Thymosin Alpha 1
Also known as: Ta1, Thymalfasin, Zadaxin
Synthetic Thymic Hormone | Immune System Modulator
Overview
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.
Key benefits
- Primary FDA-studied route with extensive clinical validation
- Maximum immune modulation through systemic circulation
- Established dosing from 35+ countries of clinical use
- Exceptional safety profile (<1% serious adverse events)
- Reduces pro-inflammatory cytokines 40-60%
- Approved in 35+ countries
Mechanism of action
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.
Molecular data
- Type
- Acetylated polypeptide
- Half-life
- ~2 hours
Sequence
Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn
Indications
What the research community uses this compound for, with self-reported effectiveness.
Immunity
Primary Immunodeficiencies
Most effectiveFDA orphan designation for DiGeorge syndrome; restores T-cell function.
Vaccine Enhancement
Most effectiveImproved antibody responses in elderly and hemodialysis patients (H1N1, COVID-19).
HIV/AIDS Support
EffectiveRestores CD4+ counts and reduces opportunistic infections.
Inflammation
Cytokine Reduction
EffectiveReduces pro-inflammatory cytokines TNF-α, IL-1β, IL-6 by 40-60%.
Hepatitis B/C Support
EffectiveEnhanced antiviral efficacy when combined with interferon.
Autoimmune Conditions
ModerateHelps manage inflammatory autoimmune conditions.
Recovery
Post-Surgical Immune Restoration
ModerateRestores immune function after surgical stress.
Exercise-Induced Immunosuppression
ModerateManages immune suppression from intense training.
Anti-Aging
Thymic Regeneration Support
ModerateSupports thymus gland function with aging.
Immune Senescence Delay
ModerateDelays age-related immune decline in elderly populations.
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Injectable
Subcutaneous injection is the primary route with 90-95% bioavailability. Standard dosing is 1.6mg twice weekly.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| Standard immune support | 1.6mg | 2x weekly | SubQ |
| Acute conditions (sepsis) | 1.6mg | 2x daily for 5 days, then daily | SubQ/IM |
| Cancer/hepatitis support | 1.6mg | 2x weekly | SubQ |
| Maintenance/prevention | 1.6mg | 2x weekly | SubQ |
Preparation
You will need
- Thymosin Alpha 1 lyophilized powder
- Sterile water (1.0mL)
- Insulin syringes
- Alcohol swabs
Steps
- Clean work surface thoroughly
- Add 1.0mL sterile water slowly to lyophilized powder
- Inject water down vial side (avoid direct powder contact)
- Gently swirl until fully dissolved (never shake)
- Final concentration: 1.6mg/mL
- Use immediately or refrigerate up to 2 hours
Work out the water volume and syringe units in the reconstitution calculator →
Nasal
Intranasal spray with limited data. Requires compounding pharmacy preparation with 40-60% bioavailability vs injectable.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| General support | 500mcg per nostril | 2x daily | Nasal spray |
| Enhanced support | 1000mcg per nostril | 2x daily | Nasal spray |
| Maintenance | 500mcg per nostril | 1x daily | Nasal spray |
Interactions
Pairwise interactions with other compounds you might be cycling — the same data behind the cycle builder's safety check.
Immunosuppressive Agents
AvoidFatal graft rejection risk in transplant patients - contraindicated.
Corticosteroids
MonitorPharmacodynamic antagonism possible.
Interferon-α
SynergisticEnhanced antiviral efficacy in hepatitis treatment.
Vaccines
CompatibleEnhances vaccine immunogenicity.
Chemotherapy
CompatibleProtective against bone marrow damage.
Timeline
Typical week-by-week effects reported in clinical and observational data.
- Week 1-2
Initial immune system activation
- Week 2-6
Enhanced immune function, reduced infection risk
- Week 6-12
Maximum immunomodulatory benefits
- Week 12+
Sustained immune support with continued use
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Mild injection site reactions (<10% incidence)
- Generally well-tolerated with exceptional safety record
Stop signs — stop and seek advice
- Signs of graft rejection in transplant recipients
- Persistent injection site reactions or infection signs
- Unusual immune system hyperactivity
- Severe allergic reactions (rare)
Contraindications
- Organ transplant recipients (risk of graft rejection)
- Pregnancy and breastfeeding
Monitoring
- Monitor for hypersensitivity with first dose
- Watch for first-dose immune activation symptoms
Quality checks
What a legitimate product looks like, what should give pause, and what should make you stop.
Good signs
- White, fluffy lyophilized powder filling vial bottom
- Crystal clear solution after reconstitution (no particles/cloudiness)
- Professional pharmaceutical labeling with batch numbers, expiration
Warning signs
- Minor powder compaction during shipping (acceptable if dissolves cleanly)
Stop signs — don't use
- Yellow, brown, or collapsed powder (heat/moisture degradation)
- Persistent cloudiness or particles post-reconstitution
- Non-professional sourcing or unclear labeling
Recent research
Newer papers and trial readouts on file for this compound, with source and date.
2024 · Journal for ImmunoTherapy of Cancer
Thymosin Alpha 1 Reverses Oncolytic Adenovirus-Induced M2 Polarization of Macrophages to Improve Antitumor Immunity
Thymosin alpha 1 reprograms M2-like tumor-associated macrophages toward an antitumoral phenotype, reshaping the tumor microenvironment to enhance antitumor immunity.
2025 · Translational Lung Cancer Research
Integrating Thymosin Alpha 1 into Concurrent Chemoradiotherapy and Consolidative Immunotherapy in Unresectable Locally Advanced NSCLC
Preliminary analysis of thymosin alpha 1 combined with chemoradiotherapy and immunotherapy in locally advanced non-small cell lung cancer, showing potential for enhanced immune response.
References
Primary literature and clinical-trial data informing this entry.
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.
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.
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.
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.
Last updated . How this page was sourced is described in the methodology.