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 KPV and TB-500 — mechanism, side effects, legal status, and pricing.
KPV (Lys-Pro-Val) is the C-terminal tripeptide of alpha-melanocyte-stimulating hormone (alpha-MSH residues 11-13), the smallest alpha-MSH fragment retaining anti-inflammatory activity. Research-only; not FDA-approved. Evidence is primarily preclinical with no controlled human trials.
TB-500 is a synthetic N-acetylated heptapeptide (Ac-LKKTETQ) corresponding to amino acids 17–23 of thymosin β4, the actin-binding region of the native 43-residue protein. Despite widespread vendor labeling, TB-500 is NOT identical to full-length thymosin β4 (Tβ4); it is a short fragment containing the central actin-binding motif. It is sold as a research chemical and is not FDA-approved for any human indication.
KPV
TB-500
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
KPV
TB-500
COA corpus from Disclosed Labs — independently tested batches only.
KPV
89
COAs
99.5%
Avg purity
15
Labs
TB-500
170
COAs
99.3%
Avg purity
16
Labs
TB-500 is among peptides under FDA review for the Category 1 (503A) list; if added, it would require a prescription to be compounded by registered 503A/503B pharmacies — not yet authorized. KPV remains research-only. In April 2026 the FDA removed 12 peptides from Category 2, which does not place them on the Category 1 list or authorize compounding. The FDA's Pharmacy Compounding Advisory Committee is advisory and meets July 23–24, 2026 to review nominations and make recommendations to the FDA.
Dalmasso et al. (Gastroenterology 2008; PMID 18061177) demonstrated PepT1-mediated uptake of KPV and reduction of DSS- and TNBS-induced colitis in mice. Kannengiesser et al. (Inflammatory Bowel Diseases 2008; PMID 18092346) showed anti-inflammatory effects in two murine colitis models at least partly independent of MC1R signaling. Brzoska et al. (Endocrine Reviews 2008; PMID 18612139) reviewed alpha-MSH and related tripeptides, summarizing NF-kB suppression across cell types. Subsequent preclinical work (largely from the Merlin group at Georgia State) has explored oral nanoparticle and polysaccharide-hydrogel delivery for IBD. No controlled human trials have been published.
Key references
Animal studies of full-length Tβ4 show accelerated dermal wound reepithelialization (Malinda et al., 1999, PMID 10469335), increased angiogenesis, improved cardiac function after ischemic injury via an ILK/Akt pathway (Bock-Marquette et al., Nature 2004, PMID 15565145), and corneal healing (Sosne & Kleinman review, 2015, PMID 26241398). The short Ac-LKKTETQ peptide sold as TB-500 was characterized analytically in the anti-doping literature as a substance with suspected doping potential (Esposito et al., 2012, PMID 22962027); controlled human efficacy trials of injected TB-500 do not exist. Full-length synthetic Tβ4 (RGN-259) has been evaluated in Phase II/III ophthalmic trials for dry eye disease and neurotrophic keratopathy with mixed results — one Phase III NK trial met healing endpoints, while a later European Phase III missed its primary endpoint. No clinically validated human injection dose exists for the short TB-500 peptide; all circulating dosing figures derive from vendor and forum protocols, not controlled trials.
KPV (Immune) and TB-500 (Recovery) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any 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
Key references
Disclosed Labs