SARMs

LGD-4033 (Ligandrol)

Evidence: moderate_human

Mechanism of Action

LGD-4033 is a potent nonsteroidal selective androgen receptor modulator with high AR binding affinity (Ki of approximately 1 nM). It demonstrates strong anabolic activity in muscle and bone with significantly reduced androgenic activity in prostate tissue, achieving an anabolic-to-androgenic ratio of approximately 10:1. LGD-4033 activates the AR with full agonist efficacy in muscle, upregulating the PI3K/Akt/mTOR pathway for protein synthesis and satellite cell recruitment. It produces dose-dependent suppression of SHBG, total testosterone, LH, and FSH, indicating significant HPG axis suppression even at low doses.

Dosing Protocol

Standard: Research indicates 5-10 mg daily orally for 8-12 weeks. Phase 1 data showed significant lean mass gains at 1 mg/day.

Maintenance: Research indicates 5 mg daily for lean mass preservation with moderate suppression profile.

Administration: oral

Timing: Once daily, consistent timing. Half-life approximately 24-36 hours. No food timing requirements.

Duration: 8-12 week cycles maximum. PCT strongly recommended after all but the shortest/lowest-dose cycles.

Notes

LGD-4033 is one of the more potent SARMs, with the Phase 1 trial (Basaria et al., 2013) demonstrating 1.2 kg lean mass increase at just 1 mg/day over 21 days in healthy young men. Phase 2 in hip fracture patients showed 4.8-9.1% lean mass increase at 0.5-2 mg/day over 12 weeks. CRITICAL: HPG suppression is significant — total testosterone dropped by 40-50% at 1 mg/day in the Phase 1 trial. Liver monitoring is mandatory. Required bloodwork: Liver function panel (AST, ALT, GGT, bilirubin, ALP) at baseline, 4 weeks, and end of cycle. Total testosterone, free testosterone, LH, FSH, SHBG, estradiol. CBC. Lipid panel. Post-cycle hormonal panel at 4, 8, and 12 weeks to confirm HPG recovery. PCT recommended for all cycles >4 weeks. Medical supervision required.

Stacking

  • Cardarine GW-501516 (endurance without additional suppression)
  • MK-677 (GH secretagogue for recovery)
  • NAC / TUDCA (liver protection)

Interactions

  • Testosterone / AAS [MEDIUM] — Additive AR activation and HPG suppression. Combined use compounds hormonal shutdown.
  • Hepatotoxic agents [MEDIUM] — Case reports of LGD-4033-induced hepatotoxicity including drug-induced liver injury. Avoid concurrent hepatotoxins.
  • SERMs (Clomiphene, Tamoxifen) [LOW] — Used in PCT to restore HPG axis function after LGD-4033 suppression.

Contraindications

  • Androgen-sensitive cancers
  • Pre-existing liver disease or elevated liver enzymes
  • Pregnancy and breastfeeding
  • Individuals under 21
  • Athletes subject to WADA/anti-doping testing

Side Effects

  • Significant testosterone suppression (dose-dependent; occurs even at 1 mg/day)
  • Suppressed SHBG, LH, and FSH
  • Elevated liver enzymes / hepatotoxicity (case reports of cholestatic liver injury)
  • HDL cholesterol suppression
  • Headache
  • Fatigue (late-cycle, from suppression)
  • Water retention

Key Papers

  • 10.1093/gerona/gls078
  • 10.1002/jcsm.12447
  • 10.1007/s40264-023-01368-3

Source Quality

Not FDA-approved. Research chemical only — sourced from vendors with third-party HPLC COA (>98% purity). Not legally sold as a dietary supplement. Multiple adulteration/contamination reports in consumer products.

Disclaimer: This information is for educational purposes only and is not medical advice. BioAccelera Labs does not diagnose, treat, or prescribe. Consult a licensed healthcare provider before using any compound.

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