S42: Investigational SARM
/u/FatFreeCheese suggested we cover S42 after it was covered on http://www.ergo-log.com/s42.html. TL:DR It’s an interesting SARM, that may carry benefit to lipids, fat loss, while being anti-catabolic.
As a SARM, it does not stimulate prostate growth while modestly increasing muscle weight in a 3 week trial on rats. It may have anti catabolic effects (lowering expression of a muscle atrophy-related gene), and seemingly improves lipid metabolism. The latter could be an especially interesting use for S42, if it does make it to the grey market at all.
The ergo-log article draws attention to UCP1, aka Thermogenin. It is an uncoupling protein found in mitochondria of brown adipose tissue. In effect, increasing production of UCP1 allows cells to consumer more energy.
Brown adipose tissue is a form of fat - the other of course being white adipose tissue. Brown adipose tissue serves a role in regulating heat, with a high amount of capillaries present which helps distribute heat produced by the thermogenesis that occurs naturally.
S42 is a weak agonist on androgen receptors in muscle (good), antagonist in prostate and other key organs (also good). It may block DHT (is antagonistic on DHT-mediated androgen receptor transactivation), and also repressed myostatin at a similar level to exogenous DHT (bottom right image).
Continuing looking at this image, you can see the dose/muscle relationship bottom left. As you will notice, it does not have the same impact to muscle growth as DHT. This would compare unfavorably to LGD4033 which significantly impacts muscle growth.
This looks like a perfect cutting SARM, and not so great for bulking/maintenance (unless stacking with an AAS). Anti-catabolic (to a point), and an increase in UCP1. I’d speculate that given the increase in UCP1 that it would not only directly lead to fat loss, it would raise the basal metabolic rate.
There are no human trials at this point to draw further data from. Let’s watch this space given the interest as researchers seek to find SARMs that impact fat loss (RIP Cardarine).