An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.
Sun. J J; Dahlén. B B; Agerberth. B B; Haeggström. J Z JZ
The study shows that the natural antimicrobial peptide LL‑37 can activate eosinophils, the white‑blood cells that drive asthma attacks, causing them to release inflammation‑triggering molecules called cysteinyl leukotrienes and eosinophil cationic protein. This effect is stronger when the cells are already primed by asthma‑related signals or come from people with asthma. In short, LL‑37 may worsen airway inflammation rather than help it.
Nylén. Frank F; Miraglia. Erica E; Cederlund. Andreas A; Ottosson. Håkan H; Strömberg...
Scientists created a lab test that can spot chemicals that make cells produce more of the immune peptide LL‑37, which helps protect against infections. They used the test to screen existing drugs and found five new compounds that boost LL‑37, but they haven’t tested them in people yet.
Ordonez. Soledad R SR; Amarullah. Ilham H IH; Wubbolts. Richard W RW; Veldhuizen. Edwin J A EJ; Haag...
The study shows that the human peptide LL‑37 can quickly kill the fungus Candida albicans by punching holes in its cell membrane, but it’s not as fast or powerful as a similar chicken peptide called CATH‑2. All three peptides work differently, and LL‑37’s action doesn’t need the fungus’s energy supply.
Rico-Mata. Rosa R; De Leon-Rodriguez. Luis M LM; Avila. Eva E EE
The study found that the human antimicrobial peptide LL‑37 and three shorter versions (KR‑12, KR‑20, KS‑30) can kill the gut parasite Entamoeba histolytica in lab tests, with KR‑20 being the strongest. However, the peptides work only at relatively high concentrations (10‑50 µM) and the parasite’s enzymes can break them down, so they aren’t ready for practical self‑use yet.
The study found that people with healthy gums have the most LL‑37, an antimicrobial peptide, in their saliva, while those with gum disease have less, and people without teeth have the least. Women with healthy gums showed slightly higher levels than men. This suggests that keeping your teeth and gums intact may help maintain natural oral defenses.
Giving pregnant women a weekly dose of vitamin D lowered the amount of the antimicrobial peptide LL‑37 inside newborn immune cells when those cells were activated, but it didn’t change the cells' ability to kill bacteria in lab tests.
Wang. Guangshun G; Hanke. Mark L ML; Mishra. Biswajit B; Lushnikova. Tamara T; Heim. Cortney E CE; C...
Scientists tweaked the human antimicrobial peptide LL-37 to make it tougher against digestive enzymes and broaden its killing power against a wide range of dangerous bacteria. The new version, called 17BIPHE2, can break bacterial membranes, bind DNA, stop biofilm formation on catheters in mice, and even boost the body's own immune response. However, it’s still only tested in labs and mice, so it isn’t ready for personal use yet.
Scientists found that the natural peptide LL-37 can turn regular immune cells (monocytes) into a new type of bone‑forming cell called monoosteophils. When these cells were put into bone holes in special mice, the bones healed faster—about two weeks instead of three or more. The effect depends on a protein called MAPK13, and the cells show high levels of bone‑related genes.
Picchianti. Monica M; Russo. Carla C; Castagnini. Marta M; Biagini. Massimiliano M; Soldaini. Elisab...
Scientists found that the immune peptide LL-37 can have up to four of its five arginine spots chemically tagged with ADP‑ribose when it meets the enzyme ART1 and lots of NAD. This tagging adds negative charge, making LL-37 less positively charged, which could weaken its ability to stick to cell membranes and other negatively charged molecules like DNA. The change might alter how LL-37 works in the body, but the experiments were done in a test tube, not in people.
Pinheiro da Silva. Fabiano F; Medeiros. Maria Cristina Rodrigues MC; Dos Santos. Ângela Batista...
Scientists found that the immune peptide LL‑37, which normally fights germs outside cells, can actually move into the cell nucleus when the body is fighting a huge infection. This suggests LL‑37 might do more than just kill bacteria, possibly influencing how genes are turned on or off, but we don’t yet know what that means for health or performance.
Eick. Sigrun S; Puklo. Magdalena M; Adamowicz. Karina K; Kantyka. Tomasz T; Hiemstra. Pieter P; Sten...
The study shows that people with Papillon‑Lefèvre syndrome can't turn the protein hCAP18 into the antimicrobial peptide LL‑37 because a key enzyme is broken. Without LL‑37, harmful bacteria build up in the gums, causing severe early‑onset gum disease. This highlights LL‑37’s crucial role in keeping the mouth healthy.
Scientists engineered bacteria to make two new antimicrobial peptides—a dimer of porcine protegrin‑1 and a hybrid of human LL‑37 linked to histatin‑5—then purified them and proved they kill E. coli and Staph aureus in lab tests. The work shows a way to produce these peptides, but it doesn’t give dosing, safety, or direct human‑use instructions.
The study shows that the antimicrobial peptide LL-37 is found at very high levels in the urine of children with spina bifida and that, when put into mouse bladders, it causes inflammation that gets worse with higher doses and involves mast cells. This suggests that too much LL-37 can irritate the bladder and trigger immune cells.
Liu. Wei W; Dong. Shi Lei SL; Xu. Fei F; Wang. Xue Qin XQ; Withers. T Ryan TR; Yu. Hongwei D HD; Wan...
Scientists made E. coli produce the human antimicrobial peptide LL‑37 inside the cells and found it stops the bacteria from growing, both with oxygen and without. The peptide creates harmful reactive oxygen species when oxygen is present and makes the bacterial membrane leaky, while also messing with the bacteria’s energy‑making genes.
Salvado. M Dolores MD; Di Gennaro. Antonio A; Lindbom. Lennart L; Agerberth. Birgitta B; Haeggstr&#x...
The study shows that the human peptide LL‑37 can make blood‑vessel cells grow new vessels by turning on a chain of chemicals (COX‑1 → PGE2 → EP3). This effect can be stopped by aspirin, which blocks the same pathway. The findings are mostly basic science and don’t give dosage or safety info for people who might want to use LL‑37 as a supplement.
Singh. Divyendu D; Qi. Rongsu R; Jordan. Jarrat L JL; San Mateo. Lani L; Kao. C Cheng CC
The human peptide LL‑37 can grab double‑stranded RNA (like viral genetic material) and help it trigger immune sensors inside cells, while the mouse version can’t do this. This effect needs a specific cell‑surface receptor (FPRL1) and changes how the RNA is trafficked inside the cell.
Liu. Quan Q; Liu. Juan J; Roschmann. Kristina Irene Lisolette KIL; van Egmond. Danielle D; Golebski....
Researchers found that chemicals that block histone deacetylases, like the drug trichostatin A and the natural compound sodium butyrate, can turn on the gene for the antimicrobial peptide LL‑37 in airway cells. This effect happens even without viral‑mimic stimulation, and the same chemicals also dampen an inflammation signal (IL‑6). However, only the lab‑grown cell line showed more LL‑37 protein, not the primary nasal cells, so it’s still early evidence.
Antoni. Lena L; Nuding. Sabine S; Weller. Dagmar D; Gersemann. Michael M; Ott. German G; Wehkamp. Ja...
The study shows that the colon’s mucus layer naturally stores antimicrobial peptides like LL‑37 and still kills bacteria even when attached to mucus, meaning the gut’s own defenses stay active. This suggests that keeping the mucus barrier healthy could be important for gut immunity, but the paper doesn’t give a new supplement or dosage plan.
Duperthuy. Marylise M; Sjöström. Annika E AE; Sabharwal. Dharmesh D; Damghani. Fatemeh F;...
The study found that the cholera bacterium can release tiny vesicles that contain a protein called Bap1, which grabs onto the human antimicrobial peptide LL‑37 and blocks its action, giving the bacteria protection against both LL‑37 and another antibiotic called polymyxin B. For biohackers, this means that some bacteria can neutralize LL‑37, so its effectiveness may be limited in infections where Bap1‑producing microbes are present.
LL-37 is a natural protein your body makes that can kill microbes, tweak the immune system, reduce inflammation, affect blood vessel growth, and even influence cancer cells, both positively and negatively. The paper is a broad review, so it doesn’t give specific dosing or protocols for DIY use.