SARMs Before & After | What Preclinical & Clinical Research Actually Shows

SARMs Before & After: What Research Actually Shows

Lean mass, bone density, and functional outcome data from published Phase I/II clinical trials and preclinical animal studies for LGD-4033, Ostarine, MK-677, RAD-140, and Andarine.

Published April 10, 2026 · Rainbow Peptide Research Team

For Research Use Only (RUO). Not for human consumption or therapeutic use. Data below is from published clinical trials and animal studies — not individual use.

Important Context: Clinical Trial Data vs Individual Use

This page summarizes published clinical trial and preclinical research findings for SARMs — specifically the "before and after" measurements taken in controlled studies. This is not individual human use documentation. Rainbow Peptide products are For Research Use Only and are not sold for human administration.

The data below comes from peer-reviewed publications by academic and pharmaceutical researchers. All endpoints were measured under controlled conditions in clinical trial participants or animal model cohorts.

Lean Mass Changes: Clinical Trial Data

SARM	Study	Dose	Duration	Lean Mass Change vs Placebo
LGD-4033	Basaria et al. (2013)	1 mg/day	21 days	+1.21 kg (statistically significant)
Ostarine	Papanicolaou et al. (2013)	3 mg/day	16 weeks	Significant LBM retention vs placebo in cancer cachexia
MK-677	Nass et al. (2008)	25 mg/day	24 months	+1.6 kg lean mass vs placebo (elderly)
LGD-4033 (VK5211)	Viking Phase II (2017)	2 mg/day	12 weeks	Significant lean mass gains in hip fracture rehabilitation

Bone Density & Bone Marker Changes

SARM	Study	Bone Outcome
Ostarine	Dalton et al. (2011)	Significant increase in bone-specific alkaline phosphatase (3mg/day, postmenopausal women)
MK-677	Chapman et al. (1996)	Increased osteocalcin, IGF-1 elevation → bone formation
Andarine	Preclinical (OVX rat)	Prevented bone loss in ovariectomized model — comparable to estrogen
LGD-4033	Viking Phase II	Bone biomarker improvements in hip fracture context

Functional Outcomes (Strength, Stair Climb, Physical Function)

LGD-4033 (Basaria et al.): Leg press strength trended higher at 1 mg/day vs placebo (non-significant given 21-day duration and study power)
Ostarine (Papanicolaou Phase II): Stair climb power improvement was a secondary endpoint — positive trend in Phase II; did not meet primary endpoint in Phase III (POWER 2)
MK-677 (Nass 2008): Grip strength and stair climb power improved vs placebo at 24 months in elderly subjects
RAD-140 (aged rat model): Improved spatial learning in Morris water maze — functional cognitive endpoint in neuroprotection research context

Preclinical Muscle Data (Rodent Models)

SARM	Model	Outcome
RAD-140	Cynomolgus monkey (Miller 2011)	Lean mass +dose-dependent at 0.01–0.1 mg/kg; prostate weight unchanged vs testosterone
LGD-4033	OVX rat	Levator ani muscle mass dose-dependent increase; 500:1 A:A ratio
YK-11	C2C12 cell culture	Follistatin induction; myostatin pathway inhibition
Cardarine	C57BL/6 mouse (Narkar 2008)	+44% treadmill distance; fiber-type slow-twitch shift

Frequently Asked Questions

What do clinical trials show for SARMs lean mass changes?

Published clinical trial data: LGD-4033 (Basaria et al., 2013): +1.21 kg lean mass at 1 mg/day for 21 days vs placebo. Ostarine (Papanicolaou et al., 2013, Phase II): significant lean mass retention in cancer patients vs placebo over 16 weeks. MK-677 (Nass et al., 2008): +1.6 kg lean mass vs placebo over 24 months in elderly subjects. These are controlled research endpoints measured under clinical trial conditions — not individual human use outcomes. All supply is For Research Use Only.

What do SARMs do to bone density in research models?

Published bone density data: Ostarine (Dalton et al., 2011): significant increases in bone-specific alkaline phosphatase (bone formation marker) at 3 mg/day in postmenopausal women. LGD-4033 (VK5211 hip fracture trial): improvements in bone biomarkers in hip fracture rehabilitation. MK-677 (multiple Phase II studies): increased osteocalcin and bone turnover markers with sustained IGF-1 elevation; bone density increases documented over 12–24 months. Andarine: significant bone density preservation in ovariectomized rat models (strongest preclinical bone data of any SARM).