LL-37 Dosage: Common Protocol, Trial Dose and Calculator
LL-37 dosage: the 100 mcg-2 mg common protocol, the topical doses published wound-healing trials used, and a calculator for injections.
The short version
Practitioner and vendor guides describe a subcutaneous LL-37 protocol of 100 mcg-2 mg, 3-5 times weekly to once daily. A course runs 4-12 weeks, with a 4-week break. That is common practice, not trial-established, and the sources disagree more than for most protocols on this site. Published trials have given people LL-37 by other routes, none by injection. A 2014 randomized trial applied it topically to venous leg ulcers at three strengths. The two lower ones healed faster than placebo (only the lowest reached statistical significance), and the highest did not. A larger 2021 trial of the lower two, in 148 people, found no overall benefit.
- The common injection protocol is 100 mcg-2 mg subcutaneous, 3-5x weekly to daily, over a 4-12 week course with a 4-week break. It is not trial-established, and sources disagree on the range.
- Randomized trials applied topical LL-37 to leg and foot ulcers, a different route, dose and use than the common protocol.
- In the 2014 trial the two lower topical strengths (0.5 and 1.6 mg/mL) healed faster than placebo, but only 0.5 was significant. A larger 2021 trial found no overall benefit.
- FDA states it lacks sufficient data to know whether administering cathelicidin LL-37 would cause harm.
LL-37 has no approved dose. Unlike some research peptides on this site, it does have a handful of small published human trials that gave it to people. Others only measured what the body already makes. This page gives the protocol practitioner and vendor guides commonly describe, then what those trials used (population, route, dose, frequency, duration) and what they do not cover. For what LL-37 is and FDA’s full regulatory review, see the main LL-37 guide.
US legal status - Research use only
LL-37 has no FDA-approved product for any indication. FDA states it lacks sufficient safety-related information regarding cathelicidin LL-37 to know whether the drug would cause harm when administered to humans.
LL-37 dosage: the common protocol
Practitioner and vendor dosing guides describe a subcutaneous protocol of 100 mcg to 2 mg, 3-5 times weekly to once daily, usually starting low and titrating up. The course runs 4-12 weeks, with a 4-week break between courses.
That is common practice, not a dose any trial or regulator has established. The sources disagree with each other more than for most protocols on this site.
Common protocol
What is commonly used, not a dose established in trials. No regulator has set a dose for LL-37. Sources differ, so the ranges below span them.
- Dose per administration
- 100-2000 mcg
- How often
- 3-5 times weekly to once daily, subcutaneous, starting low and titrating up
- Route
- Subcutaneous injection
- Cycle length
- 4-12 weeks
- Break between cycles
- 4 weeks
- Timing
- Start at the low end of the dose range and titrate upward over the first 1-2 weeks.
- Commonly paired with
- BPC-157
Sources disagree materially on both dose (100-1,000 mcg titrated vs 500-2,000 mcg) and frequency (3-5x/week vs daily/every-other-day), and both describe this as community/practitioner-derived rather than trial-validated. This is a wider and less settled range than most protocols on this site.
Plan a cycle in the protocol builder or work out injection volume in the dosage calculator.
The common LL-37 dose is 100-2000 mcg, 3-5 times weekly to once daily, subcutaneous, starting low and titrating up. From a 5 mg vial mixed with 2 mL of bacteriostatic water, 1 mg is 40 units (0.4 mL) on a U-100 insulin syringe.
LL-37 5 mg vial: units per dose
Full 5 mg vial page: mixing, doses per vial, how long it lasts →
| Water added | Concentration | 1 unit = | 100 mcg | 1 mg | 2 mg |
|---|---|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 2 units | 20 units | 40 units |
| 2 mL | 2.5 mg/mL | 25 mcg | 4 units | 40 units | 80 units |
| 3 mL | 1.67 mg/mL | 16.67 mcg | 6 units | 60 units | over 100 units |
All LL-37 vial sizes: 5 mg
Units are on a standard U-100 insulin syringe (100 units = 1 mL), rounded to the nearest half unit - half-unit marks are on 0.3 mL syringes. Water volumes are examples: more water means more units per dose, not more doses per vial. For any other vial or dose, use the calculator below.
How many 5 mg vials a cycle takes
| Scenario | Dose | Doses a week | Weeks | Total | 5 mg vials |
|---|---|---|---|---|---|
| Low end of the common protocol | 100 mcg | 3 | 4 | 1.2 mg | 1 |
| High end of the common protocol | 2 mg | 7 | 12 | 168 mg | 34 |
Whole vials, rounded up. Plan a cycle with your own numbers in the protocol builder. Keep mixed vials cold and use them within the window in how long reconstituted peptides last; where to inject: subcutaneous injection sites.
LL-37 doses used in human studies
The first published trial to give people LL-37 itself, rather than measuring the level they already carry, was a 2014 randomized, double-blind, placebo-controlled, first-in-human trial Grönberg 2014 - Grönberg A, Mahlapuu M, Ståhle M 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;22(5):613-21., in the references below.
| Detail | What the trial used |
|---|---|
| Population | 34 adults with hard-to-heal venous leg ulcers |
| Route | Topical, applied directly to the wound |
| Doses tested | 0.5 mg/mL, 1.6 mg/mL, or 3.2 mg/mL |
| Frequency | Twice weekly |
| Treatment duration | 4 weeks, after a 3-week placebo run-in, with a 4-week follow-up |
Three later trials also gave people LL-37:
- Venous leg ulcers, 2021. A phase IIb double-blind, randomized, placebo-controlled trial in 148 people tested topical LL-37 at 0.5 or 1.6 mg/mL alongside compression. Across the whole group it found no significant improvement in healing over placebo. A post hoc look suggested benefit only in ulcers of at least 10 square centimetres. The drug was reported as well tolerated and safe at both strengths Mahlapuu 2021 - Mahlapuu M, Sidorowicz A, Mikosinski J 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;29(6):938-950., in the references below.
- Diabetic foot ulcers, 2023. A randomized, double-blind trial applied LL-37 cream or placebo cream twice a week for four weeks to ulcers with mild infection. The LL-37 group’s granulation index rose more than placebo’s. The inflammatory markers IL-1 alpha and TNF-alpha and bacterial colonisation did not fall Miranda 2023 - Miranda E, Bramono K, Yunir 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;315(9):2623-2633., in the references below. The abstract does not give the cream’s strength.
- COVID-19, 2023. An open-label, randomized, placebo-controlled trial in 238 adults in hospital gave an oral product: Lactococcus lactis bacteria engineered to make LL-37, not the peptide itself. It shortened the time to a negative SARS-CoV-2 test, and no severe adverse events were seen Zhao 2023 - Zhao Y, Zhang H, Zhao Z 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;95(8):e29035., in the references below. The abstract does not give the dose.
What is not established
- No injected dose exists. The human trials applied LL-37 topically to open wounds or gave an oral product of bacteria engineered to make it. No published human study I have read has tested an injected dose of LL-37.
- No dose exists for general immune support. LL-37 is sold online for general immune support, a use none of these trials tested or supports.
- No long-term human safety data exists from the trials above. FDA states it lacks sufficient safety-related information regarding cathelicidin LL-37 to know whether it would cause harm when administered to humans. It separately cites nonclinical findings on male reproduction and tumour promotion; see the main guide for that detail.
- The common protocol above is current practitioner/vendor practice, not a trial finding. It uses a different route (subcutaneous) than any of the trials (topical or oral). Each source is recorded, but no trial or regulator has established that dose.
Reconstitution and injection volume: use the calculator, not a guess
The human trials used pre-formulated topical products or an oral product, not a vial a person reconstitutes themselves. If you are working out concentration or draw volume for a vial of any kind, that arithmetic belongs on a dedicated tool. The dosage calculator walks through vial strength, diluent volume and target amount. It performs the math. It does not tell you what amount to target.
Who should not use it
No FDA-reviewed contraindication list exists, because LL-37 has never gone through that review as an administered drug. FDA cites nonclinical research suggesting detrimental effects on male reproduction and protumorigenic effects in some tissues. These are animal findings that remain unresolved, not settled risks with a known size.
Anyone pregnant, breastfeeding, or with a diagnosed medical condition has no regulator-reviewed information to weigh a decision against, beyond the small topical and oral trials above.
LL-37 side effects and risks
FDA states it lacks sufficient safety-related information regarding cathelicidin LL-37 to know whether the drug would cause harm when administered to humans. It separately flags a risk of immunogenicity for certain routes of administration. It also cites unresolved animal findings on reproduction and tumour promotion; see the main guide for the full detail. Material sold as LL-37 is a research chemical with no regulator-verified purity, identity or concentration, a separate question from the peptide’s own biology.
Related
- LL-37: what the research and FDA review show
- KPV dosage: no human study exists
- Dosage calculator
- Are peptides safe?
LL-37 dosage calculator
Preset to a 5 mg vial and 100 mcg, the low end of the common protocol. Enter your own vial size, water and dose to get the syringe units to draw.
Your vial
Printed on the vial. There is no standard size - enter what yours says.
This changes how much you draw - never how many doses the vial holds.
100 units per mL. 1 unit = 0.01 mL. This is what almost every insulin syringe sold is, in every barrel size.
Capacity only. A 1 mL U-100 syringe holds 100 units - the scale decides that, not the barrel.
Draw this much
= 0.04 mL on a 1 mL U-100 syringe
- Concentration
- 2,500 mcg/mL
- Exact volume
- 0.04 mL
- Dose you actually get
- 100 mcg
- Doses per vial(unaffected by water volume)
- 50
Where to buy LL-37 for research
Each vendor is checked against my vendor checklist.
1.Next Level PharmFeatured
5 mg vial
- No FDA warning letter found
- Names its testing lab
- Batch COAs published
- Takes card payment
2.BioEdge Research Labs
5 mg vial
- No FDA warning letter found
- Names its testing lab
- Batch COAs published
Common questions
What is the usual LL-37 dose?
Practitioner and vendor dosing guides describe a subcutaneous protocol of 100 mcg to 2 mg, dosed 3-5 times weekly to once daily, usually starting low and titrating up. A course runs 4-12 weeks, with a 4-week break between courses. That is common practice reported by those sources, not a dose established by any trial or regulator. The sources disagree more than for most protocols on this site. The human trials (see the next question) used different routes entirely.
What dose of LL-37 has a human study used?
Four published trials gave people LL-37. The first, a 2014 randomized, placebo-controlled trial in 34 adults with hard-to-heal venous leg ulcers, applied LL-37 topically to the wound at 0.5, 1.6 or 3.2 milligrams per millilitre. It was applied twice weekly for four weeks. A larger 2021 trial in 148 people with the same kind of ulcer used 0.5 or 1.6 mg/mL alongside compression and found no overall benefit over placebo. A 2023 trial applied an LL-37 cream twice a week for four weeks to diabetic foot ulcers. A 2023 COVID-19 trial gave 238 hospital patients an oral product of bacteria engineered to make LL-37. None tested an injection.
Is there an FDA-approved LL-37 dose?
No. LL-37 has no FDA-approved product for any indication. DailyMed lists no drug label containing it. FDA states it lacks sufficient safety-related information regarding cathelicidin LL-37 to know whether administering it to humans would cause harm.
Which LL-37 dose worked best in the trial?
The two lower concentrations did better than placebo. The 0.5 mg/mL group healed roughly six times faster than placebo by one measure. The 1.6 mg/mL group healed roughly three times faster, though that result did not reach statistical significance. The highest concentration, 3.2 mg/mL, showed no difference from placebo at all, so more was not better. In the larger 2021 trial, neither 0.5 nor 1.6 mg/mL beat placebo across the whole group.
Can this wound-trial dose be used for anything else, like injections?
No study supports that. The wound trials applied LL-37 topically to open leg or foot ulcers. They say nothing about an injected or otherwise systemic dose, or about any indication besides skin ulcers. None tested a topical wound dose in a different route or condition.
How do I work out reconstitution and injection volume?
That is arithmetic about a specific vial and diluent, not a dosing decision. The human trials used topical products or an oral bacterial product, not an injection. The dosage calculator handles concentration and draw-volume math for whatever amount you are looking at. It does not tell you what dose to use.
Who should not use LL-37?
No FDA-reviewed contraindication list exists. FDA cites nonclinical findings on male reproduction and tumour promotion that remain unresolved. It also states it lacks sufficient safety information to know whether giving LL-37 to a person would cause harm. These are reasons for caution for anyone pregnant, breastfeeding, or with a diagnosed condition.
When should I stop and get medical care?
Get emergency care (call 911 in the US) for a severe allergic reaction, chest pain, fainting, or any symptom that feels dangerous. Call Poison Control at 1-800-222-1222 if you have taken an unknown or excessive amount of anything sold as LL-37. This is not a substitute for a clinician who knows your history.
References (5 sources)
Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.
- 1.Grönberg A, Mahlapuu M, Ståhle M 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;22(5):613-21.Randomised trialPMID 25041740
- 2.Mahlapuu M, Sidorowicz A, Mikosinski J 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;29(6):938-950.Randomised trialPMID 34687253full text
- 3.Miranda E, Bramono K, Yunir 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;315(9):2623-2633.Randomised trialPMID 37480520full text
- 4.Zhao Y, Zhang H, Zhao Z 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;95(8):e29035.Randomised trialPMID 37605995
- 5.National Poison Control Center - 1-800-222-1222, free and confidential poisoning and overdose guidance; phone number confirmed on the organization's own page.- America's Poison Centersother