Ecdysterone (20-hydroxyecdysone) is an ecdysteroid, a steroid found in plants such as spinach and quinoa, sold as a muscle-building supplement. One 10-week study in young men found larger gains in muscle mass and bench press, and WADA monitors it in athletes.
Also known as: 20-hydroxyecdysone, 20E, beta-ecdysterone, ecdysteroids.
The 10-week study gave ecdysterone-containing supplements at different doses (Isenmann 2019); its abstract does not state the amounts, so we do not list one.
It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling. Anti-doping: ecdysterone is on the World Anti-Doping Agency's 2026 Monitoring Program under anabolic agents, in and out of competition. That program covers substances that are not prohibited but that WADA monitors for patterns of misuse in sport (WADA 2026).
What studies show: in a 10-week strength-training study in 46 young men, those given ecdysterone had larger increases in muscle mass and in one-rep bench press than the comparison group; the authors recommended adding it to WADA's prohibited list (Isenmann 2019). In a 12-week trial in 28 trained men, a commercial ecdysterone and diosgenin product did no better than placebo, and lab testing found it contained less than 1% of the ecdysterone stated on the label (Dissemond 2025).
Safety: the 10-week study found no rise in liver or kidney markers (Isenmann 2019). There are no long-term safety studies in people in the sources here.
We could not find a single published half-life or time to peak for ecdysterone that applies to a supplement dose, so we do not list one.
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