Cochrane's 2024 review: zinc may shorten a cold by about two days, at low certainty, and probably brings more side effects, mostly a bad taste and an upset stomach. On catching fewer colds its trials, mostly in children, found little or no effect. Zinc in the nose is a separate story, with an FDA warning from 2009.
Beetroot juice lowers resting blood pressure by about 3.5 mmHg, averaged over 43 comparisons from 19 controlled trials lasting 2 to 56 days. Juice with its nitrate removed did about 3 mmHg worse. Reviews that pooled 24-hour readings found no clear drop.
In trials of women past menopause, creatine's gain in lean mass is under a pound on a scan that counts water, and three of the five trials behind that figure found no gain at all. The leg-press gain this page once reported is not in the trials it was said to come from.
Nine studies pooled in 2026 found no consistent link between cramp and blood sodium. Salty drinks do cut urine output for a few hours: in twelve hydrated young adults, by about half a pound.
A 2026 review found nine trials that measured what bovine colostrum does to body fat, and its summary credits one with a reduction: 0.4 points on 60 grams a day. The whey group in that trial fell 0.4 points too. The gut finding rests on five small trials in healthy volunteers.
Krill oil is sold on better absorption. Some trials do find more omega-3 in the blood on krill oil, the newest among them. None shows it does more for you: of 64 pooled trials, four compared the two oils, and no difference in blood fats held up.
In people who lift, protein supplementation added 0.66 lb of fat-free mass across 26 comparisons in a 2018 review. Real, and a fraction of what the tub implies. Without lifting or dieting, the pooled trials show no clear gain and cannot rule one out.
Seven trials found waists three inches smaller with a light device. Nine of the ten trials in the review used lasers, eight added the device to a diet or an exercise programme, and none tested a home LED panel. Against a sham, the gap on the scale was about a pound.
Cortisol is not a toxin that accumulates — when someone genuinely has too little, the treatment is 15 to 25 mg of hydrocortisone a day. The predecessor idea, adrenal fatigue, was reviewed across 3,470 articles and called a myth.
Collagen improved skin hydration and elasticity in the randomised trials that two overlapping reviews pooled. A company paid for, supplied or staffed at least 21 of the 26, the trials disagree with one another far more than chance would explain, and 95% of participants were women. We rate it Preliminary.