Ecdysterone
Ecdysterone (20-hydroxyecdysone), plant and insect ecdysteroid
Written by Aaron CuhaReviewed Sep 2026
Also known as: 20-hydroxyecdysone, 20E, Beta-ecdysterone, Ecdysone
The one ecdysteroid with a positive controlled human trial: more muscle mass and more bench press strength, with the authors recommending it be added to the doping ban list.
Overview
Ecdysterone is the ecdysteroid worth taking seriously, and its most-cited human study is unusual in two respects.
First, the result was positive. A controlled trial in humans found significantly higher increases in muscle mass in participants dosed with ecdysterone, and significantly more pronounced increases in one-repetition bench press performance. The same hypertrophic effect appeared in cultured muscle cells. No liver or kidney toxicity markers rose.
Second, the authors' conclusion was not a marketing claim but the opposite. They wrote that their results strongly suggest including ecdysterone on the World Anti-Doping Agency prohibited list under other anabolic agents. A paper arguing its own compound should be banned in sport is a stronger signal than a paper arguing it should be sold.
The trial also screened participants for prohibited substances and tested the supplement for anabolic steroid contamination first, which addresses the usual objection to positive ecdysteroid results.
Mechanism of action
A polyhydroxylated steroid that does not bind the androgen receptor, which is the mechanistic reason it is proposed to build muscle without androgenic effects. The best-supported route is signalling through the estrogen receptor beta, activating the phosphoinositide 3-kinase and Akt and mTOR pathway to increase muscle protein synthesis. In its pharmaceutical development it is described as an activator of the MAS receptor, part of the protective arm of the renin-angiotensin system, which is a different proposed mechanism for the same molecule. That two credible mechanisms are offered for one compound is worth noting as a sign the pathway is not settled.
Human evidence
Unusually good for a supplement in this category: a controlled trial with positive muscle and strength outcomes, a second randomised trial on metabolic endpoints, and a 233-person pharmaceutical phase 2b in sarcopenia.
- A controlled human trial found significantly greater increases in muscle mass and in one-repetition bench press performance with ecdysterone.
- Liver and kidney toxicity biomarkers did not rise in that trial.
- The trial pre-screened participants for prohibited substances and tested the supplement for anabolic steroid contamination, which removes the standard objection to positive results in this category.
- A separate randomised trial in resistance-trained males examined fat oxidation and insulin sensitivity.
- The pharmaceutical version was tested in 233 older adults with sarcopenia and missed its primary endpoint in the full analysis set.
- The researchers behind the positive strength trial recommended the compound be added to the doping prohibited list.
What this does not tell you: The strength trial is a controlled clinical trial rather than a large randomised phase 3, and participant numbers are modest. Oral bioavailability is generally reported as poor, which makes the dose-response relationship uncertain and means product formulation matters a great deal. Two different mechanisms are proposed for the same molecule, estrogen receptor beta signalling and MAS receptor activation, which suggests the pathway is unsettled. And the pharmaceutical programme's phase 2b, which is the best-powered test, did not hit its primary endpoint on the intention-to-treat analysis.
Reading the research record
Ecdysteroids are steroid hormones that control moulting in insects and appear in some plants, notably spinach, quinoa and Ajuga turkestanica. They are structurally unrelated to androgens and do not bind the androgen receptor, which is the basis of the claim that they build muscle without steroid side effects. Read the family together rather than one at a time. 20-hydroxyecdysone, also called ecdysterone, has a controlled human trial reporting increased muscle mass and bench press performance, and a 233-person pharmaceutical phase 2b in sarcopenia that missed its primary endpoint in the full analysis set. Turkesterone, the one that dominates supplement marketing, has no human trial of any kind. Evidence within this family does not transfer between members, and the member with the most evidence is not the member being sold hardest.
The honest summary for ecdysterone specifically is that it has better human evidence than most things sold in a supplement shop and weaker evidence than its strongest advocates claim. A positive controlled trial on muscle mass and bench press is real, and the same molecule missed its primary endpoint when a pharmaceutical company ran a properly designed 233-person trial with a functional outcome. Both results belong to the same compound.
The evidence, charted
Fig. 1 · evidence composition
3of 3 citations (100%) are in people
Every citation cited here is Human work; no other study type is cited on this page. This count is of our own citation list and understates any literature larger than the sources we cite.
Fig. 2 · evidence over time
Citations here span just two years, 2019 and 2025.
Too few distinct publication years on this page to plot as a timeline.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four jurisdictions shown. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Key studies & citations
- Human2019
Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans
A controlled clinical trial in humans. Significantly higher increases in muscle mass in participants dosed with ecdysterone, and significantly more pronounced increases in one-repetition bench press performance. The same hypertrophic effect appeared in C2C12 myotubes in vitro. No increase in liver or kidney toxicity biomarkers. Participants were screened for prohibited performance-enhancing substances and the supplement was tested for anabolic steroid contamination before administration. The authors conclude their results strongly suggest including ecdysterone on the prohibited list in class S1.2, other anabolic agents.
Archives of Toxicology - Human2025
Effects of asparagus-derived 20-hydroxyecdysone supplementation on fat oxidation and insulin sensitivity in resistance-trained males
A randomised controlled trial in resistance-trained males examining metabolic rather than hypertrophic endpoints, specifically fat oxidation and insulin sensitivity. Included because it is a second randomised human study of the same molecule from an independent group and a different source material.
Journal of Nutritional Science and Vitaminology - Human2025
BIO101 in sarcopenic seniors at risk of mobility disability: results of a double-blind randomised interventional phase 2b trial
The pharmaceutical-grade version of this molecule in 233 older adults with sarcopenia. The primary endpoint, gait speed on a 400-metre walk, improved 0.07 m/s against placebo in the full analysis set and was not significant, and improved 0.09 m/s in the per-protocol population at p = 0.008. Detail on the BIO101 page.
Journal of Cachexia, Sarcopenia and Muscle
Frequently asked questions
Does ecdysterone actually build muscle?
A controlled human trial found significantly greater increases in muscle mass and bench press performance, with no rise in liver or kidney toxicity markers, and it screened for steroid contamination first. That is a genuine positive result. The best-powered trial of the same molecule, a 233-person phase 2b in sarcopenia, missed its primary endpoint in the full analysis set.
Why did the researchers want it banned?
Because they found it worked. Their conclusion was that the results strongly suggest including ecdysterone in the prohibited list under other anabolic agents. A team recommending their own compound be banned in sport is a more credible signal of an effect than a marketing claim.
Is it a steroid?
It is a steroid structurally and it is not an androgen. It does not bind the androgen receptor, which is why it is not expected to cause the hormonal effects of anabolic steroids. That also means the comparison to testosterone in marketing material is misleading in both directions.
How does it compare to turkesterone?
Ecdysterone has human trials and turkesterone has none. That is the whole comparison, and it runs opposite to how the two are marketed.