P21 vs Semaglutide
Side-by-side comparison of key properties, dosing, and research.
Cognitive EnhancementAnti-Aging & Longevity
P21GLP-1 / Weight Loss Agonists
Semaglutide- 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.
- Semaglutide is an FDA-approved GLP-1 receptor agonist originally developed for type 2 diabetes that has proven remarkably effective for weight loss. Clinical trials show average 15–20% body weight reduction. It is marketed as Ozempic (diabetes) and Wegovy (weight management).
- Half-Life
- Not well characterized; likely short, but neurogenic effects persist long after administration
- ~7 days
- Admin Route
- SubQ, Intranasal
- SubQ, Oral
- Research
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- Typical Dose
- 100–500 mcg
- 0.25 mg → 0.5 mg → 1 mg → 1.7 mg → 2.4 mg
- Frequency
- Once daily
- Once weekly, subcutaneous
- 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
- Average 15–20% body weight reduction in clinical trials (STEP trials)
- Significant reduction in appetite and food cravings
- Improvement in blood sugar control and insulin sensitivity
- Reduces cardiovascular risk (SELECT trial: 20% reduction in MACE)
- May reduce risk of kidney disease
- Improves metabolic markers (cholesterol, blood pressure)
- FDA-approved — extensively studied with robust safety data
- Weekly dosing convenience
- Side Effects
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Nausea (most common, especially during titration)
- Vomiting
- Diarrhea or constipation
- Abdominal discomfort
- +4 more
- Stacks With
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