New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

Get it free
ToolsCompareThymulin vs Gonadorelin

Thymulin vs Gonadorelin

Side-by-side comparison of key properties, dosing, and research.

Immune Support
Thymulin
Sexual Health & LibidoAnti-Aging & Longevity
Gonadorelin
Summary
Thymulin is a nonapeptide hormone produced exclusively by the thymic epithelium. It requires zinc for biological activity and plays a critical role in T-lymphocyte maturation, differentiation, and immune regulation. Thymulin levels decline dramatically with age, contributing to immunosenescence.
Gonadorelin is the synthetic form of endogenous GnRH (gonadotropin-releasing hormone). It stimulates the pituitary to release LH and FSH, maintaining testicular function and testosterone production. Widely used alongside TRT to prevent testicular atrophy and preserve fertility.
Half-Life
~30 minutes active half-life
~2–4 minutes (extremely short); pulsatile dosing required to avoid desensitization
Admin Route
SubQ
SubQ, Intranasal
Research
Typical Dose
20-30 mcg
100 mcg
Frequency
10 days per month (Khavinson protocol)
Twice daily (every 12 hours)
Key Benefits
  • Enhances T-cell maturation and differentiation
  • Boosts NK cell cytotoxic activity
  • Reduces inflammatory cytokine production (TNF-α, IL-1)
  • Anti-nociceptive (pain-reducing) properties
  • Restores age-related immune decline
  • Anti-inflammatory via serotonin pathway modulation
  • Maintains testicular size during TRT
  • Preserves fertility and sperm production during testosterone use
  • Stimulates endogenous LH/FSH production
  • Maintains HPG axis function during exogenous hormone use
  • Used for HCG-free TRT protocols
  • Helps restart natural testosterone production (PCT)
Side Effects
  • Injection site reactions
  • Mild fatigue initially as immune system activates
  • Injection site reactions
  • Headache
  • Nausea at initiation
  • Tachycardia (rare)
  • +1 more
Stacks With