Thymalin
Also known as: Thymus polypeptide complex Ā· Thymarin Ā· Thymic polypeptide
A polypeptide complex extracted from calf thymus gland that broadly modulates immune function. Distinct from Thymosin Alpha-1 (a single purified peptide), Thymalin is a complex mixture of thymic peptides. Russian clinical trials show 2-2.4x reduction in acute respiratory infections and significant mortality reduction in elderly patients.
What is Thymalin? A polypeptide complex extracted from calf thymus gland that broadly modulates immune function. Distinct from Thymosin Alpha-1 (a single purified peptide), Thymalin is a complex mixture of thymic peptides. Russian clinical trials show 2-2.4x reduction in acute respiratory infections and significant mortality reduction in elderly patients.
How does Thymalin work? Thymalin contains multiple low-molecular-weight thymic peptides that stimulate T-lymphocyte differentiation, increase natural killer cell activity, restore impaired phagocytosis, and normalize T-helper/T-suppressor ratios. Unlike Thymosin Alpha-1 which targets specific receptors, Thymalin's complex composition activates multiple immune pathways simultaneously, providing broad immunomodulation.
Benefits of Thymalin: Broad-spectrum immune restoration and modulation; 2-2.4x reduction in acute respiratory infections in clinical trials; Significant all-cause mortality reduction in elderly (Russian RCTs); Restores age-related immune decline; Increases NK cell activity and T-cell function; Anti-tumor immunomodulation; Used as adjuvant therapy in cancer and HIV treatment
Thymalin dosage: Standard course: 10mg/day IM or SubQ for 5-10 days. Repeat 2-4x per year. Dose in mg not mcg.
Research status: Research Only
Source: PeptideWiki ā https://www.peptide-wiki.net/peptides/thymalin
Mechanism of Action
Thymalin contains multiple low-molecular-weight thymic peptides that stimulate T-lymphocyte differentiation, increase natural killer cell activity, restore impaired phagocytosis, and normalize T-helper/T-suppressor ratios. Unlike Thymosin Alpha-1 which targets specific receptors, Thymalin's complex composition activates multiple immune pathways simultaneously, providing broad immunomodulation.
Benefits
- Broad-spectrum immune restoration and modulation
- 2-2.4x reduction in acute respiratory infections in clinical trials
- Significant all-cause mortality reduction in elderly (Russian RCTs)
- Restores age-related immune decline
- Increases NK cell activity and T-cell function
- Anti-tumor immunomodulation
- Used as adjuvant therapy in cancer and HIV treatment
Side Effects & Risks
- Generally very well tolerated
- Mild injection site reactions
- Fever possible (immune activation)
- Limited Western clinical data
Where to Buy Thymalin
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Storage & Reconstitution Guide
Storage Temperature
-20Ā°C (lyophilized)
24 months (lyophilized), 28 days (reconstituted)
Reconstitution Solvent
Bacteriostatic water (BAC water)
Swirl gently ā do not shake or vortex
Handling Notes
Protect lyophilized peptide from moisture and light. Once reconstituted, keep refrigerated. Discard if solution becomes cloudy or discolored. Use insulin syringe for precise dosing.
Step-by-Step Reconstitution
Gather supplies
BAC water, insulin syringe, alcohol swabs, vial
Disinfect tops
Swab rubber stoppers of both vials with alcohol
Draw BAC water
Pull desired mL of BAC water into syringe
Inject slowly
Inject BAC water down the side of the peptide vial, swirl gently to dissolve
Research Protocol
- Dose Range
- 10ā20 mg
- Frequency
- Daily for 5-10 day courses
- Cycle
- 5-10 days per course, 2-4x per year
- Routes
- intramuscular injectionsubcutaneous injection
- Notes
- Standard course: 10mg/day IM or SubQ for 5-10 days. Repeat 2-4x per year. Dose in mg not mcg.
Legal & Regulatory Status
Sold for research purposes only. Not for human use. Laws vary by country.
Commonly Stacked With
View all peptide stacks āExternal Resources
Chemical Properties
- Mol. Weight
- Variable (polypeptide complex)
PeptideWiki Research Team
Evidence-based research data sourced from PubMed and ClinicalTrials.gov Ā· Last updated: February 25, 2026
Frequently Asked Questions About Thymalin
What is Thymalin?ā¾
A polypeptide complex extracted from calf thymus gland that broadly modulates immune function. Distinct from Thymosin Alpha-1 (a single purified peptide), Thymalin is a complex mixture of thymic peptides. Russian clinical trials show 2-2.4x reduction in acute respiratory infections and significant mortality reduction in elderly patients.
What are the benefits of Thymalin?ā¾
Broad-spectrum immune restoration and modulation
What are the benefits of Thymalin?ā¾
2-2.4x reduction in acute respiratory infections in clinical trials
What are the side effects of Thymalin?ā¾
Generally very well tolerated
What is the recommended dosage for Thymalin?ā¾
Standard course: 10mg/day IM or SubQ for 5-10 days. Repeat 2-4x per year. Dose in mg not mcg.
How long should a Thymalin cycle last?ā¾
5-10 days per course, 2-4x per year
More Immune Support Peptides
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Cathelicidin
The only human cathelicidin antimicrobial peptide, naturally produced by immune cells as a first-line defense. Has broad-spectrum antimicrobial, wound healing, and immunomodulatory properties.
Thymulin
FTS
The only true thymic hormone (not a thymosin). A zinc-dependent nonapeptide naturally produced by thymic epithelial cells that directly matures T-lymphocytes. Levels decline ~90% between ages 20-60, making it a key driver of immunosenescence. Requires zinc coordination to be biologically active. Distinct from Thymalin (polypeptide extract) and Thymosin Alpha-1.
Thymosin Alpha-1
TĪ±1
A 28-amino acid peptide naturally produced by the thymus gland that modulates both innate and adaptive immunity. Approved under the name Zadaxin in some countries for hepatitis B, C, and as a vaccine adjuvant.