Turkesterone: Does It Actually Build Muscle? Here’s What the Research Shows
Health disclaimer: This article is for informational and educational purposes only. It is not medical advice and is not a substitute for consultation with a qualified healthcare professional. Always speak to your doctor or pharmacist before starting a new supplement, especially if you have a medical condition, are pregnant or breastfeeding, or are taking prescription medication. Statements about dietary supplements have not been evaluated by Medsafe or the FDA, and these products are not intended to diagnose, treat, cure, or prevent any disease.
Turkesterone has 2 modern human RCTs. Both found no effect on muscle mass, strength, or body composition. If you’re spending $50 a month on it, this article is worth reading before your next order.
That’s not a tease. It’s the entire human evidence base. Two double-blind, placebo-controlled trials. Zero significant results. And yet turkesterone became one of the most-hyped muscle-building supplements of the last five years, sold as a natural alternative to anabolic steroids with none of the downsides. Here’s how that happened, and what to take instead.
Where the Hype Came From
Turkesterone is a phytoecdysteroid (a plant-derived compound structurally similar to insect moulting hormones) found in Ajuga turkestanica. Supplement companies began marketing it heavily around 2021 with claims of dramatic gains rivalling anabolic steroids.
The story starts with a case of mistaken identity. In 2019, Isenmann and colleagues published a human RCT not on turkesterone but on ecdysterone, a chemically distinct phytoecdysteroid found in spinach. That trial found roughly 2 kg greater lean mass gain in the ecdysterone group versus placebo over 10 weeks of resistance training. Supplement companies took the result, applied it to turkesterone marketing, and built a category worth hundreds of millions of dollars on a compound that had never been tested in a single human trial.
Two problems with that. Ecdysterone and turkesterone are different compounds with different pharmacokinetic profiles. And the 2019 ecdysterone study has serious methodological issues the marketing omitted: the placebo group lost lean mass over 10 weeks of supervised resistance training, an outcome so physiologically unusual it casts doubt on the trial’s dietary controls and randomisation. The finding has never been replicated.
What the Human Studies Actually Show
The first properly controlled human trial of isolated turkesterone was published in 2024 by Jose Antonio and his team at Nova Southeastern University. They randomised 31 active men and women to either 500 mg/day of turkesterone (Ajuga extract) or a rice-flour placebo for four weeks, with no mandated changes to diet or training. The results were unambiguous. There were no statistically significant differences between groups in body mass, lean body mass, fat mass, or body fat percentage. Lean body mass change was -0.6 ± 1.4 kg in the turkesterone group versus -0.3 ± 1.7 kg in placebo (p = 0.68, trivial effect size). The paper’s title (It’s Not Deca) was the authors’ own pushback against the steroid-level marketing claims.
A second double-blind RCT, this time by Crisanti and colleagues from the same Nova Southeastern lab in 2025, tested a commercial turkesterone-containing product against placebo in 24 healthy university students over four weeks. It also measured handgrip strength, mood, and sleep quality. Across every endpoint (fat-free mass, fat mass, total body water, handgrip strength, mood, and sleep) there were no significant between-group differences. Effect sizes were trivial throughout. This was one of the first properly blinded trials of a commercially available turkesterone product, testing exactly the claims on the label. It found nothing.
The dose-escalation argument doesn’t help either. Harris and colleagues in 2024 tested acute single doses of 1000 mg and 2000 mg of turkesterone against placebo in 11 recreationally active men. Neither dose produced any significant effect on resting metabolic rate, fat oxidation, carbohydrate utilisation, or IGF-1.
Why the Animal Studies Don’t Translate
Pro-turkesterone arguments often cite rodent research showing genuine ecdysteroid effects on muscle protein synthesis. Those findings are real. They also don’t generalise to humans. The doses used in rodent studies, scaled to human body weight, would be impractically high. Oral bioavailability of ecdysteroids in humans appears to be poor, meaning very little of what you swallow reaches muscle tissue at the concentrations that drove effects in mice. The Harris acute dosing data reinforce this: even at 2000 mg, the supplement produced no measurable physiological response in healthy active men.
What to Take Instead
If your goal is muscle and strength, the evidence points clearly to one alternative.
Creatine monohydrate. Turkesterone has 2 null human trials. Creatine has hundreds of trials across four decades, with consistent evidence for meaningful improvements in lean mass and strength at 3 to 5 g daily, no loading phase required. Plain micronised creatine from NOW Sports, Bulk Supplements, or Optimum Nutrition is available cheaply at iHerb NZ. Creatine doesn’t have compelling marketing. It has four decades of evidence instead.
If your total daily protein intake sits below 1.6 to 2.2 g per kilogram of bodyweight, closing that gap will do more for muscle growth than any supplement. Whey or casein from NOW Sports, Bulk Supplements, or MyProtein NZ is a practical way to close it.
Frequently Asked Questions
Does turkesterone work for building muscle?
The current human evidence says no. Two double-blind, placebo-controlled RCTs (Antonio 2024, 31 participants; Crisanti 2025, 24 participants) both found no significant effect on lean mass, fat mass, or strength versus placebo. Acute dosing studies up to 2000 mg also showed no measurable response.
Is turkesterone the same as ecdysterone?
No. Both are phytoecdysteroids but they are chemically distinct compounds with different structures and pharmacokinetics. The hype around turkesterone was largely built on the 2019 Isenmann ecdysterone trial, a different supplement. That study has not been replicated and has methodological issues that undermine confidence in its findings.
Why do some people swear it works?
Self-reports reflect placebo effect, the expectancy that comes with paying $50 a month for something, and normal variation in training outcomes. Controlled trials, which account for these factors by design, consistently find no difference versus placebo. Anecdote and controlled evidence point in opposite directions here.
Is turkesterone safe?
No serious safety signals have appeared in trials to date, but the research is too limited for strong long-term conclusions. A more practical concern is product quality: independent testing of ecdysteroid supplements has found significant variation between actual content and label claims.
The Bottom Line
Turkesterone does not have convincing evidence for building muscle or improving strength in humans. Two controlled trials in 2024 and 2025 both found nothing, and acute dosing up to 2000 mg produced no measurable response either. The category was built on animal research and a single contested ecdysterone trial from 2019, with two chemically distinct compounds treated as interchangeable by marketers. If you’re training for muscle and strength, creatine monohydrate at 3 to 5 g daily has the evidence base turkesterone never built, at a fraction of the cost.
References
All studies cited are linked to primary sources where available.
- Antonio J, et al. (2024). A Preliminary Investigation of Turkesterone: It’s Not Deca. Research Directs in Health Sciences, 4(1). doi:10.53520/rdhs2024.104126. Full authors: Antonio J, Silver T, Lukowiak A, Jiannine L. [Note: this journal is not currently indexed in PubMed; citation verified directly from the publisher.]
- Crisanti A, et al. (2025). The effects of an ecdysteroid supplement on indices of physical and mental performance. Journal of the International Society of Sports Nutrition, 22(Suppl 2):2550140. doi:10.1080/15502783.2025.2550140. Full authors: Crisanti A, Silver T, Jiannine L, Antonio J. [PMC12379694]
- Harris DR, et al. (2024). The Effects of Multiple Acute Turkesterone Doses on Indirect Measures of Hypertrophy and Metabolic Measures: A Preliminary Investigation. Muscles, 3(4):364-375. doi:10.3390/muscles3040031. Full authors: Harris DR, Chapman-Lopez T, Machek SB, Forsse JS, Sulak T, Funderburk LK. [PMID 40757520]
- Isenmann E, et al. (2019). Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans. Archives of Toxicology, 93(7):1807-1816. doi:10.1007/s00204-019-02490-x. [PMID 31123801]
Written by the What’s Optimal Editorial Team. Evidence-based, independent, and free of sponsorship bias. Read our full methodology.