Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of GSK-2881078 and YK-11 — mechanism, side effects, legal status, and pricing.
GSK-2881078 is a nonsteroidal selective androgen receptor modulator (SARM) of the indole-5-carbonitrile chemotype, developed by GlaxoSmithKline to produce tissue-selective anabolic effects in skeletal muscle with reduced activity in androgen-sensitive tissues. It has been studied in three human clinical trials (Phase I and Phase IIa) but has never been approved for any indication and is not in active further development. SARMs as a pharmacological class are prohibited in sport at all times under WADA category S1.2 (Other Anabolic Agents), though GSK-2881078 is not individually named in reviewed WADA documents.
YK-11 is a synthetic steroidal selective androgen receptor modulator (SARM) — a 19-nor DHT-derived analog with a spiro-dioxolane modification at C-17, structurally distinct from non-steroidal SARMs. It is not FDA-approved for any human use and is prohibited in competitive sport; anti-doping laboratories actively screen for YK-11 metabolites. No human safety, tolerability, or efficacy trials exist; the only published human study administered deuterated YK-11 solely to identify urinary metabolites for doping-control method development.
GSK-2881078
YK-11
Category
Legal Status
Mechanism
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
GSK-2881078
YK-11
COA corpus from Disclosed Labs — independently tested batches only.
GSK-2881078
2
COAs
99.6%
Avg purity
2
Labs
YK-11
3
COAs
99.2%
Avg purity
2
Labs
Human data are the most extensive of any compound in the SARM class: a Phase I first-in-human study in healthy men and postmenopausal women (Clark 2017) established dose-proportional systemic exposure and a long half-life (>100 hours) supporting once-daily dosing; a Phase I dose-escalation study in adults ≥50 years (Neil 2018) showed dose-dependent lean body mass gains (~3.39 kg in women, ~1.76 kg in men versus placebo at 8 weeks) accompanied by transient ALT elevations and 30–45% HDL-cholesterol reductions at the highest doses, both reversible on stopping treatment; and a Phase IIa randomized controlled trial in 97 COPD patients with muscle weakness (Mohan 2023) demonstrated increased lean body mass and leg-press strength (more consistently in men) over 13 weeks, with reversible HDL-C reduction and transient ALT increases as the main treatment-related safety signals. No peer-reviewed animal or in-vitro pharmacology/toxicology data for GSK-2881078 were located via PubMed or PubChem.
Key references
No human safety, tolerability, or efficacy trials exist for YK-11. The only published human study administered six-fold deuterated YK-11 to volunteers solely to identify urinary metabolites for anti-doping method development; no intact parent compound was recovered in urine, and 14 metabolites (unconjugated, glucuronidated, sulfated) were characterized. In vitro (mouse C2C12 myoblasts), YK-11 (1–500 nM) increased myosin heavy chain and myogenic regulatory factor expression more strongly than equimolar DHT and uniquely induced follistatin, a pathway necessary for its pro-differentiation effect. In vivo (mouse model of gram-negative bacterial sepsis), YK-11 reduced circulating pro-inflammatory cytokines and organ-damage markers, decreased sepsis mortality, and was associated with protection against sepsis-induced muscle wasting.
GSK-2881078 and YK-11 are both in the Performance category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references
Disclosed Labs