Early, small, conflicting, or animal-only. Not actionable alone.
Moringa leaf is genuinely nutritious, gram for gram. Sold as a blood sugar remedy, it put fasting sugar a few mg/dL below placebo in some small trials and not in others, and a 2025 pooling of randomised trials found no significant difference. Weight did not move; the breast milk evidence is small and mixed; pregnancy and contaminated powders are the real cautions.
In two large Japanese studies, people who ate the most natto died of heart disease and stroke at about a fifth to a quarter lower rate than people who ate little or none. That is an association, not a test. The enzyme pill sold from natto, nattokinase, lowered blood pressure a few points in two small trials tied to its makers but not significantly in two others, and in its three-year trial did not significantly slow artery thickening. If you take warfarin, natto's vitamin K works against your drug.
Hydrogen water is real: the gas is in fresh water, and it leaks out within hours. Small trials found small, mixed shifts in blood markers of inflammation and oxidation; the three biggest, of 700, 200 and 178 people, found no significant difference on their main outcome.
Sold to steer calcium into bone and out of the arteries. In the largest trial of the pair, 398 people with heavy artery calcium, it still built up, about a fifth more slowly than on a dummy pill; in a trial of 365 men it did not build up significantly more slowly. On warfarin, K2 is a drug interaction.
Not yet shown. The studies of seed cycling are few and small, nearly all in women with PCOS, and each mixed the seeds with a diet, a drug, exercise or a herb, or had no comparison group. None we found compared the rotation with the same seeds eaten all month.
Both trials of urolithin A for muscle in middle-aged and older adults, paid for by the supplement's maker, missed their main outcome. The 12% leg-strength gain was a side measure, beside a dummy-pill group whose hamstrings got 9.8% weaker. Rated Preliminary.
Interval walking beat steady walking on fitness, leg strength and blood pressure in the 2007 Japanese trial behind the trend, which analysed 42 of its 87 interval walkers. A Danish trial of 12 people a group agreed on fitness. Seven smaller trials since, by other universities, found it ahead on some measures and level on others, and poolings of interval training of every kind in type 2 diabetes put intervals slightly ahead on fitness and split on blood sugar.
Free testosterone fell in two small studies of women with excess hair who drank spearmint tea. In the one randomised hormone trial we could read, against chamomile tea, the gap was not significant and doctor-scored hair did not differ. We found no study that gave people the tea, or spearmint alone, and measured acne.
Green tea carries nearly five times the catechins of black, by USDA measurements. But in trials that gave people one or the other, cholesterol came out level over four weeks. A six-month trial set each tea against a dummy tea, never against each other: black tea's fall in blood pressure was significant only in women, a subgroup result, and green tea's change was not significant in either sex. Pooled trials put each tea at a point or two off the top blood-pressure number.
Green tea extracts and catechin drinks took off about 1.4 lb more than a dummy, averaged over 38 short trials. The trials best guarded against bias could not tell green tea from a placebo, and in 237 women drawn from those who finished a year of strong decaffeinated extract or a dummy, the extract came to 0.6 lb, against 0.3 lb. The famous calorie burn is real, small, and plain caffeine did about as much.