Thymulin (Facteur Thymique Sérique)

FTS | Zinc-Dependent Thymic Nonapeptide

Weight: 857 Da (peptide), 921 Da (with zinc)
Half-life: ~10 minutes (free form); extended with nanoparticle formulations
Chain: 9 amino acids
4 studies
2000 latest
Well Studied
Dose 1-10mcg per injection (research protocols)
Frequency Daily during research protocols
Cycle Varies by research protocol
Storage Reconstituted: 2-8°C, use within 4 weeks
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Thymulin is a nonapeptide hormone exclusively secreted by thymic epithelial cells, discovered by Jean-François Bach in the 1970s. Unlike thymalin (a peptide extract mixture), thymulin is a single, defined 9-amino-acid peptide that requires zinc binding for biological activity. It plays a crucial role in T-cell differentiation and maturation within the thymus. Serum thymulin levels decline significantly with age and zinc deficiency, contributing to age-related immune decline (immunosenescence). Research has explored thymulin's potential in restoring immune function, managing autoimmune conditions, and as an anti-inflammatory agent.

Mechanism of Action

Thymulin exerts its effects through binding to high-affinity receptors on T-lymphocytes and other immune cells. The zinc-thymulin complex is the biologically active form - without zinc, the peptide has no immunological activity. Thymulin promotes: (1) differentiation of immature T-cells into mature T-cell subsets, (2) modulation of cytokine release including IL-2 and interferon-gamma, (3) regulation of T-helper and T-suppressor cell balance, (4) enhancement of NK cell activity, and (5) anti-inflammatory effects through suppression of pro-inflammatory mediators. It also has neuroendocrine effects, influencing the hypothalamic-pituitary-adrenal axis.

01 Essential for T-cell maturation and differentiation
02 Modulates immune responses (immunomodulatory)
03 Anti-inflammatory properties
04 Declines with age - restoration may combat immunosenescence
05 Well-defined single peptide (unlike extracts)
06 Studied in autoimmune disease research
07 Neuroendocrine regulatory effects
08 Zinc-dependent activity allows for regulation

Molecular Data

Molecular Weight
857 Da (peptide), 921 Da (with zinc)
Chain Length
9 amino acids
Type
Thymic nonapeptide hormone
Amino Acid Sequence
One-letter: ?AKSQGGS???
H₂N
H
? 1
O ‖ C
N
A 2
O ‖ C
N
K 3
O ‖ C
N
S 4
O ‖ C
N
Q 5
O ‖ C
N
H
G 6
O ‖ C
N
H
G 7
O ‖ C
N
S 8
O ‖ C
N
H
? 9
O ‖ C
N
H
? 10
O ‖ C
N
H
? 11
COOH
pGl
1

pGlu

Position 1

Ala
2

Alanine

Position 2

Lys
3

Lysine

Position 3

Ser
4

Serine

Position 4

Gln
5

Glutamine

Position 5

Gly
6

Glycine

Position 6

Gly
7

Glycine

Position 7

Ser
8

Serine

Position 8

Asn
9

Asn (pyro

Position 9

Glu
10

Glu N

Position 10

ter
11

terminus)

Position 11

N-terminus C-terminus
Hydrophobic
Polar
Positive (+)
Negative (-)
Modified
Peak 0.0 mcg
Trough 0.0 mcg
SS Peak 0.0 mcg
SS Trough 0.0 mcg

Research Indications

Immune System Research
Immunosenescence effective

Age-related decline in thymulin correlates with reduced immune function; supplementation may restore T-cell parameters.

T-Cell Deficiency effective

Promotes differentiation and maturation of T-lymphocytes in thymus.

Zinc Deficiency States effective

Thymulin activity depends on zinc; studied in zinc-depleted conditions.

Inflammatory & Autoimmune Research
Anti-Inflammatory Effects moderate

Research shows thymulin suppresses pro-inflammatory cytokines and mediators.

Autoimmune Conditions emerging

Investigated for potential to restore immune balance in autoimmune states.

Type 1 Diabetes Research emerging

Studied for effects on pancreatic beta cells and immune modulation in diabetes models.

Neuroendocrine Research
HPA Axis Modulation moderate

Thymulin influences hypothalamic-pituitary-adrenal axis function.

Neuroprotection emerging

Some research suggests protective effects on neural tissue.

Dosing Protocols

Thymulin is typically administered via subcutaneous or intraperitoneal injection in research settings. As a small peptide, it can also be explored via intranasal delivery for CNS effects. Zinc status should be adequate for biological activity.

GoalDoseFrequencyRoute
Research protocol (immune)1-10 mcgDailySubQ
Intranasal (experimental)VariableAs studiedIntranasal

Reconstitution Instructions

Materials Needed:
  • Bacteriostatic water
  • Insulin syringes
  • Alcohol swabs
  • Sterile vial
  1. 1 Ensure adequate zinc supplementation for activity
  2. 2 Reconstitute with bacteriostatic water
  3. 3 Inject water slowly down vial wall
  4. 4 Gently swirl until dissolved
  5. 5 Store refrigerated at 2-8°C
  6. 6 Use within 4 weeks of reconstitution

Interactions

++
Zinc supplementation
Essential - thymulin requires zinc for biological activity. Ensure adequate zinc status.
synergistic
+
Thymosin Alpha-1
Different thymic peptides with complementary mechanisms.
compatible
+
Thymalin
Thymalin is a peptide mixture while thymulin is a single defined peptide; can complement each other.
compatible
+
Epitalon
Different mechanisms; no known negative interactions.
compatible
+
BPC-157
Different mechanisms; no known interactions.
compatible

What to Expect

Hours
Receptor binding and initial cellular signaling
Days 1-7
Immune cell modulation begins; cytokine profile changes
Weeks 2-4
T-cell differentiation effects; measurable immune parameters
Months
Long-term immune restoration in research models

Side Effects & Safety

Common Side Effects

  • Generally well-tolerated in research
  • Injection site reactions (mild)

Stop Signs - Discontinue if:

  • Signs of allergic reaction
  • Unexpected immune changes

Contraindications

  • Autoimmune diseases (use with medical supervision)
  • Organ transplant recipients on immunosuppression
  • Pregnancy or breastfeeding
  • Known hypersensitivity to thymic peptides

Quality Checklist

Good Signs

  • White lyophilized powder
  • Clear solution after reconstitution
  • Intact vacuum seal
  • Certificate of analysis with sequence verification

Warning Signs

  • Slight clumping that dissolves easily

Bad Signs

  • Discolored powder
  • Cloudy solution after reconstitution
  • Particulates present
  • Broken seal

References

  • Thymulin (FTS) - A Thymic Hormone
    Bach JF, Dardenne M
    Clinics in Immunology and Immunopathology (1989)

    Comprehensive review of thymulin discovery, structure, and immunological functions.

  • The neuroendocrine role of thymulin
    Journal of Neuroimmunology (2000)

    Thymulin modulates hypothalamic-pituitary-adrenal axis and has neuroendocrine effects beyond immunity.

  • Zinc and thymulin
    Advances in Experimental Medicine and Biology

    Zinc is essential for thymulin biological activity; zinc deficiency causes functional thymulin deficiency.

  • Thymulin and aging
    Mechanisms of Ageing and Development

    Serum thymulin levels decline dramatically with age, correlating with immunosenescence and increased infection susceptibility.

Related Peptides

Thymalin compatible

Thymalin is a peptide mixture while thymulin is a single defined peptide; can complement each other.

Epitalon compatible

Different mechanisms; no known negative interactions.

BPC-157 compatible

Different mechanisms; no known interactions.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.