LL-37
Also known as Cathelicidin LL-37, CAP-18
Human antimicrobial host-defence peptide.
Medical status: Not approved as a medicine.
Also commonly used for (off-label)
- Stubborn bacterial or biofilm issues
- Immune and gut-microbiome protocols
Off-label and research uses are what people report, not approved indications. Talk to a clinician before using any of them.
How it's taken
a small shot into the fat just under the skin (belly, thigh, or love handle)
sprayed into the nose and absorbed through the nasal lining — no needles
Availability varies by supplier — injectable is the most commonly researched form.
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- Documented dose
- 50–450 mcg
- Typical frequency
- Once daily (7 days a week for the first month, then 5 days a week)
- Cycle
- 8 weeks on, 4 off
- Half-life
- ~1 hour
- Common vial sizes
- 5 mg, 10 mg
- Regulatory status
- Not approved for human use.
Dose on a U-100 syringe (50–450 mcg)
| Vial | BAC water | Draw |
|---|---|---|
| 5 mg | 2.5 mL | 2.5–23 units |
| 5 mg | 3 mL | 3.0–27 units |
On a U-100 syringe, 100 units = 1 mL, and the syringe holds 100 units total. Most people keep a single subcutaneous injection under about 50 units — bigger volumes are usually mixed stronger (less water) or split into two shots. Only mixes that fit in one syringe are shown. Always double-check with the reconstitution calculator.
What it does
The body's own antimicrobial peptide, part of the innate immune system's first line of defence. It punches holes in bacterial membranes and helps break apart biofilms — the protective slime that makes some infections stubborn. What people look into it for: • Chronic or biofilm-based infections that resist normal treatment • Wound healing and skin repair • Balancing gut and skin bacteria • Immune support and inflammation regulation It can be irritating at the injection site and is one of the more aggressive peptides, so it is generally used in short courses.
Mechanism
Cationic peptide disrupting microbial membranes and modulating innate immunity.
Storage — lyophilisedwhat's this?
Refrigerate 2-8C, protect from light.
Storage — reconstitutedwhat's this?
Refrigerate 2-8C, use within ~28 days.
Reconstitution noteswhat's this?
Common mix: 5 mg vial + 2.5 ml bacteriostatic water = 20 mcg per unit, so a 50 mcg starting dose is about 3 units and 450 mcg is about 22 units. Titrate up slowly — LL-37 can provoke a strong inflammatory response if you jump ahead.
Stacks well with
- Thymosin Alpha-1Host-defence peptide plus immune modulation.
- KPVPaired to calm inflammation while LL-37 handles the antimicrobial side.
Popular combinations reported in the community and research literature — not a recommendation. Adding peptides multiplies side-effect risk; check with a clinician.
Commonly reported side effects
- Injection-site pain and redness
- Flu-like symptoms
- Herxheimer-type reactions
Contraindications noted
- Autoimmune disease (caution)
- Pregnancy or breastfeeding
Research notes
Can be pro-inflammatory at higher doses; short courses are typical.
Vendors carrying LL-37
These research suppliers list this compound. Prices, vial sizes and testing vary — always check the current lot certificate before you buy.
- Nexaphnexaph.com(opens in a new window)
- Penguin Peptidespenguinpeptides.com(opens in a new window)
- Peplair Researchpeplairresearch.shop(opens in a new window)
- Biotech Peptidesbiotechpeptides.com(opens in a new window)
- Core Peptidescorepeptides.com(opens in a new window)
Peptide Streak does not sell peptides and is not affiliated with these vendors. Some list metabolic compounds under coded product names.