Peptide & Experimental
Turkesterone
Plant ecdysteroid (phytoecdysteroid) from Ajuga turkestanica, a novel food not authorized in the EU · Turkesterone, Ajuga turkestanica extract, phytoecdysteroid (related: ecdysterone, 20-hydroxyecdysone, beta-ecdysterone)
Turkesterone is a plant steroid from the Central Asian bugle Ajuga turkestanica and is regarded in the strength sports scene as a natural alternative to anabolic steroids. The idea behind it is not plucked out of thin air: related ecdysteroids clearly build muscle in animals and in muscle cells. For turkesterone itself, however, the data in humans are still thin, and many products contain little of what is on the label.
In short
Turkesterone belongs to the ecdysteroids, molting hormones that control insects and that some plants produce for defense. In a German study with 46 young men over 10 weeks of strength training, the closely related substance ecdysterone increased muscle mass and bench press strength more than the control. For turkesterone itself there is so far only one single-dose study with 11 men, which found no measurable effect on IGF-1 or resting metabolic rate. In a US analysis, half of the turkesterone products contained no detectable turkesterone at all. In the EU, turkesterone is considered a novel food without authorization.
What it is
Ecdysteroids are steroids that control molting and reproduction in insects and crustaceans. Many plants produce them as well, presumably as protection against being eaten. The best known is 20-hydroxyecdysone, also called ecdysterone or beta-ecdysterone. It is found in spinach, quinoa and maral root, among others. Turkesterone is a close relative with 7 instead of 6 hydroxyl groups, including one at position C-11, and occurs mainly in Ajuga turkestanica, a member of the mint family from the mountains of Uzbekistan.
Despite the steroid backbone, ecdysteroids have little in common with testosterone or synthetic anabolic steroids. According to current knowledge, they do not bind to the classic steroid receptors inside the cell, and so not to the androgen receptor either. That is exactly what makes them interesting for many users: muscle building without the known side effects of anabolic steroids, so the promise goes.
How it is supposed to work
The most exciting data come from the laboratory. In a rat study, ecdysterone enlarged the muscle fibers of rats over 21 days more than the anabolic steroids metandienone and estradienedione and the SARM S 1 at the same dose. In muscle cell cultures, the myotubes grew about as much as under dihydrotestosterone. Estrogen receptor beta is considered the pathway; a signaling pathway via the Mas receptor is also being discussed.
The claim that turkesterone is even more potent than ecdysterone comes from older Soviet rat studies from 1976 onwards. There, muscle mass and protein content rose in castrated rats after 10 days. These studies are widely cited in today’s literature, but there are no modern comparative studies in humans.
That ecdysteroids reach the body at all in humans has been shown for ecdysterone. After a single dose of 50 mg, it was detectable in the urine of 12 volunteers for more than 2 days; around 18 percent was excreted unchanged. That is exactly why doping laboratories can detect it.
What users report
In forums and videos, strength athletes report fuller-looking muscles, better recovery and more strength. These are uncontrolled user reports that can be taken seriously but have two weaknesses: training and diet often change at the same time, and nobody knows how much turkesterone was actually in the capsule.
What is well supported
Best supported is the anabolic effect of ecdysteroids in animals and in cell culture, where it has been shown several times and in independent laboratories. In humans, one study carries most of the weight: Isenmann and colleagues had 46 young men train for 10 weeks and gave an ecdysterone product in two dosages. The ecdysterone groups gained significantly more muscle mass and bench press strength, liver and kidney values remained unremarkable, and the product had been checked in advance for hidden anabolic steroids. According to a later re-analysis, the capsules contained 6 mg of ecdysterone, so the groups took 12 and 48 mg per day. The authors recommended putting ecdysterone on the doping list. The safety of the substance class has also been reasonably well studied: purified ecdysterone was tested as the drug candidate BIO101 in 233 older people with muscle wasting over 6 to 9 months, and side effects were at placebo level.
What the studies show
The turkesterone single-dose study
At Baylor University, 11 healthy, trained men received, in random order, a single dose of 1,000 mg or 2,000 mg of a turkesterone product or a placebo. IGF-1, resting metabolic rate, blood lipids and glucose metabolism were measured before and 1, 3 and 24 hours after intake. None of the values changed significantly. IGF-1 was slightly higher under turkesterone than under placebo, but within the range of chance. The stomach and circulation tolerated the product well. The paper does not report whether the content of the capsules was checked.
The US product analysis
A team led by Pieter Cohen analyzed 57 sports supplements bought in the US, including 8 with turkesterone on the label. In 4 of them, no turkesterone was detectable. The remaining 4 contained 0.01 to 0.1 mg per serving, although, for example, 500 mg of extract with 10 percent turkesterone was stated. No prohibited drugs were found in these products.
The study with the empty product
A group from Cologne and Düsseldorf gave 28 strength-trained men a commercially available ecdysterone-diosgenin product or placebo for 12 weeks. Both groups became equally stronger and equally more muscular. The subsequent analysis showed why: the capsules contained less than 1 percent of the stated amount of ecdysterone. The study is thus less evidence against ecdysteroids than against untested products.
Where the data stop
For turkesterone itself, what is needed for a statement on muscle building is missing: a training study over weeks in which muscle mass and strength are measured and the content of the product is checked. The only human study was a single dose in 11 people. How well turkesterone is absorbed in the gut and how long it stays in the blood has not been studied in humans. For ecdysterone the half-life is a few hours, and only 1 to 3 percent is absorbed from spinach or quinoa.
The ecdysterone data are not consistent either. Alongside the positive Isenmann finding are studies without an effect: 45 trained men over 8 weeks with 200 mg of ecdysterone, 20 men over 12 weeks with 30 mg of ecdysterone from asparagus. An analysis of 13 commercial products from 2026 shows how big the problem is: products that were supposed to be standardized to 80 to 95 percent ecdysterone contained anything from undetectable to about 50 mg per capsule, and the turkesterone content also varied widely. In the older people in the BIO101 study, the gain in walking speed was not significant in the main analysis. And the results cannot be transferred one-to-one to turkesterone, because it is a different compound.
Status, approval and legal
In the EU, Ajuga turkestanica and turkesterone are considered novel foods without authorization. Since 2023, the European rapid alert system RASFF has recorded several notifications about food supplements with Ajuga extract, and in March 2026 also one explicitly about turkesterone. In Germany, turkesterone is therefore neither marketable as a food supplement nor approved as a medicine. In the US it is sold as a dietary supplement. In sport, turkesterone is not on the WADA Prohibited List 2026. Ecdysterone, however, has been observed in WADA’s Monitoring Program since 2020, including in 2026, and researchers are calling for a ban. Anyone who competes in sport also bears the risk of contaminated products.
Safety
In the only human study, turkesterone was well tolerated as a single dose; data over several weeks do not exist. For the substance class things look better: purified ecdysterone caused no more side effects than placebo in the BIO101 study over 6 to 9 months, and acute toxicity in animals is very low. A case report describes severe muscle breakdown after more than 4 hours of strength training in a young man who was taking several supplements including ecdysterone; a connection has not been established. The bigger practical risk is product quality: according to a review, just under 20 percent of the ecdysterone supplements tested contained contaminants, including prohibited anabolic steroids. Because ecdysteroids could act via estrogen receptor beta, data are lacking for pregnant and breastfeeding women, adolescents and people with hormone-dependent diseases.
BK-Score Hype far ahead of evidence
| Human evidence | 3 | |
|---|---|---|
| Mechanism | 4 | |
| Safety data | 2 | |
| Hype gap | 2 | |
| Track record of use | 4 |
Evidence 3, because for turkesterone itself there is only one randomized single-dose study with 11 men, which looks at surrogate markers and found no significant effect on IGF-1, resting metabolic rate or metabolism (Harris et al., Muscles 2024), and ClinicalTrials.gov lists no entry; the human data on the relative ecdysterone are inconsistent – more muscle mass and bench press strength in 46 men over 10 weeks (Isenmann et al., Arch Toxicol 2019), no effect in 45 trained men over 8 weeks (Wilborn et al. 2006) – and not readily transferable. Mechanism 4, because the anabolic effect of the substance class has been well shown in rat muscle and cell culture (Parr et al. 2015, 5 mg/kg over 21 days), but for turkesterone only Soviet rat data from 1976 onwards are available and neither the target structure nor absorption in humans has been confirmed. Safety 2, because turkesterone has only been studied as a single dose; the controlled data over 6 to 9 months come from the purified ecdysterone BIO101 (Fielding et al. 2025, n = 233). Hype 2, because turkesterone is sold as a natural anabolic agent although training data are lacking and no turkesterone was detectable in 4 of 8 US products (Cohen et al., JAMA Netw Open 2023). Use 4, because it is widely used as a supplement, above all in the US, without content or effect being checked in a regulated way; in the EU it is not authorized. Direction open, because the substance class is promising, but meaningful human data for turkesterone are simply lacking.
The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)
Frequently asked questions about turkesterone
Is turkesterone a steroid?
Chemically yes, it has a steroid backbone. According to current knowledge, however, it does not bind to the classic steroid receptors and therefore acts differently from testosterone or anabolic steroids. An effect via estrogen receptor beta is being discussed.
Does turkesterone build muscle?
In animals and in muscle cells, ecdysteroids are clearly anabolic, and a study with the relative ecdysterone showed more muscle mass in 46 men. For turkesterone itself there is no training study in humans; the only single-dose study found no measurable effect.
What is the difference between turkesterone and ecdysterone?
Both are ecdysteroids from plants. Turkesterone carries 7 instead of 6 hydroxyl groups and usually comes from Ajuga turkestanica, ecdysterone from spinach, quinoa or maral root. There are considerably more human data on ecdysterone.
Is turkesterone legal in Germany?
It is not authorized as a food supplement in the EU, because turkesterone and Ajuga turkestanica are considered novel foods without authorization. There is no approved medicine either.
Is turkesterone doping?
Turkesterone is not on the WADA Prohibited List 2026. Ecdysterone has been observed in the Monitoring Program since 2020. Contaminated products can nevertheless lead to a positive test.
Why do some turkesterone products not work?
Because there is often hardly anything in them. In a US analysis, 4 of 8 turkesterone products contained no detectable turkesterone at all, the rest only traces. With ecdysterone products, too, the content often deviates considerably from the label.
Related
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- Related topicMethylstenbolone
- Related topicAndarine (S-4)
- Related topicOstarine (Enobosarm)
- Related topicDHB (1-testosterone, dihydroboldenone)
Sources
- Harris et al., Muscles 2024 – single doses of turkesterone, IGF-1 and resting metabolic rate
- Cohen et al., JAMA Netw Open 2023 – content of botanical ingredients in sports supplements
- Isenmann et al., Arch Toxicol 2019 – ecdysterone and strength training in humans
- Dissemond et al., J Int Soc Sports Nutr 2025 – 12-week RCT with a phytosteroid product
- Parr et al., Biol Sport 2015 – ecdysteroids as anabolic agents
- Fielding et al., J Cachexia Sarcopenia Muscle 2025 – BIO101 in sarcopenia, phase 2b
- Wilborn et al., J Int Soc Sports Nutr 2006 – ecdysterone without training effect
- Todorova et al., Molecules 2026 – ecdysteroid content in supplements
- WADA Monitoring Program 2026
- RASFF Window – notifications on Ajuga turkestanica and turkesterone
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-27.