Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library

Thymopentin (TP-5, Timunox): what the evidence says

Name: Thymopentin (TP-5, Timunox)
Published: 2026-10-27

At a glance

What it is: a synthetic pentapeptide (Arg-Lys-Asp-Val-Tyr) matching residues 32–36 of the thymic hormone thymopoietin. ^R1

What the evidence says: two small placebo-controlled trials in atopic dermatitis reported modest benefit. ^{R2, R3} A meta-analysis found no significant overall boost to hepatitis B vaccine response in dialysis patients. ^R4 It did not help chronic hepatitis B ^R5 or significantly cut postoperative infections. ^R6

Biggest risks: no thymopentin-related adverse events were reported in a 12-week dermatitis trial. ^R3

Rating


Human Human evidence	Limited: small RCTs, mixed results ^{R2, R3, R5, R6, R4}
Animal Animal / lab evidence	Mouse thymocyte differentiation ^R1
Regulatory	Not FDA-approved · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page ^{R7, R8, R9} · not named by WADA ^R10
Established human dose	No (see Study details for trial amounts)

Evidence verdict: Atopic dermatitis: Limited (two small positive RCTs) · Hepatitis B vaccine boost in dialysis: Limited (meta-analysis not significant overall) · Chronic hepatitis B: no benefit in one RCT · Postoperative infection: no significant benefit

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: the trials are small and old, and several were negative. HIV trials run by its US sponsor are listed as completed without posted results. ^{R11, R12}

What is it?

Related pages: Thymosin alpha-1, Thymalin, Thymulin, Thymogen.

Does it work?

Human Atopic dermatitis: 100-patient RCT, severity fell more than placebo after 6 weeks (P = 0.04) ^R2; 39-patient RCT, greater improvement at 12 weeks. ^R3
Human Hepatitis B vaccine in dialysis: 11 studies, 272 patients, pooled odds ratio 0.68 (not significant); benefit only in higher-dose subgroup. ^R4
Human Chronic hepatitis B: no benefit over controls (n = 30). ^R5
Human Surgery: infection rate 17.5% vs 24.3%, not significant (n = 206). ^R6
Unknown Anti-aging or general immune boosting in healthy people: no data.

Is it safe?

Human No drug-related adverse events reported in the 12-week dermatitis RCT. ^R3

Gray-market vials: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.

Is it legal?

US: not FDA-approved; no Drugs@FDA application found (openFDA searched Oct 26, 2026).
Compounding: not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R7, R8, R9}
Sport: not named on WADA's 2026 Prohibited List. ^R10

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
Leung 1990	100 atopic dermatitis	SC daily	Per study	6 weeks	Severity score P = 0.04 vs placebo	PMID 2185294
Stiller 1994	39 severe atopic dermatitis	SC 3×/week	50 mg	12 weeks	Greater improvement vs placebo	PMID 8157786
Fattovich 1994	30 chronic hepatitis B	Injection	Per study	6 months + follow-up	No benefit	PMID 7836705
Braga 1994	206 cancer surgery	Perioperative	Per study	Postoperative	Infection 17.5% vs 24.3%, NS	PMID 8156337
Fabrizi 2006	11 studies, 272 dialysis	Adjuvant	Varied	Meta-analysis	OR 0.68, NS	PMID 16696803

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Goldstein G, et al. Science. 1979. PMID 451537
^R2 Leung DY, et al. J Allergy Clin Immunol. 1990. PMID 2185294
^R3 Stiller MJ, et al. J Am Acad Dermatol. 1994. PMID 8157786
^R4 Fabrizi F, et al. Aliment Pharmacol Ther. 2006. PMID 16696803
^R5 Fattovich G, et al. J Hepatol. 1994. PMID 7836705
^R6 Braga M, et al. Br J Surg. 1994. PMID 8156337
^R7 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R8 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R9 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R10 WADA. The 2026 Prohibited List, full list checked; compound not named. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R11 ClinicalTrials.gov NCT00002109, Immunobiology Research Institute phase 3 Timunox HIV trial, completed, no results posted (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT00002109
^R12 ClinicalTrials.gov NCT00002066, Immunobiology Research Institute double-blind HIV trial, completed, no results posted (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT00002066

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Thymopentin (TP-5, Timunox). This compound is not FDA-approved. Any product sold under this name in the US is unregulated. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).