P21 vs IGF-1 LR3
Side-by-side comparison of key properties, dosing, and research.
- Summary
- 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.
- IGF-1 LR3 is a synthetic analog of Insulin-like Growth Factor-1 with an extended half-life. It is one of the most potent anabolic peptides available, directly stimulating muscle cell hyperplasia and hypertrophy, and is the downstream mediator of many of GH's anabolic effects.
- Half-Life
- Not well characterized; likely short, but neurogenic effects persist long after administration
- 20–30 hours
- Admin Route
- SubQ, Intranasal
- SubQ, IM
- Research
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- Typical Dose
- 100–500 mcg
- 40–80 mcg
- Frequency
- Once daily
- Once daily or split twice daily
- Key Benefits
- 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
- Direct muscle hypertrophy via IGF-1R stimulation
- Muscle hyperplasia (new fiber formation) — unique among peptides
- Rapid gains in lean muscle mass
- Accelerated recovery from training and injury
- Increased nutrient uptake by muscle cells
- Fat oxidation enhancement
- Bone density improvement
- Cartilage and connective tissue repair
- Side Effects
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Hypoglycemia (significant risk — insulin-like activity)
- Acromegaly-like effects with excessive long-term use
- Jaw and hand swelling
- Organ hypertrophy with extreme doses
- +2 more
- Stacks With
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