Metformin for slowing aging
The trial meant to settle this has never enrolled anyone. The question that has been tested twice is whether metformin blunts what exercise does.
Rapamycin for slowing aging
The best lifespan result ever produced in mice, and a single 114-person human trial whose positive findings were confined to women on the higher dose.
Modafinil for cognitive enhancement
It works for the sleep disorders it is licensed to treat. Whether it makes a rested person think better is a different question, with a messier answer.
Ginkgo biloba for preventing dementia
Two multi-year trials in nearly six thousand older adults, one publicly funded and one paid for by the manufacturer. Both found nothing.
DHEA for anti-aging
Tested more thoroughly than almost anything else we grade — two years, restored hormone levels, and no benefit. The one positive finding belongs to the hormones it turns into.
Growth hormone for anti-aging
An industry built on twelve men, six months, and no placebo group — and what the seventeen years of controlled trials that followed actually found.
Tirzepatide for weight loss
The largest weight loss of any approved drug, and a head-to-head win over semaglutide — with independent replication that amounts to 24 people.
Semaglutide for weight loss
The best-evidenced compound on this site — and the only one shown to prevent heart attacks, not just move a scale.
Retatrutide for weight loss
The largest weight-loss results ever published for a drug of this kind — and the lowest grade we have given to a compound that clearly works.
Magnesium for sleep quality
Does taking magnesium before bed actually help you fall asleep faster or sleep through the night?
Testosterone replacement and the heart
Does testosterone replacement therapy increase cardiovascular risk?
L-theanine and caffeine for focus
Does the combination beat caffeine on its own — and how would we know?