RAD-150 (TLB-150) SARM: What the Evidence Actually Shows

Key takeaways

What Is RAD-150 (TLB-150)?

RAD-150, also sold under the name TLB-150 or TLB-150 Benzoate, is marketed by online research-chemical and supplement vendors as a chemically modified, longer-acting version of RAD-140 (testolone, development name vosilasarm), a nonsteroidal selective androgen receptor modulator (SARM). Chemical supplier listings consistently describe RAD-150 as the benzoate ester of RAD-140, catalogued under CAS number 1208070-53-4 with the molecular formula C27H20ClN5O3 and a molecular weight of approximately 497.9 g/mol. Independent chemical databases and multiple commercial suppliers describe the same structure: a benzoate group attached to the propan-2-yl position of the RAD-140 molecule.

Vendor product descriptions state that the ester bond is intended to increase lipophilicity and thereby extend the compound's half-life and produce steadier blood levels compared with unmodified RAD-140. One chemical vendor's product page notes that the ester moiety increases the molecule's lipophilicity and states this can influence metabolic half-life and tissue distribution in experimental systems. This is a supplier characterization rather than a finding published in a peer-reviewed pharmacokinetic study, and no data comparing blood levels, tissue exposure, or androgen receptor occupancy of RAD-150 against RAD-140 in animals or humans has been located in the peer-reviewed literature.

One notable finding did surface in supplier documentation rather than marketing copy: a major chemical reagent supplier lists TLB-150 Benzoate not as an anabolic research chemical but under a "nerve conduction blocker" heading, stating that the compound spontaneously cyclizes under physiological conditions to form a related molecule (RAD-179), producing a persistent, reversible, slow neuronal conduction blockade. This chemistry, if accurate, would mean the ester is not simply a slow-release version of RAD-140 but a compound that transforms into a structurally distinct molecule with an entirely different reported pharmacological action once inside the body. This has not been corroborated by an independent peer-reviewed pharmacokinetic study of RAD-150 in animals or humans, so it should be treated as an unverified but concerning signal rather than an established fact.

No dedicated identity or purity analysis of RAD-150 products sold online, comparable to the type of independent chemical testing that has been done on other SARM products, was identified in the peer-reviewed literature. A JAMA-published investigation that purchased and chemically analyzed 44 products marketed online as SARMs (though not testing RAD-150 specifically) found that SARMs accounted for only 23 of the 44 products tested (52 percent), while an additional 17 products (39 percent) contained a different unapproved drug entirely. Because no comparable independent testing of RAD-150 specifically has been published, buyers have no external, peer-reviewed way to confirm the identity or purity of a given RAD-150 product beyond the manufacturer's own claims.

How RAD-150 Is Claimed to Work

Marketing copy for RAD-150 asserts that, like other SARMs, it binds selectively to androgen receptors concentrated in muscle and bone tissue while largely sparing other androgen-sensitive organs such as the prostate. This description is borrowed directly from the pharmacology described for the parent compound: RAD-140 acts as an agonist of the androgen receptor, and preclinical studies describe a dissociation of effect between tissues, with agonistic and anabolic effects in muscle, agonistic effects in breast tissue, and partially agonistic or antagonistic effects in the prostate gland. This tissue-selective profile is the basis for distinguishing SARMs as a class from testosterone and traditional anabolic-androgenic steroids.

Retail listings for RAD-150 state that its research applications include studying androgen receptor interaction, anabolic signaling, and structure-activity relationships compared with non-esterified SARMs. These are chemistry-supplier characterizations intended for a research-chemical audience, not findings from a published pharmacodynamic or pharmacokinetic study conducted specifically on RAD-150.

Is There Any Published Research on RAD-150 Itself?

A search of the peer-reviewed literature and clinical trial registries does not return dedicated pharmacology, toxicology, or clinical studies of RAD-150 or TLB-150 Benzoate as a muscle-building or performance compound. Even vendor product pages acknowledge this gap directly, with one retailer stating plainly that RAD-150 is a new compound with no clinical studies on humans, distinguishing it from its parent compound RAD-140, which has at least been examined in early-phase clinical trials for a cancer indication.

In practical terms, this means every benefit attributed to RAD-150 for muscle gain, recovery, or body composition is an extrapolation from data generated on a different molecule, RAD-140, rather than a finding specific to the ester product being sold. Given the documented chemical instability described by at least one reagent supplier, in which the benzoate ester reportedly converts to a different molecule under physiological conditions, this extrapolation is even less reliable than it would be for a simple, stable ester.

What We Actually Know About the Parent Compound, RAD-140

RAD-140, also known by the development name vosilasarm, is an investigational drug that has been studied in a first-in-human phase 1 trial for androgen-receptor-positive, estrogen-receptor-positive, HER2-negative metastatic breast cancer in postmenopausal women, using doses of 50, 100, and 150 mg daily. That trial reported a plasma half-life of approximately 44.7 hours and found that sex hormone-binding globulin decreased significantly in all patients. One patient in the trial showed a partial tumor response.

The same phase 1 trial reported substantial rates of liver-related laboratory abnormalities: elevated AST occurred in roughly 59 percent of participants, elevated ALT in about 46 percent, and elevated total bilirubin in about 27 percent, alongside dehydration, vomiting, anorexia, and weight loss occurring in roughly a quarter of participants each. In preclinical models, RAD-140 has been shown to increase lean muscle mass and strength, with the tissue-selective agonism described above distinguishing its prostate effects from those of testosterone.

Despite its investigational status and the absence of FDA approval for any indication, RAD-140 is described in the medical case-report literature as readily accessible on the consumer market, where it is used off-label by bodybuilders and athletes rather than under clinical supervision.

No comparable phase 1 data, case series, or systematic pharmacovigilance analysis exists for RAD-150. Any assumption that RAD-150 shares RAD-140's efficacy or safety profile is unverified; esterification, and the reported chemical conversion of TLB-150 Benzoate into a structurally distinct compound, can change absorption, distribution, and clearance in ways that are not automatically predictable from the parent compound alone.

Reported Side Effects and Safety Concerns

Because RAD-150 itself has not been studied in animals or humans, the safety literature that exists concerns RAD-140 and the broader SARM class. Case reports describe cholestatic liver injury with jaundice, pruritus, and markedly elevated bilirubin in bodybuilders who had used RAD-140 for five weeks, as well as a separate case of jaundice, nausea, and fatigue after four months of RAD-140 use with a liver panel showing severe hyperbilirubinemia. In several of these cases, symptoms and liver enzyme abnormalities resolved after the drug was discontinued.

Cardiac harms have also been reported. A 16-year-old boy developed myopericarditis with chest pain beginning a few hours after his first and only dose of RAD-140. A separate case report describes a 32-year-old man with poorly controlled type 1 diabetes who developed congestive heart failure attributed to myocarditis after several doses of RAD-140, and other reporting describes a 22-year-old user who suffered heart failure after roughly six months of use despite having no prior cardiac conditions. A more recent case report describes a 48-year-old man with hypogonadism on testosterone replacement therapy who developed arterial thrombosis with extensive infarcts while also taking RAD-140 obtained outside the pharmaceutical supply chain; the report's authors noted this was the first published case of arterial thrombosis associated with RAD-140 and proposed that concurrent androgenic exposure from two sources may have contributed to the risk.

At the class level, the FDA has stated that SARMs in bodybuilding products have been associated with increased risk of heart attack or stroke, psychosis, sleep disturbances, sexual dysfunction, liver injury or acute liver failure, infertility, pregnancy miscarriage, and testicular shrinkage. The agency has also stated that life-threatening reactions, including liver injuries requiring hospitalization, have occurred in people taking SARM-containing products.

Retail pages selling RAD-150 note that, consistent with androgen receptor agonism generally, the compound may suppress natural testosterone production, particularly at higher doses or over longer periods. The existence of such marketing-side acknowledgments is itself evidence of expected endocrine suppression; it is not evidence that RAD-150 is safer than testosterone or anabolic steroids.

Because there are no dedicated toxicology or human safety studies of the RAD-150 ester, and because at least one supplier's own chemistry data suggests the molecule may not remain intact in the body, it is not possible to state with confidence whether RAD-150 carries the same, greater, or lesser risk than RAD-140 for liver, cardiac, or reproductive harm. The honest conclusion is that its risk profile is unknown, not that it has been shown to be safer.

Legal and Regulatory Status

No SARM, including RAD-150 or its parent RAD-140, has been approved by the FDA for any medical use. The FDA has stated that these products are illegally marketed as dietary supplements when in fact they are unapproved drugs that the agency has not reviewed for safety or effectiveness, and it has issued warning letters to multiple companies distributing SARM-containing products for this reason. The FDA has also stated that SARM-containing bodybuilding products are associated with the potential for heart attack, stroke, and life-threatening liver damage.

SARMs as a class are prohibited from use by athletes under anti-doping rules enforced by national and international anti-doping agencies, and this prohibition applies to the class of compounds generally rather than to any single named product. Because RAD-150 has not been separately characterized in doping-control science, it should be assumed to fall under this same class-wide prohibition, though this specific assumption has not been independently confirmed in the sources reviewed for this article.

Major U.S. dietary supplement trade associations and anti-doping bodies have publicly supported FDA enforcement action against SARM-containing products.

Bottom Line: How Strong Is the Evidence?

Grading the evidence honestly requires separating three different bodies of information that are often blurred together in online marketing. For RAD-150 itself, the evidence is essentially absent: no peer-reviewed pharmacology, toxicology, or clinical study of the compound as a performance product was identified, chemical supplier data raises an unresolved question about whether the ester remains stable in the body, and even some vendors selling the product openly state it is undertested. For RAD-140, the parent compound, the evidence is preclinical and early-phase clinical: animal studies and a completed phase 1 human trial exist, alongside legitimate pharmaceutical development for a breast cancer indication, but the trial itself documented substantial rates of liver enzyme elevation and no regulatory approval has been granted for any use. For the SARM class as a whole, the strongest and most consistent evidence is a growing body of published case reports and FDA statements documenting serious liver, cardiac, and endocrine harms in real-world users, none of which were collected under controlled clinical conditions and all of which describe outcomes in people using unregulated, unapproved products obtained outside medical supervision.

Put simply, claims about RAD-150's muscle-building or recovery benefits rest on marketing language extrapolated from a different, also-unapproved molecule, while the safety concerns documented for that molecule and its class are real, serious, and reported in the medical literature.

Frequently asked

References