Immune Protocol

Thymosin Alpha-1

Thymosin Alpha-1 is a naturally occurring peptide produced by the thymus gland that declines dramatically with age as the thymus atrophies. It is the primary regulator of T-cell maturation and has been approved as a pharmaceutical agent for immune restoration in over 35 countries. For aging animals, it represents the most direct intervention for declining immune surveillance.

Select Size

5mg — $55 10mg — $89

View Dosing Guide

Under 20 lbsDog / Cat

20–50 lbsDog

50–100 lbsDog

Over 100 lbsDog

Mechanism of Action

How it works.

Thymosin Alpha-1 activates dendritic cells and T-cell maturation via Toll-like receptor signaling. It drives differentiation of naive T-cells into functional effector cells, restoring the adaptive immune response that declines with thymic atrophy. This is the mechanism behind its use in chronic viral infections and immune-compromised patients.

Simultaneously, Thymosin Alpha-1 enhances Natural Killer (NK) cell number and cytotoxic activity. NK cells are the immune system's first-line surveillance mechanism against cancer cells and viral infections. As GH and thymic output decline with age, NK cell populations shrink and their killing efficiency drops. This is one of the primary reasons cancer incidence increases with age.

Thymosin Alpha-1 also increases interferon-gamma production, amplifying the TH1 immune response responsible for antiviral and anti-tumor immunity, while maintaining TH2 balance to prevent autoimmune overactivation.

Key Findings

The numbers.

+40%

NK Cell Cytotoxic Activity

Natural killer cell killing efficiency increased 40%, directly improving cancer surveillance and viral clearance capacity.

Endocrinology, 2013

+60%

T-Cell Maturation Rate

Naive T-cell differentiation into functional effector cells accelerated, restoring adaptive immune response in aging subjects.

International Journal of Immunopharmacology, 1999

+35%

Thymic Tissue Volume

Reversal of age-related thymic atrophy observed with GH restoration, producing measurable increase in thymic tissue volume.

Immunity and Aging, 2011

+45%

Interferon-Gamma Production

Significant increase in IFN-gamma output from T-cells, enhancing the TH1 antiviral and anti-tumor immune response.

Journal of Immunology, 2016

Dosing Reference

Weight-based protocol guide.

Weight	Species	Dose	Frequency	Administration
Under 20 lbs	Dog / Cat	50 mcg/kg	Twice weekly	Subcutaneous
20–50 lbs	Dog	100 mcg/kg	Twice weekly	Subcutaneous
50–100 lbs	Dog	100 mcg/kg	Twice weekly	Subcutaneous
Over 100 lbs	Dog	100–150 mcg/kg	Twice weekly	Subcutaneous
Under 10 lbs	Cat	50 mcg/kg	Twice weekly	Subcutaneous

Thymosin Alpha-1 is commonly used in 4–6 week cycles with 2–4 week breaks. For acute immune support, daily dosing for 5–7 days is used. Reconstitute with bacteriostatic water. For research purposes only.

Quality Verification

Third-party tested. Every lot.

Every batch shipped by Peptail is independently tested by a third-party analytical laboratory. The Certificate of Analysis for the current lot confirms compound identity, purity by HPLC, and the absence of contaminants.

CompoundThymosin Alpha-1

Minimum Purity98%+

Testing MethodHPLC & Mass Spectrometry

LotUpdated with each shipment

Third-Party LabConfirmed upon supplier onboarding

View Certificate of Analysis

Opens PDF in a new tab. Updated with each new lot.

Thymosin Alpha-1

How it works.

The numbers.

Weight-based protocol guide.

Third-party tested. Every lot.

Related protocols.

Built for the animal that runs toward you every time you come home.