HomePeptide dosagesLL-37
LL-37 dosage: chart, reported range and vial math
The range reported for LL-37 is 100 to 250 mcg a day. No human study has injected LL-37 under the skin. In people it has been put on leg ulcers and, in one very small trial, injected into tumours. It is not approved in the US or Canada.
LL-37 dosage chart
Reported range, not a label dosePick your vial size. Each row shows the dose in milligrams or micrograms, the volume to draw and the mark on a U-100 syringe.
| Dose | Volume | Syringe units |
|---|---|---|
| 100 mcg | 0.06 mL | 6 units |
| 250 mcg | 0.15 mL | 15 units |
Source Reported range, not a label dose. Some reports go up to 500 mcg, in 2 to 4 week cycles. Human studies were on the skin or into a tumour, not under the skin. Vial math is arithmetic.
Which syringe fits each dose
For the 5 mg vial at 1.6667 mg/mL.
| Dose | Volume | Units | 0.3 mL syringe | 0.5 mL syringe | 1 mL syringe |
|---|---|---|---|---|---|
| 100 mcg | 0.06 mL | 6 units | Yes | Yes | Yes |
| 250 mcg | 0.15 mL | 15 units | Yes | Yes | Yes |
How long a vial lasts
Whole doses in one vial. The row for the size picked above is marked.
| Vial | 100 mcg | 250 mcg |
|---|---|---|
| 5 mg vial | 50 doses | 20 doses |
How to mix a LL-37 vial
These steps are for the 5 mg vial picked in the chart. Change the size there and the amounts here change with it.
- Wash your hands. Wipe the stopper of the peptide vial and the water vial with an alcohol swab.
- Draw 3 mL of bacteriostatic water into a syringe.
- Push the needle through the stopper of the peptide vial and let the water run slowly down the glass, not straight onto the powder.
- Swirl the vial gently until the powder is gone. Do not shake it.
- Write the date and 1.6667 mg/mL on the vial, then put it in the fridge.
| Vial | Bacteriostatic water | Concentration |
|---|---|---|
| 5 mg vial | 3 mL | 1.6667 mg/mL |
What LL-37 is
LL-37 is a naturally occurring 37-amino-acid peptide that is part of the innate immune system in human skin. A synthetic version has been tested in people on leg and foot ulcers and, in one very small trial, injected into melanoma tumours. [1]
Other names: LL37, cathelicidin LL-37.
How it has been given to people: Applied to the surface of leg and foot ulcers (topical), and injected directly into melanoma tumours in one small Phase 1 trial. No human study of injection under the skin was found.
What to know before reading a dose
- No human study of LL-37 injected under the skin was found. The human doses on record are strengths of a wound treatment (mg per mL) and amounts injected into tumours; neither is a dose for injection under the skin.
- The larger wound trial did not beat placebo. The 34-person trial showed better healing at the two lower strengths and no benefit at the highest, so more was not better [2]; the 148-patient trial found no significant benefit overall [3].
- Skin tumours and tumour-like growths appear in the injection data: one case report of multiple atypical squamous skin lesions that cleared after stopping [1], and squamous cell carcinoma listed as an adverse event in the posted trial results [6]. The two reports may describe the same patient, and with 3 participants this cannot show cause.
- FDA cites nonclinical findings of harm to male reproduction and of tumour promotion in some tissues [7].
- FDA no longer lists LL-37 in category 2. Its page, current as of 22 April 2026, shows it under substances previously in category 2 whose nominations were withdrawn [7], and the 14 May 2026 category list does not contain it [8].
- Health Canada listed LL-37 among unauthorized injectable peptide drugs in advisory RA-77807 of 1 August 2025 [10].
- The COVID-19 trial named Oral LL-37 gave an engineered bacterium, not the peptide [5]. It says nothing about injected or swallowed LL-37 peptide.
Doses on record for LL-37
Every dose below was given in a human study or printed on an approved label, and each links to its source. Doses set by body weight are left that way.
| From | Where it was used | Dose | How often | For how long | Source |
|---|---|---|---|---|---|
| Human study | First-in-human randomized placebo-controlled trial in hard-to-heal venous leg ulcers. Applied to the ulcer, not injected. Lowest strength. | 0.5 mg/mL applied to the ulcer | twice weekly | 4 weeks | [2] |
| Human study | Same venous leg ulcer trial, middle strength. Applied to the ulcer, not injected. | 1.6 mg/mL applied to the ulcer | twice weekly | 4 weeks | [2] |
| Human study | Same venous leg ulcer trial, highest strength, which was no better than placebo. Applied to the ulcer, not injected. | 3.2 mg/mL applied to the ulcer | twice weekly | 4 weeks | [2] |
| Human study | Phase 2b HEAL LL-37 trial in hard-to-heal venous leg ulcers, with compression therapy. Topical, not injected. Lower strength. | 0.5 mg/mL, topical | not stated in the abstract | not stated in the abstract | [3] |
| Human study | Same Phase 2b trial, higher strength. Topical, not injected. | 1.6 mg/mL, topical | not stated in the abstract | not stated in the abstract | [3] |
| Human study | Phase 1/2 trial at a US cancer centre, injected into melanoma tumours (intratumoral), not under the skin. Starting dose. | 250 mcg per tumour, into 2 to 4 tumours | once a week | up to 8 weeks | [6] |
| Human study | Same melanoma trial, second dose level. Injected into tumours, not under the skin. | 500 mcg per tumour | once a week | up to 8 weeks | [6] |
What the evidence shows
Each finding is tagged by the kind of study it comes from. Human trials are listed first.
Randomized human trial
In the first human trial (34 people with hard-to-heal venous leg ulcers), the two lower strengths cut mean ulcer area by 68% and 50%. [2]
Randomized human trial
In that trial the highest strength, 3.2 mg/mL, healed no better than placebo. [2]
Randomized human trial
The larger follow-up trial (148 patients) found no significant healing benefit over placebo in the full study population. A benefit was seen only in an after-the-fact analysis of patients with large ulcers. [3]
Randomized human trial
In a randomized double-blind trial in diabetic foot ulcers with mild infection, LL-37 cream twice a week for 4 weeks increased granulation tissue more than placebo cream but did not lower inflammatory markers or bacterial counts. [4]
Randomized human trial
An open-label randomized trial called Oral LL-37 in 238 inpatients with COVID-19 used a bacterium (Lactococcus lactis) engineered to make LL-37. It did not give the peptide itself. [5]
Small human study
In the melanoma trial, 3 participants are in the posted results: 2 at 250 mcg per tumour and 1 at 500 mcg per tumour, injected weekly for up to 8 weeks. No serious adverse events are recorded. [6]
Side effects and warnings
Reported in human studies or on a label:
- In the 34-person leg ulcer trial there were no safety concerns about local or systemic adverse events. [2]
- In the 148-patient leg ulcer trial the topical drug was well tolerated at both strengths. [3]
- Case report from the melanoma trial: a 63-year-old woman who had 8 weekly LL-37 tumour injections developed multiple wart-like bumps and a blistering lesion on the trunk and limbs about 45 days after starting. [1]
- In that case all skin lesions cleared within 2 months of stopping the injections. [1]
- Non-serious adverse events listed in the posted melanoma trial results include squamous cell carcinoma (1 of 2 participants at 250 mcg), actinic keratosis, anaemia, skin hypopigmentation and hypothyroidism. [6]
- FDA says nonclinical research suggests harm to male reproduction and that LL-37 can promote tumours in some tissues. [7]
- FDA says compounded LL-37 may carry a risk of immune reactions for some routes of administration. [7]
LL-37 has no approved label in the US or Canada for this use, so there is no official list of who should not use it, no interaction list and no missed-dose rule.
Storage
Keep an unmixed vial the way its label says. Once it is mixed, keep it in the fridge, do not freeze it, and write the mixing date on the vial.
LL-37 dosage questions
How many units is 250 mcg of LL-37 from a 5 mg vial?
Mixed with 3 mL of bacteriostatic water, a 5 mg vial is 1.6667 mg/mL. 250 mcg is 0.15 mL, which is 15 units on a U-100 syringe.
How much water goes in a 5 mg LL-37 vial?
3 mL gives 1.6667 mg/mL. At that strength the doses in the chart sit at 6, 15 units on a U-100 syringe.
How many doses are in a 5 mg vial?
Whole doses in one vial: 50 at 100 mcg, 20 at 250 mcg.
Is LL-37 approved in the US?
Not FDA approved. FDA lists cathelicidin LL-37 among bulk substances that were in compounding category 2 until the nominations were withdrawn, and says it lacks the safety information to know whether it would cause harm in humans.
Is LL-37 authorized in Canada?
Not authorized in Canada. Health Canada lists LL-37 among unauthorized injectable peptide drugs seized from an online seller (advisory of 1 August 2025).
What human dosing data is there for LL-37?
No human study of LL-37 injected under the skin was found. The human doses on record are strengths of a wound treatment (mg per mL) and amounts injected into tumours; neither is a dose for injection under the skin.
Sources
Each one was opened on 10 Oct 2026 and matched to the line it supports.
- Dolkar T et al. Dermatologic toxicity from novel therapy using antimicrobial peptide LL-37 in melanoma: A detailed examination of the clinicopathologic features. J Cutan Pathol 2018. PubMed 29665030.
- Gronberg A et al. Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial. Wound Repair Regen 2014. PubMed 25041740.
- Mahlapuu M et al. Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial. Wound Repair Regen 2021. PubMed 34687253.
- Miranda E et al. Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial. Arch Dermatol Res 2023. PubMed 37480520. Trial NCT04098562.
- Zhao Y et al. Efficacy and safety of Oral LL-37 against the Omicron BA.5.1.3 variant of SARS-COV-2: A randomized trial. J Med Virol 2023. PubMed 37605995.
- Intratumoral Injections of LL37 for Melanoma ClinicalTrials.gov 2015. clinicaltrials.gov. Trial NCT02225366.
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks US Food and Drug Administration 2026. fda.gov.
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act US Food and Drug Administration 2026. fda.gov.
- World Anti-Doping Code International Standard Prohibited List 2026 World Anti-Doping Agency 2026. wada-ama.org.
- Unauthorized injectable peptide drugs seized and sold by Canada Peptide may pose serious health risks Health Canada 2025. recalls-rappels.canada.ca.
Looked for and not found
- Any human study of LL-37 injected under the skin. PubMed searches for LL-37 or cathelicidin with subcutaneous, injection, patients and volunteers, and for LL-37 clinical trials, found only the topical, intratumoral and oral-bacterium studies listed here.
- A human half-life or any human pharmacokinetic figure.
- An approved product or label in the US or Canada, so no official dose, contraindications or storage instructions.
- A full published report of the melanoma trial NCT02225366. Only the registry results [6] and one case report [1] were found.
- The strength of the LL-37 cream in the diabetic foot ulcer trial [4]: not stated in the abstract.
- How often and for how long LL-37 was applied in the Phase 2b leg ulcer trial [3]: not stated in the abstract.
- LL-37 is not named on the WADA 2026 Prohibited List [9]. The list was searched for LL-37 and cathelicidin. Section S0 of the list prohibits any pharmacological substance with no current approval by a governmental health authority; the list does not say whether that covers LL-37.
Change log
10 Oct 2026Page published. 10 sources checked. Vial math added for the 5 mg vial.
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