LL-37
Reviewed
Short answer
LL-37 is a peptide made of 37 amino acids. The body releases it from a larger starting protein. Human studies tested different products for wounds, melanoma, and COVID-19. Melanoma is a type of skin cancer. These studies do not prove a general health benefit. No FDA-approved U.S. LL-37 drug was found in the records checked.
The Peptide Field explains research. Its pages are not independently medically reviewed, and they do not diagnose, prescribe, or recommend treatment.
Read the study findingsAlso known as LL37 · Cathelicidin LL-37 · Ropocamptide
Legal status Is LL-37 legal? See the status table
Study and product details
What it is
LL-37 is a defense peptide made by the body. It helps protect against germs. It has 37 amino acids. The body makes it by cutting a larger protein called hCAP18. Ropocamptide is another name used in FDA records. LL-37 amide is a different chemical form with its own FDA record.
Type of peptide: Body-made host-defense peptide. This describes what the substance is or how it works. It does not show that it is safe, effective, or approved.
What has been studied?
- Limited: Research is too small or incomplete, or does not directly answer this question.
- Unclear: There is not enough reliable detail about the product or research to judge.
Wound studies found mixed results. In a later study, 148 people received LL-37 or placebo. It found no clear healing benefit in the full group.
The studies do not show how each LL-37 form moves through or affects the body. Researchers used different products in different ways.
FDA says there is not enough safety information. It notes possible immune reactions, impurities, and uncertainty about product contents. Animal and cell findings do not prove harm in people.
FDA keeps LL-37 amide in a separate chemical record. An online product name does not prove its contents or quality.
Products with the same ingredient can differ.
The ingredient name does not tell you everything about a product. Check its other ingredients, its form, how it enters the body, and the use and people covered by the research or approval.
None identified in the United States.
- Human research in venous leg ulcers
- Human research in diabetic foot ulcers
- Early research in melanoma and COVID-19
Have a lab test report (COA) for a product sold under this name? Check what the report shows in 10 questions
Not sure if a product sold under this name is a prescription, compounded, or research-only vial? Sort it in 5 questions
What studies found
An early 34-person study of hard-to-heal leg ulcers caused by vein problems reported signs of better healing. A later double-blind study assigned 149 people to topical LL-37 or placebo. Both groups also received compression care. Of those people, 148 received a study treatment. The study found no clear healing benefit in the full group. A later analysis suggested more benefit in people with larger wounds. That was not the study's main test and needs confirmation.
A 25-person study of diabetic foot ulcers used a topical cream for four weeks. It found a higher score for new tissue growth. It found no clear difference in signs of inflammation or the amount of bacteria. A melanoma study enrolled four people in one group. Melanoma is a type of skin cancer. The study cannot prove a cancer benefit.
A 238-person COVID-19 study used a modified bacterium that made a lab-produced form of LL-37. The full group did not clear the virus faster on testing. A group of 48 people started treatment within six days of a positive test.
That group included 20 people assigned to LL-37 and 28 assigned to placebo. The early group had a signal. Patients and researchers knew which treatment was given. The study took place at one medical center and covered the Omicron BA.5.1.3 variant.
These studies do not prove that LL-37 heals wounds in general, prevents or treats cancer or COVID-19, or improves health for people in general. The wound results differed by study and subgroup. The COVID-19 study did not test a standard LL-37 vial, spray, or plain peptide product.
FDA says there is not enough safety information. It notes possible immune reactions, impurities, and uncertainty about product contents. FDA also cites animal and cell findings about male reproduction and possible tumor growth. These findings do not prove harm in people.
The person or group that asked FDA to consider LL-37 for its pharmacy-compounding list withdrew the request. This is not a ban or a place on the list. FDA plans a discussion with an advisory committee before the end of February 2027. The committee will give advice. It will not make a final FDA decision.
Which products do these findings apply to?
LL-37 is also called ropocamptide. LL-37 amide is a separate FDA substance record, not an exact alias. FDA records and human studies do not show that an online product has the same form, contents, quality, or study material.
LL-37 side effects and safety: what FDA has said
This page has no trial or drug-label side-effect table for LL-37. FDA keeps a page of bulk substances that may be risky when a pharmacy mixes (compounds) them. Here is what that page says about LL-37, in plain words.
FDA's page does not name specific side effects for LL-37.
- FDA says it lacks the safety information to know whether LL-37 would harm people.
- Lab and animal research suggests harm to male reproduction.
- That research also suggests LL-37 can help tumors grow in some tissues. These findings do not prove harm in people.
- The body's immune system may react against it. FDA says this risk depends on how it is given.
- Making it may leave unwanted peptide by-products in the product.
- It may be hard to confirm exactly what the main ingredient is.
These points come from FDA's review of compounded drugs. They are not a full list of side effects. Having no reports does not mean a product is safe.
Read FDA's exact words
Cathelicidin LL-37: “Compounded drugs containing cathelicidin LL-37 may pose risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization. FDA lacks sufficient safety-related information regarding cathelicidin LL-37 to know whether the drug would cause harm when administered to humans. Nonclinical research findings suggest detrimental effects on male reproduction and that this drug can be protumorigenic in some tissues.”
Source: FDA, Certain bulk drug substances for use in compounding that may present significant safety risks , page dated .
Compare side-effect data across peptides
Report a side effect
You can report a suspected side effect to the FDA at 1-800-FDA-1088 or through FDA MedWatch . If a reaction feels serious, get medical care first.
FDA page checked .
Fact checks
6 statements checked. Read what the results mean.
“LL-37 is a 37-amino-acid human peptide.”
FDA's detailed chemical record lists ropocamptide as a peptide with 37 amino acids. This record does not show product quality or human benefit.
- What this answer is based on
- Official record or product label
- Limits of this answer
- FDA identity records for LL-37 and ropocamptide; this does not establish the identity or quality of an online product.
Sources for this fact check (2)
“LL-37 is proven to heal wounds in people.”
The first 34-person leg-ulcer study reported possible benefit. A later study assigned 149 people to LL-37 or placebo. Of those people, 148 received a study treatment. It found no clear benefit for the full group. A 25-person diabetic-foot-ulcer study found a limited sign of new tissue growth, but no clear changes in other measures. These results do not prove general wound healing.
- What this answer is based on
- Health results from a study with randomly assigned groups
- Limits of this answer
- The reviewed venous-ulcer studies and small diabetic-foot-ulcer study; results apply only to their defined products, groups, wound types, and follow-up periods.
Sources for this fact check (3)
“The LL-37 COVID-19 study tested a standard LL-37 peptide product.”
The 238-person study used an engineered bacterium that made a lab-produced form of LL-37. Patients and researchers knew which treatment was given. The study took place at one medical center. It did not test a standard LL-37 vial, spray, or plain peptide product.
- What this answer is based on
- Health results from a study with randomly assigned groups
- Limits of this answer
- The engineered bacterium used in the study and the one-center setting; this does not establish results for other LL-37 materials.
Sources for this fact check (1)
Show 3 more fact checks
“LL-37 is FDA-approved in the United States.”
No FDA-approved U.S. LL-37 drug was found when Drugs@FDA was checked for LL-37 and ropocamptide on August 30, 2026. An FDA chemical record identifies a substance. It does not mean that FDA approved a drug.
- What this answer is based on
- Official record or product label
- Limits of this answer
- United States approval status as reviewed August 30, 2026.
Sources for this fact check (2)
“FDA has banned LL-37.”
The person or group who asked FDA to consider LL-37 for its pharmacy-compounding list withdrew the request. That request was called a 503A nomination. Its withdrawal is not a ban. The current federal rule does not list LL-37. FDA plans an advisory-committee discussion before the end of February 2027. That discussion is not a final decision or drug approval.
- What this answer is based on
- Official record or product label
- Limits of this answer
- The U.S. pharmacy-compounding status as reviewed August 30, 2026; an advisory discussion is not a final FDA action.
Sources for this fact check (4)
“LL-37, LL-37 amide, and products sold online as LL-37 are interchangeable.”
FDA has separate records for ropocamptide (LL-37) and LL-37 amide. An online product name does not prove the same chemical form, amino-acid order, purity, or quality.
- What this answer is based on
- Official record or product label
- Limits of this answer
- FDA identity records and online product names; this is not advice on how to use a product.
Sources for this fact check (2)
Questions people ask about LL-37
No final FDA ban was identified. The person or group who asked FDA to consider LL-37 for its pharmacy-compounding list withdrew the request. FDA plans to ask an advisory committee about LL-37 before the end of February 2027. That future advice will not approve a drug or make a final decision about the list.
FDA's page on risky compounding substances says this about LL-37. It does not name specific side effects for LL-37. FDA says it lacks the safety information to know whether LL-37 would harm people. Lab and animal research suggests harm to male reproduction. That research also suggests LL-37 can help tumors grow in some tissues. These findings do not prove harm in people. The body's immune system may react against it. FDA says this risk depends on how it is given. Making it may leave unwanted peptide by-products in the product. It may be hard to confirm exactly what the main ingredient is. These points come from FDA's review of compounded drugs. They are not a full list of side effects.
Risks and safety limits
FDA's review does not show that every LL-37 form or product is safe. It includes animal and cell concerns that do not prove risk in people. This guide does not tell readers how much to use, how to take it, where to buy it, which product to choose, or how to treat a condition.
This editorial review did not determine sport eligibility. Athletes must check the current prohibited list, Global DRO, and their governing body.
Reviewed .Check the rules for athletes ↗Terms used in the studies
- peptide
- a short chain of amino acids
- amino acid
- a small building block that makes peptides and proteins
- placebo
- an inactive treatment used for comparison
- mechanism
- how a substance may cause a body change
- biomarker
- a body or lab measurement, not automatically a health benefit
- randomized
- assigned to study groups by chance
- outcome
- what the study measured
Read the sources
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Review history
Initial review covered FDA records and human studies of leg ulcers, melanoma, and COVID-19. It also covered FDA's planned advisory-committee discussion.
Not independently medically reviewed. This page is not a dosing, sourcing, or treatment guide.
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