LL-37 (Cathelicidin) vs PT-141 (Bremelanotide)
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
LL-37 (Cathelicidin)
LL-37 is the only human cathelicidin antimicrobial peptide. It plays crucial roles in innate immunity and has shown diverse biological activities including antimicrobial, immunomodulatory, and wound healing properties.
Full details →PT-141 (Bremelanotide)
PT-141, also known as Bremelanotide, is a synthetic peptide analog of alpha-melanocyte-stimulating hormone. It is the only FDA-approved treatment for hypoactive sexual desire disorder (HSDD) in premenopausal women.
Full details →Side-by-Side Comparison
| Aspect | LL-37 (Cathelicidin) | PT-141 (Bremelanotide) |
|---|---|---|
| Mechanism | Disrupts bacterial membranes, neutralizes endotoxins, modulates immune cell function, and promotes wound healing. Has both direct antimicrobial and immunomodulatory effects. | PT-141 activates melanocortin receptors (MC3R and MC4R) in the central nervous system, particularly in areas associated with sexual arousal. Unlike PDE5 inhibitors, it works through the nervous system rather than the vascular system. |
| Typical Dosage | Research protocols vary widely. Typical ranges: 50-200mcg administered subcutaneously 2-3 times weekly. Some protocols use higher doses for acute infections. | FDA-approved dose: 1.75mg administered subcutaneously at least 45 minutes before anticipated sexual activity. Not to be used more than once within 24 hours or more than 8 times per month. |
| Administration | Subcutaneous injection. Can cause significant injection site reactions. Often used in conjunction with other immune-supporting protocols. | Subcutaneous injection in the abdomen. Available as Vyleesi (commercial product). Research use may involve different dosing protocols. |
| Side Effects | Injection site pain and reactions are common. May cause flu-like symptoms, temporary fatigue, or immune activation responses. | Common side effects include nausea (40% of users), flushing, headache, and injection site reactions. Transient blood pressure increases may occur. |
| Best For |
What They Have in Common
Both LL-37 (Cathelicidin) and PT-141 (Bremelanotide) are commonly used for: