Ecdysterone
Also known as: 20-Hydroxyecdysone, 20E, 20-HE, Beta-ecdysterone
Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
A plant/insect-derived ecdysteroid marketed as a natural anabolic. It is the most-studied ecdysteroid, but the human evidence is genuinely mixed and disputed: a 2006 trial found no effect on resistance-training responses, while a 2019 WADA-funded study reported significant muscle and strength gains. It is structurally a steroid but NOT an androgen, no androgen-receptor binding, no aromatization, no HPTA suppression, so no PCT. WADA took it seriously enough to place it on the Monitoring Program (it is not prohibited). Rated 1 as a non-hormonal supplement with modest and contested evidence.
Overview
Ecdysterone (20-hydroxyecdysone) is an ecdysteroid, a steroid hormone that controls moulting and metamorphosis in arthropods, also found in plants such as Rhaponticum carthamoides, Cyanotis vaga and Ajuga turkestanica. Sold as a "natural anabolic" supplement. Unlike most such products it has some human data, but that data is mixed and its strongest positive study is disputed.
Purpose & Use Cases
Claimed Muscle & Strength
Marketed to increase lean mass and strength; one WADA-funded RCT reported dose-responsive gains, but a smaller earlier trial found no effect.
Non-Hormonal "Anabolic"
Promoted as a way to gain muscle without shutting down natural testosterone, via a proposed ERβ mechanism rather than the androgen receptor.
Benefits
- Some human data (unusual for a "natural anabolic"), but mixed and disputed
- Proposed non-androgenic (ERβ) mechanism
- Does not aromatize or suppress natural testosterone, no PCT
- Low reported toxicity (no rise in liver/kidney markers in the 2019 study)
Good to Know
The evidence is genuinely disputed, one null study, one positive
A 2006 trial (30mg/day) found no effect on anabolic/catabolic responses to resistance training. A 2019 WADA-funded study in 46 young men reported significantly greater muscle mass and 1-rep-max bench press gains with a dose-response. The positive result is real but contested (supplement content, replication), so this is "promising but unproven," not settled.
WADA put it on the Monitoring Program: but did NOT ban it
After the 2019 study (whose authors recommended prohibiting it under S1.2 "other anabolic agents"), ecdysterone was included in WADA’s Monitoring Program to watch for patterns of misuse in sport. As of this writing it is monitored, not prohibited, an important distinction for tested athletes.
Steroid by structure, ERβ by proposed mechanism: not an androgen
Despite the "steroid" and "anabolic" labels, ecdysterone does not act on the androgen receptor and humans lack the insect ecdysone receptor. Its proposed muscle effect is via estrogen receptor beta (ERβ), a non-androgenic route, which is why it does not require PCT.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 100 – 300 mg/day |
| Intermediate | 300 – 500 mg/day |
| Advanced | 500 – 800 mg/day |
The 2006 null study used just 30mg/day. The 2019 WADA-funded trial tested a range of doses reportedly reaching roughly 200-800mg/day, with the strongest, dose-responsive gains reported at the higher end, supplement marketing commonly cites similarly high (500-1000mg/day) doses. There is no single established, validated dose. A real-world caution: several products marketed as high-dose ecdysterone have been found to contain far less than labelled, so actual intake is uncertain.
Side Effects
Generally low reported toxicity
uncommonThe 2019 human study reported no increase in liver or kidney toxicity biomarkers. Long-term human safety data is still limited.
Use third-party-tested product; do not assume long-term safety is proven.
Sourcing / label-accuracy risk
commonProducts often contain much less ecdysterone than claimed, and quality varies widely in this category.
Buy third-party-tested product with a certificate of analysis.
General Mitigation Strategies
Ecdysterone appears low in toxicity at studied doses (no rise in liver/kidney markers in the 2019 trial), but long-term human safety is not well established. The bigger practical issue is product quality. Many supplements are under-dosed relative to the label. Use tested product and keep expectations modest given the disputed efficacy.
Post Cycle Therapy (PCT)
Not an androgen and does not suppress the HPTA. No PCT required.
How It Works
Humans do not possess the ecdysone receptor that these compounds act on in insects. In mammals ecdysterone is hypothesised to work through the estrogen receptor beta (ERβ), a non-androgenic pathway proposed to drive skeletal-muscle hypertrophy, and has more recently been described as a MAS1 agonist. It does NOT bind the androgen receptor, does not aromatize to estrogen, and does not suppress natural testosterone. So any anabolic effect would be non-hormonal (in the steroid/androgen sense), which is also why no PCT is involved.
Hormonal & Androgenic Profile
N/A: non-androgenic; does not bind the androgen receptor
No AI needed: does not aromatize; proposed mechanism is via estrogen receptor beta (ERβ), not androgen-to-estrogen conversion.
No adverse lipid or blood-pressure signal reported in the 2019 human RCT; long-term cardiovascular data in humans remains limited.
Fundamentals
Reference on the practices relevant to Ecdysterone: how they are done and where they go wrong. Not a recommendation to use it.
WADA Status
Ecdysterone (20-hydroxyecdysone) is NOT on the WADA Prohibited List, but it WAS placed on WADA’s Monitoring Program (to detect potential patterns of misuse in sport) after a 2019 WADA-funded study reported anabolic effects; that study’s authors explicitly recommended adding it to the Prohibited List under S1.2 "other anabolic agents." It remains listed as a monitored anabolic agent (in- and out-of-competition) on the 2026 Monitoring Program, effective 1 January 2026. Status could change. Tested athletes should verify the current list.