BPC-157 vs LL-37

BPC-157 and LL-37 have been studied in wound-related research, but their results come from different settings. BPC-157 accelerated closure of chemical burns in rats. LL-37 has randomized topical ulcer trials in people: an early study found faster wound shrinkage, while the larger trial did not establish better complete closure overall. These sources do not compare the peptides directly or support a general healing ranking.

Research reviewed October 15, 2026. Educational information only.

A repair-research peptide and a human defense peptide

BPC-157 is a synthetic fifteen-residue peptide studied across experimental injury models. LL-37 is a fragment of the human precursor protein hCAP18, part of innate defense. Its wound research includes laboratory observations in human skin and controlled trials of a defined topical peptide formulation. The larger venous-ulcer trial used LL-37 acetate in polyvinyl alcohol; its placebo contained polyvinyl alcohol without the peptide.

The shared word “healing” can conceal different measurements. Closing a rat chemical burn, shrinking a chronic human ulcer and achieving confirmed complete ulcer closure are distinct outcomes. A useful comparison explains each experiment before asking what it can teach about treatment.

The main differences

BPC-157 accelerated chemical-burn closure in rats

Huang and colleagues applied BPC-157 to alkali-burn wounds in rats and compared them with rats given the same alkali injury and plain hydrogel without BPC-157. Wounds closed faster. At day 18, tissue sections showed more regrowth of the surface lining, granulation tissue, collagen deposition and dermal remodeling. Granulation tissue is the new vascular connective tissue that fills a healing wound. These observations connect the visible wound area with the structure developing underneath it.

Separate cultures of human umbilical-vein endothelial cells, which line blood vessels, multiplied, migrated and formed tube-like structures more readily with BPC-157 under the tested conditions. The study also reported changes in VEGF, a protein that supports vessel growth, and signaling through ERK, extracellular signal-regulated kinases that help relay growth and migration signals inside cells. Those cell assays help investigate repair biology. They do not demonstrate functional new circulation or clinical wound healing in a treated person.

LL-37 biology led to a specific topical hypothesis

Heilborn and colleagues examined healing skin and chronic ulcers. The hCAP18/LL-37 signal appeared in cells at the advancing surface of healing wounds but was low or absent at chronic ulcer edges. In organ-cultured human skin, antibodies that bound LL-37 slowed surface regrowth. This experiment tested whether the body’s own peptide contributed to repair; it did not compare administration of LL-37 with BPC-157.

The findings supplied a rationale for topical clinical studies. They also illustrate the difference between observing a molecule at a wound, interfering with its endogenous action and administering a manufactured preparation. Each step requires its own experiment and cannot be assumed from the previous one.

The human studies measured wound shrinkage and complete closure

The 2014 first-in-human trial enrolled 34 people with difficult venous leg ulcers. After a placebo run-in, participants received one of three topical LL-37 concentrations or placebo for four randomized weeks. At the lowest concentration, wound area decreased faster: the model-estimated healing-rate constant, a number fitted to the speed of wound shrinkage, was approximately sixfold the placebo value (P=0.003). The middle concentration gave an approximately threefold estimate, but that comparison was uncertain (P=0.088). The highest did not establish faster shrinkage. This does not mean that six times as many people healed or that complete closure occurred six times sooner.

The later HEAL LL-37 trial randomized 149 people; 148 received treatment and 144 entered the main efficacy analysis. Compression and dressing care accompanied both peptide and placebo. At 13 weeks, estimated confirmed closure was 26.5% and 24.7% with the two LL-37 concentrations versus 25.3% with placebo. Neither comparison established a closure benefit. The reported 90% intervals were 17.1–38.7%, 15.8–36.4% and 16.4–36.9%, respectively, and the one-sided P values against placebo were 0.4453 and 0.5274.

An analysis undertaken after the main analysis examined ulcers at least 10 cm² and suggested a possible lower-concentration benefit. Because that subgroup was post hoc, it generates a question for confirmation. It cannot replace the whole-trial result or establish that people with large ulcers will benefit.

A separate 2023 trial in Jakarta assigned 25 people with uninfected or mildly infected diabetic foot ulcers to LL-37 cream (13) or matching base cream without peptide (12), alongside standard cleansing, removal of dead tissue and dressings. More of the wound bed filled with new granulation tissue with LL-37. By day 28, wound area had decreased by 2.35 ± 3.86 cm² versus 1.54 ± 0.94 cm² with placebo (means ± standard deviations), but the wound-area comparisons remained uncertain. Most ulcers were uninfected at entry, and the study did not establish a reduction in aerobic bacterial counts or the measured inflammatory proteins.

Local wound exposure and systemic kinetics are different

The BPC-157 pharmacokinetic study measured intact peptide after intravenous and intramuscular administration in rats and dogs. Rapid disappearance from plasma was measured in those animals; the measurements do not define human exposure after topical, oral or injected products. Radiolabel findings included breakdown products and need separate interpretation.

In fluid collected from nine non-healing venous ulcers, added LL-37 showed no apparent breakdown during incubation for up to 24 hours. Separate enzyme tests found breakdown with trypsin but not matrix metalloproteinase-9. These are laboratory stability observations outside the body, rather than a measured human elimination half-life. Neither local wound-fluid stability nor the duration of an ulcer trial supplies a human plasma elimination half-life. No shared human exposure measurement permits a numerical pharmacokinetic comparison between these peptides.

The clinical formulation and route define the safety observation

The small topical LL-37 study reported no local or systemic safety concern under its observation conditions, and the larger trial described the tested concentrations as well tolerated. Those findings concern specified topical formulations used with wound care. FDA’s compounding-risk page separately identifies missing safety information and potential immune-response or impurity concerns for cathelicidin LL-37 and BPC-157. For LL-37, FDA also cites nonclinical findings of harmful effects on male reproduction and tumor-promoting activity in some tissues. These findings do not quantify human risk. Results from topical ulcer treatment cannot characterize an independently supplied injected product.

BPC-157’s rat burn result and LL-37’s human ulcer trials therefore occupy different positions. LL-37 has more direct controlled evidence for the particular human ulcer setting, and that larger trial did not establish overall closure benefit. BPC-157’s animal result cannot resolve that clinical question. Neither evidence set establishes which peptide is safer or more effective across injuries.

Frequently asked questions

Profiles and related reading

References

1. U.S. Food and Drug Administration. FDA Briefing Document: BPC-157-Related Bulk Drug Substances (BPC-157 free base and BPC-157 acetate). Pharmacy Compounding Advisory Committee, July 23–24, 2026.

   The briefing finds inadequate evidence for ulcerative-colitis effectiveness and insufficient clinical safety information. It distinguishes limited rectal studies from the other proposed routes.

2. Huang T, Zhang K, Sun L, Xue X, Zhang C, Shu Z, Mu N, Gu J, Zhang W, Wang Y, Zhang Y, Zhang W. Body protective compound-157 enhances alkali-burn wound healing in vivo and promotes proliferation, migration, and angiogenesis in vitro. Drug design, development and therapy. 2015;9:2485–2499. doi:10.2147/DDDT.S82030. PMID:25995620.

   Topical BPC-157 accelerated closure of alkali-burn wounds in rats, with more surface repair and collagen at day 18; separate vessel-lining cells showed growth and migration responses.

3. Heilborn JD, Frohm Nilsson M, Kratz G, Weber G, Sørensen O, Borregaard N, Ståhle-Bäckdahl M. The cathelicidin anti-microbial peptide LL-37 is involved in re-epithelialization of human skin wounds and is lacking in chronic ulcer epithelium. Journal of Investigative Dermatology. 2003;120(3):379–389. doi:10.1046/j.1523-1747.2003.12069.x.

   Human wound samples showed different peptide staining in healing skin and chronic ulcer edges. Blocking LL-37 in cultured human skin slowed surface regrowth.

4. Grönberg A, Mahlapuu M, Ståhle M, Whately-Smith C, Rollman O. 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 and Regeneration. 2014;22(5):613–621. doi:10.1111/wrr.12211.

   A 34-person topical LL-37 trial found faster estimated wound shrinkage at the lowest concentration; the middle-concentration result remained uncertain and the highest did not establish improvement.

5. Mahlapuu M, Sidorowicz A, Mikosinski J, Krzyżanowski M, Orleanski J, Twardowska-Saucha K, Nykaza A, Dyaczynski M, Belz-Lagoda B, Dziwiszek G, Kujawiak M, Karczewski M, Sjöberg F, Grzela T, Wegrzynowski A, Thunarf F, Björk J, Ekblom J, Jawien A, Apelqvist J. Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial. Wound Repair and Regeneration. 2021;29(6):938–950. doi:10.1111/wrr.12977.

   In the larger venous-ulcer trial, complete closure estimates were similar with both topical LL-37 concentrations and placebo. A later analysis suggested a possible benefit in larger ulcers, requiring confirmation.

6. He L, Feng D, Guo H, Zhou Y, Li Z, Zhang K, Zhang W, Wang S, Wang Z, Hao Q, Zhang C, Gao Y, Gu J, Zhang Y, Li W, Li M. Pharmacokinetics, distribution, metabolism, and excretion of body-protective compound 157, a potential drug for treating various wounds, in rats and dogs. Frontiers in pharmacology. 2022;13:1026182. doi:10.3389/fphar.2022.1026182. PMID:36588717.

   Researchers measured intact BPC-157 and its breakdown in rats and dogs. Parent peptide disappeared rapidly from plasma, while radiolabel also represented fragments and later metabolites.

7. Grönberg A, Zettergren L, Ågren MS. Stability of the cathelicidin peptide LL-37 in a non-healing wound environment. Acta Dermato-Venereologica. 2011;91(5):511–515. doi:10.2340/00015555-1102.

   Added LL-37 showed no apparent breakdown in fluid from nine non-healing venous ulcers during the tested incubation, while separate enzyme experiments found breakdown with trypsin but not matrix metalloproteinase-9. These were laboratory observations outside the body.

8. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Agency webpage accessed October 15, 2026.

   FDA identifies insufficient safety information for compounded BPC-157 and LL-37, with potential immune-response and peptide-impurity concerns. The LL-37 entry also cites nonclinical male reproductive harm and tumor-promoting effects in some tissues. It does not quantify human risk or rank the peptides.

9. Miranda E, Bramono K, Yunir E, Reksodiputro MH, Suwarsa O, Rengganis I, Harahap AR, Subekti D, Suwarto S, Hayun H, Bardosono S, Baskoro JC. Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial. Archives of Dermatological Research. 2023;315(9):2623–2633. doi:10.1007/s00403-023-02657-8.

   In 25 adults with diabetic foot ulcers, LL-37 cream produced more new tissue filling the wound bed than matching base cream. Greater wound shrinkage, reduced bacterial counts and reduced inflammatory proteins were not established.