Thymosin alpha-1 with KPV and LL-37
Thymosin alpha-1 with KPV and LL-37 (immune and gut blend)
Written by Aaron CuhaReviewed Sep 2026
Also known as: TA1 KPV LL-37, Immune blend, Gut immune trio
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
A three peptide immune blend from the clinic side of this market. One organises the immune system, one calms inflammation, one kills bugs. The one with the biggest trial behind it was tested in 1,106 people and it did not work.
What people take it for
- Getting fewer colds and infections.
- Long term infections that will not clear.
- Gut inflammation.
- Immune support after being ill.
What the trials actually showed
Nobody has tested the three together. Thymosin alpha-1 got a proper test. A blinded trial put 1,106 adults with sepsis into two groups across 22 hospitals. Deaths at 28 days were 23.4 percent on the drug and 24.1 percent on the dummy. No real difference. Nothing else differed either. Several of the doctors running it got grants from the maker, which the paper says. LL-37 has the best file of the three, and it is for wounds you put it on. Thirty four people with stubborn leg ulcers got it as a topical treatment. The two lower strengths healed about six times and three times faster than the dummy, and ulcer size dropped 68 percent and 50 percent. The strongest one did nothing at all. Read that again, because it matters: more was not better. A later trial tested an LL-37 cream on diabetic foot ulcers. KPV has no human data of any kind. Sellers do not agree on vial sizes, so no per unit number here.
What people report
Reports, not trial results
The good
- Fewer or shorter colds over a winter.
- Gut symptoms settling, credited to the KPV.
The bad
- Flu like symptoms and tiredness in the first days.
- Shot site reactions and hot itchy flushing, reported more for the LL-37 part.
- Nothing at all.
- One part calms inflammation, one part stirs the immune system up, and one part can do either. Nobody has checked whether they add up or cancel out.
Where these come from: Clinic write-ups and forums for long term infection. People talking, about something that changes with the seasons and that almost nobody counted before they started.
My bottom line
The wound trial here teaches the thing blends get wrong. The strongest dose worked no better than nothing. More of a good ingredient is not automatically better, and nobody picked these amounts from data.
An opinion, not a finding. I am a coach, not a doctor.
Overview
A three-peptide immune blend from the clinic end of the market. The component with the largest trial, thymosin alpha-1, was tested in 1,106 adults with sepsis and did not reduce 28 day mortality. LL-37 has two small positive topical wound trials. KPV has no human data. The combination has never been tested and no vial size is canonical.
The pitch is that one peptide organises the immune response, one calms inflammation and one kills microbes while helping tissue repair. Each third has its own evidence, and one of those files contains a large negative trial that rarely appears in the marketing.
Thymosin alpha-1 is a 28 amino acid thymic peptide and is an approved medicine in several countries. The TESTS trial randomised 1,106 adults with sepsis across 22 centres in China to subcutaneous thymosin alpha-1 or placebo every 12 hours for seven days. Twenty eight day all cause mortality was 23.4% in the treated group and 24.1% in the placebo group, hazard ratio 0.99, and no secondary or safety outcome differed significantly. The trial concluded there was no clear evidence that thymosin alpha-1 decreases 28 day mortality in sepsis. Prespecified subgroups suggested different effects by age and by diabetes status. Several investigators received grants from the manufacturer, disclosed in the paper.
That is a properly powered, double-blinded, placebo-controlled phase 3 trial of the best-evidenced component in this blend, and it was negative in the population it studied. It does not mean the peptide does nothing in every setting, and it is the single most informative result about it.
LL-37 is the human cathelicidin and has the most favourable file of the three, in topical wounds. In a first-in-man randomised placebo-controlled trial in 34 people with hard-to-heal venous leg ulcers, healing rate constants at 0.5 and 1.6 mg/mL were about six-fold and three-fold higher than placebo, mean ulcer area fell 68% and 50% in those groups, and the highest dose at 3.2 mg/mL showed no difference from placebo. A later randomised double-blind trial studied LL-37 cream in diabetic foot ulcers. Both are topical, on wounds.
KPV has no human data at all, by any route, and no registered study.
No vendor or compounder split is canonical for this trio, so this page does not state per-unit amounts. What can be said is that the component with a large negative trial and the component with no data are being sold alongside the one with small positive topical results, and the product is injected rather than applied to a wound.
Mechanism of action
Thymosin alpha-1 modulates T lymphocyte function, interleukin-2 signalling and interferon gamma production. LL-37 is a cationic amphipathic antimicrobial peptide with direct antimicrobial and immunomodulatory activity, and can also promote inflammation in some contexts. KPV is the C-terminal tripeptide of alpha-MSH and suppresses NF-kB and MAP kinase signalling. No publication describes what the three do together, and the fact that one component is pro-inflammatory in some settings while another is anti-inflammatory is an interaction nobody has characterised.
Human evidence
One component has a large negative phase 3 trial, one has two small positive topical wound trials, and one has no human data.
- The blend: no published study, no registered trial.
- Thymosin alpha-1 in sepsis: 1,106 adults, 28 day mortality 23.4% against 24.1% on placebo, hazard ratio 0.99. No clear evidence of benefit.
- LL-37 in venous leg ulcers: 34 participants, healing rate constants about six-fold and three-fold higher than placebo at the two lower doses, mean ulcer area down 68% and 50%, with no effect at the highest dose.
- LL-37 in diabetic foot ulcers: a randomised double-blind controlled trial of the topical cream.
- KPV: no human data of any kind and no registered study.
What this does not tell you: The LL-37 evidence is topical, on open wounds, at defined concentrations. Injecting it for systemic immune effect is a different intervention that has not been studied, and the peptide has pro-inflammatory as well as antimicrobial actions depending on context.
What it has been measured to do
Measured in people
Goals Thymosin alpha-1 with KPV and LL-37 has been measured for in a human being, most people first. Counts come from the study lines on this page and deliberately undercount.
- Living longer1,106 people · 1 study
- Wound and skin healing34 people · 2 studies · 1 found nothing
Measured in animals or cells, not yet in people
Real results that answer a different question from a trial. Where a human trial is missing on a compound nobody can patent, the reason is usually that no sponsor would ever recover the cost of running one. The record on this one is set out below.
- Losing weight1 preclinical study
What people using it report
Uncontrolled and self-selected, so it cannot show that anything works. It is still the best guide on this page to what people actually do with Thymosin alpha-1 with KPV and LL-37, what they expect, and what goes wrong. The full account, including the negative reports, is below.
31 of the 36 indexed goals have no study of any kind behind Thymosin alpha-1 with KPV and LL-37
No trial, no animal work, no cell work on this page reports a result for these. That is an absence of evidence rather than evidence of absence, but it does mean anything you have been told about Thymosin alpha-1 with KPV and LL-37 and one of these did not come from a study cited here.
Reading the research record
The LL-37 dose-response result is the most instructive thing on this page and it deserves to be read carefully. The two lower concentrations worked and the highest concentration did not differ from placebo. That is the opposite of the assumption underlying most blend dosing, which is that more of a good ingredient is better. Where a real dose-response has been measured in this family, the curve was not monotonic.
The second point is about the sepsis trial. A negative phase 3 in critically ill patients does not settle whether a peptide modulates immunity in a healthy person with recurrent infections. It does mean that the component here with the largest and best-conducted human trial did not improve the outcome it was tested for, and that fact belongs next to any claim made for it.
Third, the interaction question. One component is anti-inflammatory, one is immunostimulatory and one has both antimicrobial and pro-inflammatory properties depending on context. Combining them in a fixed ratio assumes those actions sum. Nobody has checked whether they cancel.
The evidence, charted
Fig. 1a · evidence scale
1,140people, across 2 human studies cited here
- 2025 · BMJ1,10697%
- 2014 · Wound Repair and Regeneration343%
One study holds 97% of these participants, so the total is less independent than its size suggests. Counts are the enrollment each human citation on this page states, which includes observational cohorts where nobody was given the compound. 1 further human citation states no participant count and is not counted here. Studies still recruiting are excluded, and only studies cited on this page are counted.
Fig. 1b · evidence mix
3 of 5 citations here are human work, the rest are not.
- Human · given to people360%
- Animal · given to animals120%
- Review · summarises other work120%
Counted from the citation list on this page, typed as this page types it. It understates any literature larger than the sources we cite, and a review counts once however many studies it covers.
Fig. 2 · evidence over time
Evidence spans 5 distinct years, 2008 to 2025, counted from the citation list on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four jurisdictions shown. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Fig. 4 · dose response
No human dose response curve exists
We draw this figure where the data supports it. For this compound in humans it does not, so the panel stays empty rather than borrowing an animal curve and implying it transfers.
Fig. 5 · molecular identity
- Modality
- Blend
- Molecular weight
- Not on file
- Half-life
- Stated in words, not a number
- Sequence length
- None on file
see the exact wording below
Half-life as stated on file: Not defined for the blend. No pharmacokinetic study of the mixture exists and the components differ in clearance.
No amino acid sequence is on file for Thymosin alpha-1 with KPV and LL-37, which is expected: a blend is not built from residues.
Fig. 6 · what is in the vial
No mass split can be drawn for this blend
Sellers do not publish a consistent vial size for Thymosin alpha-1 with KPV and LL-37, so the share of each component is not knowable from the outside. Splitting the bar evenly would invent the number this page exists to question.
- Thymosin alpha-1amount not stated
- KPVamount not stated
- LL-37amount not stated
Component list from the product labels we hold. Amounts are label mass, never a dose.
Key studies & citations
- Human2025
The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial
1,106 adults with sepsis across 22 centres in China, randomised 1 to 1 to subcutaneous thymosin alpha-1 or placebo every 12 hours for seven days. 28 day all cause mortality was 23.4% on thymosin alpha-1 and 24.1% on placebo, hazard ratio 0.99, 95% CI 0.77 to 1.27, p = 0.93. No secondary or safety outcome differed significantly. The trial found no clear evidence that thymosin alpha-1 decreases 28 day mortality in sepsis. Several authors received grants from the manufacturer, disclosed in the paper.
BMJ - Human2014
Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial
34 participants with venous leg ulcers, three week open-label placebo run-in then four weeks of randomised double-blind twice weekly topical LL-37 at 0.5, 1.6 or 3.2 mg/mL or placebo. Healing rate constants at 0.5 and 1.6 mg/mL were about six-fold and three-fold higher than placebo, p = 0.003 and p = 0.088. Mean ulcer area fell 68% and 50% in those groups. The highest dose showed no difference from placebo. Topical, on wounds, first in man.
Wound Repair and Regeneration - Human2023
Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial
A randomised double-blind controlled trial of LL-37 cream in diabetic foot ulcer healing. The second controlled human study of this peptide and again topical, on a wound, rather than injected for systemic immune effect.
Archives of Dermatological Research - Animal2008
Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease
In two mouse colitis models KPV produced earlier recovery, greater body-weight regain, fewer inflammatory infiltrates and lower myeloperoxidase activity in colon tissue. Mice, KPV given alone, nothing here about a blend or about people.
Inflammatory Bowel Diseases - Review2019
Are melanocortin peptides future therapeutics for cutaneous wound healing?
A dermatology review describing KPV as a truncated alpha-MSH peptide that keeps the anti-inflammatory activity without the pigment-inducing activity, and proposing peptides of this class as future candidates for cutaneous wounds. The experimental approaches it surveys are in silico, in vitro, ex vivo and animal.
Experimental Dermatology
What users report
Self-reported experiences, not evidence. Nothing below was measured under controlled conditions, and reports like these cannot separate a real effect from placebo, from the training or diet change that accompanied it, or from what the product actually contained. They are here because knowing what people describe, including what goes wrong, is worth reading alongside the studies.
- Fewer or shorter respiratory infections over a season, the main claimed effect.
- Gut symptoms settling, credited to the KPV.
- Flu-like symptoms or fatigue in the first days, which people describe as an immune response.
- Injection site reactions and histamine-type flushing, reported more often for the LL-37 component than for the others.
- Nothing at all.
Sources: Clinic write-ups, chronic infection and peptide forums. Uncontrolled self-reports in a domain where seasonal variation dominates and where infection frequency is rarely counted before starting.
Frequently asked questions
Did the thymosin alpha-1 trial work?
No. In 1,106 adults with sepsis, 28 day all cause mortality was 23.4% on thymosin alpha-1 and 24.1% on placebo, hazard ratio 0.99. The trial concluded there was no clear evidence of benefit.
What is the LL-37 evidence?
Two randomised controlled trials, both topical on wounds. In venous leg ulcers the two lower concentrations increased healing rate constants about six-fold and three-fold over placebo while the highest concentration did nothing. A later trial studied the cream in diabetic foot ulcers.
Does KPV have human data?
None, by any route, and no registered study. The record is mouse colitis, cell culture and review commentary.
Is more of each better?
The one dose-response measured in this family says no. In the venous leg ulcer trial the highest LL-37 concentration performed no better than placebo while the two lower ones worked.
What vial size should I expect?
There is no canonical split for this trio, which is why this page does not print per-unit amounts. Work them from the milligram breakdown on your own label.