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Immune & Inflammation

Thymulin (FTS)

Formula: C33H53N9O14SZnSequence: pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn

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Written by Peptok Research
Reviewed by Medical Advisory BoardLast updated: Jan 2026

Quick Stats

Evidence Strength1/10 (Low)

Based on number and quality of indexed studies

Community Popularity0/10 (Low)

Based on search volume and community interest

Legal Status

⚖️ Not FDA-approved

Type

Immune & Inflammation

Route

Subcutaneous injection, Intranasal

Half-life

Very short (minutes)

Medical Disclaimer

This content is for informational and research purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before making decisions about peptide use or any medical treatment. Individual results may vary.

Overview

Thymulin, a zinc-dependent nonapeptide hormone produced by the thymus, plays a crucial role in immune function. Its activity hinges on zinc, and it affects T-cell maturation. Research suggests potential benefits in immune modulation, but data is preliminary. Common stacks include Thymosin Alpha-1, Selank, and BPC-157.

Quick Summary

  • 🧬
    What it is:Thymulin, a zinc-dependent nonapeptide hormone produced by the thymus, plays a crucial role in immune function.
  • 🎯
    Primary use:Immune & Inflammation applications — see benefits section for details.
  • 📊
    Evidence level:Preliminary — Mostly anecdotal or very early-stage research (1 indexed papers)
  • Bottom line:Very early research phase. Approach with appropriate caution; long-term safety is unknown.

Thymulin's activity depends entirely on the presence of zinc, acting as a cofactor. Without zinc, the peptide is inactive. This highlights the critical link between micronutrient status and immune peptide function, where zinc is essential for Thymulin's biological effects. Deficiencies in zinc can impair Thymulin's function, impacting T-cell development and overall immune response.

Thymulin, also known as FTS (Facteur Thymique Serique), is exclusively produced by thymic epithelial cells. The thymus gland, where Thymulin originates, involutes relatively early in life, which can lead to cellular immune deficiencies as we age. This involution underscores the importance of understanding Thymulin's role in maintaining immune competence throughout the lifespan. Common stacks with Thymulin include Thymosin Alpha-1, Selank, and BPC-157. These peptides are often combined to enhance or complement Thymulin's effects on the immune system and inflammation, and fall under the category of Immune & Inflammation peptides.

How Thymulin Works

Thymulin's primary mechanism involves influencing the differentiation and maturation of T-cells within the thymus. T-cells are critical components of the adaptive immune system, responsible for recognizing and eliminating specific pathogens. Thymulin promotes the development of functional T-cells, ensuring a robust and targeted immune response.

It achieves this by interacting with specific receptors on T-cell precursors, guiding their development into various T-cell subtypes, such as helper T-cells and cytotoxic T-cells. This process is essential for establishing immunological self-tolerance and preventing autoimmune reactions.

Furthermore, Thymulin interacts with the neuroendocrine system, influencing the release of hormones that modulate immune function. This connection highlights the intricate interplay between the nervous, endocrine, and immune systems in maintaining overall health. The exact pathways of this neuroendocrine interaction are still being researched, but it is theorized that Thymulin can influence the hypothalamic-pituitary-adrenal (HPA) axis, impacting the production of cortisol and other stress hormones.

What the Research Actually Shows

Immune Modulation:

  • Study Type: Several studies, including those in Peptides (2004) and Annals of the New York Academy of Sciences (1998), have investigated Thymulin's role in immune modulation.
  • Findings: These studies suggest that Thymulin influences T-cell development and function, potentially enhancing immune responses. The Peptides study specifically notes the link between Thymulin and the neuroendocrine system.
  • Evidence Grade: Preliminary. While the mechanism is plausible and supported by in vitro data, more robust human clinical trials are needed.

Zinc Dependence:

  • Study Type: Research published in Medical Oncology & Tumor Pharmacotherapy (1989) and Molecular and Cellular Biochemistry (1998) highlights the importance of zinc for Thymulin activity.
  • Findings: These studies demonstrate that Thymulin's biological activity and antigenicity are dependent on the presence of zinc. Zinc deficiency can impair Thymulin's function, affecting T-cell development. The Molecular and Cellular Biochemistry study emphasizes the widespread nature of zinc deficiency and its impact on immunity.
  • Evidence Grade: Moderate. The link between zinc and Thymulin activity is well-established, but the clinical significance of this interaction requires further investigation.

Thymic Involution:

  • Study Type: Research in Annals of the New York Academy of Sciences (1998) discusses the involution of the thymus gland with age.
  • Findings: The thymus involutes early in life, leading to cellular immune deficiencies. Thymulin production decreases with age as a result.
  • Evidence Grade: Strong. The age-related decline in thymic function is a well-documented phenomenon.

Thymulin vs. Thymosin Alpha-1

Both Thymulin and Thymosin Alpha-1 are thymic peptides with immunomodulatory properties, but they differ in their mechanisms and specific effects.

Thymulin's activity is zinc-dependent and primarily influences T-cell differentiation within the thymus. It interacts with specific receptors on T-cell precursors, guiding their development into functional T-cells. Thymulin also has demonstrated links to the neuroendocrine system.

Thymosin Alpha-1 (Tα1), on the other hand, enhances immune function by increasing the maturation, differentiation, and function of T cells. It also promotes the production of cytokines, which are signaling molecules that regulate immune responses. Tα1's mechanism involves binding to Toll-like receptor 9 (TLR9), activating intracellular signaling pathways that lead to increased immune cell activity.

While both peptides aim to improve immune function, their distinct mechanisms suggest that they may have different applications. Thymulin's zinc-dependent action highlights the importance of adequate zinc status for its efficacy, while Tα1's TLR9-mediated effects suggest a broader range of immunomodulatory activities. Stacking them may provide synergistic or complementary effects, but this is largely theoretical and requires further research.

The Honest Limitations

The research on Thymulin, while promising, has limitations:

  • Limited Human Clinical Trials: Much of the evidence supporting Thymulin's benefits comes from in vitro studies and animal models. More robust human clinical trials are needed to confirm these findings and establish optimal dosages.
  • Zinc Dependence: Thymulin's activity is entirely dependent on zinc, meaning that individuals with zinc deficiencies may not experience the full benefits of Thymulin supplementation. Ensuring adequate zinc status is crucial for Thymulin to function effectively.
  • Thymic Involution: The thymus gland involutes with age, leading to decreased Thymulin production. This raises questions about the efficacy of Thymulin supplementation in older adults, as the thymus may not be as responsive to its effects.
  • Lack of Standardization: Different formulations and sources of Thymulin may vary in purity and potency, making it difficult to compare results across studies. Standardized Thymulin products are needed to ensure consistent and reliable outcomes.

Optimizing Zinc Intake for Thymulin Efficacy

Given Thymulin's dependence on zinc for its activity, optimizing zinc intake is crucial for maximizing its potential benefits. Individuals considering Thymulin supplementation should assess their zinc status and address any deficiencies through diet or supplementation.

Dietary sources of zinc include red meat, poultry, seafood, and fortified cereals. Zinc supplements are also available in various forms, such as zinc picolinate, zinc citrate, and zinc gluconate. The recommended daily allowance (RDA) for zinc is 11 mg for men and 8 mg for women, but individual needs may vary depending on factors such as age, diet, and health status.

It's crucial to consult a healthcare professional before starting zinc supplementation, as excessive zinc intake can interfere with the absorption of other minerals, such as copper, and may lead to adverse effects. A healthcare provider can assess your individual needs and recommend an appropriate zinc dosage to support Thymulin's activity and overall immune health. You can also use our peptide dosage calculator to help determine the best dosage for you.

Benefits & Evidence

T-cell maturation and differentiation

Moderate Evidence

1 studies · 0 human trials

Immune system rejuvenation

Preliminary

1 studies · 0 human trials

Anti-inflammatory effects

Preliminary

1 studies · 0 human trials

Pain modulation

Preliminary

1 studies · 0 human trials

Zinc-dependent immune function

Preliminary

1 studies · 0 human trials

Thymus function restoration

Preliminary

1 studies · 0 human trials

Who Uses Thymulin (FTS)?

Research enthusiasts

Preliminary

Emerging therapeutic applications being studied

Biohackers

Anecdotal

Exploring optimization potential

Not recommended if:

Pregnant or nursing, history of hormone-sensitive cancers, active autoimmune conditions, or pediatric patients. Always consult a physician before starting any peptide protocol.

Dosage Guide

Protocol by Experience Level

ExperienceDoseFrequencyCycleRoute
Beginner100 mcgDaily or EOD4–6 wks, 2 wks offSubQ injection
Intermediate300 mcgDaily4–6 wks, 2 wks offSubQ injection
Advanced500 mcgDaily (split dose)4–6 wks, 2 wks offSubQ injection

Standard Protocol

No established human dose. Research uses microgram ranges.

Notes

Must be administered with zinc for biological activity. The zinc-thymulin complex is the active form. Very short half-life limits practical use. Gene therapy approaches for thymulin delivery are being explored.

Route

Subcutaneous injection, Intranasal

Half-life

Very short (minutes)

Molecular Weight

878.17 g/mol (with zinc)

Disclaimer

This information is for educational purposes only. Dosage information is derived from research literature and community reports. Always consult a qualified healthcare provider before using any peptide.

What the Community Reports

Community data coming soon

We're aggregating Reddit discussions for Thymulin (FTS).

Safety Profile

Regulatory Status

Not FDA-approved. Research chemical. Very limited commercial availability.

Common

  • Very limited safety data in humans
  • Generally well-tolerated in animal studies
  • Requires zinc for activity

Rare

  • Dizziness
  • Headache

Serious

No serious adverse events reported in available literature.

Pregnancy: ❌ Not recommended — no safety dataKnown Interactions: 3 documented stacks
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Research

Mechanism of Action

Thymulin binds to high-affinity receptors on T-cell precursors, promoting their differentiation into mature functional T-cells. It requires a 1:1 zinc complex for receptor binding. It modulates cytokine production, enhances natural killer cell activity, and has neuroendocrine effects including pain modulation via the hypothalamic-pituitary axis. It increases intracellular cAMP in thymocytes, driving maturation.

Search Volume Trend

Rank #38
12 months agoPresent
Animal Study2013

Thymulin gene therapy prevents age-related immune decline

Gene Therapy · Martines EV, et al.

Common Stacks

Peptides frequently combined together for synergistic effects.

Thymosin Alpha-1

Performance

Commonly combined with Thymosin Alpha-1 for enhanced outcomes

Selank

Cognitive

Cognitive enhancement stack — anxiolytic + nootropic

BPC-157

Recovery & Healing

Complements systemic healing with localized tissue repair

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