Selective androgen receptor modulators (SARMs) have become increasingly popular in bodybuilding subculture. They are now a somewhat common “supplement” used for increasing muscle mass, reducing body fat, boosting strength, and enhancing athletic performance. In most cases, SARMs mimic the anabolic effects of steroid hormones like testosterone and nandrolone. However, SARMs are technically not anabolic androgenic steroids (AAS).
So, what are SARMs, exactly? How do they work? Are they safe? This article will take a critical look at the use of "bodybuilding SARMs" and the implications these drugs can have on health and fitness based on recent research.
A selective androgen receptor modulator (SARM) is any chemical that modifies the activity of tissue-specific androgen receptors. Most synthetic SARMs are investigational drugs that act as full or partial agonists of androgen receptors in skeletal muscle tissue .
To better understand why SARMs are a subject of ongoing research for clinical use, it's pertinent to discuss the androgen receptor itself. The androgen receptor belongs to a family of intracellular receptors that primarily regulate DNA transcription, and therefore, gene expression and cellular proliferation .
Since androgen receptors are ubiquitous in body tissues of both men and women, taking steroid hormones that activate or inhibit these receptors can have undesirable systemic effects. For example, men who take large doses of testosterone for building muscle may also experience an increase in the size of the prostate gland and loss of hair. Similarly, women who take large doses of testosterone over time may develop masculine characteristics, such as a deeper voice and excess body hair growth.
Essentially, anabolic steroids that activate the androgen receptor are generally non-specific or non-selective. Hence, selective androgen receptor modulators are, theoretically, like steroids that can target distinct androgen receptors in the body.
However, most SARMs are not steroids; rather, they are synthetic compounds that agonize or antagonize the androgen receptor in specific tissues. Drug companies suspect that SARMs are an attractive alternative to traditional androgen replacement therapy due to their selective nature, and the fact that nonsteroidal SARMs aren't metabolized to estrogen or dihydrotestosterone (DHT).
Bodybuilders and athletes have taken a keen interest in using certain SARMs recreationally for increasing muscle mass, strength, and performance. Since SARMs work by modulating the activity of androgen receptors, it's thought that they can produce effects comparable to anabolic steroid hormones like testosterone, trenbolone, and boldenone without commensurate health risks.
The most popular SARMs include Andarine (S4), ostarine (enobosarm/MK-2866), ligandrol (LGD-4033), and testolone (Rad-140). Only a handful of clinical studies have been conducted on testolone, ostarine, and ligandrol, and as of March 2021, there are no clinical trials on andarine .
Ostarine, a compound developed by Gtx, Inc. is arguably the most "thoroughly" studied SARM to date, with generally promising results across a range of patient subpopulations . It remains an investigational drug for muscle-wasting conditions (cachexia) and osteoporosis.
The adverse effects of using SARMs in clinical doses (well below the amount used for performance enhancement) are generally mild. The side effects also typically subside upon cessation of SARM use .
Nevertheless, the U.S. Food and Drug Administration (FDA) warns against using SARMs or any dietary supplements containing these compounds. The World Anti-Doping Agency (WADA) and FDA remain extremely concerned about unscrupulous companies that sell "muscle-building" products containing SARMs, often without actually listing any SARMs on the supplement label to avoid legal ramifications.
Anecdotal reports of liver toxicity, heart attack, stroke, and life-threatening reactions suggest that supplements containing SARMs are fraught with potentially dangerous ingredients. Since they are banned for over-the-counter sale as dietary supplements in the United States, there are virtually no reliable qualitative regulations in place for SARMs.
The loophole that many SARMs purveyors use to sell these compounds is marketing them as being for “research purposes only.” In other words, SARMs are legal to sell in the U.S. so long as they are labeled "research chemicals."
Due to the potency of SARMs and their illicit use, these compounds carry a high risk of adverse effects in larger performance-enhancing doses. The long-term health effects of SARMs remain unknown, and some clinical trials have shown compounds like ostarine (enobosarm/MK-2866) may damage the liver and, somewhat ironically, suppress testosterone levels .
Likewise, cardarine (GW501516), a peroxisome proliferator-activated receptor (PPAR) modulator, has been shown to rapidly induce cancer growth in numerous organs . As such, it is no longer being studied in clinical trials; yet, it remains readily available for purchase as a "research chemical."
Safety concerns of SARM use are ostensibly what has limited the clinical applications of these compounds. However, clinical trials are still ongoing and there does seem to be therapeutic promise for some SARMS, especially as an adjunct for mitigating muscle- and bone-wasting in cancer patients [8, 9].
Research scientists also believe that SARMs will serve as an alternative to traditional hormone-based therapies, such as testosterone replacement therapy . If and when SARMs are approved for medical use by the FDA, odds are they will become federally controlled substances. Though, that's never stopped supplement companies from spiking their formulas with performance-enhancing drugs in the past.
SARMs are officially banned for use in athletic competitions sanctioned by WADA drug-testing policies and many other sporting bodies, such as natural bodybuilding organizations. They are also prohibited for sale as over-the-counter supplements in the United States. Hence, if you purchase SARMs online as "research chemicals," it's anybody's guess what you're truly getting.
A recent study analyzed the contents and chemical identities of dietary supplements and "research chemicals" marketed and sold online as SARMs to see if the label claims matched . The verdict: Not great.
Of the 44 products tested, barely half (52%) contained any SARMs, and 59% contained doses significantly different from what the label stated. Worse yet, 39% of the products tested positive for an undisclosed, unapproved drug, and 9% of the products had no active compounds at all (literally placebos).
These findings highlight an alarming lack of regulatory oversight and pose significant safety concerns regarding the use of products and dietary supplements containing SARMs.
Steroids are hormones derived from cholesterol. They fall into five categories: androgens, estrogens, progestins, mineralocorticoids, and glucocorticoids. These hormones have either anabolic or catabolic properties throughout the body, meaning they either stimulate tissue hypertrophy (growth) or atrophy (shrinkage).
Testosterone and its metabolite dihydrotestosterone (DHT) are among the most potent anabolic androgenic steroids naturally produced in the human body. As such, testosterone is typically the foundation of any steroid cycle. Bodybuilders and athletes will often stack other anabolic steroids, most of which don't naturally occur in the body, with testosterone for even greater effects.
While the increase in muscle mass and strength during a cycle of anabolic steroids may be substantial, the use of these drugs in performance-enhancing/supraphysiologic doses is not without consequences. Adverse effects may include :
The advantage of SARMS over steroids is that they have reliable tissue specificity and are able to dissociate anabolic from androgenic activities. More simply, using SARMs can modulate specific androgen receptors, such as those found in skeletal muscle tissue, while not affecting androgen receptors in the heart or prostate gland, for example.
Therefore, SARMs are plausibly a safer option to increase muscle than anabolic androgenic steroids, at least in the context of performance enhancement. But to reiterate, using SARMs in typical "bodybuilding" doses, which are often 10-20 times the clinically studied amounts, is undoubtedly risky from a health standpoint.
Not to mention, you are placing a lot of faith in the integrity of veritable drug dealers when you buy SARMs on the Internet. Based on the evidence, you're statistically unlikely to get the actual SARM you ordered.
Selective androgen receptor modulators have been around since the late 20th century and show no signs of vanishing anytime soon. Pharmaceutical companies are adamant that novel SARMs like andarine (S4), ligandrol (LGD-4033), ostarine (enobosarm/MK-2866), and testolone (Rad-140) will be the future of drug therapy for conditions associated with muscle- and bone-wasting, and possibly even as a remedy for prostate cancer. These currently unapproved drugs also show promise as ancillaries to conventional medical treatment of life-threatening health conditions, such as lung cancer and breast cancer.
So yes, SARMs do help increase muscle mass and strength, and they may even be health-promoting in some instances. However, the recreational use of selective androgen receptor modulators and dietary supplements containing these compounds is a concerning issue.
Athletes, bodybuilders, and fitness enthusiasts need to seriously consider the potential health risks of taking any supplement or product that claims to contain an investigative SARM, whether it's andarine, ostarine, LGD-4033, ABC-123, XYZ-456, or any other "research chemical" for that matter.
If you plan to compete as a natural bodybuilder, or you're a competitive athlete, steer clear of SARMs and any supplements with these compounds. Stick to the ingredients that are time-tested, like the natural testosterone boosters ashwagandha and tongkat ali (longjack).
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