Reference/Acetylated polypeptide

Thymosin Alpha 1

Synthetic Thymic Hormone · Immune System Modulator

Human clinical

research use only

Thymosin Alpha 1 is a synthetic 28-amino acid peptide identical to naturally occurring thymic hormone, studied in 11,000+ patients across 30+ clinical trials with less than 1% serious adverse events. Approved in 35+ countries for immune modulation.

Primary FDA-studied route with extensive clinical validationMaximum immune modulation through systemic circulationEstablished dosing from 35+ countries of clinical useExceptional safety profile (<1% serious adverse events)

4 citations·1 with human data·Updated 10 Aug 2026

Overview

Activates TLR pathways, enhances T-cell maturation, stimulates NK cells, and modulates dendritic cell function via systemic circulation. Injectable route achieves 90-95% bioavailability with 2-hour peak time.

Evidence profilederived from 4 references

Human clinical

Strongest design among the references on this page. Grade and effect size are separate facts and are never merged into one score.

Research indications

What the compound has been studied for, grouped by body system. Effect size is the reported magnitude where it was measured — not a recommendation.

Immunity3

Primary Immunodeficiencies

FDA orphan designation for DiGeorge syndrome; restores T-cell function.

Large

Vaccine Enhancement

Improved antibody responses in elderly and hemodialysis patients (H1N1, COVID-19).

Large

HIV/AIDS Support

Restores CD4+ counts and reduces opportunistic infections.

Moderate

Inflammation3

Cytokine Reduction

Reduces pro-inflammatory cytokines TNF-α, IL-1β, IL-6 by 40-60%.

Moderate

Hepatitis B/C Support

Enhanced antiviral efficacy when combined with interferon.

Moderate

Autoimmune Conditions

Helps manage inflammatory autoimmune conditions.

Small

Recovery2

Post-Surgical Immune Restoration

Restores immune function after surgical stress.

Small

Exercise-Induced Immunosuppression

Manages immune suppression from intense training.

Small

Anti-Aging2

Thymic Regeneration Support

Supports thymus gland function with aging.

Small

Immune Senescence Delay

Delays age-related immune decline in elderly populations.

Small

A large effect in a weak study and a small effect in a strong one are different things. Effect size is never evidence of use in people.

Quick factsreference only

Class: Acetylated polypeptide
Chain length: 28 residues
Molecular weight: 3108 Da
Half-life: ~2 h
Typical dose: 1.6mg per injection (standard dose across all protocols)
Frequency: 2x weekly (e.g., Monday and Thursday) for standard immune support
Administration: Subcutaneous injection
Cycle length: 6 months continuous for therapeutic protocols
Storage: Use immediately after reconstitution or refrigerate up to 2 hours

Molecular data

Type: Acetylated polypeptide
Molecular weight: 3108 Da
Chain length: 28 residues
Half-life: 120 min

Dosing reference

Doses reported in the literature and by suppliers. These are a record of what has been used in research — reference, never instruction.

Context	Route	Amount	Frequency
Standard immune support	SubQ	1.6mg	2x weekly
Acute conditions (sepsis)	SubQ/IM	1.6mg	2x daily for 5 days, then daily
Cancer/hepatitis support	SubQ	1.6mg	2x weekly
Maintenance/prevention	SubQ	1.6mg	2x weekly
General support	Nasal spray	500mcg per nostril	2x daily
Enhanced support	Nasal spray	1000mcg per nostril	2x daily
Maintenance	Nasal spray	500mcg per nostril	1x daily

Interactions

Immunosuppressive Agents

Fatal graft rejection risk in transplant patients - contraindicated.

avoid

Corticosteroids

Pharmacodynamic antagonism possible.

monitor

Interferon-α

Enhanced antiviral efficacy in hepatitis treatment.

synergistic

Vaccines

Enhances vaccine immunogenicity.

compatible

Chemotherapy

Protective against bone marrow damage.

compatible

Quality checklist

✓White, fluffy lyophilized powder filling vial bottom
✓Crystal clear solution after reconstitution (no particles/cloudiness)
✓Professional pharmaceutical labeling with batch numbers, expiration
!Minor powder compaction during shipping (acceptable if dissolves cleanly)
×Yellow, brown, or collapsed powder (heat/moisture degradation)
×Persistent cloudiness or particles post-reconstitution
×Non-professional sourcing or unclear labeling

What to expect

Week 1-2Initial immune system activation

Week 2-6Enhanced immune function, reduced infection risk

Week 6-12Maximum immunomodulatory benefits

Week 12+Sustained immune support with continued use

Safety

Commonly reported2

Mild injection site reactions (<10% incidence)
Generally well-tolerated with exceptional safety record

Stop and seek advice4

Signs of graft rejection in transplant recipients
Persistent injection site reactions or infection signs
Unusual immune system hyperactivity
Severe allergic reactions (rare)

Contraindications2

Organ transplant recipients (risk of graft rejection)
Pregnancy and breastfeeding

FAQ

Can Thymosin Alpha-1 be combined with coronavirus vaccines to boost protection?

Yes, Thymosin Alpha-1 enhances antibody responses to vaccines in elderly and immunocompromised patients. Clinical trials show improved vaccine immunogenicity with co-administration. This is particularly relevant for high-risk groups seeking enhanced vaccine protection.

Does Thymosin Alpha-1 actually work for COVID-19 or just reduce symptoms?

A clinical trial showed Thymosin Alpha-1 significantly reduced mortality in severe COVID-19 (11.11% vs 30% untreated, P=0.044) by restoring CD4+ and CD8+ T-cell numbers and reversing T-cell exhaustion. It works by immune restoration rather than direct antiviral activity.

Why is Thymosin Alpha-1 less popular than other immune peptides if it's studied so extensively?

Despite 11,000+ patients in 30+ trials with excellent safety (<1% serious adverse events), Thymosin Alpha-1 has limited commercial availability. It's not FDA-approved for most indications (only orphan status for DiGeorge syndrome), making prescription access difficult outside research settings or specific countries.

Is intranasal Thymosin Alpha-1 as effective as injectable?

Injectable has 90-95% bioavailability versus nasal spray's 40-60%. Injectable is the primary FDA-studied route with most clinical validation. Nasal spray may work for local immune effects but requires compounding pharmacy preparation and shows lower systemic absorption - inject for maximum efficacy.

References

1
Thymosin Alpha 1: A Historical Overview
Garaci E · Annals of the New York Academy of Sciences · 2007
Comprehensive overview of thymosin alpha 1 from discovery to clinical application. Evidence for combined treatments with interferon or IL-2 restoring immune responses depressed by tumor growth and/or cytostatic drugs.
reviewPubMed 17567941 ↗
2
Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells
Liu Y, Pang Y, Hu Z, et al. · Clinical Infectious Diseases · 2020
Mortality significantly reduced in severe COVID-19: 11.11% with thymosin alpha 1 vs 30.00% untreated (P=0.044). Restored CD4+ and CD8+ T-cell numbers and reversed T-cell exhaustion markers PD-1 and Tim-3.
reviewPubMed 32442287 ↗
3
Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials
Johnson EK, et al. · Expert Opinion on Drug Safety · 2024
Narrative review of 11,000+ patients across 30+ clinical trials. Exceptional safety profile with <1% serious adverse events. Applications in COVID-19, autoimmune conditions, hepatitis, and cancer.
reviewPubMed 38308608 ↗
4
The Efficacy and Safety of Thymosin Alpha 1 for Sepsis (TESTS): Multicentre, Double-Blinded, Randomised, Placebo-Controlled, Phase 3 Trial
Liu J, Li J, He L, et al. · BMJ · 2025
1,106 adults with sepsis across 22 centres. 28-day mortality: 23.4% thymosin alpha 1 vs 24.1% placebo (HR 0.99, P=0.93). No overall benefit, but prespecified subgroup analysis showed potential benefit in elderly and diabetic patients.
human-rctPubMed 39814420 ↗