Ashwagandha

Multiple independent RCTs show reduced perceived stress, lower cortisol, and improved sleep quality at 300-600 mg/day of root extract. Strength and hormone findings are positive but from fewer, smaller trials.

Of all the adaptogens, ashwagandha is the one where the modern trial record most nearly matches the traditional reputation. Used in Ayurvedic practice for millennia as a calming tonic, it now has a stack of randomized controlled trials measuring exactly that: in stressed adults, 300-600 mg of root extract daily reliably lowers perceived-stress scores and morning cortisol versus placebo over 8-12 weeks.

The sleep findings are nearly as consistent. Trials in both insomniacs and healthy adults report faster sleep onset and better sleep efficiency, with the effect concentrating in people whose sleep problem is the wired-and-anxious kind — unsurprising if stress-axis moderation is the mechanism. This is a different tool than melatonin: melatonin shifts your clock; ashwagandha quiets the arousal keeping you from using it.

The muscular claims deserve a more careful reading. A handful of trials in untrained men found meaningfully larger strength gains and small testosterone increases when supplementation accompanied a new lifting program. The results are genuinely positive but come from fewer, smaller studies with commercial sponsorship common — grade C territory, promising rather than proven.

Two caveats keep this entry honest. First, case reports of liver injury, while rare against the scale of use, are real and documented; the pattern typically resolves after stopping, but it argues for buying tested brands and respecting doses rather than indefinite daily use. Second, ashwagandha nudges hormone systems — it can raise thyroid hormone levels, matters in pregnancy (avoid), and can add to sedatives and immunosuppressants. None of that makes it dangerous for a healthy adult at trial doses; it makes it a compound to treat like the pharmacologically active thing it is, rather than a harmless herb.

How it works

Withanolides appear to moderate hypothalamic-pituitary-adrenal axis output — trials consistently measure lower morning cortisol — and to act on GABAergic signaling, which fits the reduced-anxiety and improved-sleep findings. Effects on strength and testosterone are downstream of the same stress-axis moderation, per the leading hypothesis.