Non-steroidal SARMs

LGD-4033 vs S23 vs S4

The table compares the compounds’ key data from their entry pages. Open each compound’s full entry for details. Educational content, not medical advice.

What it is
LGD-4033 (Ligandrol)Non-steroidal SARM, Ligand Pharmaceuticals 2007. Phase I in healthy male subjects (Basaria 2013 PMID 23413266) – dose-dependent lean mass gain, moderate HPTA suppression. The second most famous SARM after RAD-140 on the bodybuilding market. 2017-2020 hepatotoxicity cases documented (Hilal 2020 PMID 32492288). WADA-banned S1.2.
S23 (Most Potent SARM)Non-steroidal SARM, the MOST POTENT compound of the SARM class in in vivo AR-binding affinity (Jones 2009 PMID 19299500). Originally investigated as a male contraceptive candidate – REVERSIBLE azoospermia in rat trials (Jones 2010 PMID 20308559). In bodybuilding context FULL HPTA suppression + intense side effects. WADA-banned.
S4 (Andarine, GTx-007)Non-steroidal SARM (Andarine, GTx-007), GTx Inc 2005. UNIQUE side effect: dose-dependent YELLOW VISION and night blindness (Marhefka 2004 PMID 15267281 – retinal opsin binding). On the bodybuilding market a 'fat-loss + cutting' SARM reputation. WADA-banned.
Mechanism
LGD-4033 (Ligandrol)Non-steroidal selective AR modulator (pyrrolidinecarboxamide). Strong AR agonist in muscle, moderate prostate activity.
S23 (Most Potent SARM)Non-steroidal selective AR modulator (aryl-propionamide). MOST POTENT SARM in AR binding affinity.
S4 (Andarine, GTx-007)Non-steroidal selective AR modulator + UNIQUE retinal opsin binding (visual side effect)
Anabolic activity (Basaria 2013)
LGD-4033 (Ligandrol)Dose-dependent lean mass gain: 1.21 kg @ 1 mg/day, 3 weeks, healthy men.
S23 (Most Potent SARM)
S4 (Andarine, GTx-007)
Half-life
LGD-4033 (Ligandrol)~24-36 h (oral)
S23 (Most Potent SARM)~12 h (oral)
S4 (Andarine, GTx-007)~4 h (oral, SHORT – requires 2-3x daily dosing)
Onset
LGD-4033 (Ligandrol)1-2 weeks (anecdotal strength gain)
S23 (Most Potent SARM)1-2 weeks
S4 (Andarine, GTx-007)1-2 weeks
Legal status
LGD-4033 (Ligandrol)Never an Rx. UGL 'research chemical'. WADA-banned S1.2 since 2008.
S23 (Most Potent SARM)Never an Rx (Phase I never started in humans). UGL 'research chemical'. WADA-banned S1.2.
S4 (Andarine, GTx-007)Never an Rx (GTx deprioritized after Phase II in 2010). UGL 'research chemical'. WADA-banned S1.2.
Anabolic activity (Jones 2009)
LGD-4033 (Ligandrol)
S23 (Most Potent SARM)~95% testosterone-level in vivo (rat bioassay). Higher than RAD-140.
S4 (Andarine, GTx-007)
Anabolic activity (Gao 2005)
LGD-4033 (Ligandrol)
S23 (Most Potent SARM)
S4 (Andarine, GTx-007)In rat bioassay anabolic activity ~60-70% Test-level (in vivo)