Adaptogens
Adaptogens like ashwagandha, rhodiola, and reishi carry centuries of traditional use in Ayurvedic and Chinese medicine, but rigorous modern clinical trials are a more recent and uneven addition. A few now have a meaningful body of human trials behind specific claims like stress and cortisol; others still rely mainly on smaller trials, animal studies, or traditional-use records. Long history of use is evidence of tolerability, not proof of efficacy for a specific modern claim.
6 products · sorted by evidence grade
Common questions
Which adaptogen has the best evidence?
The three best-supported adaptogens in this category all sit at Grade B, and none reaches Grade A. Ashwagandha (B) rests on a solid base of RCTs, and its strongest, most consistent signal is reduced perceived stress and cortisol plus improved sleep quality; rhodiola rosea (B) has the clearest signal for stress-related mental fatigue, plus newer endurance-performance data from a 2025 meta-analysis; Panax ginseng (B) is most convincing for fatigue in people with a chronic illness, with a smaller memory benefit in healthy adults. The category's other three products — reishi, tongkat ali, and fadogia agrestis — are all Grade C, so if you want the sturdiest evidence, start with that Grade B trio rather than the testosterone-marketed herbs.
Do adaptogens like tongkat ali or fadogia agrestis actually boost testosterone?
This is the thinnest-evidence corner of the category. Tongkat ali (Grade C) shows a real but limited signal: a 2022 meta-analysis of 5 RCTs (232 men) found a significant increase in total testosterone, but the effect was driven mainly by men who already had low (hypogonadal) levels, with very high heterogeneity (I²=87%), signs of publication bias, and a literature that is mostly manufacturer-funded. Fadogia agrestis (Grade C) is weaker still: it has zero published human trials, the entire claim rests on two rat studies from a single Nigerian lab, and that lab's 28-day follow-up flagged dose-dependent testicular toxicity — irreversible at the higher doses. If testosterone is your goal, both should be treated as experimental rather than proven.
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