IGF-1 LR3vsP21
IGF-1 LR3 vs P21 — 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 long-acting analog of insulin-like growth factor-1 (IGF-1) with an arginine substitution that reduces binding to IGF-binding proteins, extending its half-life. IGF-1 is the primary downstream mediator of growth hormone's anabolic effects.
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.
Best choice depends on your insurance, budget, and treatment history.Take the quiz to get a personalized recommendation.
IGF-1 LR3 vs P21: At a Glance
Full comparison across all key factors.
| Factor | IGF-1 LR3 | P21 |
|---|---|---|
| Category | growth-hormone | cognitive |
| Also Known As | Insulin-like Growth Factor-1 Long R3, Long R3 IGF-1 | CNTF analog, Colostrinin fragment |
| Administration | Subcutaneous or intramuscular injection | Intranasal spray |
| Prescription | Required | Required |
| Providers | 3 providers | 3 providers |
| 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 IGF-1 LR3 and P21.
| Provider | IGF-1 LR3 | P21 | Consultation | Lab Testing |
|---|---|---|---|---|
 | $55/one-time | $55/one-time | Async Telehealth | No |
 | $250/monthly | $180/monthly | Video Telehealth | Yes |
 | $320/monthly | $230/monthly | Video Telehealth | Yes |
Key Differences
IGF-1 LR3
A long-acting analog of insulin-like growth factor-1 (IGF-1) with an arginine substitution that reduces binding to IGF-binding proteins, extending its half-life. IGF-1 is the primary downstream mediator of growth hormone's anabolic effects.
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.
Which Is Right for You?
Choose IGF-1 LR3if…
- You want a growth-hormone medication
- You prefer subcutaneous or intramuscular injection administration
- 3 providers available on our platform
- Your primary goal is muscle hypertrophy
- Your primary goal is fat loss
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
Frequently Asked Questions
What is the difference between IGF-1 LR3 and P21?
Which is cheaper, IGF-1 LR3 or P21?
Can I switch from IGF-1 LR3 to P21?
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.