GTX-027
A next-generation SARM developed by GTx Inc. as an optimized follow-up to Ostarine (GTX-024) with improved anabolic potency and selectivity.
Evidence-led profile
Research snapshot
- Evidence stage
- Emerging research
- References
- 1 linked sources
- Research coverage
- 1 area
- Editorial review
- Mar 8, 2026
Published by the PepGuide Editorial Team using our research methodology.
Overview
GTX-027 is a non-steroidal selective androgen receptor modulator (SARM) developed by GTx Inc. (now Oncternal Therapeutics) as part of their continued effort to develop tissue-selective androgen receptor agonists for muscle-wasting and oncology-related indications. It emerged from the same research program that produced Ostarine (GTX-024, Enobosarm), one of the most extensively studied SARMs in clinical history, and was designed to offer improved pharmacological properties including greater anabolic potency and enhanced tissue selectivity.
GTx Inc. developed a series of arylpropionamide-derived SARMs, with GTX-027 representing a structural optimization over the parent compound. Preclinical data indicated that GTX-027 maintained favorable selectivity for muscle and bone tissue over the prostate, with potentially enhanced efficacy in building lean mass. The compound was investigated in the context of cancer-associated cachexia and stress urinary incontinence, conditions where anabolic therapies could provide significant clinical benefit without the risks associated with traditional androgens like testosterone.
GTX-027 is part of a family of GTx-developed SARMs that also includes GTX-024 (Ostarine) and other analogs. While Ostarine advanced to Phase III clinical trials for cancer cachexia (the POWER trials), GTX-027 has had a more limited public clinical profile. The SARM class continues to attract research interest for conditions where preservation of lean mass is critical, and compounds like GTX-027 contribute to the evolving understanding of how structural modifications affect tissue selectivity and clinical outcomes.
Research
Reported Effects
Stress Urinary Incontinence:: Highly effective in animal models for treating muscle weakness associated with involuntary urine leakage.. Postmenopausal Support:: Specifically effective in reversing muscle loss caused by estrogen deficiency in ovariectomized subjects.. Comparison to Enobosarm:: Shows similar potency to Ostarine (GTx-024) but with potentially distinct tissue-selective profiles.. Clinical Status:: While promising in labs, it lacks the extensive human trial data of more popular SARMs like Ostarine or Ligandrol.
Safety and Limitations
Safety Profile: GTX-027 (Selective Androgen Receptor Modulator)
Common Side Effects
- GTX-027 is an investigational SARM from GTx, Inc. (now Oncternal Therapeutics); limited published clinical data
- Based on SARM class effects and available data: headache, fatigue, nausea
- Mild-to-moderate HDL cholesterol suppression (dose-dependent; consistent SARM class effect)
- Transient liver enzyme elevations (ALT/AST)
- Decreased SHBG levels
- Mild acne and skin oiliness
Serious Adverse Effects
- Hormonal axis suppression: Suppression of endogenous testosterone, LH, and FSH in a dose-dependent manner; recovery kinetics not fully characterized
- Hepatotoxicity: Potential for significant transaminase elevations; hepatic injury risk inherent to SARM class
- Cardiovascular risk: HDL reduction raises long-term cardiovascular concern; lipid profile changes may not fully reverse after short-term use
- Virilization in women: Androgenic side effects including voice changes, hirsutism, and acne
- Unknown carcinogenic potential: AR modulation may theoretically affect hormone-sensitive tumor biology
Contraindications
- Known or suspected androgen-sensitive cancers (prostate, breast)
- Severe hepatic dysfunction or elevated transaminases at baseline
- Pregnancy and breastfeeding (androgenic compounds are teratogenic)
- Women of childbearing age not on reliable contraception
- History of thromboembolic disease
- Concurrent use of exogenous androgens, anabolic steroids, or other SARMs
- Severe untreated cardiovascular disease
Drug Interactions
- Warfarin and anticoagulants: SARMs may enhance anticoagulant effects; monitor INR closely
- CYP3A4 inhibitors/inducers: May affect GTX-027 exposure; specific CYP profile not fully published
- Insulin and oral hypoglycemics: SARMs may modulate glucose handling; monitor blood glucose
- Lipid-lowering agents: Unpredictable effects on lipid panel; monitor closely
- Corticosteroids: Combined metabolic side effects; may increase risk of glucose dysregulation and muscle protein catabolism
Population-Specific Considerations
- Women: Virilization risk at any dose; use only in controlled clinical settings with appropriate monitoring
- Elderly: Potential benefit for sarcopenia and muscle wasting, but requires careful cardiovascular and hepatic risk assessment
- Adolescents/Children: Strictly contraindicated; risk of growth plate fusion and permanent endocrine disruption
- Hepatic impairment: Avoid or use with extreme caution; dose reduction and close LFT monitoring required
- Athletes: GTX-027, like all SARMs, is prohibited by WADA under the S1 Anabolic Agents category
- Note: GTX-027 is an investigational compound. Safety data are incomplete and may be revised as further clinical studies are conducted
Common Side Effects
- Hormonal Suppression:: As an AR ligand, it carries a theoretical risk of suppressing natural testosterone or interfering with endocrine balance.
- Unknown Long-term Profile:: Due to the lack of widespread human use, long-term safety and organ toxicity data are limited compared to earlier SARMs.
- Virilization Risk:: Though designed to be selective, high doses in females could potentially lead to androgenic side effects like hair growth or voice deepening.
Mechanism of Action
Selective Androgen Receptor Modulation
GTX-027 is a non-steroidal selective androgen receptor modulator (SARM) developed by GTx, Inc. It binds the androgen receptor (AR) with high affinity and selectivity, inducing a distinct conformational change in the receptor's ligand-binding domain that differs from classical steroidal androgens. This unique conformation drives differential co-regulator recruitment — preferentially engaging anabolic co-activators (e.g., SRC-1, SRC-3) in muscle tissue while showing reduced interaction with co-activators in androgen-sensitive tissues like prostate (PMID: 22498816).
Tissue-Selective Genomic Signaling
The AR-GTX-027 complex translocates to the nucleus and binds androgen response elements (AREs), activating transcription of genes involved in myogenesis and muscle maintenance. In skeletal muscle, this includes upregulation of IGF-1 signaling, satellite cell activation markers, and myosin heavy chain genes. The tissue selectivity arises from both the differential co-regulator landscape across tissues and the compound's intrinsic partial agonist activity, which produces full agonism in muscle but attenuated activity in prostate and seminal vesicles.
Antiproliferative Activity in Cancer
GTX-027 demonstrates AR-mediated antiproliferative effects in androgen receptor-positive triple-negative breast cancer (AR+ TNBC) cell lines. Activation of the AR by GTX-027 suppresses the MYC and E2F proliferative transcriptional programs while upregulating tumor suppressor gene expression, including p21/CDKN1A. This leads to G1 cell cycle arrest and growth inhibition, positioning SARMs as potential therapeutic agents in AR+ breast malignancies (PMID: 26315559).
Musculoskeletal Anabolic Effects
In preclinical models, GTX-027 promotes muscle hypertrophy via activation of the mTOR/p70S6K pathway and increases pelvic floor muscle mass, with potential applications in stress urinary incontinence, sarcopenia, and muscle wasting conditions while maintaining a favorable androgenic safety profile compared to exogenous testosterone.
Research protocol summary
- Typical Dose
- No established human recreational dose exists due to its status as a specialized research compound rather than a mass-market supplement.
These values summarize cataloged research protocols. They are not personal dosing instructions or medical guidance.
Molecular Structure
- Formula
- C18H14ClN3O3
- Weight
- 355.8 Da
- PubChem CID
- 23653581
- Exact Mass
- 355.0724 Da
- LogP
- 2.4
- TPSA
- 106 Ų
- H-Bond Donors
- 2
- H-Bond Acceptors
- 5
- Rotatable Bonds
- 5
- Complexity
- 573
Identifiers (SMILES, InChI)
InChI=1S/C18H14ClN3O3/c1-18(24,11-25-15-6-2-12(9-20)3-7-15)17(23)22-14-5-4-13(10-21)16(19)8-14/h2-8,24H,11H2,1H3,(H,22,23)/t18-/m0/s1
IEGVUEFEHAFTNS-SFHVURJKSA-NReferences (1)
- [1]Tissue Selective Androgen Receptor Modulators (SARMs) Increase Pelvic Floor Muscle Mass in Ovariectomized Mice
→ This study found that GTx-027 increases pelvic floor muscle mass and reverses the expression of genes associated with muscle wasting in animal models of postmenopausal muscle loss.
Continue researching GTX-027
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