LL-37 Dosage: Gel, Cream and Tumor Doses Studied (2026)

Not dosing advice. This page reports doses that studies and approved labels used, with their sources. It does not recommend a dose, and we do not give mixing, injection or unit-conversion instructions. Gray-market vials often do not contain what their label says. How we report doses.

Every dose studied in people

Study	Who	People	Dose and route	What happened
HEAL (Mahlapuu 2021), randomized placebo-controlled Phase IIb trial	Men and postmenopausal women with hard-to-heal leg ulcers (mainly venous) of 2 to 40 cm², in Poland and Sweden	149	0.5 or 1.6 mg/mL gel, 12.5 or 40 µg per cm² of ulcer, twice a week Gel on the ulcer, under compression bandages · 13 weeks, after 3 weeks on placebo	The trial missed its main goal: an estimated 26.5% of ulcers closed on 0.5 mg/mL, 24.7% on 1.6 mg/mL and 25.3% on placebo⁷. Average ulcer area fell 35.63%, 4.02% and 51.69% in those groups, and none of these differences was statistically significant⁷. There were no deaths, and none of the 12 serious adverse events was judged related to the treatment⁷.
Grönberg 2014, randomized placebo-controlled first-in-human dose-finding trial	People with hard-to-heal venous leg ulcers, in Sweden	34	0.5, 1.6 or 3.2 mg/mL gel, twice a week Gel on the ulcer · 4 weeks, after 3 weeks on placebo, then 4 weeks of follow-up	The healing rate constant was about six times placebo’s at 0.5 mg/mL (p = 0.003) and three times at 1.6 mg/mL, a difference short of statistical significance (p = 0.088)⁸. Mean ulcer area fell 68% and 50% at those strengths, while 3.2 mg/mL did no better than placebo⁸. The authors reported no local or systemic safety concerns⁸.
Miranda 2023, randomized double-blind placebo-controlled trial	Adults aged 18 to 60 with diabetic foot ulcers of at least 2 cm², in Jakarta	25	0.5 mg/g cream, 0.025 mL per cm² of wound, twice a week Cream on the ulcer · 4 weeks	Granulation tissue, the new tissue that fills a healing wound, increased more than on placebo on days 7, 14, 21 and 28 (p = 0.031, 0.009, 0.006 and 0.037), but wound area did not shrink significantly more⁹. Bacterial counts fell more on LL-37 on days 7, 14 and 21 and more on placebo on day 28, with no significant difference⁹. One of 13 people given LL-37 had mild skin irritation, which the authors put down to excess wound fluid⁹.
NCT02225366 (M.D. Anderson Cancer Center), open-label Phase 1/2 dose-finding study	Adults with melanoma spread to the skin, with at least 3 skin tumors that surgery could not fully remove	4	250 or 500 µg into each tumor, once a week Injection into tumors · Up to 8 weeks	The record lists 4 people enrolled, but its tables show 3 who started: 2 at 250 µg, 1 of whom stopped for lack of efficacy, and 1 at 500 µg¹⁰. No deaths or serious adverse events were reported; other adverse events included a squamous cell carcinoma, a type of skin cancer, and two other skin conditions at 250 µg, and anemia at both doses¹⁰.
Dolkar 2018, case report	A 63-year-old woman with stage IIIC melanoma that had grown despite nivolumab and chemotherapy	1	Amount not stated in the abstract, once a week Injection into tumors · 8 weekly injections	The injected tumors shrank, but about 45 days in, wart-like bumps and a blistering lesion appeared on her trunk and limbs¹¹. Eleven of 12 skin biopsies showed an abnormal growth of skin cells, and all the lesions cleared within 2 months of stopping the injections¹¹.

Studies, animals and users: kept apart

Doses below are what studies used or what a label says. They are not advice, and gray-market products may not contain what their label says.

In human studies

Topical gel on leg ulcers: 0.5, 1.6 or 3.2 mg/mL twice a week for 4 weeks in the first trial, and 0.5 or 1.6 mg/mL twice a week for 13 weeks in the larger one. The lowest strength performed best, and 3.2 mg/mL was no better than placebo⁷⁸. Topical cream on diabetic foot ulcers: 0.5 mg/g twice a week for 4 weeks⁹. Into tumors: 250 or 500 micrograms per tumor each week for up to 8 weeks, in a 4-patient study¹⁰. We found no human study that tested injection under the skin, a nasal spray, or any dose meant as a general immune booster or a treatment for infection¹⁴.

In animal studies

As reported in the papers, in animals only. Rats with lethal gram-negative sepsis: 1 mg/kg into a vein¹⁵. Rabbits with hind-limb ischemia: 200 micrograms split across five injections into thigh and calf muscles, 4 animals per group¹⁶. Mice: LL-37 applied to skin wounds increased vessel growth and skin regrowth¹⁷. Contraceptive research: sperm became immotile at 3.6 micromolar in mice and 10.8 micromolar in human samples, and none of 26 female mice inseminated with sperm plus LL-37 became pregnant¹⁸. These are animal doses. They are not human doses, and we do not convert them.

What users report Anecdotal · not validated · not a recommendation

One community protocol page lists 50 to 400 micrograms a day, injected under the skin¹². A second site lists 0.5 to 1.6 milligrams, which are in fact the gel strengths used on ulcers in the leg-ulcer trials, not daily doses by any other route⁷¹³. We found no human study that supports these figures as daily doses¹⁴.

Half-life and how it is taken

Routes: Gel or cream on the skin (the only route with controlled human trials we found)
Injection into tumors (one small cancer study)
Injection under the skin (a common gray-market route; no human data found)
Nasal spray (no human data found)
By mouth as live engineered bacteria that make it (one trial; a different product)

No human dose for immunity, infections or injections under the skin

We searched ClinicalTrials.gov and PubMed on 7 October 2026¹²³⁴. As of that date, no study we found had given LL-37 to people by injection under the skin, into a vein, as a nasal spray or by inhaler, and none had tested the peptide as a general immune booster or to treat an infection¹²³. The one human study with an immune aim, the melanoma study described below, injected LL-37 into the tumors themselves¹⁰. The studies in the table above are the only human studies we found that gave LL-37 itself¹²³⁴.

The closest to an infection test is the foot-ulcer cream trial, which also counted bacteria in the wounds⁹. Most of its ulcers were not infected, 9 of 13 on LL-37 and 8 of 12 on placebo, and LL-37 did not lower the bacterial counts significantly⁹.

A 2023 trial in 238 hospitalized adults with COVID-19 gave live bacteria engineered to make LL-37 in the gut, not the peptide itself¹⁹. That is a different product taken by mouth, so its dose does not carry over to LL-37 sold in vials¹⁹.

A separate lab-made peptide derived from LL-37, P60.4Ac, was tested as ear drops of 0.25 to 2.0 mg/mL twice a day for 2 weeks in adults with chronic middle-ear infection⁶. It is a different molecule, so its doses do not carry over to LL-37 either⁶.

What changed with gel strength on leg ulcers

The 149-person trial kept 0.5 and 1.6 mg/mL because those strengths had the most pronounced effect on early healing in the first trial⁷. It was sized to test 0.5 mg/mL against placebo, because the lower strength was expected to work better than 1.6 mg/mL⁷.

The first trial’s paper reported no local or systemic safety concerns, but the 2021 paper notes that, in that first trial, people on 3.2 mg/mL had more frequent and more severe local reactions than the other groups⁷⁸. The 2021 authors suggest that this inflammation may explain the bell-shaped pattern, in which benefit rises and then falls as the dose goes up⁷.

Across all patients in the larger trial, the 1.6 mg/mL group had the lowest average healing rate, 0.0112 per day, against 0.0204 on placebo and 0.0261 on 0.5 mg/mL, and neither strength was significantly better than placebo⁷. Only a subgroup analysis done after the fact (post hoc) found a significant difference: in ulcers of 10 cm² or more, 28.1% closed on 0.5 mg/mL against 8.1% on placebo (P = 0.0458)⁷. Those subgroups held only 21 to 24 people each, the tests were one-sided, and ulcers under 10 cm² showed no improvement⁷.

Because the amount of gel was set by ulcer area, errors in measuring an ulcer meant too much or too little LL-37 could be applied, the authors note⁷. Overdoses of the study gel, placebo included, were recorded as adverse events in 13 patients and underdoses in 6, generally less than 30% off the planned amount⁷.

The tumor-injection study: doses planned and given

The melanoma study set out to find the right dose of LL-37 to give and to learn whether it could stimulate the immune system to help control the cancer¹⁰. Its protocol set out up to four dose levels, 250, 500, 1,000 and 2,000 µg per tumor once a week, for successive groups of 2 patients, with 36 patients planned in all⁵¹⁰. The protocol’s own dose table lists only the first three of these levels, up to 1,000 µg⁵.

The protocol based these levels on the team’s mouse studies, which injected 100 µg into tumors of 0.1 to 0.2 cm³, and on LL-37 levels seen in psoriasis, where the immune cells the study aimed to switch on are strongly activated⁵.

Only the first two levels were reported as given, and the record does not say why no higher dose followed; the study was marked completed on 24 November 2020¹⁰. Its outcome tables list all 3 treated patients under both the dose outcome and ‘antitumor immune response’, though one stopped for lack of efficacy, and the record draws no conclusion on whether the injections worked¹⁰.

The 2018 case report does not say, in its abstract, whether its patient was in this study¹¹. The registry lists all 3 of its treated patients as 65 or older, while the case report’s patient was 63¹⁰¹¹. FDA says lab and animal findings suggest LL-37 can promote tumors in some tissues, a risk covered in the LL-37 review²⁰.

Why the dose in a vial is unknown

As of 5 October 2026, Finnrick, an independent testing service, listed no published lab test of LL-37, so there are no independent results showing what gray-market vials contain²¹. One seller’s product page listed a sequence that differs from LL-37 at 24 of its 37 positions²²²³.

By contrast, every batch of the LL-37 product used in the 149-person trial was tested before use: it met its limits of 90% to 110% of the stated content, passed an identity test and had impurities totaling 0.5%⁷.

Questions people ask

How much LL-37 should I take?

No dose of LL-37 is established for any use, and its largest trial missed its main goal⁷. Studies used a 0.5, 1.6 or 3.2 mg/mL gel or a 0.5 mg/g cream on chronic wounds, and weekly injections of 250 or 500 µg into each melanoma tumor⁷⁸⁹¹⁰. LL-37 is not FDA approved, and US pharmacies may not compound it²⁰²⁴²⁵.

Can you inject LL-37?

In people, LL-37 has been injected only into melanoma tumors, at 250 or 500 µg per tumor once a week in a small study¹⁰. As of 7 October 2026, no study we found had tested it as an injection under the skin, so the safety and effect of that route are unknown¹². FDA says compounded LL-37 may pose a risk of unwanted immune reactions by certain routes²⁰.

How often was LL-37 applied to wounds in studies?

Twice a week in every wound trial⁷⁸⁹. In the 149-person leg-ulcer trial, that meant every 3 days, give or take a day, at routine dressing changes⁷. The foot-ulcer cream was put on at clinic visits on days 1, 3, 7, 10, 14, 17, 21, 24 and 28⁹.

What strength of LL-37 gel was used on wounds?

The leg-ulcer trials used gels of 0.5, 1.6 and 3.2 mg/mL, and in the larger trial the two lower strengths delivered 12.5 or 40 µg per cm² of ulcer⁷⁸. The foot-ulcer trial used a 0.5 mg/g cream⁹. In the larger trial, even 0.5 mg/mL did not close significantly more ulcers than placebo⁷.

What is the LL-37 dose for immunity?

There is none: as of 7 October 2026, no study we found had given LL-37 to people as a general immune booster or to treat an infection¹³. The only immune aim in a human study was the melanoma study’s, which injected it into tumors to see whether it could stimulate an immune response against the cancer¹⁰. In the foot-ulcer trial, which counted bacteria in the wounds, the cream did not lower them significantly⁹.

Go deeper

Sources

1ClinicalTrials.gov search for cathelicidin, ropocamptide or ‘LL-37’ (98 records; only two gave LL-37 to people) ClinicalTrials.gov, accessed 7 Oct 2026. clinicaltrials.gov
2PubMed search: LL-37, LL37 or ropocamptide with injection, nasal, intravenous or inhaled use in human studies (47 results; the only one giving LL-37 was the tumor-injection case report) National Library of Medicine (PubMed), accessed 7 Oct 2026. pubmed.ncbi.nlm.nih.gov
3PubMed search: LL-37, LL37 or ropocamptide with infection, immunity, sepsis or COVID-19, clinical trials only (48 results; the only one giving the peptide itself was the foot-ulcer cream trial) National Library of Medicine (PubMed), accessed 7 Oct 2026. pubmed.ncbi.nlm.nih.gov
4PubMed search: LL-37, LL37 or ropocamptide with first-in-human, phase, dose-finding or intratumoral (10 results; three human studies giving LL-37, all in the table) National Library of Medicine (PubMed), accessed 7 Oct 2026. pubmed.ncbi.nlm.nih.gov
5Induction of Antitumor Response in Melanoma Patients Using the Antimicrobial Peptide LL37: study protocol and statistical analysis plan, version 8 (NCT02225366) M.D. Anderson Cancer Center, via ClinicalTrials.gov, 4 Jan 2017. cdn.clinicaltrials.gov
6Ototopical drops containing a novel antibacterial synthetic peptide: Safety and efficacy in adults with chronic suppurative otitis media PLoS One, 2020. pubmed.ncbi.nlm.nih.gov
7Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial Wound Repair and Regeneration, Nov 2021. pubmed.ncbi.nlm.nih.gov
8Treatment 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 and Regeneration, Sep 2014. pubmed.ncbi.nlm.nih.gov
9Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial Archives of Dermatological Research, Nov 2023. pubmed.ncbi.nlm.nih.gov
10Intratumoral Injections of LL37 for Melanoma (NCT02225366), registry record with posted results ClinicalTrials.gov, 9 Dec 2021. clinicaltrials.gov
11Dermatologic toxicity from novel therapy using antimicrobial peptide LL-37 in melanoma: A detailed examination of the clinicopathologic features Journal of Cutaneous Pathology, Jul 2018. pubmed.ncbi.nlm.nih.gov
12LL-37 5 mg vial: dosage protocol PeptideDosages.com, 20 Sep 2026. peptidedosages.com
13LL-37 Dosage, Safety & Stacks Peptide Initiative, 10 Aug 2026. peptideinitiative.com
14ClinicalTrials.gov intervention search for ‘LL-37’ (20 records; only two gave LL-37 to people) ClinicalTrials.gov, accessed 5 Oct 2026. clinicaltrials.gov
15LL-37 protects rats against lethal sepsis caused by gram-negative bacteria Antimicrobial Agents and Chemotherapy, May 2006. pubmed.ncbi.nlm.nih.gov
16An angiogenic role for the human peptide antibiotic LL-37/hCAP-18 The Journal of Clinical Investigation, Jun 2003. pubmed.ncbi.nlm.nih.gov
17Wound healing activity of the human antimicrobial peptide LL37 Peptides, Jul 2011. pubmed.ncbi.nlm.nih.gov
18Antimicrobial host defence peptide, LL-37, as a potential vaginal contraceptive Human Reproduction, Apr 2014. pubmed.ncbi.nlm.nih.gov
19Efficacy and safety of oral LL-37 against the Omicron BA.5.1.3 variant of SARS-CoV-2: A randomized trial Journal of Medical Virology, Aug 2023. pubmed.ncbi.nlm.nih.gov
20Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks U.S. Food and Drug Administration, 22 Apr 2026. fda.gov
21LL-37: safety testing results and vendor ratings (no published tests) Finnrick, accessed 5 Oct 2026. finnrick.com
22LL37 5mg product page (research peptide seller; sequence, CAS number and purity claims) Medica Depot (vendor), accessed 5 Oct 2026. medicadepot.com (seller page, deliberately not linked)
23Cathelicidin LL-37 (ropocamptide), CID 16198951 PubChem, U.S. National Library of Medicine, accessed 5 Oct 2026. pubchem.ncbi.nlm.nih.gov
24Drugs@FDA API searches for the active ingredient names ‘ropocamptide’, ‘cathelicidin’ and ‘LL-37’ (no matches) U.S. Food and Drug Administration (openFDA), accessed 7 Oct 2026. api.fda.gov · data query
25Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act (categories list) U.S. Food and Drug Administration, 14 May 2026. fda.gov

Not medical advice. Talk to a licensed clinician before using any drug. Report an error.