LL-37 Peptide Guide New – Dosages and Side Effects

LL-37 is a potential antimicrobial peptide known to strengthen your immune system. Read more to know everything about LL-37!

Resistance to antibiotics has become a growing cause of concern for scientists all over the world.

This happens when an antibiotic is taken over a long period, and as a result, offending pathogens change to evade the antibiotic.

It’s a growing concern for scientists all over the world, and the statistics are not looking good.

Did you know that in the United States alone, at least 2 million people get infected with antibiotic-resistant bacteria each year, leading to at least 23,000 deaths? That’s a staggering number!

But fear not, for LL-37 peptide is here to save the day! It’s like the superhero of the peptide world, with the ability to treat those pesky resistant infections that antibiotics just can’t handle.

And that’s not all – LL-37 is also a potent modulator of the immune system and an anti-inflammatory peptide. It’s the full package, boosting the overall immunity of the body.

In this LL-37 peptide guide, we are going to explore the benefits of LL-37 using the current scientific literature as well as anecdotal evidence that will ultimately help you make an informed decision regarding the use of this peptide!

Key Takeaways

  • LL-37 is a peptide with potential anti-microbial, anti-inflammatory, and anti-tumor properties.
  • LL-37 triggers and modules your immune response against inflammatory diseases.
  • While the theoretical stuff on LL-37 may sound solid, there is a sheer lack of scientific as well as anecdotal evidence.

Warning: The content on Muscleandbrawn.com and the information included in this article is intended for entertainment and informational purposes only. It is not intended nor implied to be a substitute for professional medical advice. Prior to buying anything, check that it is compliant where you live with your current government laws. We frequently mention research chemicals that are not made for human consumption. Therefore, before purchasing any product for personal use, consult with your doctor or healthcare provider first.

LL-37 Peptide Guide – What is LL-37?

LL-37 is also known as Human Cathelicidin Antimicrobial Peptide (CAMP) and consists of 37 amino acids. (1) It belongs to the group of antimicrobial peptides (AMPs).

It is derived from the C-terminal of Cathelicidin, which is a larger protein and is produced naturally in the human body.

It is expressed by various tissues and bone marrow cells such as neutrophils, keratinocytes, myelocytes, natural killer cells, etc.

What is the Mechanism of Action of LL-37?

The main function of LL-37 is the modulation of the immune system, through which it helps the body in fighting off various harmful microorganisms in the body.

It does this by several mechanisms that are fairly easy to understand!

It is important to note that LL-37 specifically targets microorganisms that have otherwise achieved resistance to conventional antibiotics and are harder to treat.

Therefore, it is a special peptide that targets antimicrobial resistance

Since neutrophils are the first-line cells of the innate immune system that interact with pathogens, they are the main source of LL-37.

Neutrophils synthesize inactive LL-37 precursors, which are released upon exposure to active toll-like receptors. (2

LL-37 belongs to a group of cationic antimicrobial peptides and thus has a net positive charge of 6 which allows it to bind to the negatively charged outer membrane of bacteria, therefore, disrupting it. (3

Fig 1. Real time effects of LL-37 against E.coli 

LL-37 then recruits immune cells such as cytokines, chemokines, T-cells, monocytes, and mast cells to the site of infection, which greatly boosts immune function. (4

A study showed that LL-37 rapidly destroys the lipoprotein membranes of bacteria which are enveloped in phagosomes.

This action can inhibit biofilm formation, which are highly infective communities of microbial cells. One common example is the pseudomonas aeruginosa biofilm. (5)  

LL-37 stimulates the maturation of antigen-presenting dendritic cells. Besides this, LL-37 can also directly kill microbes by initiating apoptosis. (6)  

Apart from its immunomodulatory functions, LL-37 can also act as a potent anti-inflammatory peptide and protect the body from inflammatory damage by activating anti-inflammatory cytokines. 

LL-37 suppresses the translocation of NF-kB to the nucleus, which is a proinflammatory transcription factor.

A study in mice showed that LL-37 strongly reduced the levels of pro-inflammatory cytokines and chemokines. (7

Another lesser-known function of LL-37 is its ability to produce new blood vessels.

It also stimulates the proliferation and migration of endothelial cells required for regeneration, which alongside angiogenesis, promotes quicker wound healing. (8)  

Studies have also suggested that LL-37 can prevent the build-up of plaque within coronary arteries, which protects the body against atherosclerosis and, subsequently, other cardiac conditions. (9

Moreover, evidence suggests that LL-37 can promote bone formation by recruiting stem cells to the site of injury. (10

Benefits of LL-37

Now that we know the mechanism of action of LL-37, we can very easily correlate its benefits!

As an antimicrobial peptide, LL-37 is highly effective in mounting an inflammatory response against antibiotic-resistant pathogens.

This is especially true for staphylococcus aureus, a gram-positive bacteria which is otherwise resistant to many antibiotics.  

LL-37 modulates the immune system of the body through various mechanisms and, as a result, strengthens innate and adaptive immunity, subsequently helping people overcome recurrent infections and illnesses. 

The anti-inflammatory functions of LL-37 make it extremely useful in autoimmune diseases that are predominated by excessive inflammation, such as inflammatory bowel disease, psoriasis, and arthritis. (11)  

This also includes various lung diseases that are often exacerbated by inflammatory responses. LL-37, therefore, attenuates the progression of lung injury by controlling inflammation and preventing infections.   

The apoptotic functions of LL-37 make it a very important peptide in suppressing cancer growth.

This has been observed in studies where the administration of LL-37 suppressed the growth of oral squamous cell carcinoma and colon cancer cells. (12)  

Research has shown that it can also inhibit the migration and invasiveness of prostate cancer cells. (13)  

By promoting angiogenesis and proliferation of mesenchymal stem cells, LL-37 can be extremely beneficial in terms of accelerating wound healing as well as bone repair, which may result from an injury. 

Moreover, by preventing atherosclerosis, LL-37 can act as a cardio-protective peptide by significantly reducing the risk of myocardial infarctions in people. 

Who should use LL-37?

Since LL-37 is primarily an antimicrobial peptide, it can be used to fight off stubborn bacterial infections that are otherwise resistant to common antibiotics. 

It can also be used in chronic inflammatory autoimmune diseases such as psoriasis to fight off complications like psoriatic lesions, which may hinder everyday activities. 

LL-37 has proven to be effective against cancer cells as well. Therefore it can be used in the treatment of various types of cancer, which will eventually improve the prognosis of the disease. 

For patients who are at risk of developing cardio-pulmonary infections, LL-37 can be a useful peptide because of its anti-microbial and anti-inflammatory properties

LL-37 can also be used by people who may have suffered an injury and are looking to promote wound healing.  

Forms of LL-37

LL-37 is only available in the form of an injection so far. This is by the far most potent method of delivery, through which rapid results can be observed. 

How To Use LL-37

LL-37 is most preferably injected intradermally.

Furthermore, while there are no specific guidelines on the administration of LL-37, some common directions must be adhered to. This includes disinfecting the site of injection as well as the needle. 

LL-37 Dosage

Since LL-37 can be used for different purposes, its dosing may vary according to the condition, and therefore a healthcare professional’s advice must be taken. 

General suggestions are to start with 100 mcg per day

LL-37 Cycling

100 mcg vial of LL-37 can be safely administered in a day for up to a maximum of 3 months. To observe benefits, it should be taken for at least one month.

The dosing can also be increased gradually once the peptide has been introduced into the body. 

After one cycle, a break of approximately 2-4 weeks must be given before starting another cycle for the body to regenerate equilibrium. 

LL-37 Stacks

To obtain quicker benefits, stacking of LL-37 is often recommended. 

LL-37 is mostly stacked with TB-500, which is a regenerative peptide that enhances tissue healing and employs anti-inflammatory properties.

It can also be paired with vitamin D, which is thought to have synergistic benefits on the working of LL-37. 

LL-37 User Reviews

Time to dig into some of the user reviews and see what people have to say about the antimicrobial activity of this peptide.

One of the users said,

“I used it for a couple weeks and feel great. My wife and daughter caught a cold and I didn’t.”

Another one said,

“I was on it about three weeks and quit. I had swelling and tenderness in my lymph glands under my arms. Resolved after quitting in about 7-10 days. I was taking 100mcg a day Sub-Q for approximately 3 weeks. Intended to go 50 days but like I said, I cut it off after noticing the tenderness.”

One of the users felt extreme adverse effects as he shared,

“Took LL-37 for 4 weeks 18 months ago. My life hasn’t been the same since (awful spinal muscle spasms, hair dried out, just my entire body feeling completely off). Turns out that this peptide is highly toxic.”

Umm, another peptide user said,

“Incredibly toxic! Ruined my life!”

Seems like people have not had safe experiences with LL-37, time to reconsider your decision, I guess.

πŸ’‰Become a Peptide Expert (Protect your Health) πŸ’‰

Take our FREE 25-email course to learn everything you need to know about the scientific application of peptides. Discover how to protect your health, avoid sketchy peptide vendors, and stop wasting your hard-earned money. πŸ”₯ πŸ§ͺ πŸ’Š πŸ’ͺ πŸ’‰ 🩸πŸ₯ πŸ₯Ž

LL-37 Side Effects

The direct side effects of LL-37 have not been sufficiently reported in the literature, which could be due to a lack of enough research on human subjects.

Other side effects may pertain to the method of delivery of this peptide which includes redness and swelling at the site of injection.    

Where Can I Buy LL-37?

Because LL-37 is not widely used, you will not find many authentic vendors selling LL-37 but needless to worry because, just like every time, BioTech peptides is there to the rescue! 

LL-37 Peptide Summary

LLL-37 Peptide

LL-37 is a naturally occurring antimicrobial peptide that forms a part of the innate immunity. When the body encounters a foreign particle, neutrophils reach to the site of action and release LL-37, even though it is also stored in other tissues and cells. It then binds and disrupts the cell membrane of microbes and recruits immune cells to the site of infection which greatly boosts the body’s immunity.

LL-37 also works as an anti-inflammatory peptide by suppressing the translocation of NFkB to the nucleus and halting the production of inflammatory cytokines. Furthermore, studies have reported that LL-37 can prevent the buildup of plaque in coronary arteries thereby protecting the body from myocardial infarction.


πŸ’‰ Forms : Injectable
πŸ’Š Dosage
: Start with 100 mcg per day
Benefits: Anti-inflammatory and could lower cancer risk
πŸ’Έ Cost : $85.99
⚠️ Side Effects: None reported
Stacks: Ipamorelin, GHK Peptides, and Glutathione

  • Anti-inflammatory
  • Could lower cancer risk
  • None

LL-37 vs. Other Peptides

LL-37Thymosin Beta-4 (TB4)Thymosin Alpha-1KPV
OriginReleased from neutrophils upon interaction with microbesReleased from the thymusIsolated from the hormone alpha-MSH
Wound HealingYesYesYes
Tissue RegenerationYesYes
FDA ApprovalNot approvedNot approvedSome countriesNot approved
Available FormsInjectionInjectionInjectionCream, vial, capsule

LL-37 vs. Thymosin Beta-4 (TB4)

LL-37 and thymosin beta-4 are both naturally occurring peptides that have similar effects on the damaged tissues of the body.

These peptides accelerate wound healing by promoting the development of tissue fibers and blood vessels.

However, LL-37 is an antimicrobial peptide that is released from neutrophils upon interacting with a microbe, whereas thymosin beta-4 is released from the thymus.

LL-37 vs. Thymosin Alpha-1

Both these peptides are strong immunomodulators and therefore reinforce the immune system of the body.

Similarly, like LL-37, thymosin alpha-1 protects the body from foreign microbes.

Due to its efficacy in the treatment of hepatitis and cancer, thymosin alpha-1 has been approved for use in 30 countries as compared to LL-37, which the FDA has not approved as of yet. 

LL-37 vs. KPV

LL-37 and KPV are both very similar peptides due to the effects they produce in the body.

Both these peptides trigger an immune response and possess anti-microbial, anti-inflammatory, and wound-healing properties. 

At the same time, they differ in their source of origin. LL-37 is predominantly released from the neutrophils, whereas KPV is isolated from the hormone alpha-MSH.

It is also available as a cream, vial, and capsule, unlike LL-37, which is only administered as an injection. 

Is LL-37 Legit?

The effects of LL-37 on highly resistant strains of bacteria, such as staphylococcus aureus, have been incomparable so far.

This makes it a highly unique peptide, as it can target antimicrobial resistance.

Moreover, its anti-inflammatory, anti-cancer, and wound-healing properties take it a step further in its role of protecting the body from damage which also makes it more efficacious.

It is, however, important to note that the lack of scientific data about this peptide is a matter of concern.

Side effects of LL-37 have not been fully explored as of yet, and therefore more research is required. And, user experiences also seem to put a break on the ideality of LL-37 as of now.

What I would recommend is to use other alternatives such as KPV or Thymosin Beta 4 before we really know something solid on LL-37!


What is LL-37 peptide usage against fungus?

LL37, a short fragment composed of 37 amino acids, is a unique member of human cathelicidin antimicrobial peptides (CAMPs). It presents with broad-spectrum antimicrobial activity against various pathogens, including prokaryotic and fungal organisms.

What is LL-37 in psoriasis?

In particular, the cathelicidin LL-37 is overexpressed in inflamed skin in psoriasis, binds to extracellular self-DNA released from dying cells, and converts self-DNA in a potent stimulus for plasmacytoid dendritic cells (pDCs). Subsequently, pDCs secrete type I interferons and trigger an auto-inflammatory cascade.

What does cathelicidin LL-37 do?

The human cathelicidin LL-37 serves a critical role in the innate immune system defending against bacterial infections. LL-37 can interact with molecules of the cell wall and perforate cytoplasmic membranes resulting in bacterial cell death.

Comments and questions?

Join our closed Facebook group and get custom answers from the community.

Drop us a comment down below and one of our expert coaches will respond to it.


Kumar Rathi

Kumar Rathi | Writer

Kartik is a medical student with a passion for anatomy and physiology. He writes research papers, articles and blogs to raise awareness and also has a strong interest in teaching and public speaking. Aspiring to be a successful cardiologist, Kartik believes in connecting with people on a personal level and is an expert in peptides.

Read all articles
Notify of

Newest Most Voted
Inline Feedbacks
View all comments
10 months ago

Hello, I recently purchased a peptide blend of Fragment 176-191(6mg) & CJC-1295(3mg) & Ipamorelin(3mg). I have my bacteriostatic water. I have no idea how to mix or the dosage for an adult male. Can someone help me? Thank you.

Daniel Louwrens BSc PT
8 months ago
Reply to  Matt

Mechanism of Action

LL-37 is a naturally occurring antimicrobial peptide that forms a part of the innate immunity. When the body encounters a foreign particle, neutrophils reach to the site of action and release LL-37, even though it is also stored in other tissues and cells. It then binds and disrupts the cell membrane of microbes and recruits immune cells to the site of infection which greatly boosts the body’s immunity. LL-37 also works as an anti-inflammatory peptide by suppressing the translocation of NFkB to the nucleus and halting the production of inflammatory cytokines. Furthermore, studies have reported that LL-37 can prevent the buildup of plaque in coronary arteries thereby protecting the body from myocardial infarction.

Class of Compound


Street Names

LL-37, Human Cathelicidin Antimicrobial Peptide


Anti-microbial ,Anti-inflammatory ,Boosts immune function

Side Effects and Dangers

Redness at site of injection


Check out our best peptide company rankings comparing 🏷️costs, πŸ“¦ delivery times, πŸ“„ πŸ§ͺtesting methods, and ⭐️ public reviews!