.
Oxygen transport, energy and immunity.
Commonly used: 18-65 mg per day
45 mg/day — IOM, for healthy people. EFSA in 2024 could not set a limit and gave a safe level of 40 mg instead. Treating diagnosed deficiency under medical supervision is a different matter.
The main mineral in bone. Absorption is best at 500 mg or less per dose, so a single 1,000 mg tablet wastes about half of itself.
Maintaining bone alongside vitamin D, particularly after menopause. Food first, then supplement only the gap.
No effect on sex hormones. Blood calcium is governed by parathyroid hormone, which adjusts itself.
Does not reduce fat.
Nothing to do with sleep.
Bone, teeth, muscle contraction and nerve conduction.
Commonly used: 500-1,000 mg per day
2,500 mg/day for ages 19-50 and 2,000 mg from 51 — IOM. This app warns at 2,000, the number that is safe at any age. Counts food as well.
A mineral used to build antioxidant enzymes and to convert thyroid hormone into its active form.
Correcting deficiency. In people who are not deficient, large trials found no reduction in cancer or heart disease.
Required to convert T4 into T3. In autoimmune thyroiditis some trials show lower antibody levels, though the effect on symptoms is unclear.
Does not reduce fat.
Nothing to do with sleep.
Thyroid, immunity and antioxidant defence.
Commonly used: 55-200 mcg per day
400 mcg/day — IOM; EFSA cut theirs to 255 mcg in 2023. The gap between the recommended amount (55) and the ceiling is unusually narrow.
The mineral the thyroid uses to build its hormones. Iodised salt has made deficiency far less common than it once was.
Preventing goitre and hypothyroidism from deficiency. It matters most in pregnancy, where it affects fetal brain development.
It is the raw material of thyroid hormone — but both too little and too much cause thyroid disease, which surprises most people.
Does not reduce fat. Taking iodine to speed up a normal thyroid does not work and can be harmful.
No direct effect on sleep.
Thyroid, basal metabolism and fetal brain development.
Commonly used: 150-300 mcg per day
1,100 mcg/day — IOM; EFSA says 600. Kelp products are the easiest way to exceed it, since their iodine ranges from 16 to 2,984 mcg per gram.
A mineral needed in small amounts but indispensable. The main reason to take it is to offset high-dose zinc, which blocks its absorption.
Preventing copper deficiency in people on sustained high-dose zinc — a real and easily prevented situation.
No measurable hormonal effect.
Nothing to do with fat loss.
Nothing to do with sleep.
Red blood cells, connective tissue, and mobilising stored iron. Copper deficiency causes an anaemia that iron will not fix.
Commonly used: 1-2 mg per day
10 mg/day — IOM, based on liver damage. EFSA sets no limit but gives an acceptable intake of about 5 mg/day.
The mineral that governs blood pressure and heart function. It should come mainly from fruit and vegetables.
Lowering blood pressure, especially in people eating a lot of sodium — but that comes from food, not from a 99 mg tablet, which is far too small to matter.
No direct hormonal effect.
Nothing to do with fat loss.
Nothing to do with sleep.
Blood pressure, heart rhythm and muscle function.
Commonly used: 99 mg per day
No nutritional limit, but supplements are legally capped at 99 mg per serving because higher oral doses ulcerate the small bowel. Potassium salt substitutes are the real route to excess.
A trace mineral involved in insulin signalling, sold as a weight-loss aid and sugar-craving suppressant.
Cochrane concluded there is no reliable evidence to inform a decision — in those words.
Effects on insulin sensitivity are unreliable outside genuine chromium deficiency, which is rare.
The Cochrane pooled figure is about 1 kg, on low-quality evidence. Plainly: it barely works, but the marketing story has outlived the data.
Nothing to do with sleep.
No confirmed benefit in people who are not chromium deficient.
Commonly used: 200-500 mcg per day
No limit — because the data are insufficient to set one, not because it is proven safe. People with kidney or liver disease may be more susceptible.
Powder or liquid carrying sodium, potassium and magnesium to replace what sweat takes away.
Replacing losses from hard exercise over an hour, hot weather, or an extended fast. On an ordinary day with normal meals it is unnecessary.
No direct hormonal effect, but during an extended fast low insulin makes the kidneys dump sodium, so replacing it eases the fatigue and headaches.
Does not reduce fat. Weight that moves with electrolytes is water, not fat.
No good evidence, though sodium depletion during a fast does cause night cramps.
Fluid balance, blood pressure and muscle function.
Commonly used: 1-2 ซอง per day
No combined limit, but check the sodium on the label if you are managing blood pressure.
Fatty acids from oily fish; the two that matter are EPA and DHA. Read the EPA+DHA figure, not the total fish oil per capsule — they often differ threefold.
Lowering triglycerides by 15-30% at 2-4 g/day — very well established. Whether it prevents actual cardiac events is still contested; the large trials split between positive and neutral.
Mild improvements in insulin sensitivity and inflammatory markers. No effect on testosterone.
Does not reduce body fat, even though it improves the blood lipid numbers.
Small studies in children suggest DHA helps sleep; in adults there is no good evidence.
Triglycerides, brain, retina and inflammation.
Commonly used: 1,000-3,000 mg per day
No official limit. This app warns at 4,000 mg EPA+DHA, above which the atrial fibrillation signal becomes clearer.
Omega-3 from Antarctic krill, carried as phospholipids rather than triglycerides, with the red pigment astaxanthin along for the ride.
The same as fish oil but much more expensive, and usually carrying less EPA+DHA per capsule. The better-absorption claim has some support, not enough to justify the price gap.
As for fish oil.
Does not reduce fat.
No evidence.
As for fish oil. Its genuine advantage is that it rarely causes fishy burps.
Commonly used: 500-1,500 mg per day
No limit; use the same EPA+DHA reasoning as fish oil.
Medium-chain fat that goes straight to the liver and converts to ketones quickly, unlike ordinary fat. It is still fat, at 8.3 calories per gram.
Genuinely and quickly raises ketones — useful on a ketogenic protocol or with fat malabsorption.
No confirmed hormonal effect.
About 0.5 kg of weight loss when it replaces ordinary fat, not when added on top. The trials are short and the effect fades. It is not a fat burner — added to coffee without cutting anything else, it is simply added calories.
Nothing to do with sleep.
A quickly available energy source during a fat fast — though at that point it is no longer a true fast.
Commonly used: 5-30 g per day
No limit; the constraint is your stomach — too much at once causes cramps and loose stools.
A fatty acid found in beef and dairy, long sold as a fat reducer.
Almost no confirmed benefit in humans.
Worsens insulin sensitivity and lowers HDL — effects in the wrong direction.
One of the clearest collapses in this whole list. The pooled figure is about 0.09 kg of fat per week — half a kilo to a kilo over six months — and it comes from small early trials; the larger ones trend to nothing.
Nothing to do with sleep.
Reports of fat accumulation in the liver. Weighing benefit against harm, this one does not pass.
Commonly used: 3,000-6,000 mg per day
No limit set, but this app does not recommend it — see the caution.
Fast-absorbing milk protein with a complete amino acid profile. It is food, not medicine — its advantage is convenience and cost per gram of protein.
Adds 0.30 kg of fat-free mass and 2.49 kg of 1RM alongside resistance training — but with no advantage over whole food if your intake is already adequate.
Raises insulin transiently after a serving, which is normal for protein. No meaningful effect on testosterone or growth hormone.
It does not burn fat, but it protects muscle during a deficit, which is the real reason to use it while dieting — and protein is more filling than carbohydrate or fat.
Nothing to do with sleep.
Muscle mass, strength, and preserving muscle with age.
Commonly used: 20-50 g per day
No limit. What matters is total daily protein, and the benefit plateaus around 1.6 g per kg of body weight per day.
The other milk protein. It clots in the stomach and releases amino acids slowly over several hours.
The same as whey in daily terms. Its slowness may offer a small edge before bed or before a long gap without food.
No different from other protein.
Protects muscle in a deficit, like whey.
No evidence that it improves sleep, despite being commonly taken at bedtime.
Muscle mass and satiety.
Commonly used: 20-40 g per day
No limit; look at total daily protein.
Protein from animal skin and bone, broken into short peptides. It is an incomplete protein missing tryptophan, so it cannot replace whey for building muscle.
Skin elasticity and hydration have reasonable support, though most trials are industry-funded, which is worth discounting for. Knee osteoarthritis pain improves slightly.
No hormonal effect.
Nothing to do with fat loss.
Nothing to do with sleep directly. Any effect people notice probably comes from the glycine it is rich in.
Skin, joints and tendons — the tendon and ligament data are still weak.
Commonly used: 5-15 g per day
No limit set.
A compound muscle uses to recharge energy for short, hard efforts. The body makes some, and meat supplies more. It is the most studied supplement in existence.
Increases strength and adds 1.1-1.4 kg of lean mass with resistance training over 4-12 weeks, part of it muscle water. There is also a small memory benefit.
Does not change total testosterone, free testosterone or DHT. A 12-week 2025 trial found no DHT change and no hair shedding, contradicting the single 2009 study people have cited for years.
Does not directly reduce fat. Weight goes up 1-2 kg in the first week from water held in muscle — not fat. Do not be alarmed on the scale.
Does not improve sleep, though a single 0.35 g/kg dose blunts the cognitive damage of sleep deprivation — a different thing from sleeping well.
Muscle, strength and brain function. It is the safest and cheapest of the supplements that actually work.
Commonly used: 3-5 g per day
No limit. Nearly every trial used 3-5 g/day, and more than that adds nothing.
The nine essential amino acids in free form, absorbed faster than whole protein.
Stimulating muscle protein synthesis in older adults or people who cannot eat much protein. In anyone eating enough, it offers nothing over whey and costs far more.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
It has a genuine place in swallowing difficulty, poor appetite in older age, and muscle wasting.
Commonly used: 10-20 g per day
No limit set.
Three of the nine essential amino acids, long sold as a muscle builder.
A small reduction in post-training muscle soreness. That is genuinely all.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
This is where the marketing collapses: it cannot build muscle on its own because six amino acids are missing. Leucine alone lifts protein synthesis briefly, then it falls below baseline. Anyone eating enough protein already gets all the BCAA they need from food.
Commonly used: 5-15 g per day
No limit, but this app does not recommend it — see below.
The most abundant amino acid in blood. The body makes its own, except in serious illness or major injury.
A genuine place in burns and critical illness, where the body is breaking down muscle severely.
No hormonal effect.
Meta-analysis finds no effect on body composition.
Nothing to do with sleep.
Gut lining in critical illness. For ordinary people who train, essentially nothing.
Commonly used: 5-10 g per day
No limit set.
An amino acid the body uses to build muscle carnosine, which buffers acid during hard efforts.
A 2.85% performance gain, but only in efforts lasting 60-240 seconds. Very narrow and very clear. Below 60 seconds or beyond 10 minutes, nothing.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
Performance in a very specific time window; no other health effect.
Commonly used: 3-6 g per day
No limit, but over 800 mg in one go causes skin tingling — split the dose.
An amino acid the body converts to arginine and then to nitric oxide, widening blood vessels.
A few more repetitions in the later sets of a lifting session. Real but small, and the pooled data are inconsistent.
No confirmed hormonal effect in humans.
Does not reduce fat.
Nothing to do with sleep.
Blood flow. The pumped feeling during training is genuine vasodilation, but it does not mean the muscle grew.
Commonly used: 6-8 g per day
No limit set.
A compound the body makes from leucine, used to slow muscle protein breakdown.
Preserving muscle in older people, bed rest and illness. In already-trained athletes the effect is nil.
A 2025 meta-analysis reports a fairly large testosterone increase. That sits awkwardly beside unchanged body composition in the same population, so it is more likely small-study bias than a real effect. Read it cautiously.
In trained people, no effect on fat or muscle.
Nothing to do with sleep.
Age-related muscle wasting, which is where it genuinely helps.
Commonly used: 3 g per day
No limit; 3 g/day is the standard research dose.
The molecule that carries fatty acids into the mitochondria to be burned — the origin of its fat-burner reputation.
A genuine place in carnitine deficiency and in dialysis patients.
No confirmed hormonal effect.
Across 37 trials the pooled loss is 1.2 kg, and it shrinks further in the higher-quality trials. The mechanism sounds convincing; the actual number is a rounding error.
Nothing to do with sleep. The acetyl form is mildly stimulating, so not at bedtime.
Energy use in muscle and heart.
Commonly used: 1,000-2,000 mg per day
No limit set.
An amino acid abundant in heart and brain, which the body makes for itself.
Lowers blood pressure by about 3/1.3 mmHg — small but consistent.
No confirmed effect in humans.
Does not reduce fat.
Nothing to do with sleep.
Blood pressure and heart function. Worth knowing: the energy in an energy drink comes from the caffeine, not the taurine.
Commonly used: 1-3 g per day
No limit set.
The smallest amino acid, and also an inhibitory neurotransmitter. It is abundant in collagen and bone broth.
Falling asleep faster and reaching deep sleep sooner, measured objectively — but the entire evidence base is two small Japanese trials of 10-15 people from one manufacturer research group, never independently replicated.
No confirmed hormonal effect.
Does not reduce fat.
See the helps field. In short: cheap, safe, possibly effective — but the evidence rests on a single lab.
A building block of glutathione and collagen.
Commonly used: 3 g per day
No limit; 3 g before bed is the dose used in the research.
A hormone the pineal gland releases in darkness, telling the body it is night. It is a clock, not a sedative.
Shifting the body clock — jet lag, shift work, delayed sleep phase — where the evidence is strong and the effect clear. For chronic insomnia, objective measurement gives 7 minutes faster to sleep and 8 minutes more of it. Very small.
It is itself a hormone, and modestly suppresses nocturnal LH — but at 0.5-3 mg there is no clinically meaningful effect.
No direct effect on fat, but sleeping enough makes eating well much easier — an indirect effect that genuinely matters.
When you take it matters more than how much: 0.5-1 mg two to three hours before bed beats 10 mg at lights out.
Circadian rhythm. There are no multi-year safety data.
Commonly used: 0.5-3 mg per day
No official limit; this app warns at 5 mg because the most effective dose is 0.5-1 mg — more does not work better and leaves morning grogginess.
An amino acid from tea leaves that produces calm without drowsiness.
A single 200 mg dose improves attention and reaction time, and it takes the edge off caffeine jitters — the most worthwhile way to use it.
No measurable hormonal effect.
Does not reduce fat.
Sold for sleep, but a 2026 meta-analysis of 31 trials in 1,168 people found no sleep benefit. Its real evidence is daytime attention, not night-time sleep.
Relaxation and focus.
Commonly used: 100-200 mg per day
No limit; it has a good safety record.
The brains main inhibitory neurotransmitter. The problem is that oral GABA does not cross into the brain in any meaningful amount.
Almost nothing confirmed. A review of 14 studies found limited evidence for stress and very limited for sleep — and in 11 of the 14, the authors worked for the manufacturer.
No hormonal effect. The growth hormone claim comes from very high doses with a transient measurement.
Does not reduce fat.
This is a clear collapse. If it feels like it works, that is likely the enteric nervous system or placebo — a real feeling, but not the mechanism being sold.
No confirmed benefit.
Commonly used: 100-750 mg per day
No limit, but read below before buying it.
A plant root used as a sleep remedy since antiquity, with a famously strong smell.
People report sleeping better in some trials, but objective measurements do not move. A 2024 umbrella review was unfavourable, and the American sleep medicine society recommends against it for chronic insomnia.
No measurable hormonal effect.
Does not reduce fat.
Subjective improvement without objective change — the mirror image of tart cherry.
No confirmed benefit beyond a feeling of calm.
Commonly used: 300-600 mg per day
No limit, but preparations vary so much in strength that doses are barely comparable between brands.
Cherry extract carrying natural melatonin and anti-inflammatory compounds.
Recovery from training and reduced muscle soreness, plus lower uric acid, which matters for gout.
Modestly raises circulating melatonin.
Does not reduce fat.
Interesting because it inverts valerian: objective sleep efficiency and total sleep time improve clearly while subjective ratings stay flat — people sleep better without noticing. Only three trials so far.
Recovery, inflammation and uric acid.
Commonly used: 480-1,000 mg per day
No limit set.
A direct serotonin precursor that bypasses the step the body uses to regulate the rate of production.
Weak evidence across the board. Cochrane could find only two usable trials totalling 108 people.
Raises peripheral serotonin — the source of both the hoped-for effect and the danger.
Small trials suggest appetite suppression, but far too small to conclude anything.
Weak evidence.
No clearly established use.
Commonly used: 50-200 mg per day
No official limit; this app warns at 200 mg, but the real issue with this one is not the dose — it is what you must not take alongside it.
A stimulant that blocks adenosine receptors — the molecule that builds up through the day and makes you sleepy. It does not give energy; it mutes the signal for a while.
Improves exercise performance by 2-4% across endurance, strength and power, confirmed by an umbrella review of 21 meta-analyses. One of the few here that genuinely and clearly works.
Raises cortisol transiently, which fades as tolerance develops, and briefly lowers insulin sensitivity after a dose.
Raises energy expenditure by 4-6% acutely, but tolerance and compensatory eating cancel it, leaving nearly nothing long term. The real benefit is training harder, not burning fat directly.
This is caffeines clearest effect, and it is negative: 400 mg taken six hours before bed still cuts over an hour of measured sleep, and the drinkers did not notice. If you want to fix your sleep, this is the first thing to address.
Alertness, focus and performance. Whole coffee carries other beneficial compounds that a caffeine tablet does not.
Commonly used: 100-300 mg per day
400 mg/day is the figure most food agencies use. Count coffee, tea, energy drinks, pre-workout and green tea extract together — not just the tablets.
A concentrated extract of green tea leaves whose main compound is EGCG. It is very different from drinking green tea, being many times stronger.
Cochrane found 0.2 kg of weight loss, described as neither statistically nor clinically important. There are small effects on blood pressure and lipids.
No reliable hormonal effect in humans.
The fat-burning claim does not survive scrutiny. Most of what people feel comes from the caffeine that comes with it.
Nothing on its own, but count the caffeine it carries.
For this one, safety matters more than efficacy — see the caution.
Commonly used: 250-500 mg per day
No official limit; this app warns at 800 mg EGCG because liver injury reports begin around there.
A plant alkaloid that behaves much more like a glucose-lowering drug than like a supplement. Think of it as medicine, not as a vitamin.
Lowers HbA1c by 0.7-0.9% and reduces insulin resistance, matching low-dose metformin in head-to-head trials — though most trials are small, Chinese, and at high risk of bias.
This is the strongest insulin sensitivity signal in the entire list. In women with PCOS some trials also show improved cycles.
BMI down about 0.5-0.8 and weight down about 2 kg — more than most of the fat-loss products in this list.
Nothing to do with sleep.
Blood glucose and blood lipids. Its oral absorption is poor, which is a real limitation.
Commonly used: 500-1,500 mg per day
No official limit; trials use 500 mg two or three times a day.
An antioxidant soluble in both water and fat.
Reducing the numbness and pain of diabetic peripheral neuropathy at 600 mg — its best-supported and best-replicated use.
A modest improvement in insulin sensitivity.
About 1.27 kg of weight loss. Small.
Nothing to do with sleep.
Peripheral nerves and antioxidant defence.
Commonly used: 300-600 mg per day
No official limit; 600 mg is the dose used in the diabetic neuropathy trials.
An extract from the rind of the garcinia fruit, long sold for weight loss.
No confirmed benefit.
No measurable hormonal effect.
The pooled figure is 0.88 kg with very high heterogeneity, and the largest, best-blinded trial (JAMA 1998, 135 people) found exactly nothing. When the best trial reads zero, the pooled number should not be trusted.
Nothing to do with sleep.
No confirmed benefit, and risk that is not worth taking.
Commonly used: 500-1,500 mg per day
No limit, but this app does not recommend it.
Vinegar fermented from apples; the active compound is acetic acid.
Genuinely blunts the glucose spike after a high-carbohydrate meal, though the effect is small and short-lived.
No measurable hormonal effect.
This needs saying plainly. The viral 8 kg figure comes from a single trial that the journal formally retracted on 25 September 2025, citing statistics that were not possible and raw data that could not be relied on. A meta-analysis published the same month reporting 7.5 kg pools that retracted trial, so it cannot be trusted either.
Nothing to do with sleep.
What remains is a small post-meal glucose effect. Nothing wrong with that — just far smaller than advertised.
Commonly used: 15-30 ml per day
No limit set.
Soluble fibre from seed husks that swells into a gel in the gut.
Lowers LDL by about 13 mg/dL and relieves constipation. One of the best-evidenced items in this whole list, and the least talked about.
Improves glycaemic control in proportion to how disordered it was to begin with — the worse the baseline, the more it helps.
A small effect on weight, but it genuinely increases fullness.
Nothing to do with sleep.
Blood lipids, bowel regularity and glucose. Cheap, safe and effective.
Commonly used: 5-15 g per day
No limit; the constraint is how much water you drink with it.
A sugar-like molecule that forms part of the intracellular insulin signalling system.
In women with PCOS it reduces insulin resistance and androgens and restores cycle regularity — the best hormonal evidence in this list, though the 2023 international guideline rates the quality as low.
Lowers androgens and improves ovulation in PCOS; no proven effect on live birth rates.
A small effect on weight, coming indirectly through insulin resistance.
No good evidence.
PCOS, insulin resistance and some forms of anxiety.
Commonly used: 2-4 g per day
No limit; trials use 2 g twice a day.
An Ayurvedic root classed as an adaptogen — something said to help the body cope with stress.
It genuinely lowers cortisol: 15 trials in 873 people give a fall of 2.36 mcg/dL. But perceived stress and quality of life move far less than the cortisol number does — worth remembering.
Cortisol clearly down. Testosterone up 10-15% in a few small trials, not established. There is a case of thyrotoxicosis in someone already on thyroid medicine.
No direct effect on fat.
A small but real improvement in sleep quality, clearest at 600 mg for at least 8 weeks and in diagnosed insomnia — but measured mostly by questionnaire rather than by instrument.
Stress and anxiety. All the trials are Indian and most are small.
Commonly used: 300-600 mg per day
No official limit; 600 mg is the dose in most trials. Safety data extend only to about three months.
An arctic plant root, also classed as an adaptogen.
Reducing subjective fatigue — but reviews find the trials small, methodologically flawed and inconsistent, and the exercise performance work is null.
No reliably measured hormonal effect in humans.
Does not reduce fat.
Nothing to do with sleep, and mildly stimulating — not in the evening.
Fatigue, which is hard to measure and highly placebo-sensitive.
Commonly used: 200-600 mg per day
No limit set.
A Southeast Asian root long used for male vitality.
It does genuinely raise testosterone in men, confirmed by a 2022 meta-analysis — but the effect is concentrated in men who are already low, older, or under high stress, not in healthy young men.
This is the one that genuinely differs from the other testosterone products in this list — but still downgraded, because the trials are small, heterogeneous and often industry-linked.
Weak evidence.
Nothing to do with sleep.
Testosterone in men with a low baseline. If you suspect low testosterone, get a blood test rather than guessing and supplementing.
Commonly used: 200-400 mg per day
No limit, and extract strength varies so much between brands that doses are not comparable.
An Andean root eaten as food for centuries.
It does modestly increase sexual desire — and interestingly, it does so without any hormonal change at all.
Testosterone does not change — clearly confirmed in controlled trials. A case where the effect may be real but the mechanism sold alongside it is false.
Does not reduce fat.
Nothing to do with sleep.
Libido, and mood around menopause.
Commonly used: 1.5-3 g per day
No limit set.
An adrenal hormone the body converts onward into testosterone and oestrogen. Sold as a supplement in some countries, but a hormone by nature.
A genuine place in adrenal insufficiency, and as an intravaginal preparation for vaginal atrophy after menopause.
Raises testosterone substantially in postmenopausal women, but minimally and unreliably in men — the opposite of what most buyers expect.
About 0.5 kg of fat in older men, which is clinically meaningless.
Nothing to do with sleep.
Adrenal insufficiency. It is banned in competitive sport.
Commonly used: 25-50 mg per day
No nutritional limit, because this is a hormone rather than a nutrient. It should be used only under medical supervision.
The yellow compound in turmeric. Its big problem is near-zero absorption without black pepper or a special formulation — a product without one is close to taking nothing.
Reducing knee osteoarthritis pain, in some analyses comparably to anti-inflammatory drugs — but the trials are small, at high risk of bias, and probably subject to publication bias.
No confirmed hormonal effect.
Weak evidence.
Nothing to do with sleep.
Joints and inflammation. Check the label for piperine or a phospholipid formulation — without one, you are getting very little.
Commonly used: 500-1,500 mg per day
No limit, but the enhanced-absorption forms carry a growing number of liver injury reports.
An extract from the seeds of a thistle, long used for the liver.
The liver evidence remains unclear despite long use. There are some data on glucose control in type 2 diabetes.
No effect on sex hormones.
Does not reduce fat.
Nothing to do with sleep.
Liver. If your liver tests are abnormal, the thing to do is find out why with a doctor, not take this and wait.
Commonly used: 200-600 mg per day
No limit set.
An extract from a palm fruit, used for an enlarged prostate.
Large, good-quality trials found it no better than placebo for prostate symptoms, which sits awkwardly with its popularity.
Said to inhibit 5-alpha reductase, but the measurable hormonal effect in humans is unclear.
Does not reduce fat.
Nothing to do with sleep.
Prostate. Urinary symptoms deserve a proper assessment, not self-treatment with a supplement.
Commonly used: 160-320 mg per day
No limit set.
A herb used for mild to moderate depression, with reasonable evidence for that use.
Mild to moderate depression, performing close to standard antidepressants in several trials.
No direct hormonal effect, but it can make oral contraceptives fail — a drug effect, not a hormonal one.
Does not reduce fat.
Not a sleep aid.
Mood — but the interaction risk is high enough that a pharmacist should always be consulted first.
Commonly used: 300-900 mg per day
No limit, but this is the most dangerous drug-interacting supplement in the entire list — read the caution.
A compound from African tree bark that strongly stimulates the sympathetic nervous system.
Some evidence in erectile dysfunction, but far safer medicines exist for that.
Increases adrenaline release — both the intended mechanism and the dangerous one.
Small studies suggest it mobilises stubborn fat, but the risk is far too high to be worth it.
Causes insomnia and anxiety.
This app does not recommend it. Poison control data show callers about yohimbe are more likely to need medical care than other callers, and many countries restrict or ban it.
Commonly used: 5-20 mg per day
No official limit; this app warns early because it has caused deaths and most labels do not state the actual yohimbine content.
A stimulant from bitter orange, adopted as an ephedrine replacement after ephedrine was banned.
Very little confirmed benefit.
Stimulates the sympathetic system like a mild adrenaline.
The metabolic effect is very small and inconsistent.
Causes insomnia.
This app does not recommend it. Of 23 products tested, only 5 contained close to the labelled amount.
Commonly used: 20-50 mg per day
No official limit; this app warns because nearly every cardiovascular report involves it stacked with caffeine.
A bile acid — the taurine-conjugated form of UDCA, which is itself a licensed medicine for bile duct disease and gallstones. TUDCA is sold as a supplement.
Cholestatic liver disease. The strong evidence belongs to UDCA, the licensed drug — not to TUDCA the supplement, whose own human trials remain small.
No effect on sex hormones.
Does not reduce weight or fat. In 20 obese people (Kars 2010, 1,750 mg/day for four weeks) liver and muscle insulin sensitivity improved, but body weight did not change and adipose tissue did not improve.
Nothing to do with sleep.
Liver and bile flow. It was trialled for ALS with sodium phenylbutyrate and approved as Relyvrio in 2022, but the larger phase 3 (PHOENIX) found no benefit and the drug was withdrawn in 2024 — a clean example of a small-trial result not surviving.
Commonly used: 250-1,500 mg per day
No authority has set a ceiling. Trials have used 250-1,750 mg/day.
Live microorganisms. The most important thing to know is that probiotics is not one thing — the evidence attaches to named strains, not to the word.
Preventing antibiotic-associated diarrhoea and C. difficile infection — well established. It also helps irritable bowel symptoms, but only for the strains actually studied.
No confirmed hormonal effect.
About 0.5 kg, which is meaningless.
No good evidence.
Gut. When choosing, look for the full strain name on the label, such as L. rhamnosus GG or S. boulardii. A product that states only a count inherits none of those strains evidence.
Commonly used: 1-50 CFU per day
No limit — the count is not a measure of quality; the strain is what matters.
A molecule mitochondria use to make energy. Statins lower blood CoQ10, which is the main reason people take it.
Reducing statin-associated muscle symptoms, where meta-analyses conflict but the 2025 update is favourable. In heart failure, the Q-SYMBIO trial found fewer cardiac events and deaths.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
Muscle and heart, particularly for people on statins.
Commonly used: 100-300 mg per day
No limit set.
A precursor of glutathione, the body main antioxidant.
As a hospital infusion it is a decisively effective antidote for paracetamol poisoning — but that is a different thing from a supplement. As a supplement, its best-supported use is trichotillomania and skin picking.
Some data on insulin sensitivity in PCOS.
Does not reduce fat.
Nothing to do with sleep.
Antioxidant defence and airway mucus.
Commonly used: 600-1,800 mg per day
No limit set.
A compound from red grape skin, linked in popular writing to longevity.
The human effects are far smaller than its reputation; most of the work is in animals or test tubes.
Mild oestrogen-like activity, which is a reason for caution in hormone-sensitive conditions.
Does not reduce fat in humans.
Nothing to do with sleep.
No confirmed human use as yet.
Commonly used: 150-500 mg per day
No limit set.
A flavonoid from onions and apples.
Small and inconsistent effects in humans, with a slight blood pressure signal.
No confirmed effect.
Does not reduce fat.
Nothing to do with sleep.
Inflammation and allergy, on thin evidence.
Commonly used: 250-1,000 mg per day
No limit set.
Nitrate from beetroot, which mouth bacteria convert to nitrite and then to nitric oxide.
Lowers blood pressure by 4.4/1.1 mmHg and improves endurance in recreational exercisers — though in elite athletes the effect largely disappears.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
Blood pressure and blood flow.
Commonly used: 300-600 mg per day
No limit set.
A component of cartilage, taken for knee osteoarthritis.
A small and inconsistent effect on knee pain, and the independently funded trials tend to find less.
No hormonal effect. The concern about raising blood sugar has not been borne out in controlled trials.
Does not reduce fat.
Nothing to do with sleep.
Knees. If three months brings no difference, there is no reason to continue.
Commonly used: 1,500 mg per day
No limit set.
A mushroom sold for memory and brain health.
Its entire reputation rests on a single 2009 Japanese trial of 30 people plus small acute studies with mixed results.
No hormonal effect.
Does not reduce fat.
No evidence.
The nerve growth mechanism it is sold on comes from cell culture and has never been shown in people, and the active compound content varies enormously between brands.
Commonly used: 500-3,000 mg per day
No limit set.
The red pigment from algae that makes salmon flesh orange.
Slightly lowers markers of inflammation and oxidative stress; no trial has moved a clinical endpoint.
No hormonal effect.
Does not reduce fat.
Nothing to do with sleep.
Skin and inflammation; the wrinkle studies are small and mostly manufacturer funded.
Commonly used: 4-12 mg per day
No limit set.
A blue-green alga high in protein.
Some improvement in blood lipids, but on small trials, mostly Iranian, at high risk of bias.
No hormonal effect.
About 1.5 kg in obesity trials, on weak evidence.
Nothing to do with sleep.
Blood lipids.
Commonly used: 2-5 g per day
No limit set.