Thymulin
Zinc-Dependent Thymic Nonapeptide | Immune Modulation & Anti-Inflammatory
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What is Thymulin?
Thymulin is a very small hormone, just nine amino acids, plus a bound zinc ion it needs to work, made by the thymus gland and involved in training the immune system's T-cells. Levels drop off naturally with age, which is part of why researchers study it for immune and inflammation research in older age groups. Research-grade Thymulin sold here is intended strictly for laboratory study, not for use in people or animals.
Key terms:
Thymulin is a synthetic metallopeptide hormone (zinc-dependent).
Thymulin, also called Serum Thymic Factor or FTS (Facteur Thymique Sérique), is a hormone of nine amino acids. Only the thymus gland's epithelial cells make it. Bach and colleagues first characterized it in 1977. It is unusual: it needs a bound zinc ion, one per molecule, to work at all. The zinc-thymulin complex folds into a specific shape, and that shape is what allows its immune effects, including T-cell differentiation, stronger NK cell activity, and suppressor T-cell regulation. Researchers also report anti-inflammatory and pain-relieving activity, traced to inhibition of NF-κB, p38 MAPK, and pro-inflammatory cytokines. Blood levels peak before adolescence and fall steadily with age, contributing to immunosenescence. Studies point to lung disease, neuropathic pain, and age-related immune dysfunction, though human clinical trials remain limited.
Key research areas
- Immune modulation
- T-cell differentiation
- Anti-inflammatory effects
- Potential analgesic properties
Researched dosing
This table shows the animal-study dosing used in published Thymulin research, alongside anecdotal human research protocols, presented as reference data, not personal usage guidance.
| Phase | Dose | Frequency | Route |
|---|---|---|---|
| Animal protocol (inflammation) | 15 μg/100g body weight | Single dose or short course | IP or SubQ |
| PAT analog (pain research) | 25-50 μg per rat (~100-200 μg/kg) | 30 min before inflammatory challenge | IP |
| Unverified community protocol | 1-5 mg per injection | Once daily for 5-10 days | SubQ |
Commonly cycled 2 weeks on, 4+ weeks off.
How it works
At the cell level, Thymulin research looks at how the zinc-bound peptide interacts with receptors on T-cells to guide their development, plus a separate anti-inflammatory pathway that dials down signaling molecules like NF-κB, the terms below describe those steps.
Zinc-dependent metallopeptide that binds to high-affinity T-cell receptors. Induces T-cell differentiation, enhances suppressor T-cell function, and modulates NK cell activity. Anti-inflammatory action via NF-κB inhibition, p38 MAPK suppression, and reduction of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). May also act through α7-nicotinic acetylcholine receptor potentiation for analgesic effects.
Molecular data
These figures, molecular weight, amino-acid sequence, chain length, are the chemistry ID researchers use to confirm a Thymulin sample's identity; at just nine amino acids it's one of the smaller compounds in this encyclopedia, and it requires a bound zinc ion to be biologically active.
- Weight
- 858.86 Da
- Length
- 9 amino acids
- Type
- Metallopeptide hormone (zinc-dependent)
H-Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-OH (pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn)
Pharmacokinetics
This chart shows how quickly a research dose of Thymulin clears the body, notice the very short, sub-hour timescale, reflecting its brief presence in circulation in animal studies.
- Peak
- 0.25 hr
- Half-life
- 0.167 hrs
- Cleared
- ~0.85 hrs
Dardenne & Pleau 1994
What the studies report
This section lists the body systems and research areas scientists have studied for Thymulin, a summary of what's been studied in the literature, not medical claims about people.
Immunity
Induces T-cell surface markers and functions in immature lymphoid cells, essential for adaptive immunity. Notably enhances suppressor T-cell function, helping regulate immune responses. Enhances natural killer cell activity for improved innate immune surveillance.
Inflammation
PAT analog (25-50 μg) abolished increased TNF-α and significantly reduced IL-1β, IL-6, and NGF levels. Long-term treatment notably reduced microglial activation, p38 MAPK phosphorylation, and spinal pro-inflammatory cytokines. Broad inhibitory effect on pro-inflammatory cytokines, suppresses p38 (implicated in glucocorticoid resistance), and inhibits NF-κB.
Longevity
Serum thymulin levels decline progressively with age (peaking in pre-adolescence), contributing to immunosenescence. Supplementation may address age-related immune decline.
Neuroprotection
Thymulin treatment attenuates inflammatory pain and neuroinflammation via spinal mechanisms. May act through α7-nicotinic acetylcholine receptor potentiation for analgesic effects. Research shows promise in neuropathic pain management.
Dosage reference
- Doses used in research
- No established research dose; unverified community reports mention 1-5 mg.
- Frequency in studies
- Once daily for 5-10 day cycles
- Handling
- Reconstituted solution, research use only; not for administration
- Timeline reported in studies
- Immune effects may take weeks to manifest. Pain/inflammation effects may be faster.
- Storage
- Lyophilized: -20°C. Reconstituted: 2-8°C, use within 7-10 days
- Cycle length
- 5-10 days (based on thymic preparation protocols)
- Break between cycles
- Monthly to quarterly cycles (anecdotal)
Interactions
This list shows which other immune- and longevity-research peptides are studied alongside Thymulin, and why.
Reconstitution & storage
This is the standard laboratory method for turning freeze-dried Thymulin powder into a liquid research solution.
- Allow vial to reach room temperature
- Add sterile water slowly down vial side
- Gently swirl until dissolved - do not shake
- Solution should be clear; discard if cloudy
- Ensure adequate zinc intake for biological activity
- Store the reconstituted solution refrigerated (2-8°C), labeled with the date and concentration, for laboratory research use only.
Lyophilized: -20°C, use within As per manufacturer expiry
Reconstituted: 2-8°C, use within 7-10 days
Open the Thymulin reconstitution calculatorQuality indicators
These are the checks researchers use to confirm a Thymulin sample is pure and correctly identified, including verifying it's the zinc-bound form needed for biological activity.
Zinc dependency critical - Thymulin requires zinc for biological activity. Ensure adequate zinc status or supplementation.
Very short half-life - Serum half-life only ~10 minutes. Cellular/tissue effects may persist longer.
Limited human data - Most research is preclinical. Human dosing extrapolated from animal studies.
Excellent safety profile in studies - No toxicity observed even at high doses in animal models. No immunosuppressive effects.
Third-party testing recommended - Verify peptide identity and purity. Ensure zinc-bound form if available.
What to expect
This timeline reflects what the available research literature reports at each study stage, research context for comparing studies, not a personal-results promise.
No measurable changes reported at this stage, consistent with the mechanism
Changes in immune parameters reported, measurable only by assay
Animal models reported effects on pain and inflammation within days
Immune-reconstitution endpoints were assessed over multiple courses across months
Safety notes
This section covers handling cautions for Thymulin, research-use-only scope, not medical safety advice for people.
- CRITICAL: Requires zinc for biological activity - supplement if needed
- Limited human safety data - preclinical research only
- Circadian variation in natural thymulin - timing may matter
- Not FDA approved for any indication
- Very short serum half-life (~10 minutes)
- No toxicity observed even at high doses in preclinical studies
- Did not affect normal physiological parameters in animal studies
- No immunosuppressive effects unlike corticosteroids
Regulatory status
- Not approved by the FDA for any indication.
- Supplied and described for laboratory research use only, not for human or veterinary use.
How it is studied
In the published studies listed below. Each one names the species it was run in, the dose, how long it ran, and what it reported.
Thymulin analog PAT (25-50 μg) abolished increased TNF-α and significantly reduced IL-1β, IL-6, and NGF levels. Demonstrated comparable or stronger analgesic effects than indomethacin and dexamethasone without affecting normal physiological parameters.
Thymulin notably reduced thermal hyperalgesia and paw edema. Molecular analysis showed reduced microglial activation, p38 MAPK phosphorylation, and spinal pro-inflammatory cytokines (TNF-α, IL-6). Long-term treatment effective for neuroinflammation.
Comprehensive review showing thymulin has consistent beneficial effects in experimental lung disease models. Broad inhibitory effect on pro-inflammatory cytokines, suppresses p38 (implicated in glucocorticoid resistance), and inhibits NF-κB. No toxicity even at high doses - good candidate for gene therapy.