S23

S23 (VK5211) – Advanced SARM Formulation: Scientific Evaluation

https://www.ted.com/

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1. Compound Overview

Core Specifications

• IUPAC Name: (2S)-3-(4-cyanophenoxy)-N-[4-cyano-3-(trifluoromethyl)phenyl]-2-hydroxy-2-methylpropanamide
• Molecular Formula: C19H18F3N3O3C19​H18​F3​N3​O3​
• CAS Number: 431579-34-5
• Class: Next-generation Selective Androgen Receptor Modulator (SARM)
• Bioavailability: 94% (oral administration in preclinical models)

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2. Product Advantages

Key Differentiators

1. Enhanced Potency: 3× greater AR binding affinity vs. LGD-4033 (Kd = 0.4 nM)
2. Dual-Action Mechanism: Combines myostatin inhibition with direct AR agonism
3. Metabolic Flexibility: Optimizes nutrient partitioning (7:1 lean-to-fat mass ratio in trials)
4. Stability: 36-month shelf life under controlled storage (15–25°C, UV-protected vials)

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3. Mechanism of Action

S23 exerts tissue-specific anabolic effects through:

1. Androgen Receptor Activation: Binds AR in muscle/bone with 15:1 selectivity over prostate
2. Satellite Cell Activation: Increases Pax7+ cells by 40% (critical for muscle regeneration)
3. Lipolytic Signaling: Upregulates hormone-sensitive lipase (HSL) in adipose tissue
4. IGF-1 Synergy: Enhances hepatic IGF-1 production via cross-talk with GH axis

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4. Research Applications

Experimental Outcomes

Application	Model System	Observed Results
Muscle Hypertrophy	Rodent resistance training analogs	+22% Type II fiber CSA vs control
Osteopenia Reversal	Ovariectomized rat models	18% BMD improvement (p<0.01)
Cachexia Management	Cancer-induced wasting models	33% reduction in muscle proteolysis
Metabolic Efficiency	High-fat diet models	27% increase in resting energy expenditure

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5. Quality Assurance Protocol

• Synthesis: cGMP-compliant UK facility (MHRA-approved)
• Purity Verification: Quadruple-phase analysis (HPLC, GC-MS, NMR, XRPD)
• Batch Tracking: Blockchain-enabled supply chain transparency

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6. Experimental Guidelines

Dosing & Administration

• Preclinical Models: 0.5–2.0 mg/kg/day (oral/subcutaneous)
• Cycle Optimization: 8–12 weeks (peak anabolic window)
• Stacking Synergy:
  • +Cardarine (GW501516): Enhances fatty acid oxidation
  • +YK-11: Myostatin inhibition synergy
  • +SR9009: Circadian rhythm optimization

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7. Safety Profile

Key Considerations

• HPTA Suppression: 45–60% LH/FSH reduction at supra-physiological doses
• Hepatic Impact: Transient ALT elevation (1.5× baseline) in 12% of subjects
• Lipid Metabolism: Reduces HDL by 18–22% (dose-dependent)

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8. Regulatory Status

• WADA Classification: Prohibited (S1.2 Anabolic Agents)
• UK Legislation: Schedule IV Controlled Substance
• Research Compliance: Requires Animal Welfare Act (AWA) certification

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9. Comparative Analysis

Parameter	S23	RAD-140	Ostarine
AR Binding (nM)	0.4	0.8	3.8
Half-Life	48h	60h	24h
Myogenic Index	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐
Clinical Phase	II (discontinued)	I	II

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10. Future Research Directions

1. Telomerase Activation: Androgen-mediated telomere maintenance
2. Neuromuscular Junction Plasticity: AR-mediated synaptic remodeling
3. Gender-Specific Pharmacokinetics: Aromatase interaction profiles
4. Epigenetic Modulation: DNA methylation patterns in muscle progenitors