P21vsTB-500
P21 vs TB-500 — 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 fragment of thymosin beta-4, a naturally occurring peptide involved in tissue repair and regeneration. Studied for its ability to promote healing of muscles, tendons, ligaments, and skin.
Best choice depends on your insurance, budget, and treatment history.Take the quiz to get a personalized recommendation.
P21 vs TB-500: At a Glance
Full comparison across all key factors.
| Factor | P21 | TB-500ALLY PICK |
|---|---|---|
| Category | cognitive | recovery |
| Also Known As | CNTF analog, Colostrinin fragment | Thymosin Beta-4 Fragment |
| Administration | Intranasal spray | Subcutaneous injection |
| Prescription | Required | Required |
| Providers | 3 providers | 6 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 TB-500.
| Provider | P21 | TB-500 | Consultation | Lab Testing |
|---|---|---|---|---|
 | $55/one-time | $40/one-time | Async Telehealth | No |
 | $180/monthly | $180/monthly | Video Telehealth | Yes |
 | $230/monthly | $240/monthly | Video Telehealth | Yes |
 | Not offered | $195/monthly | Video Telehealth | Yes |
 | Not offered | $165/monthly | Video Telehealth | No |
 | Not offered | $199/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.
TB-500
More ProvidersA synthetic fragment of thymosin beta-4, a naturally occurring peptide involved in tissue repair and regeneration. Studied for its ability to promote healing of muscles, tendons, ligaments, and skin.
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 TB-500if…
- You want a recovery medication
- You prefer subcutaneous injection administration
- You want more provider options (6 available)
- Your primary goal is muscle repair
- Your primary goal is tendon healing
Frequently Asked Questions
What is the difference between P21 and TB-500?
Which is cheaper, P21 or TB-500?
Can I switch from P21 to TB-500?
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.