P21vsSemax
P21 vs Semax — independent comparison of uses, administration, pricing across providers, and key differences. Last reviewed April 21, 2026.
Quick Verdict
Based on clinical evidence and real patient data
A 21-amino-acid peptide that mimics the action of ciliary neurotrophic factor (CNTF). Studied for neurogenesis, cognitive improvement, and neuroprotection. Shows promise in animal models for enhancing memory consolidation and protecting against neurodegenerative decline.
A synthetic peptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10. Developed in Russia for cognitive enhancement and neuroprotection, it modulates BDNF and serotonin levels.
Best choice depends on your insurance, budget, and treatment history.Take the quiz to get a personalized recommendation.
P21 vs Semax: At a Glance
Full comparison across all key factors.
| Factor | P21 | SemaxALLY PICK |
|---|---|---|
| Category | cognitive | cognitive |
| Also Known As | CNTF analog, Colostrinin fragment | ACTH 4-10 Analog |
| Administration | Intranasal spray | Intranasal spray |
| Prescription | Required | Required |
| Providers | 3 providers | 4 providers✓ Better |
| Common Uses |
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Data sourced from FDA prescribing information and peer-reviewed clinical trials. Prices reflect telehealth platform costs as of April 21, 2026. See our methodology.
Pricing by Provider
3 providers offer both P21 and Semax.
| Provider | P21 | Semax | Consultation | Lab Testing |
|---|---|---|---|---|
 | $55/one-time | $45/one-time | Async Telehealth | No |
 | $180/monthly | $120/monthly | Video Telehealth | Yes |
 | $230/monthly | $160/monthly | Video Telehealth | Yes |
 | Not offered | $140/monthly | Video Telehealth | Yes |
Key Differences
P21
A 21-amino-acid peptide that mimics the action of ciliary neurotrophic factor (CNTF). Studied for neurogenesis, cognitive improvement, and neuroprotection. Shows promise in animal models for enhancing memory consolidation and protecting against neurodegenerative decline.
Semax
More ProvidersA synthetic peptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10. Developed in Russia for cognitive enhancement and neuroprotection, it modulates BDNF and serotonin levels.
Which Is Right for You?
Choose P21if…
- You want a cognitive medication
- You prefer intranasal spray administration
- 3 providers available on our platform
- Your primary goal is neurogenesis
- Your primary goal is memory consolidation
Choose Semaxif…
- You want a cognitive medication
- You prefer intranasal spray administration
- You want more provider options (4 available)
- Your primary goal is cognitive enhancement
- Your primary goal is neuroprotection
Frequently Asked Questions
What is the difference between P21 and Semax?
Which is cheaper, P21 or Semax?
Can I switch from P21 to Semax?
Medical Disclaimer
This comparison is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting, stopping, or changing any medication. Individual results may vary. The information presented reflects publicly available data and may not account for your specific health situation.