§ — Researched for · Immune function & inflammation
Thymosin alpha-1 is the only immune peptide with randomized trials behind it, and it is approved in over 30 countries — but not by the FDA or EMA. LL-37 and KPV remain at animal or early-phase stage; an FDA advisory committee recommended listing KPV in July 2026 — FDA has not decided — and will review LL-37 before the end of February 2027.
Reviewed October 2026 · Sources: FDA, EMA
02 — What is being studied
Research here splits between immune modulation and antimicrobial defence. Thymosin alpha-1 has been studied in sepsis, hepatitis B and as a vaccine adjuvant, with randomised trials and mortality endpoints in critical care. LL-37 is a human cathelicidin studied for direct antimicrobial activity and wound colonisation; KPV is an alpha-MSH fragment studied for mucosal inflammation in colitis models.
The endpoints under study are infection rates, mucosal healing and inflammatory markers rather than the general 'immune support' language used in marketing. Human data outside thymosin alpha-1 is early-phase or absent, and the concept of boosting an immune system that is not deficient has no measured endpoint at all. FDA has scheduled LL-37 for reconsideration in early 2027, so the regulatory picture in this group is expected to move.
03 — The table
| Peptide | Researched for | Evidence | Regulatory status | As of |
|---|---|---|---|---|
| Thymosin alpha-1 | Hepatitis B and C adjunct, sepsis, vaccine response, cancer adjunct, COVID-19. | B | Not FDA-approved in the United States. The advisory committee reviewed it on December 4, 2024, and did not recommend it for the 503A Bulks List. It is not on the list and cannot be compounded under section 503A. | 2026-10-22 |
| BPC-157 | Tendon, ligament and muscle healing; gastrointestinal mucosal protection; ulcerative colitis (the indication FDA reviewed in 2026). | C | Not FDA-approved for any use. Removed from 503A Category 2 on April 15, 2026, after its nomination was withdrawn — which is not a listing in Category 1. On July 23, 2026, the Pharmacy Compounding Advisory Committee voted 8–6 (one abstention) to recommend it for the 503A Bulks List; FDA's own scientists had recommended against. FDA has not decided. It is not on the 503A Bulks List, so it cannot yet be compounded under section 503A. | 2026-10-22 |
| KPV | Inflammatory bowel disease, skin inflammation. | C | Not FDA-approved. Removed from 503A Category 2 on April 15, 2026. On July 23, 2026, the advisory committee voted 8–6 (one abstention) to recommend it for the 503A Bulks List, against the advice of FDA's scientists. FDA has not decided; it cannot yet be compounded under section 503A. | 2026-10-22 |
| LL-37 | Chronic wound infection, biofilm disruption, venous leg ulcers. | C | Not FDA-approved. Removed from 503A Category 2 on April 15, 2026, and scheduled for review by the advisory committee before the end of February 2027. It is not on the 503A Bulks List. | 2026-10-22 |
04 — Per peptide
Regulatory status · United States · as of October 2026
Not FDA-approved in the United States. The advisory committee reviewed it on December 4, 2024, and did not recommend it for the 503A Bulks List. It is not on the list and cannot be compounded under section 503A.
Source: FDA 503A Bulks List · PCAC meeting records · verified October 2026
Researched forHepatitis B and C adjunct, sepsis, vaccine response, cancer adjunct, COVID-19.
Full profile: Thymosin alpha-1 →Regulatory status · United States · as of October 2026
Not FDA-approved for any use. Removed from 503A Category 2 on April 15, 2026, after its nomination was withdrawn — which is not a listing in Category 1. On July 23, 2026, the Pharmacy Compounding Advisory Committee voted 8–6 (one abstention) to recommend it for the 503A Bulks List; FDA's own scientists had recommended against. FDA has not decided. It is not on the 503A Bulks List, so it cannot yet be compounded under section 503A.
Source: FDA 503A Bulks List · PCAC meeting records · verified October 2026
Researched forTendon, ligament and muscle healing; gastrointestinal mucosal protection; ulcerative colitis (the indication FDA reviewed in 2026).
Full profile: BPC-157 →Regulatory status · United States · as of October 2026
Not FDA-approved. Removed from 503A Category 2 on April 15, 2026. On July 23, 2026, the advisory committee voted 8–6 (one abstention) to recommend it for the 503A Bulks List, against the advice of FDA's scientists. FDA has not decided; it cannot yet be compounded under section 503A.
Source: FDA 503A Bulks List · PCAC meeting records · verified October 2026
Researched forInflammatory bowel disease, skin inflammation.
Full profile: KPV →Regulatory status · United States · as of October 2026
Not FDA-approved. Removed from 503A Category 2 on April 15, 2026, and scheduled for review by the advisory committee before the end of February 2027. It is not on the 503A Bulks List.
Source: FDA 503A Bulks List · PCAC meeting records · verified October 2026
Researched forChronic wound infection, biofilm disruption, venous leg ulcers.
Full profile: LL-37 →05 — What the data does not show
General immune 'boosting' in healthy adults and immune rejuvenation with age have not been shown.
06 — Questions for your physician
Every practice in the registry that lists peptide therapy, sorted by distance and nothing else. You contact the practice directly.
Austin, TX
Focus matches this goal: Concierge / Membership Model, Functional Medicine, GLP-1 / Medical Weight Management
Physician credentials on file
La Jolla, CA
Focus matches this goal: Biological Age & Epigenetics, Cognition & Brain Health, Functional Medicine
No physician listed on the practice website
Chandler, AZ
Focus matches this goal: CGM / Metabolic Diagnostics, Concierge / Membership Model, DEXA / Body Composition
Physician credentials on file
San Francisco, CA
Focus matches this goal: Advanced Blood Biomarkers, Biological Age & Epigenetics, Cognition & Brain Health
Ahvie Herskowitz, MD · Ann Lee, MD
Studio City, CA
Focus matches this goal: Biological Age & Epigenetics, Cryotherapy / Sauna / Red Light, Functional Medicine
No physician listed on the practice website
Asheville, NC
Focus matches this goal: Advanced Blood Biomarkers, Concierge / Membership Model, DEXA / Body Composition
Physician credentials on file
Listed for transparency, not as an endorsement of any practice, substance or protocol. Most peptides are not FDA-approved for the uses they are offered for.
Reviewed October 2026 · Sources: FDA, EMA
This page reports on the state of research and regulation for orientation. It is not medical advice, not a recommendation for or against any substance, and not an offer. Regulatory status changes; the date shown is the date of our last verification. Discuss any treatment with a licensed physician.
Most peptides used in longevity practice are not FDA-approved for these uses. Check the status of each substance first.