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

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ToolsCompareThymagen vs P21

Thymagen vs P21

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

Immune Support
Thymagen
Cognitive EnhancementAnti-Aging & Longevity
P21
Summary
Thymagen is a dipeptide bioregulator (Glu-Asp) developed by Professor Vladimir Khavinson, tissue-specific for the thymus gland. It supports T-lymphocyte maturation, thymic function, and immune system normalization. As the thymus involutes with age (thymic atrophy), immune competence declines. Thymagen is used to support immune restoration, particularly in aging, post-illness recovery, and immunodeficiency states.
P21 is a synthetic peptide derived from CNTF (ciliary neurotrophic factor) that promotes hippocampal neurogenesis, enhances memory and spatial learning, and may reduce amyloid-beta pathology. It is used as a neurogenic and cognitive enhancer with potential anti-Alzheimer's applications.
Half-Life
Short (minutes); sustained gene-regulatory effects
Not well characterized; likely short, but neurogenic effects persist long after administration
Admin Route
SubQ, Oral
SubQ, Intranasal
Research
Typical Dose
10 mg per day
100–500 mcg
Frequency
Daily for 10–30 days
Once daily
Key Benefits
  • Supports thymic epithelial cell function and T-cell maturation
  • May partially restore thymic output reduced by age-related atrophy
  • Normalizes T-lymphocyte subpopulation balance
  • Supports immune recovery after illness, surgery, or chemotherapy
  • Anti-aging effects on thymic tissue
  • Complementary to Thymosin Alpha-1 and Thymalin in immune protocols
  • May improve vaccine responsiveness in older individuals
  • Promotes hippocampal neurogenesis
  • Enhances spatial memory and learning
  • Increases BDNF expression
  • Reduces amyloid-beta plaque formation (animal models)
  • Anti-tau pathology potential
  • Cognitive enhancement without stimulant effects
  • Potential therapeutic for Alzheimer's and cognitive aging
Side Effects
  • Generally well tolerated
  • Mild injection site reactions
  • No significant immunological adverse events reported
  • Generally well tolerated in animal studies
  • Limited human clinical data
  • Injection site reactions
  • Potential mild fatigue at initiation
Stacks With