Cardarine: Human Trials

Credit to /u/Enlilasko for humoring my repeated requests. He located three studies below where cardarine (GW501516) was given to humans, rather than rats. The studies themselves did not focus on cancer, at all, but on lipids and other markers.

> wtf, human cardarine studies? Why do people only talk about the rat studies?

Toxicity has been evaluated in long-term animal studies, showing an increase in tumour formation. These animal studies (usually performed in parallel with early clinical development) resulted in termination of the clinical development program. The increase in tumour development was not replicated in the early human studies, which used lower doses and shorter study duration, so long-term effects in humans are unknown.

Human Studies

To recap for our newer readers, or those new to PEDs, cardarine is a popular PPAR agonist that improves endurance and catabolizes fat. But, there are rumors around it causing cancer, based on two studies. More on that further on, or read about it in detail here.

Study 1, 2007: folks were given placebo (n=6), 2.5mg (n=9) or 10mg (n=9) once daily for 2 weeks while sedentary. No significant adverse effects were noted.

Study 2, 2011: similar in scope to the first study, with administration of 2.5mg once daily or placebo (n=13). No significant adverse effects were noted and no changes in liver, muscle enzymes, creatine or protein in urine that might demonstrate kidney damage. There were significant changes (positive) to triglycerides, HDL cholesterol.

Study 3, 2012: Actually two studies, with similar results. In the core study, folks were given placebo (n=78), 2.5mg (n=48), 5mg (n=83) or 10mg (n=59). Notably, 14% were women (female rats had a higher mortality rate in Cardarine studies), but there was no differences in trends between men and women. In the exploratory study of men only, 16 subjects given 5mg and then 10mg, with 21 given placebo.

In both, LDL and triglycerides were lowered significantly, and HDL was increased. All were dose dependent. The study notes that no plateau was achieved, meaning that improvements in these numbers may have continued beyond the 12 weeks. Both studies saw improvements in insulin sensitivity and decline in fatty acid ~20%.

Presumably, all of this came with body composition benefits, but body fat% was not captured. Body weight changes were not significant (the 10mg group gained a kg on average).

So What?

That some groups received 10mg for 12 weeks is also very promising for our purposes as this is the recommended starting dose in the PEDsR DB, though I typically shy away from long cardarine cycles personally. Cancer was found in a human equivalent dose of 43.2mg (200lb male) in rats, so the 10mg dose represents the closest dose we have.

In all of these human trials, there was no evidence included in the journal that indicated tumor growth, benign or otherwise... they weren’t looking for it. Or perhaps it was never there to begin with.

Finally, we still do not have data on long term effects of cardarine use on humans.