Glutathione vs P21
Side-by-side comparison of key properties, dosing, and research.
Anti-Aging & LongevityImmune Support
GlutathioneCognitive EnhancementAnti-Aging & Longevity
P21- Summary
- Glutathione is the body's master endogenous antioxidant tripeptide, composed of glutamate, cysteine, and glycine. It neutralizes reactive oxygen species, supports detoxification in the liver, recycles other antioxidants (vitamins C and E), and plays a central role in immune function, DNA repair, and cellular redox balance.
- 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
- Minutes to hours depending on route; IV half-life approximately 10-30 minutes
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Admin Route
- Oral (liposomal preferred), Sublingual, Intravenous, Nebulized/inhaled, Topical
- SubQ, Intranasal
- Research
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- Typical Dose
- 250-1000 mg per day
- 100–500 mcg
- Frequency
- Once or twice daily
- Once daily
- Key Benefits
- Primary endogenous antioxidant and free radical scavenger
- Supports hepatic detoxification of xenobiotics and heavy metals
- Recycles vitamins C and E to maintain antioxidant network
- Modulates immune function and T-cell activity
- Skin brightening via inhibition of tyrosinase (IV/topical routes)
- Neuroprotective in oxidative stress-related conditions
- Mitochondrial protection and energy metabolism support
- 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
- Oral bioavailability is limited (largely hydrolyzed in gut); liposomal or sublingual forms preferred
- IV administration: rare allergic reactions, vein irritation
- High-dose supplementation may cause zinc depletion over time
- Inhaled glutathione may trigger bronchoconstriction in asthmatics
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Stacks With
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