Peptide Association

Insights

NewsBlog
Start free intake

DisclosurePeptide Association LLC is a for-profit company. We receive compensation from the clinical providers listed on this site. We are not an accrediting body, a licensing board, or a government-affiliated organization. See exactly how we make money.

All peptides

Immune · Research Phase

Thymulin

No lawful US pathway

Tell me if this changesRead the free 2026 Peptide Safety Checklist →
Written by Peptide Association Editorial TeamLast reviewed Editorial policy

01 · Overview

A zinc-containing nonapeptide (facteur thymique serique) produced exclusively by thymic epithelial cells, whose biological activity depends on bound zinc (PMID 19236333). Thymulin is involved in intrathymic and extrathymic T-cell differentiation and has anti-inflammatory properties in experimental models (PMID 19236333).

Mild zinc deficiency lowers serum thymulin activity and is corrected by zinc supplementation, linking nutritional status to immune competence (PMID 3262625).

02 · Research summary & key findings

Serum thymulin declines with age in healthy men and women, with the decline starting about a decade earlier in men (PMID 3772725). In institutionalized elderly people, low-dose zinc supplementation partially restored serum thymulin activity (Boukaiba et al., Am J Clin Nutr, 1993) (PMID 8460613). In a mouse model of allergic asthma, inhaled nanoparticle-delivered thymulin gene therapy reversed airway inflammation and fibrosis (PMID 32577505). A 2026 mouse study found thymulin suppressed age-associated inflammatory myeloid cells by inhibiting NF-kB signaling and improved response to anti-PD-L1 therapy (PMID 42481458). Therapeutic evidence remains animal-based.

03 · Regulatory status

Thymulin is in the research phase with limited clinical data in humans. Current evidence is primarily derived from preclinical (animal or in vitro) studies.

No lawful pathway today

Thymulin is not FDA-approved and does not currently have a lawful prescription or compounding pathway in the United States, so we do not sell it and will not book a consultation for it. That can change: in 2026 FDA began reviewing several peptides for compounding.

See the 1 FDA-approved compound in Immune

Tell me if the status changes

One email, only if this compound's regulatory standing actually moves. Not a newsletter, not a sales sequence.

04 · Administration routes

  • Subcutaneous injection
  • Intranasal

References

  1. [1]The thymus-neuroendocrine axis: physiology, molecular biology, and therapeutic potential of the thymic peptide thymulin Ann N Y Acad Sci, 2009. PMID 19236333
  2. [2]Nanoparticle-based thymulin gene therapy therapeutically reverses key pathology of experimental allergic asthma Sci Adv, 2020. PMID 32577505
  3. [3]Serum thymulin in human zinc deficiency J Clin Invest, 1988. PMID 3262625
  4. [4]Melatonin, thymic serum factor, and cortisol levels in healthy subjects of different age and patients with skin melanoma J Pineal Res, 1986. PMID 3772725
  5. [5]Thymulin restrains age-associated myeloid inflammation and enhances cancer immunotherapy Nat Commun, 2026. PMID 42481458
  6. [6]A physiological amount of zinc supplementation: effects on nutritional, lipid, and thymic status in an elderly population Am J Clin Nutr, 1993. PMID 8460613

Primary literature

Related peptides in Immune

Disclaimer: This information is provided for educational and research purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide therapy. The Peptide Association does not endorse or recommend any specific treatment protocol. See our editorial policy for how this content is produced and reviewed. Clinicians: join the network.