RAD-140 and LGD-4033 are frequently compared because they occupy a similar position in research: both are potent, full or near-full AR agonists with significant lean mass effects and meaningful testosterone suppression. Understanding the distinctions between them helps researchers select the most appropriate compound for their specific protocol objectives.
Both RAD-140 and LGD-4033 are non-steroidal SARMs that bind to the androgen receptor with high affinity. However, their structural classes differ:
Preclinical studies suggest RAD-140 has a higher anabolic-to-androgenic selectivity ratio than LGD-4033 in some assays. However, this does not necessarily translate linearly to clinical or research outcomes.
LGD-4033 has superior published human clinical data. The Basaria et al. (2013) Phase I trial in The Lancet provides clean, double-blind, placebo-controlled data on lean mass gains (+1.21 kg at 1 mg/day), testosterone suppression kinetics, SHBG changes, and safety markers in healthy men. This is the gold standard of published SARM human data.
RAD-140 has entered Phase I/II trials in breast cancer patients (Bardia et al., 2020). The dataset is of different character — oncology patients, higher doses, different primary endpoints — making direct comparison with the LGD-4033 healthy volunteer trial difficult. Preclinical data for RAD-140 (primate studies, Jones et al.) provides supportive mechanistic evidence.
| Parameter | RAD-140 | LGD-4033 |
|---|---|---|
| Structural class | Pyrazolo[1,5-a]pyrimidine | Arylpropionamide |
| AR agonism | Full (muscle/bone) | Full |
| Half-life | ~16 hours | ~24–36 hours |
| Typical research dose | 10–20 mg/day | 5–10 mg/day |
| Human trial data quality | Moderate (oncology) | High (healthy volunteers) |
| Testosterone suppression | Moderate–significant | Moderate–significant |
| Aromatisation | None | None |
| Neuroprotective data | Yes (preclinical) | Limited |
Preclinical selectivity data favours RAD-140, with some assays showing a higher muscle-to-prostate anabolic ratio than LGD-4033. However, LGD-4033 is typically used at lower doses (5–10 mg vs. 10–20 mg for RAD-140) and produces significant lean mass effects. In the absence of head-to-head human trials, definitive statements about relative potency in human research are not possible from published data alone.
Both compounds produce significant lean mass effects in preclinical and, for LGD-4033, controlled human research. The choice between them typically depends on protocol design, target dose, desired half-life, and the body of evidence the researcher wishes to build upon. For protocols requiring the most thoroughly characterised human data, LGD-4033 has the advantage.
Both suppress endogenous testosterone dose-dependently. The Basaria 2013 LGD-4033 trial documents suppression kinetics in detail. Comparative suppression data from equivalent dose ranges in controlled human settings does not exist in published literature. Both compounds typically require post-cycle support considerations in research protocols.
