Ecdysterone is a naturally occurring hormone found in animals and plants.

Some people believe that when it’s ingested by humans, ecdysterone is a more potent anabolic agent than many other well-known performance enhancing drugs, and comes with none of the negative side effects.

Others are more skeptical. They say that ecdysterone is largely untested in humans, and that the few studies that exist are of substandard quality and not to be trusted. 

Who’s right?

The short answer is there’s not a lot of research looking at the effects of ecdysterone in humans, and the studies that are available report very unusual findings that probably shouldn’t be taken at face value.

As the old saying goes, if it’s too good to be true . . . 

What Is Ecdysterone?

Ecdysteroids are a class of compounds that are structurally similar to androgens—hormones that promote the development of masculine traits like hair and muscle growth, deepening of the voice, and strength.

Ecdysterone is a naturally occurring ecdysteroid hormone which controls the moulting and metamorphosis of arthropods—animals with exoskeletons—such as insects and crabs. When ecdysterone levels rise, this helps the exoskeleton release from the animal, allowing it to crawl out and grow a new one.

Ecdysterone is also produced by various plants, where it’s thought to act as a defense against insect pests by disrupting their development and reproduction.

In the world of fitness, ecdysteroids are widely marketed to athletes as dietary supplements purported to increase strength and muscle mass, reduce fatigue, and ease recovery.

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Ecdysterone Benefits

Some research suggests ecdysterone can . . .

. . . which sounds incredible—a true panacea! In reality, though, ecdysterone is literally in-credible, as in, not credible.

The first problem surrounding the claims about ecdysterone is that almost all of the studies—especially the ones relevant to athletic performance—were conducted on animals. While animal studies are helpful for teasing out the different mechanisms by which a substance might work, the results of these studies can never be fully extrapolated to humans.

For example, one study found that rats’ grip strength improved after taking ecdysterone. Another study found that rats that took ecdysterone could stay afloat longer in a “forced swim test” than rats that took nothing. Does that mean it’ll improve humans’ strength and endurance? 

We have no idea, but it seems unlikely. 

There is some research into how ecdysterone affects humans, but the problem is—it’s difficult to believe.

For instance, in one study published in a now-defunct journal from 1988, researchers tested the effect of ecdysterone on muscle mass, fat mass, and hormone levels over a 10-day period in highly-trained athletes. They found that the athletes who took ecdysterone experienced a 6 to 7% increase in muscle mass and a 10% reduction in fat . . . in just 10 days . . . with no negative side effects.

That’s both very impressive and very, very hard to believe. In fact, those results are better than what you could expect from most true anabolic steroids like testosterone, trenbolone, and winstrol

If that weren’t enough, a more recent study conducted by scientists at German Sport University Cologne found even more unbelievable results. In this case, the researchers divide 46 athletes with at least one year of weightlifting experience into four groups:

  1. A placebo group, who took placebo pills every day and lifted weights 3 days per week.
  2. A low-dose group, who took 200 mg of ecdysterone per day and lifted weights 3 days per week.
  3. A high-dose group, who took 800 mg of ecdysterone per day and lifted weights 3 days per week.
  4. A control group, who took 200 mg of ecdysterone per day and didn’t lift weights.

At the end of the 10-week study, the high-dose group gained about 4.5 pounds of muscle and the low-dose group gained about 3.5 pounds. Impressive results, but not enough to raise eyebrows. 

Here’s the weird part: somehow, the group that took a placebo and lifted weights lost almost a pound of muscle, whereas the group that took 200 mg of ecdysterone and sat on their butts the whole time gained about 0.5 pounds of muscle. 

And we got a word for that kind of result in English—it’s called, suspicious. 

Somehow, simply taking ecdysterone turned out to be more effective than lifting weights for gaining muscle. 

Not only are these results implausible, they’ve also been challenged by research which found that ecdysterone has no effect on fat loss, muscle and strength gain, or hormone levels.

The bottom line is that while ecdysterone is an interesting molecule, there’s more or less no credible scientific evidence showing it will boost muscle or strength gain or increase fat loss. 

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Ecdysterone Side Effects

There’s not enough research on ecdysterone to determine whether it has any negative side effects or how severe they might be. 

In rodent studies, ecdysterone becomes toxic when injected at a dose of 6,400 mg per kg of body weight or 9,000 mg per kg of body weight when taken orally. The highest dose used on humans so far was 800 mg, which is roughly the equivalent of about 10 mg per kg for a 180-pound man.

In other words, the doses most people take are probably safe, but we can’t know for certain until more research is done.

FAQ #1: Does ecdysterone increase testosterone levels?


Taking 200 mg of ecdysterone per day and following a well-designed 8-week strength training program had no effect on active or free testosterone levels in one study on resistance-trained men.

FAQ #2: Is ecdysterone a steroid?

Technically, yes, but it doesn’t behave like other steroids in the body.

Ecdysterone is an ecdysteroid hormone produced naturally by animals and plants, which is very different from the kind of drugs typically referred to as “steroids” in bodybuilding circles. 

When we refer to steroids in a bodybuilding or sports context, these are often unnatural substances known as anabolic-androgenic steroids (AAS). Some animal studies have reported that ecdysterone has a stronger anabolic effect than the AAS metandienone, though this hasn’t been replicated in humans. Given ecdysterone’s dubious track record, I wouldn’t hold your breath, either. 

FAQ #3: Is ecdysterone a banned substance?

Not yet, but some scientists have called for it to be added to the list of prohibited substances by the World Anti-Doping Agency (WADA) as a class S1 Anabolic Agent.

Keep in mind that WADA and other regulatory agencies can be a bit trigger happy when it comes to banning substances. For instance, the International Olympic Committee banned caffeine from 1984 to 2004. So, just because a substance gets added to a list of banned substances doesn’t necessarily mean it’s effective (or dangerous). 


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