|SARMs may build muscle, but they don't have significant effect on body fat and thus the visibility of the muscles.|
Before you are now telling me once more that "rodents are no little men", let me remind you of the fact that other SARMs, like LGD-4033 have recently been tested in humans at the Boston Medical Center (Basaria. 2013).
In said study, Basaria et al. found that 28 days. on this experimental drug lead to highly significant dose-dependent increases of the lean mass of their young, healthy male subjects who didn't even train, Against that backround it is highly unwarranted to grumble that mice are no little men and this study says nothing about possible effects in human.
I do agree: Future human studies appear warranted, but a direct comparison to "toxic" steroids, such as the one that was done in the study at hand, will probably not get the approval of the ethics commission of any Western University, anyway. To circumvent this problem and still learn something about the effects of anabolic steroids in humans, the Germans recruited a handful of "bros" who were juicing anyway and used their (lowered) hormone levels, as well as those of non-juicing bodybuilders as a reference (yes, they drug-tested them to be sure).
|Currently available SARMS (Iasuja. 2012)|
"Therefore intact male Wistar rats were dose-dependently treated with metandienone, estradienedione and the selective androgen receptor modulator (SARM) S-1. In serum cortisol, testosterone, 17b-estradiol (E2), prolactin, inhibin B, follicle-stimulating hormone (FSH), luteinizing hormone (LH), Insulin-like growth factor 1 (IGF-1), and thyroxine (T4) concentrations were determined" (Hengevoss. 2015).As previously hinted at, Hengevoss et al. got data to compare the effects to from (a) six human volunteers who were single treated with 1-androstenedione and (b) abusing and clean body builders whose serum concentrations of inhibin B, IGF-1, cortisol, prolactin, T4, thyroid-stimulating hormone (TSH), testosterone and LH were determined, as well.
|Figure 1: Overview of the (imho) most significant results (Hengevoss. 2015).|
What other SARMs are there? The most prominent research chemicals that bind to the androgen receptor and act as selective agonists in tissues like muscle and bone, but antagonists in the prostate and hypothalamus (➲ this is how they build muscle and bone, without affecting prostate health or triggering shut down) are unquestionably S4 and ostarine. Both are already heavily (ab-)used in the bodybuilding scene. The previously mentioned LGD-4033 (see Figure 2) is the powerful and highly selective new kid on the block and with agents like S-40503, a recently developed tetrahydro-quinoline and other new SARMs, several new research chemicals are already on the horizon... obviously they are all just used by scientists to treat sarcopenia, not available on the (grey) market and not being abused by athletes all around the world ;-)As it was to be expected, the administration of estradienedione resulted in an additional increase of E2. What is a bit surprising, though is the S-1-induced increase in cortisol, which is in contrast to the the effects the single administration of 1-androstenedione had on the six previously "non-using" young men who saw decreases in both cortisol and inhibin B serum concentrations. LH was not affected.
|Table 1: Overview of the results of the comparison of drug-using (ABB) vs. clean bodybuilders (BB). As you can see, both E2 as well as the thyroid hormones were affected also in those who only trained hard (Hengevoss. 2015).|
- Basaria, Shehzad, et al. "The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral, selective androgen receptor modulator, in healthy young men." The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 68.1 (2013): 87-95.
- Hengevoss, Jonas, et al. "Combined effects of androgen anabolic steroids and physical activity on the hypothalamic-pituitary-gonadal axis." The Journal of Steroid Biochemistry and Molecular Biology (2015).
- Iasuja, Ravi, Mikhail N. Zacharov, and Shalender Bhasin. "The state-0f-the-art in the development of selective androgen receptor modulators." Testosterone: Action, Deficiency, Substitution (2012): 459.