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

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ToolsCompareNAD+ vs P21

NAD+ vs P21

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

Anti-Aging & Longevity
NAD+
Cognitive EnhancementAnti-Aging & Longevity
P21
Summary
NAD+ (Nicotinamide Adenine Dinucleotide) is a coenzyme found in all living cells that declines dramatically with age. It is critical for energy metabolism, DNA repair, and sirtuin activation. IV and subcutaneous NAD+ supplementation is used in anti-aging protocols and addiction recovery programs.
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
Varies by route; IV provides direct cellular delivery
Not well characterized; likely short, but neurogenic effects persist long after administration
Admin Route
IV, SubQ, Oral
SubQ, Intranasal
Research
Typical Dose
500–1000 mg
100–500 mcg
Frequency
Daily for 4–10 days (loading), then monthly maintenance
Once daily
Key Benefits
  • Restored cellular energy production (ATP)
  • Sirtuin activation for longevity and metabolic regulation
  • Enhanced DNA repair capacity
  • Improved mitochondrial function and biogenesis
  • Cognitive clarity and mental energy
  • Reduced inflammation
  • Addiction withdrawal support (opioids, alcohol, benzodiazepines)
  • Improved sleep quality
  • Enhanced athletic endurance
  • 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
  • Flushing and warmth during IV infusion
  • Nausea during rapid IV administration
  • Chest tightness (from rapid infusion — slow the rate)
  • Injection site irritation (subcutaneous)
  • +1 more
  • Generally well tolerated in animal studies
  • Limited human clinical data
  • Injection site reactions
  • Potential mild fatigue at initiation
Stacks With