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News, research and guides
348 articles from our editorial and science team.
GuidesMelatonin and Jet Lag: What Do Clinical Trials Actually Say?
Melatonin is one of the few "jet lag" supplements to have earned its own Cochrane review — an organization regarded as the gold standard of rigor in evidence-based medicine. The conclusion from that review is surprisingly clear-cut by supplement-science standards, but comes with an honest caveat: it's an evidence base over two decades old, worth knowing precisely because newer, equally solid work rarely replaces it.
JWJulia Wiśniewska11 min
August 25, 2026
GuidesCitrulline Malate and Training Performance: Real Effect or Overhyped Supplement?
Citrulline malate is a staple ingredient in nearly every pre-workout on the market, marketed as a way to squeeze out noticeably more reps at the gym. The newest, and so far largest, meta-analysis on this topic from 2026 gives an answer more measured than the marketing suggests — the effect is real and statistically detectable, but certainty of evidence was rated low, and an earlier meta-analysis of the same question found a result that wasn't even statistically significant.
MNMichał Nowak11 min
August 25, 2026
GuidesCollagen and Skin Health: What Do Two Meta-Analyses Show?
Collagen powder or capsules are one of the fastest-growing segments of the beauty supplement market — and, rare for this category, one of the few where the popular promise ("firmer, better-hydrated skin") has earned solid confirmation in two independent, well-designed meta-analyses. This is a rare situation in supplement science, worth a closer look precisely because the evidence here is unusually consistent.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesVitamin D3 and Testosterone: Where Did This Popular Theory Come From, and Does It Hold Up?
"Vitamin D raises testosterone" is one of the most repeated claims in the biohacking community, resting largely on one small study from over a decade ago. A newer, better-designed, and significantly larger randomized trial, conducted on healthy men, gave an answer that should clearly cool those expectations — and it's exactly this contrast that makes this topic worth tracing carefully.
PZdr Piotr Zieliński12 min
August 25, 2026
GuidesFasted Training and Fat Loss: A Real Mechanism, a Wrong Conclusion?
Fasted training has a reputation as a "hack" for faster fat loss — and, rare in the world of popular fitness advice, the underlying mechanism itself is scientifically true. The problem is that the study testing whether this mechanism translates into a real, long-term difference in body composition gave an answer that undermines the entire rationale for this strategy as a weight-loss tool.
MNMichał Nowak12 min
August 25, 2026
GuidesAspirin for Primary Prevention: Should Healthy People Take It Every Day?
"An aspirin a day for your heart" is one of the most enduring pieces of health advice of the 20th century — millions of healthy people in midlife and beyond, who had never had a heart attack or stroke, took it daily "just in case," often without a specific doctor's recommendation. Three large, independent randomized trials from recent years — including one with a genuinely surprising mortality finding — showed that in people who never had a cardiovascular event, daily aspirin provides essentially no measurable reduction in cardiovascular risk, while consistently increasing the risk of serious bleeding. The distinction between primary and secondary prevention is central here, and it's exactly the distinction that gets lost in casual conversation.
PZdr Piotr Zieliński13 min
August 25, 2026
GuidesVitamin D and Colds: What Do the Large Meta-Analyses Show?
"Vitamin D boosts immunity and protects against colds" is one of the most repeated claims in supplement conversations — and in this case, the popular claim is both true and misleading at the same time. Two large meta-analyses of randomized trials, including one built on individual participant data from 25 trials, show a real but modest protective effect against respiratory infections — provided vitamin D is taken daily or weekly in a moderate dose. The "one large dose per month or quarter" model popular in supplement marketing does not, in practice, deliver that effect. This article explains why how you dose matters more than the simple decision to supplement or not.
JWJulia Wiśniewska13 min
August 25, 2026
GuidesHigh-Dose Omega-3 and Atrial Fibrillation: An Unexpected Side Effect?
Omega-3 fatty acids have a well-established reputation as an unambiguously heart-healthy supplement. Two independent, large clinical trials evaluating high, prescription-strength omega-3 doses (4g/day) in cardiac patients show a consistent and concerning signal: this therapy meaningfully increases the risk of new-onset atrial fibrillation — an irregular heart rhythm — even in a trial where the same supplement produced a real, measurable cardiovascular benefit. This is not a warning about a typical over-the-counter fish oil supplement, but a specific signal tied to the high doses used to treat hypertriglyceridemia — a distinction that's easy to lose in simplified headlines.
PZdr Piotr Zieliński13 min
August 25, 2026
GuidesStatins and Type 2 Diabetes Risk: Do Cholesterol Drugs Raise Your Risk?
Statins are among the most widely prescribed drugs on earth, and their benefit in preventing heart attacks and strokes is one of the best-documented facts in all of cardiology. Less often discussed is another well-confirmed effect: statins genuinely increase the risk of newly diagnosed type 2 diabetes — not a fringe finding from a single study, but a result confirmed independently in the randomized JUPITER trial and in a meta-analysis of 13 trials covering more than 91,000 participants. The key, often-missed nuance is different from what the headline suggests: the increased risk falls almost entirely on people who already had diabetes risk factors, and the cardiovascular benefit of statins — even in that same group — is several times larger than the risk of causing one extra case of diabetes. This article explains why both facts are true at once, and why the authors of both studies, despite confirming the effect, unambiguously recommend continuing statin therapy.
PZdr Piotr Zieliński13 min
August 25, 2026
GuidesHigh-Dose Vitamin D and Falls in Older Adults: Does More Mean Worse?
"More vitamin D is better for bones" is one of the most widespread beliefs in osteoporosis and fall prevention for older adults. Two independent randomized trials — one Swiss, using monthly dosing, the other Australian, using a single annual dose — show the opposite: high, infrequently administered doses of vitamin D increased the number of falls, and in one case fractures too, despite raising blood vitamin D levels more effectively than standard doses. The problem turns out not to be the amount of vitamin D itself, but how it's delivered — a sharp spike in blood levels after a large, infrequent dose, rather than a stable level maintained through daily supplementation. This distinction matters directly for people over 70, for whom even a single fall can result in a hip fracture and permanent loss of independence.
AKdr Anna Kowalczyk13 min
August 25, 2026
GuidesAshwagandha and Male Fertility: What Did the Clinical Trial on Sperm Quality Show?
Ashwagandha is best known for lowering stress and cortisol, but a small Indian clinical trial tested something different: whether the same adaptogen could improve semen parameters in men with reduced sperm quality. The numbers from this pilot RCT are impressive — the question is how much can really be concluded from them.
PZdr Piotr Zieliński11 min
August 25, 2026
GuidesInositol and PCOS: What Does a Review of 13 Meta-Analyses Show?
Myo-inositol and D-chiro-inositol have featured for years in recommendations for women with PCOS as a way to improve insulin sensitivity, cycle regularity, and fertility. A new umbrella review pooling results from 13 earlier meta-analyses shows a consistent picture of benefit across hormones, insulin resistance, and ovulation — with one major caveat the authors themselves state outright: most of the underlying evidence is of low or very low quality, and the results "should not, on their own, guide clinical decisions."
PZdr Piotr Zieliński11 min
August 25, 2026
GuidesZinc and Male Fertility: What Did the Large FAZST Trial Show?
Zinc with folic acid is one of the most heavily marketed combinations "for fertility" in men. The largest and most rigorous trial on the subject — randomized, multicenter, in over 2,300 couples — tested whether this supplementation actually improves semen quality and the chances of a live birth. The result contradicts popular belief, and along the way reveals a signal that warrants caution.
PZdr Piotr Zieliński11 min
August 25, 2026
GuidesCurcumin and Joint Pain — Does It Work Like an Anti-Inflammatory Drug?
Curcumin is marketed as a "natural anti-inflammatory" for joint pain. One of the few studies to compare it head-to-head with a real drug — diclofenac — in patients with knee osteoarthritis paints a more interesting picture than the marketing slogans: similar pain relief, but clearly better tolerability and fewer side effects.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesApple Cider Vinegar and Blood Sugar — Myth or Fact?
A spoonful of apple cider vinegar before a meal is one of the most popular wellness trends on social media — promising lower blood sugar, reduced appetite, and faster fat burning. The truth is more nuanced than the viral clips suggest: one randomized trial in people with type 2 diabetes did show a beneficial effect on glucose and lipids, but it's still a single, small study, not proof that vinegar replaces treatment.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesMagnesium and Nocturnal Leg Cramps — Does Supplementation Actually Help?
Magnesium is the most commonly heard advice for nocturnal leg cramps — recommended by family doctors, pharmacists, and nearly every health guide. But the largest available systematic review (Cochrane, 11 trials, 735 participants) paints a far more complicated picture than a simple "yes, it helps": in people with idiopathic cramps, mostly older adults, the difference versus placebo was small and not statistically significant, while for pregnancy-related cramps the results remain conflicting and need further research. This isn't an article saying "magnesium doesn't work" — it's an attempt to show what's actually known, and what isn't.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesProtein Before Sleep and Muscle Recovery — Does It Really Help Build Mass?
"Eat cottage cheese or take casein before bed so your muscles grow all night" — this is one of the more popular pieces of advice in strength-training circles, based on a real observation: protein consumed right before sleep really does raise the rate of overnight muscle protein synthesis. But the question is different: does this momentary, cellular-level effect translate into real, additional gains in strength and muscle mass after weeks of training? A 12-week randomized controlled trial tested this directly — and the result is more tempered than popular guides suggest.
MNMichał Nowak11 min
August 25, 2026
GuidesAshwagandha and Insomnia — What Did the Clinical Trial Show About Sleep Quality?
Ashwagandha is mostly associated with cortisol and stress, but one clinical trial tested something narrower and more clinical: does the same adaptogen help people with diagnosed insomnia — not just stressed, poorly-sleeping adults, but patients meeting the criteria for insomnia. A double-blind, randomized trial using actigraphy instead of questionnaires alone gives concrete numbers on shortened sleep onset and improved sleep efficiency.
JWJulia Wiśniewska11 min
August 25, 2026
GuidesVitamin D and Female Fertility — What Does the Largest Review of Studies Show?
Vitamin D is sometimes presented as almost a prerequisite for successful in vitro fertilization — clinics routinely test for it, and supplements are marketed as a way to improve the odds of pregnancy. The largest systematic review with meta-analysis to date examined this claim rigorously: the initial analysis did suggest a benefit, but after a sensitivity analysis the difference stopped being statistically significant — for clinical pregnancy rates, live births, and miscarriage alike. That doesn't mean vitamin D is unimportant for health — it just means it isn't a cure for infertility.
PZdr Piotr Zieliński11 min
August 25, 2026
GuidesGinger and Nausea in Pregnancy — What Does a Meta-Analysis of 12 Trials Show?
Nausea and vomiting of pregnancy (NVP) affect most women in the first trimester and can significantly lower quality of life. Ginger is one of the few home remedies actually backed by real, pooled evidence — a systematic review of 12 randomized trials in 1,278 pregnant women found a statistically significant improvement in nausea severity versus placebo, with no significantly increased risk of miscarriage or other adverse effects. It's not a miracle cure and won't replace treatment in severe cases, but it's rare to find a topic in this field with such a consistent, reassuring body of evidence.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesTaurine and Longevity — What Do We Know, and What Don't We Know Yet?
In 2023, the journal Science published a headline-making study: declining taurine levels with age may drive aging, and supplementing it extended lifespan in mice and improved health in monkeys. Headlines quickly turned this into a "fountain of youth," but the study's own authors end their paper by saying that "clinical trials in humans seem warranted." We explain exactly what was shown in animals, what was merely correlated in humans, and why those two things are not the same.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesLutein and Zeaxanthin for Macular Degeneration — What Does the Cochrane Review Actually Show?
Lutein and zeaxanthin are marketed as "vitamins for the eyes" almost everywhere vision comes up. The strongest available evidence — a Cochrane review covering 26 trials and nearly 12,000 participants — does show that a particular antioxidant combination slows the progression of age-related macular degeneration (AMD). The problem is that this effect applies to a specific, older supplement formula, a specific patient group, and isn't nearly as clearly attributable to lutein itself as most advertising suggests.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesXylitol and Dental Caries — What Does the Cochrane Review Show?
Chewing gum, mints, and toothpaste containing xylitol are marketed as something more than a "sugar-free product" — as active protection against tooth decay. A systematic Cochrane review, covering 10 trials and almost 6,000 participants, tested this claim and found evidence that is much narrower, weaker, and more ambiguous than the marketing suggests — with one important methodological caveat rarely mentioned on the packaging.
AKdr Anna Kowalczyk11 min
August 25, 2026
GuidesCreatine and Kidney Health — Is Supplementation Safe?
“Creatine destroys your kidneys” is one of the most persistent supplement myths — repeated not only by online skeptics but sometimes by doctors who spot elevated creatinine in a patient's blood test. A fresh 2025 meta-analysis, covering 12 studies and 440 participants, lets us separate two things that are easily confused: a small, real rise in blood creatinine from actual damage to kidney function, as measured by GFR.
MNMichał Nowak11 min
August 25, 2026