S42, the Japanese fat loss SARM
Japanese researchers are experimenting with a weird SARM. It's called S42. Its structural formula is so similar to that of estradiol that we wonder whether S42 will ever come on the market as a rogue supplement or research chemical. Though we can not deny that S42 does extremely interesting things in test tubes and lab rats.
The Japanese found S42 when they were searching for steroid molecules with a possible fat loss effect. In that search, the researchers screened 119 interesting compounds and then discovered that S42 increased UCP1 in cells. This suggests that S42 stimulates cells to consume more energy.
2019: in vitro study
In a study. that the researchers, who are affiliated with Fukuoka University, published in Biochemistry and Biophysics Reports, the researchers exposed muscle cells to S42.
[Biochem Biophys Rep. 2019 Jan 15;17:177-81.]
In these tests, S42 did not make cells to produce more androgen receptors, but the substance did switch off catabolic signal molecules, and did switch on anabolic signal molecules. This suggests that S42 has no or few androgenic side effects, but may have anti-catabolic and anabolic effects.
2009: in vitro and animal study
These results become more interesting if you take into consideration previous in vitro and animal data, which the researchers published in 2009. [Endocrinology. 2009 Dec;150(12):5606-16.]
In vitro, S42 increased the production of UCP1. As said before, this suggests that S42 allows cells to consume more energy. At the same time, S42 reduced the production of PSA in prostate cancer cells. That would mean that S42 can protect against prostate cancer.
Well, based on its structural formula, you might think that S42 is an estrogen. However, the substance does interact with the androgen receptor. And when the Japanese gave S42 3 weeks to castrated rats, the substance increased their levator ani muscle. S42 has an anabolic effect.
The human equivalent of the highest dose was about 70-100 milligrams per day.
As you can see below, S42 had no effect on the size of the prostate.
Remarkably, S42 increased the LH level. The substance also reduced the concentration of triglycerides in the blood. S42 had no adverse effects on the cholesterol and insulin levels.
The Japanese are ready to study the effect of S42 in humans, they write in their 2019 publication.
Biochem Biophys Rep. 2019 Jan 15;17:177-81.
The anabolic effect of GSK20881078: human study 31.10.2018
GSK2881078 - SARM star rising 30.01.2018
How safe is S23? 07.12.2015