Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of LL-37 and Thymalin — mechanism, side effects, legal status, and pricing.
LL-37 is the only human cathelicidin antimicrobial peptide — a 37-amino-acid peptide (starting with two leucines) cleaved from the hCAP-18 precursor. It has broad-spectrum antimicrobial activity and immunomodulatory roles, but is also implicated in the pathogenesis of autoimmune and inflammatory skin diseases including psoriasis, rosacea, and lupus. Not FDA-approved; research-use only.
Thymalin is a heterogeneous polypeptide extract from calf thymus (a mixture, not a single defined peptide) developed in the 1970s by V. Kh. Khavinson and V. G. Morozov at the Military Medical Academy / St. Petersburg Institute of Bioregulation and Gerontology. Registered as a pharmaceutical in the USSR/Russia for immunocorrection. Distinct from Thymulin (Bach's zinc-dependent nonapeptide pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, originally called FTS) and from Thymosin alpha-1 (a 28-amino-acid synthetic peptide). Not FDA-approved in the US; research-use only.
LL-37
Thymalin
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
LL-37
Thymalin
COA corpus from Disclosed Labs — independently tested batches only.
LL-37
31
COAs
99.2%
Avg purity
8
Labs
Thymalin
13
COAs
99.5%
Avg purity
6
Labs
LL-37 was characterized in the mid-1990s as the processed antimicrobial product of hCAP-18 (Gudmundsson et al., 1996). Dürr et al. (2006, Biochim Biophys Acta, PMID 16716248) provided a foundational review of its structure and activity as the sole human cathelicidin. Overhage et al. (2008, Infection and Immunity, PMID 18591225) showed LL-37 prevents Pseudomonas aeruginosa biofilm formation at 0.5 µg/mL — far below its MIC. A randomized, placebo-controlled Phase 1/2 trial (Grönberg et al., 2014, Wound Repair and Regeneration, PMID 25041740) found topical LL-37 safely accelerated healing of hard-to-heal venous leg ulcers at low doses. Its dual role in autoimmunity is well established: Lande et al. (2014, Nature Communications, PMID 25470744) identified LL-37 as a T-cell autoantigen in two-thirds of moderate-to-severe plaque psoriasis patients. No FDA approval exists for any indication. Injectable grey-market protocols for Lyme, biofilm, or mold illness lack controlled clinical evidence and carry theoretical autoimmune risk given LL-37's role in psoriasis, lupus, and rosacea pathogenesis.
Key references
Evidence base is almost entirely single-lab (Khavinson/Morozov, St. Petersburg). Long-term observational work in elderly Russian cohorts reported reduced all-cause mortality and lower incidence of respiratory infections with Thymalin (alone or with Epithalamin) over 6–8 years, but these were not blinded Western RCTs and have not been independently reproduced. No FDA-registered clinical trials.
Key references
LL-37 and Thymalin are both in the Immune category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Disclosed Labs