LL-37 vs Somatropin
Overview
LL-37 is primarily a immune support peptide, while Somatropin is used for hormonal.
This page compares LL-37 and Somatropin 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 | Somatropin | |
|---|---|---|
| Category | Immune Support | Hormonal |
| Regulatory status (US) | Compounding (Rx) — Apr 2026 | FDA approved |
| Typical dosage | 2-5 mg | 0.16-0.24 mg/kg/week (pediatric growth hormone deficiency); about 0.2 mg/day (adult growth hormone deficiency) |
| Frequency | twice weekly | daily subcutaneous injection |
| Reported benefits | Antimicrobial activity, immune modulation, wound healing, anti-inflammatory | In labeled use, somatropin increases linear growth in children with growth failure from growth hormone deficiency, Turner syndrome, Prader-Willi syndrome, small size for gestational age and idiopathic short stature. In adults with diagnosed growth hormone deficiency, professional guidelines describe benefits in body composition, exercise capacity, skeletal integrity and quality-of-life measures, with the largest benefit in the most severely deficient patients. |
| Reported side effects | Generally safe, minimal side effects | Fluid retention, edema, arthralgia and carpal tunnel syndrome are common in adults. Labeled warnings include glucose intolerance and new-onset diabetes, intracranial hypertension, slipped capital femoral epiphysis and scoliosis progression in children, hypothyroidism, hypoadrenalism, pancreatitis and hypersensitivity reactions. |
Key differences
Primary use. LL-37 is categorised under Immune Support, while Somatropin falls under Hormonal. 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. Somatropin: FDA-approved.
Dosing. LL-37 is typically dosed at 2-5 mg (twice weekly). Somatropin is typically dosed at 0.16-0.24 mg/kg/week (pediatric growth hormone deficiency); about 0.2 mg/day (adult growth hormone deficiency) (daily subcutaneous injection).
Can you stack them?
Some protocols combine peptides, but stacking LL-37 and Somatropin 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 Somatropin?
- LL-37 is primarily a immune support peptide, while Somatropin is used for hormonal. LL-37 is not FDA-approved; compounding permitted with a prescription (as of April 2026), whereas Somatropin is FDA-approved for one or more indications.
- What is LL-37 used for?
- Antimicrobial defense peptide.
- What is Somatropin used for?
- Recombinant human growth hormone, FDA-approved for growth failure in children and growth hormone deficiency in adults.
- Can you take LL-37 and Somatropin together?
- Some users combine peptides within a single protocol, but stacking LL-37 and Somatropin 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 Somatropin FDA-approved?
- LL-37 is not FDA-approved; compounding permitted with a prescription (as of April 2026). Somatropin is FDA-approved for one or more indications.
Read the full articles
- LL-37 — full monograph: mechanism, research, dosing & references
- Somatropin — full monograph: mechanism, research, dosing & references