For how we live.
A final FDA guidance sets out the safety information companies should provide when notifying the agency of a new dietary ingredient, replacing the old 'comprehensive safety profile' with a single 'safety narrative.'
The UV-free TransVitD patch raised vitamin D in animals and lab-grown skin. In a randomised trial of 108 volunteers it was safe but did not lift blood levels beyond what a small oral dose would.
An order effective 25 September lets manufacturers use inactive baker's yeast to add vitamin D2 to cereals, grain products, milk and milk products, at the same limits already set for vitamin D2 mushroom powder.
A small crossover trial found 5 mg of melatonin worsened glucose handling and cut early insulin secretion in people carrying the MTNR1B risk variant, but not in non-carriers.
SOLARIS, a publicly funded phase 3 trial, tested vitamin D3 added to chemotherapy after a promising phase 2 signal. Progression-free survival was 11.8 versus 10.3 months — not a significant difference.
VICTORY randomised 238 adults with severe burns to intravenous vitamin C or placebo. It was stopped early: 28-day mortality was 15.0% versus 7.6%, and the trial crossed a prespecified harm threshold.
The muscle-building literature converges on roughly 1.6 grams of protein per kilogram of bodyweight a day, with gains flattening above that — a target well clear of the deficiency floor most official figures quote.
The whole scare traces to one 2009 study that measured a hormone, not hair. In 2025, the first trial to actually assess hair follicles found no difference between creatine and placebo.
The viral drink pairs tart cherry juice with a magnesium supplement. Both have some human trial data for sleep, but it is thin, small and low-quality — far short of what the trend implies.
Garlic supplements modestly lower blood pressure in hypertensive people, and may nudge cholesterol down a little. The cold-prevention evidence rests on a single trial, and no study shows garlic prevents heart attacks.
Sea moss is sold as a 92-mineral cure-all, but no human trial shows it delivers those benefits — and because seaweed's iodine content is wildly variable, the documented risk falls on the thyroid.
Greens powders are sold as insurance against a poor diet. There are almost no independent trials of the products themselves — and the strong evidence is for eating vegetables, not drinking them.
Early studies made elderberry look promising for colds, and sales topped $100 million. But the trials are small, and the most rigorous one — a randomised flu trial in emergency patients — found no benefit at all.
Echinacea is a pharmacy staple every winter. But a Cochrane review of 24 trials found no reliable treatment benefit, and the largest trial shaved barely half a day off a cold — a difference too small to be sure was real.
Barely, and some carry real risk. Caffeine has a small, measurable effect; the other headline 'thermogenic' ingredients mostly don't, and high-dose green tea extract has caused liver injury.
By age 80 most people have a cataract or have had one removed. You can lower some risks, but the antioxidant vitamins tested in a 4,629-person trial did not slow them, and surgery is the only cure.
The large trials built to confirm vitamin E's promise came back null, and a meta-analysis tied 400 IU a day or more to a small rise in all-cause mortality.
In deficient populations, vitamin A supplements cut child deaths by 12% — among the best-evidenced global-health interventions. In the well-nourished, added vitamin A does no good and can do harm.
A 21,442-person trial of cocoa flavanol extract missed its main heart target. The blood-pressure effect is real but small — and nearly half of dark chocolate products exceeded a strict lead limit.
Trials can show cinnamon nudging fasting glucose down, but the effect is inconsistent, leaves long-term control (HbA1c) untouched, and cheap cassia cinnamon carries a coumarin safety flag.
An analysis of 50 top-selling 'T booster' products found only 24.8% contained an ingredient with data showing it raises testosterone — and 10.1% contained something shown to lower it. Two herbs are partial exceptions.
Surveys have flagged lead, cadmium and arsenic in some powders, but a risk assessment of those same numbers found typical intakes stayed below the thresholds used to judge harm.
Omega-3 supplements are widely recommended for dry eye, but the largest randomised trial found them no better than an olive-oil placebo. A Cochrane review leaves the case uncertain at best.
Short courses look well tolerated, but trials rarely run past a few weeks, so long-term safety is untested. Two clearer problems: variable supplement content, and a surge in children's accidental ingestions.
In people who are iron-deficient without anaemia, supplements ease self-reported fatigue in trials — but do nothing for objective exercise capacity, and the benefit hinges on being iron-deficient, not just tired.
Products promising to 'balance your hormones' lean on botanicals like maca, black cohosh and phytoestrogens, and on the hormone DHEA. When those ingredients are put in controlled trials, the evidence is limited or null.
A JAMA Dermatology review found the best-evidenced products — Viviscal, Nutrafol and a few others — but flagged weak studies and industry funding. For people who eat normally, the case is thin.
For most people eating normally, added electrolytes do little, and plain water rehydrates fine for ordinary exercise. The clearest endurance danger is drinking too much — and the proven use is illness, not the gym.
Supplement makers sell K2 (menaquinone) for stronger bones and cleaner arteries. The observational signal is real; the randomised trials, so far, mostly are not.
Daily vitamin C does not stop you catching colds and does nothing once one starts. It trims a cold's length by about 8% in adults; for the heart, trials show no benefit.
Pooled trials show a genuine but small fall in blood pressure, around 2 mmHg. The bigger pitches — sleep, cramps, energy, anxiety — run ahead of the evidence.
Creatine is not a testosterone booster — the trials show it leaves testosterone unchanged. The baldness scare traces to a single 20-man study that found a rise in DHT, a result no one has replicated in 15 years.
Failing mitochondria are one of ageing's core hallmarks, and human trials of mitochondria-targeted compounds show flickers of benefit — but the strongest endpoints keep coming back null.
For people whose pancreas cannot make enzymes, replacement therapy is proven in randomised trials. For healthy people with bloating, the flagship study is a single-arm survey of customers who bought the product online.
TikTok's 'liquid gold' is real cow's first-milk, rich in antibodies and growth factors. But the robust human evidence sits in specific gut conditions, not the immunity, skin and hair benefits sold to healthy adults.
In a study of 633 people with gout, eating cherries over two days was linked to a 35% lower risk of a flare. It is suggestive, observational evidence — no randomised trial has yet confirmed it.
A varied diet covers most of the 13 essential vitamins. The evidence-based exceptions are specific: vitamin D is hard to get from food, older adults and vegans need B12, and folic acid is advised before pregnancy.
Nausea in early pregnancy is common and usually mild. Ginger has the best trial support for nausea, vitamin B6 and doxylamine are options, and acupuncture shows no clear benefit.
Branched-chain amino acids can nudge muscle protein synthesis and modestly ease soreness, but they cannot build muscle on their own — and a complete protein does everything they do and more.
A small 1990s trial hinted selenium supplements cut cancer, launching a supplement boom. The much larger SELECT trial found no benefit — and signals of harm, including more type 2 diabetes.
Diets rich in colourful fruit and vegetables track with less cancer, so supplement makers bottled beta-carotene. Two large trials in smokers found the pills raised lung cancer and death — the opposite of the hope.
Pooled trials put the herb roughly on a par with standard antidepressants for mild-to-moderate depression, with fewer dropouts for side effects. The catches are dangerous drug interactions and wildly variable products.
The bestselling herbal for an enlarged prostate flopped in the trials: even at triple the usual dose it beat placebo by nothing. The hair-loss claim rests on a handful of small, weak studies rather than proof.
For 70 years the idea that oxidative damage drives ageing justified a supplement industry. Large randomised trials found antioxidant pills do not extend life, and some raise mortality.
True dietary magnesium shortage in healthy people is rare, and reference guidance does not currently advise supplements. The clear deficiencies come from illness, alcohol and certain drugs, not a missed daily pill.
A 2025 meta-analysis of 10 trials found small, short-term reductions in weight and BMI — but the studies were heterogeneous, and the viral single trial that fuelled the hype is one small study, not a settled result.
The popular claim is that a shot before meals fires up digestion. The controlled measurement shows vinegar slows the stomach down — helpful for blood sugar, unhelpful if you already digest slowly.
Artificial tears are still the mainstay, but the trial evidence cannot say which brand is best. A 3,000 mg fish-oil study in 535 people found no benefit over an olive-oil placebo.
Meta-analyses found calcium pills raised heart-attack risk by around a quarter. A later review — funded by an osteoporosis foundation — found no such link. The disagreement is the story.
Classic B12 deficiency is relatively uncommon, but it clusters: in people over 50 whose absorption fails, in vegans whose intake does, and around metformin, acid-lowering drugs and stomach surgery.
A 2019 pooling of 12 trials rated peppermint oil safe and effective for IBS, with a number-needed-to-treat of three. The largest, most rigorous trial then missed its primary endpoint against placebo.
Every documented case of biotin helping hair involved a deficiency. In people who are not deficient the evidence is absent — and high-dose supplements can skew blood tests, including a heart-attack marker.
Magnesium is one of the most popular over-the-counter sleep aids, but a 2026 review of the randomised trials concluded the evidence does not support it as a routine treatment for insomnia.
Real deficiency shows as bone pain, muscle weakness or, in children, rickets. But US surveys suggest most people meet their needs, and both a 2011 and a 2024 review advise against routine testing in healthy adults.
VITAL, with 25,871 adults, and D-Health, with 21,315, both tested vitamin D against placebo. Neither cut cancer incidence or cancer death — and one saw a signal pointing the wrong way.
The most-cited meta-analysis found a faint signal that valerian might improve sleep, then flagged publication bias and poor-quality trials. Sleep-medicine guidelines suggest against using it.
Adults need about 2.4 micrograms a day, and most meat-eaters get it easily. Real deficiency clusters in older people, whose absorption fails, and in vegans, whose intake does.
The idea that a little stress makes the body stronger is sound biology, and the best-evidenced example is ordinary exercise. Stretched to cold, fasting and antioxidant pills, the human evidence thins fast.
Autophagy is the cell's self-clearing recycling process, and it wanes with age. Fasting, spermidine and rapamycin switch it on in lab animals — whether that extends human life is unproven.
The puffy 'cortisol face' and the 'cortisol cocktails' sold to fix it lean on 'adrenal fatigue' — a condition a systematic review of 58 studies found no evidence for. True cortisol excess is a diagnosable disease.
Too little iodine, especially in pregnancy, is the world's leading preventable cause of impaired brain development. Salt iodisation fixed most of it — but mild deficiency has crept back in some rich countries.
Large randomised trials mostly find no cardiovascular benefit from ordinary fish-oil capsules. One high-dose prescription drug is the striking exception, and the case for brain protection is weak.
The official figure is 0.8 grams per kilogram of bodyweight a day — but that number is a floor to prevent deficiency, not a target for optimal health, and that distinction drives most of the argument.
A large Cochrane review found fish-oil supplements cut early preterm birth substantially. The biggest single trial since found no effect at all — a genuine split the marketing skips over.
Pooled trials show a small boost to oxygen uptake and exercise tolerance from dietary nitrate. The effect shrinks toward zero in the most trained athletes.
The DO-HEALTH sub-study is the first randomised evidence that a supplement can nudge DNA-methylation ageing clocks. The effect was tiny, and the parent trial found no benefit on health outcomes that matter.
Started early and at high enough doses, zinc lozenges may cut a cold short by a day or two. But the evidence leans on a handful of small trials, formulation matters, and prevention claims are weaker.
Dietary spermidine tracks with markedly lower mortality in one population study. The first year-long randomised trial of a spermidine supplement found no effect on memory.
Small trials suggest curcumin can modestly reduce arthritis pain, sometimes on par with painkillers — but the evidence is thin, and turmeric supplements are linked to a rising number of serious liver injuries.
Pooled randomised trials show real improvements in skin hydration and elasticity versus placebo, but the effect is moderate, the measures are instrument readings, and the evidence base is shaky.
Randomised trials show lower self-reported stress and anxiety, but the certainty is low, the studies are small and wildly inconsistent, and a separate evidence strand flags liver and thyroid risks.
Marketed as a natural weight-loss drug, berberine rests on small, mostly low-quality trials showing modest effects on blood sugar and cholesterol — with no weight-loss evidence to match the hype.
The NAD+ precursors sold to slow ageing reliably raise NAD+ and are well tolerated. What the randomised trials do not show is a benefit to muscle, metabolism or how old you are.
The trend treats the gut as a dashboard to be tuned with home tests, probiotics and 'gut-healing' protocols. The one intervention with the broadest evidence is the least sold: fibre.
It extends life in yeast, worms and flies, and in mice on a high-fat diet. In people it fails to reliably switch on the enzyme it targets, and higher intake tracks no drop in death, cancer or heart disease.
The most popular cognitive-enhancer stack has one modest, well-tested combination at its heart. Beyond caffeine and L-theanine, the evidence in healthy people thins out fast.
A network meta-analysis of 163 trials found EPA, vitamin D and a St John's wort extract beat placebo by margins so large the researchers treat them as a warning about the evidence, not a green light.
The training and creatine at its core rest on strong evidence. The supplement stack around them mostly doesn't — and the SARMs some users add are frequently not even the drug on the label.
A meta-analysis of 30 randomised trials found fibre supplements work in IBS, with the benefit concentrated in psyllium. Wheat bran was the most-studied type and did not carry the effect.
Young men are chasing higher testosterone with 'natural boosters' and direct-to-consumer TRT. The supplements are largely unproven; unnecessary therapy carries real costs to fertility.
Photobiomodulation raised skin temperature by 8 °C and left mitochondrial respiration exactly where it found it. Ketone esters across an eight-day stage race did nothing for performance, cognition or sleep.
Appetite fades with age and malnutrition is common and under-screened. Supplement drinks produce small, real weight gains — and cut deaths mainly in those already undernourished, not everyone.
Participants on Magtein scored better on memory and reaction-time tests after six weeks. On sleep — the reason most people buy it — an Oura Ring found no measurable difference at all.
A meta-analysis of 26 trials found creatine raises serum creatinine without markers of kidney injury. Weeks earlier, a Nature Communications paper reported that supplementation promoted metastasis in mice.
Two ingredients carry most of the real evidence. The rest of the multi-step routine adds cost and, when actives are layered too hard, a damaged skin barrier.
A systematic review of 113 studies found real biology in NAD+ supplementation — and not one eligible human trial testing the IV or IM version clinics actually sell for anti-aging.
Cochrane reviews covering more than 19,000 participants found no reduction in cold incidence from regular vitamin C, a possible reduction in duration from zinc, and a clear increase in adverse events.
A Cochrane review of 50 trials found cranberry products lower UTI risk in women with recurrent infections and in children, but no benefit in the elderly, in pregnancy, or in bladder-emptying problems.
GAIT randomised 1,583 people and found neither supplement beat placebo overall. A later network meta-analysis found effects below the clinically important threshold, and smaller still in industry-independent trials.
Cochrane found cognitive behavioural therapy cuts the impact of tinnitus by about 11 points on a 100-point scale. Against active audiological care the difference was 5.65 points, below the noticeable threshold.
The trend stacks mouth tape, magnesium, trackers and a 'sleepy girl mocktail'. Sleep physicians say one unglamorous treatment carries the evidence; most of the rest is theatre.
In 2023 declining taurine was proposed as a driver of ageing. Two years later the same journal published human, monkey and mouse data in which taurine rose or stayed flat.
A Cochrane review of 18 trials and an NIH-funded randomised trial both failed to show that milk thistle improves liver disease. Product quality is also inconsistent, with some pills contaminated or mislabelled.
The trials that made eye vitamins a standard recommendation enrolled only people who already had substantial disease. In AREDS2, neither omega-3 nor lutein beat placebo on the primary endpoint.
A 2026 meta-analysis pooled every randomised human trial of the gut-derived supplement for muscle health. Only one outcome, from two trials, could be combined — and it missed significance.
Two randomised trials in more than 1,800 children found no benefit in acute gastroenteritis. A Cochrane review of 23 trials found fewer upper respiratory infections, on low-certainty evidence.
In 390,124 US adults followed up to 27 years, daily multivitamin use showed no mortality benefit. Randomised trials within COSMOS found a real but modest effect on memory, and none on physical function.
No randomised controlled trial has tested a commercial detox diet in people, and the reviews that exist find no compelling evidence they remove toxins or aid weight. Some carry real risks.
There is no trial showing a cleanse product improves kidney function, which already filters blood continuously. One class of herbal kidney remedy is a proven cause of kidney failure and cancer.
Its 2024 guideline also advises against routine blood testing for vitamin D, on the grounds that no trial evidence supports it. The largest randomised trial found no effect on cancer, heart disease or fractures.
The pooled effect is about seven minutes off the time it takes to fall asleep. The American Academy of Sleep Medicine recommends against it — on evidence it grades as weak in both directions.
Twenty-one amateur runners took vitamin D3 or a placebo before a marathon. Some muscle and oxidative-stress markers looked better in the supplement group — but most measures showed no difference.
A systematic review located 19 articles on melatonin in children aged 0 to 6. Trials covered 167 children, all with neurologic conditions. There was no efficacy data for typically developing children.
Black cohosh, Chinese herbal medicine and vitamin D reached moderate certainty for specific outcomes. Most of the rest of the field — 158 studies deep — sits at low or very low certainty.
A meta-analysis of eleven depression trials found an average effect below the threshold for clinical importance, with signs of bias favouring creatine. A separate review found no change in kidney filtration.
PISCES randomised 1,228 haemodialysis patients in Canada and Australia. The headline hazard ratio of 0.57 counts every event, not just the first — and that choice explains part of the gap.
October brought pooled analyses of ginger and of marine omega-3s. Both report significant effects on blood markers. Neither measured whether anyone got healthier.
A meta-analysis of 20 trials found a two-kilogram gain in one-rep max and no effect on bone density. A small crossover trial found functional strength gains largely independent of muscle mass.
A 21-trial meta-analysis found effects concentrated in older age groups and largely absent elsewhere. A separate safety review of the most-used strain found no excess adverse events — and a big reporting gap.
Ten weeks of a legal broad-spectrum CBD product produced detectable cannabigerol and cannabidivarin in most participants. After a 90-minute ride, detection rates rose to 74% and 84%.
Collagen, flavanols and polyphenols beat their comparators on skin elasticity and sun tolerance. The pooled estimates carry heterogeneity of 95% to 98%, and some comparators were low doses of the same ingredient.