LL-37 vs Thymosin Alpha-1
Overview
LL-37 is primarily a immune support peptide, while Thymosin Alpha-1 is used for healing & recovery.
This page compares LL-37 and Thymosin Alpha-1 across their primary use, typical dosing, reported benefits and side effects, and U.S. regulatory status. For the full monograph on either compound — mechanism of action, clinical research, and references — follow the article links.
Side-by-side comparison
| LL-37 | Thymosin Alpha-1 | |
|---|---|---|
| Category | Immune Support | Healing & Recovery |
| Regulatory status (US) | Compounding (Rx) — Apr 2026 | Research use only |
| Typical dosage | 2-5 mg | 1.6-3.2 mg |
| Frequency | twice weekly | twice-weekly |
| Reported benefits | Antimicrobial activity, immune modulation, wound healing, anti-inflammatory | Immune enhancement, antiviral properties, chronic infection support, cancer therapy adjunct |
| Reported side effects | Generally safe, minimal side effects | Well-tolerated. Rare: injection site reactions, mild flu-like symptoms |
Key differences
Primary use. LL-37 is categorised under Immune Support, while Thymosin Alpha-1 falls under Healing & Recovery. Their differing categories mean they are usually chosen for different goals rather than as direct substitutes.
Regulatory status. LL-37: not FDA-approved; compounding permitted with a prescription as of April 2026. Thymosin Alpha-1: not FDA-approved; treated as a research compound.
Dosing. LL-37 is typically dosed at 2-5 mg (twice weekly). Thymosin Alpha-1 is typically dosed at 1.6-3.2 mg (twice-weekly).
Can you stack them?
Some protocols combine peptides, but stacking LL-37 and Thymosin Alpha-1 has not been validated for safety or efficacy in controlled trials. Combining compounds can change their effects and risks. Nothing here is medical advice — consult a qualified healthcare provider before starting or combining any protocol.
Frequently asked questions
- What is the difference between LL-37 and Thymosin Alpha-1?
- LL-37 is primarily a immune support peptide, while Thymosin Alpha-1 is used for healing & recovery. LL-37 is not FDA-approved; compounding permitted with a prescription (as of April 2026), whereas Thymosin Alpha-1 is not FDA-approved; generally classified as a research compound.
- What is LL-37 used for?
- Antimicrobial defense peptide.
- What is Thymosin Alpha-1 used for?
- Immune system support.
- Can you take LL-37 and Thymosin Alpha-1 together?
- Some users combine peptides within a single protocol, but stacking LL-37 and Thymosin Alpha-1 has not been established as safe or effective in controlled trials. Neither this comparison nor PeptideSciences101 is medical advice — consult a qualified healthcare provider before combining any compounds.
- Is LL-37 or Thymosin Alpha-1 FDA-approved?
- LL-37 is not FDA-approved; compounding permitted with a prescription (as of April 2026). Thymosin Alpha-1 is not FDA-approved; generally classified as a research compound.
Read the full articles
- LL-37 — full monograph: mechanism, research, dosing & references
- Thymosin Alpha-1 — full monograph: mechanism, research, dosing & references