RAD-140 (Testolone) is one of the most talked-about SARMs (Selective Androgen Receptor Modulators) on the market today. Originally developed as a potential treatment for conditions like muscle wasting, osteoporosis, and even certain cancers, RAD-140 has become popular in the bodybuilding and performance community for its reputation as a “safer alternative to anabolic steroids.”
But while RAD-140 may provide impressive benefits — including lean muscle growth, strength increases, and improved recovery — the conversation often skips over the risks and side effects. Like all SARMs, RAD-140 is not FDA-approved, lacks long-term human safety data, and is classified as a research chemical only. That means anyone considering a cycle is entering uncharted territory with limited clinical oversight.
Understanding the potential side effects of RAD-140 is critical before deciding whether it’s worth the risk. From hormonal suppression to liver strain and cardiovascular concerns, RAD-140 can have real consequences — some temporary, others potentially long-lasting.
“While SARMs like RAD-140 are marketed as selective, preclinical data and user reports consistently show endocrine disruption, liver toxicity, and cardiovascular risks.” — Narayanan et al., Endocrine-Related Cancer
In this guide, we’ll break down what RAD-140 is, its common and long-term side effects, how it compares to anabolic steroids, and why careful consideration (and medical caution) is essential before starting a cycle.
What Is RAD-140?
RAD-140, also known as Testolone, is a Selective Androgen Receptor Modulator (SARM). It was originally developed by Radius Health as a potential treatment for conditions linked to muscle and bone loss, including cachexia, osteoporosis, and certain cancers such as breast cancer.
Unlike anabolic steroids, which broadly activate androgen receptors throughout the body, SARMs like RAD-140 were designed to be more tissue-selective. That means they preferentially target muscle and bone tissue, with less activity in reproductive organs such as the prostate. In theory, this should allow for anabolic benefits like muscle growth, strength gains, and improved bone density while reducing the androgenic side effects associated with steroids.
Mechanism of Action
→ RAD-140 binds to androgen receptors in muscle and bone, stimulating protein synthesis and muscle hypertrophy.
→ It has a much stronger binding affinity than testosterone, giving it powerful anabolic potential.
→ Preclinical studies suggest it may also have neuroprotective effects, supporting cognitive health.
Status as a Research Chemical
→ RAD-140 has not been approved by the FDA for medical use.
→ Human clinical trials are limited, with most data coming from animal research and anecdotal reports.
→ It is classified as a research chemical, meaning it is not legally sold as a dietary supplement.
→ RAD-140 is listed on the World Anti-Doping Agency (WADA) Prohibited List, making it illegal in competitive sports.
“RAD-140 is a potent, orally available nonsteroidal selective androgen receptor modulator that shows strong anabolic effects in preclinical models of muscle wasting.” — Dalton et al., Journal of Medicinal Chemistry
Common Side Effects of RAD-140
Although marketed as a “safer alternative to steroids,” RAD-140 carries real risks. Many users report side effects during and after a cycle, most of which stem from its impact on hormone balance and androgen receptor activity.
1. Testosterone Suppression
→ Despite being “selective,” RAD-140 still signals the body to reduce natural testosterone production.
→ LH (luteinizing hormone) and FSH (follicle-stimulating hormone) levels often drop, leading to reduced endogenous testosterone.
→ Symptoms include fatigue, low libido, erectile dysfunction, and difficulty maintaining muscle mass post-cycle.
→ Even short cycles (6–8 weeks) can lead to measurable suppression, making post-cycle therapy (PCT) essential.
2. Mood Swings & Irritability
→ Some users experience anxiety, aggression, or depression during or after a cycle.
→ Hormonal fluctuations and suppressed testosterone are the primary drivers.
3. Sleep Disruption
→ Insomnia and restless sleep are common, especially at higher doses.
→ Linked to overstimulation of androgen receptors and hormonal imbalance.
4. Androgenic Effects (Genetic Sensitivity Dependent)
→ Hair shedding or accelerated male pattern baldness in those genetically predisposed.
→ Possible acne or oily skin due to androgen receptor activity in sebaceous glands.
5. Gastrointestinal Discomfort
→ Nausea and stomach irritation have been reported, though less common than hormonal side effects.
“Suppression of endogenous testosterone is a consistent finding across SARM use, despite their receptor selectivity, underscoring the need for post-cycle therapy.” — Narayanan et al., Endocrine-Related Cancer
Hormonal & Endocrine Effects of RAD-140
One of the biggest misconceptions about SARMs is that they don’t affect hormone balance the way anabolic steroids do. In reality, RAD-140 still disrupts the hypothalamic–pituitary–gonadal (HPG) axis, leading to suppressed natural testosterone production.
Suppression of LH & FSH
→ The body senses the strong androgen receptor activity from RAD-140 and reduces secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary.
→ This results in a downstream drop in endogenous testosterone and reduced sperm production.
Testosterone Suppression
→ Studies and user bloodwork consistently show that RAD-140 can cause marked reductions in total and free testosterone, even at moderate cycle lengths.
→ Symptoms include:
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Fatigue and low energy
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Decreased libido and sexual dysfunction
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Difficulty retaining muscle mass post-cycle
Estrogen Imbalance
→ Because testosterone is suppressed, estrogen levels may also fall, leading to joint discomfort, mood instability, and poor recovery.
→ In some cases, users experience estrogen rebound post-cycle if testosterone production does not recover quickly.
Long-Term Endocrine Risks
→ Chronic or repeated RAD-140 cycles without recovery could contribute to secondary hypogonadism (permanently reduced testosterone production).
→ Fertility concerns may arise with prolonged suppression of LH and FSH.
“Even selective androgen receptor modulators such as RAD-140 have been shown to disrupt gonadotropin secretion, resulting in suppression of testosterone and impaired endocrine function.” — Dalton et al., Journal of Medicinal Chemistry
Potential Long-Term Risks of RAD-140
While many side effects of RAD-140 show up during a cycle, some risks may persist long after use. Because SARMs like RAD-140 lack long-term human studies, much of what we know comes from animal research, clinical parallels to anabolic steroids, and user bloodwork reports.
1. Liver Toxicity
→ RAD-140 is an oral, nonsteroidal compound, and like many oral SARMs, it has been linked to elevated liver enzymes (AST, ALT) in users.
→ Case reports exist of drug-induced liver injury associated with SARM use.
→ Prolonged liver stress can affect detoxification, cholesterol metabolism, and overall metabolic health.
2. Lipid Profile Disruption
→ RAD-140 may lower HDL (“good”) cholesterol while raising LDL (“bad”) cholesterol.
→ This shift increases the risk of atherosclerosis and long-term cardiovascular disease, especially with repeated cycles.
3. Cardiovascular Concerns
→ Some preclinical studies suggest SARMs could negatively affect heart tissue.
→ Altered lipid profiles, combined with higher blood pressure and hormonal stress, may increase cardiovascular strain.
→ Long-term risks remain uncertain, but parallels with anabolic steroid use raise concern.
4. Cancer Risk Uncertainty
→ RAD-140 was investigated for breast cancer treatment because of its receptor selectivity.
→ However, in animal studies, certain SARMs have shown potential links to tumor promotion in other tissues.
→ Without long-term human data, the risk profile for cancer remains unknown.
5. Endocrine Recovery Issues
→ Repeated cycles without proper post-cycle therapy (PCT) can impair the body’s ability to restore natural testosterone production.
→ Risk of developing secondary hypogonadism, potentially requiring medical testosterone replacement therapy (TRT) long term.
“Reports of hepatotoxicity, dyslipidemia, and endocrine disruption highlight the safety concerns of non-approved SARM use in humans.” — Partridge et al., JAMA
RAD-140 vs. Anabolic Steroids: Side-Effect Profile
Bottom line: RAD-140 is not side-effect free. It shares core risks with anabolic steroids (AAS)—notably testosterone suppression, lipid disruption, and liver strain—but tends to be less androgenic at skin/hair/prostate in many users. The catch: AAS have decades of clinical data; SARMs don’t. That uncertainty is a risk by itself.
“Despite receptor selectivity, SARMs still suppress the HPG axis and present hepatic and cardiometabolic safety concerns—exacerbated by unregulated sourcing.” — Narayanan et al., Endocrine-Related Cancer
| Aspect | RAD-140 (SARM) | Anabolic Steroids (e.g., Testosterone, Oxandrolone) |
|---|---|---|
| Testosterone suppression | Yes (LH/FSH ↓; T ↓). Recovery varies; PCT often needed. | Yes (dose-dependent). PCT or taper often required. |
| Androgenic effects (acne, hair loss, prostate) | Typically lower than high-dose AAS, but not zero in sensitive users. | Higher, especially with DHT-like AAS; prostate/hairline risk greater. |
| Liver toxicity | Possible: enzyme elevations and case reports of DILI with oral SARMs. | High with many 17-α-alkylated orals; injectables less hepatotoxic. |
| Lipids / CV risk | HDL ↓ / LDL ↑ reported; CV risk signals plausible but under-studied. | Well-documented HDL ↓ / LDL ↑; BP ↑; LVH risk with abuse. |
| Estrogen issues | Estrogen usually falls with suppression → dry joints, mood; rebound possible post-cycle. | Aromatizable AAS → E2 ↑ (gyno, water) unless controlled with AI/SERM. |
| Clinical evidence base | Sparse human data; mostly preclinical + anecdote. | Extensive (TRT, AAS studies); long-term risks better characterized. |
| Regulatory & purity | Not FDA-approved; often misbranded/adulterated in “supplements.” | Prescription hormones exist; UGL AAS still carry purity risks. |
| Anti-doping | WADA-banned; assays detect many SARMs. | WADA-banned; extensive testing panels. |
Sources: Narayanan 2018 (Endocr-Relat Cancer); Partridge 2018 (JAMA); Dalton 2011 (J Med Chem); USADA/FDA advisories on SARMs in “supplements” (USADA, FDA).
Legal Status
→ Not FDA-approved for any medical indication; sold online as “research chemicals.”
→ Multiple FDA and USADA warnings cite adulteration and mislabeling in SARM-labeled products.
→ WADA-prohibited at all times (in- and out-of-competition).
“Products marketed as SARMs are often unapproved drugs with potentially dangerous ingredients.” — FDA Advisory
Closing Thoughts
RAD-140 can build muscle—but it also suppresses your own testosterone, stresses the liver, and can worsen your cardiometabolic profile. Add in unregulated sourcing and limited long-term human data, and the risk-reward calculus shifts quickly. If you’re weighing a cycle, know exactly what you’re trading off:
→ Short-term strength/lean mass vs. HPG-axis suppression, lipid hits, and unknown long-term risks.
→ No medical oversight, no quality control, and zero FDA approval.
If your goal is muscle, performance, and healthspan, anchor on proven levers first: dialed-in training, sleep, and nutrition—then layer evidence-based staples:
→ Whey Protein Isolate for high-leucine, low-fat protein to support MPS and satiety.
→ Kre-Alkalyn® Creatine for strength, power, and training volume.
→ Krill Oil to support lipids and inflammation while you chase body-comp goals.
→ ZMT to support sleep, recovery, and a favorable anabolic environment.
If you still choose to proceed with a SARM, get baseline labs (lipids, AST/ALT, CBC, total/free T, LH/FSH), monitor mid-cycle, and plan an evidence-based PCT—ideally under clinician supervision. That’s harm-reduction, not an endorsement.
Legal Disclaimer
This article is for educational purposes only and is not medical advice. RAD-140 (Testolone) is an unapproved drug and is banned by WADA. Do not use prescription drugs, research chemicals, or performance-enhancing substances without medical supervision. Swolverine does not sell or promote SARMs.
