Does Cardarine Directly or Indirectly Cause Fat Loss?

TL:DR Yes to both. It will of course help you do an endurance event for longer and help you go further. It also has a direct action against body fat.

Cardarine (GW501516) is a PPARδ agonist. PPAR α, -β/δ, and -γ are confusing ways of saying peroxisome proliferator-activated receptors. It’s these receptors that regulate lipid metabolism, and it’s δ that cardarine is selective of. A lipid is a fatty acid, which serves as a source of vitamins and energy (fat is an example of a type of lipid).

So… Does It?

This is the answer to a very common question in /r/PEDs: PPARs, such as cardarine, increase skeletal muscle fatty acid catabolism. To be clear, just by taking cardarine you will reduce stored body fat all other things being equal. This impact to fat loss is above and beyond the improvement in cardio that may also enable you to burn fat by being more active, running further etc. This is shown in in models of high-fat diet–induced obesity where the targeted activation of PPARdelta in adipose tissue specifically induces expression of genes required for fatty acid oxidation and energy dissipation, which in turn leads to improved lipid profiles and reduced adiposity.

In full disclosure, there is a conflicting study where a 4-month treatment of obese rhesus monkeys with variable doses of GW501516 did not affect body weight which at first reading throws this claim into some doubt. Monkeys can be a better analog for humans than mice or rats, after all. However, we also see this same result in rat studies: here’s some nice graphs which illustrate it. Table A shows that all groups increased weight throughout the study, but there are significant difference in adipose tissue weight, indicating that cardarine is effective in lowering body fat% compared to other groups due to its increase on fatty acid catabolism.

There’s an important conclusion that can be drawn from these latter two studies when taken together - cardarine will not undo a caloric surplus. In that sense, it’s not DNP where it effectively raises the metabolism of the individual, or at least nowhere near as dramatically.

In parallel to the body fat loss, cardarine improves insulin sensitivity, and increases HDL by 79%, decreases triglycerides by 56%, and decreases LDL by 29%. All in line with what you would expect from body fat loss and all highly beneficial. Just a shame about the cancer.

Cardarine has a marginal improvement to blood glucose but a significant difference in distance ran between the sedentary control (NN) and the sedentary cardarine (NG) groups, with the latter running about 50% further. Notably, the trained control group (TN) outperformed the sedentary cardarine group - even PEDs can’t make up for a lack of training.

Conclusion

If you were to eat at maintenance and be entirely sedentary, taking cardarine would be effective in lowering body fat. Yet, that’s not taking advantage of the drugs full potential - significantly increasing your ability to do cardio is an enormous benefit to fat loss, and should be considered a primary benefit of the compound if incorporating cardarine into your cycle. Its other benefits (lipids) mean that some choose to run it alongside compounds that have highly negative effects on lipids.