Thymulin
A zinc-dependent nonapeptide thymic hormone that supports T-lymphocyte differentiation and immune regulation. A genuine endogenous immunomodulator with an older research literature, but limited modern controlled trials of exogenous administration.
01 Overview
Thymulin is a thymus-derived peptide whose biological activity depends on bound zinc; the zinc-thymulin complex modulates T-cell maturation, cytokine balance and neuroendocrine-immune signalling. Circulating thymulin declines with age and zinc deficiency, prompting interest in immunosenescence and anti-inflammatory applications.
Much of the human-relevant work is older, and modern well-powered trials of therapeutic thymulin are scarce. It is sold on the peptide grey market for immune support and anti-ageing, ahead of robust efficacy data, and its activity is tightly coupled to zinc status.
02 Mechanism
Zinc-dependent thymic nonapeptide that promotes T-lymphocyte differentiation and modulates cytokine and neuroendocrine-immune signalling.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Experimental | 1–5 mg/wk | SubQ | No standardised human regimen; grey-market figures are anecdotal. Activity depends on adequate zinc status. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Immune modulationSupports T-cell differentiation and can rebalance cytokine responses in models and older studies. | Altered T-cell and cytokine measures | Preclinical | |
| Anti-inflammatory activityPreclinical anti-inflammatory and analgesic signals; human confirmation is limited. | Reduced inflammatory signalling (models) | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Immune dysregulation riskManipulating immune signalling could theoretically aggravate autoimmune or inflammatory conditions. | Moderate | Unknown | Unconfirmed | |
| Injection-site reactionsLocal irritation from subcutaneous injection of unregulated peptide. | Mild | Unknown | Unconfirmed |