LL-37
Also known as Cathelicidin
A natural antibiotic made by your own immune system.
Quick facts
- Status
- Not an approved medicine
- Evidence
- Preclinical, with early clinical studies for wound healing
- Taken as
- Injection or on the skin
- Common sizes
- 5 mg
- Category
- Antimicrobial peptide (experimental)
How it works
It punches holes in bacteria and helps direct the immune response. Too much of it can also drive inflammation.
What people use it for
- Infections
- Wound healing
- Immune support
What the research shows
- Early human studies for slow-healing leg ulcers.
- Most research is in the lab.
Side effects & risks
- High levels are linked to skin conditions like rosacea and psoriasis
- Effects of injecting it are unknown
Is it legal?
Not an approved medicine in the EU, UK or US. In most countries it is illegal to sell it for use in people. Products labelled "research use only" are not checked for quality or purity.
Storage & safe handling
- Mix with bacteriostatic water: let it run slowly down the inside of the vial and swirl gently — never shake.
- Store the mixed vial in the fridge and follow the use-by period on the label.
- Wipe the vial top with alcohol and use a new sterile needle and syringe every time.
- Rotate injection sites so the same spot is not used again and again.
- Put used needles in a sharps container, not the household bin.
- Get medical help for redness that spreads, fever, swelling or trouble breathing.
Open in PepTimerTrack your protocol, calculate how much to draw and get reminders — free.Open in PepTimer
Sources: Reviews of human cathelicidin LL-37 biology; early clinical trials in venous leg ulcers.
Last updated 12 October 2026. Information — not medical advice. PepTimer does not replace a doctor. Many peptides are not approved medicines in the EU, UK or US. Talk to a qualified healthcare provider before starting, changing or stopping any treatment.
Last updated 12 October 2026. Information — not medical advice. PepTimer does not replace a doctor. Many peptides are not approved medicines in the EU, UK or US. Talk to a qualified healthcare provider before starting, changing or stopping any treatment.