RAD-140 vs LGD-4033: Comparing Two Researched SARMs

RAD-140 and LGD-4033 are two of the most searched and most often compared SARMs. They are routinely discussed in terms of which builds more muscle, but a useful comparison has to start a step back, with what these compounds are, what the actual research found, and why their regulatory and safety status matters as much as their effects.

What SARMs Are

SARM stands for selective androgen receptor modulator. Like anabolic steroids, SARMs act on the androgen receptor, the same receptor testosterone uses. The selling point in their design was selectivity: the goal was compounds that stimulate muscle and bone tissue while having less effect on other tissues such as the prostate. That is the theory. In practice, the selectivity is partial, and the research record shows meaningful effects beyond muscle and bone.

It is worth noting at the outset that both compounds discussed here are investigational. They were developed as drug candidates and studied in early clinical trials; neither completed the path to approval.

RAD-140 (Testolone)

RAD-140, also called testolone, was developed by a pharmaceutical company as an investigational compound, with early interest in contexts such as muscle wasting and as a potential element of breast cancer research. It is generally described as one of the more potent and more androgenic SARMs. That potency is part of its reputation in fitness circles, but potency cuts both ways: an early clinical trial involving RAD-140 reported evidence of liver toxicity, which is a significant safety signal for any compound.

LGD-4033 (Ligandrol)

LGD-4033, also called ligandrol, was developed as an investigational candidate for conditions involving muscle loss, such as recovery from hip fracture and age-related muscle wasting. It is among the more studied SARMs. A Phase 1 study in healthy men reported dose-dependent increases in lean body mass and described the compound as relatively well tolerated over the short study period. However, that same research also documented suppression of total testosterone and of sex hormone-binding globulin, and effects on blood lipids. LGD-4033 is often characterized as producing steadier, leaner gains than RAD-140, with a comparatively milder profile, but milder is a relative term among compounds that are all under-studied.

How They Compare

Potency and effects

In the available picture, RAD-140 is generally treated as the more potent and more androgenic of the two, associated with faster strength and size changes, while LGD-4033 is treated as more measured. Both increase lean mass in the research and anecdotal record. Direct head-to-head clinical trials comparing the two are not the basis for these characterizations; they come from separate studies and from non-clinical use, which limits how precisely they can be compared.

Side effects and testosterone suppression

A consistent finding across SARM research, including studies of RAD-140, LGD-4033, and MK-2866, is suppression of the body’s own testosterone production. This is the same HPG-axis suppression seen with external androgens, and it means the selective in selective androgen receptor modulator does not extend to sparing natural hormone production. Commonly reported effects across SARMs also include headaches, dry mouth, and gastrointestinal symptoms.

Liver and cardiovascular signals

Regulatory and Anti-Doping Status

Neither RAD-140 nor LGD-4033 is approved by the FDA for any use. The FDA has explicitly warned consumers about SARMs and has stated that they are not legal ingredients in dietary supplements, despite being widely sold as such. Both compounds are also on the World Anti-Doping Agency prohibited list, and athletes have tested positive for them. Anyone subject to drug testing should treat these compounds as disqualifying.

The Quality and Mislabeling Problem

A practical issue sits on top of the pharmacology. Independent testing has repeatedly found that products sold as SARMs often do not contain what the label claims: wrong compounds, wrong doses, undisclosed ingredients, or contaminants. This means a comparison of RAD-140 versus LGD-4033 on paper may not reflect what is actually in a given product. Our guide to purity testing and third-party lab reports explains what verification documents can and cannot tell you. It is also a reminder that recreational use typically involves doses and durations well beyond anything tested in a clinical study.

This article is for educational and informational purposes only. It is not intended as medical advice and should not be used to diagnose, treat, or prevent any condition. Always consult with a qualified healthcare professional before making health-related decisions. Clinical trial data referenced here is sourced from peer-reviewed publications and may not reflect the most current findings.