Turkesterone and ecdysteroids

The verdict

Our read at a glance.

Whether a plant and insect steroid with no androgen receptor activity produces meaningful muscle gain in humans.

The signal

The interesting human data point is a controlled study reporting performance enhancement with ecdysterone in resistance-trained subjects, with effect sizes large enough that the authors raised the question of whether it should be prohibited in sport, and it was subsequently placed under monitoring. Around that sit registered trials of 20-hydroxyecdysone in obesity and prediabetes, chemistry work on the minor ecdysteroids of Ajuga turkestanica, reviews of phytoecdysteroid biology, and human excretion work following spinach consumption, which is where dietary ecdysterone actually comes from. Independent replication of the performance finding is thin.

The unknown

Both whether the effect is real at scale, and what people are actually taking. Independent analyses of retail turkesterone products have repeatedly found quantities far below label, and much of the supportive human data concerns ecdysterone rather than turkesterone specifically.

Our read

The most interesting supplement claim in this category and the one most damaged by its own market. One good trial, real enough to attract anti-doping attention, attached to products that repeatedly test as not containing the ingredient. Before asking whether turkesterone works, ask whether the bottle has any in it.