Thymosin Alpha-1 vs Vilon
Your immune system's master trainer—a naturally occurring thymus peptide that wakes up tired immune cells, helps your body fight infections, and keeps your defenses sharp as you age.
Immunomodulatory dipeptide bioregulator (Lys-Glu) that upregulates SIRT1 expression 6-fold through direct DNA promoter binding, activates T-cell differentiation via sphingomyelin signaling, and reduces pro-inflammatory cytokines by up to 6-fold as a natural inducer of TNF tolerance
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Thymosin Alpha-1
1.6–1.6 mg
Vilon
500–500 mcg
Frequency
Thymosin Alpha-1
Twice weekly
Vilon
Once daily
Administration
Thymosin Alpha-1
Subcutaneous injection
Vilon
Subcutaneous injection
Cycle length
Thymosin Alpha-1
8-12 weeks
Vilon
12+ weeks
Onset speed
Thymosin Alpha-1
Moderate (1-2 weeks)
Vilon
Gradual (3-4 weeks)
Evidence level
Thymosin Alpha-1
Moderate human trials (Phase 1-2)
Vilon
Limited human trials
Benefit ratings
Immune Activation
Infection Fighting
Immune Balance
Immune System Revival
Healthy Aging
Digestive Support
Compound specifications
Thymosin Alpha-1
Molecular formula
C129H215N33O55
Molecular weight
3108.32 g/mol
Half-life
Approximately 2 hours
Bioavailability
High when injected subcutaneously (rapid absorption, peak at ~2 hours)
CAS number
62304-98-7
Vilon
Molecular formula
C11H21N3O5
Molecular weight
275.3 g/mol
Half-life
Short plasma half-life typical of dipeptides (minutes); biological effects persist for weeks to months through epigenetic modifications to SIRT1/PARP gene expression; metabolized to constituent amino acids
Bioavailability
Absorbed via intestinal peptide transporters (PepT1) when administered orally (demonstrated in animal studies); rapid absorption from subcutaneous injection sites; efficient cellular uptake and nuclear penetration due to ultra-short dipeptide structure
CAS number
45234-02-4
Dosing compared
Thymosin Alpha-1
Subcutaneous injection
1.6 mg
Twice weekly (3-4 days apart) · 6-12 months
Established clinical dose for thymalfasin (Zadaxin); body-surface-scaled as 900 mcg/m2 [4][6]. Phase III chronic hepatitis B trials used 1.6 mg SC twice weekly for 6-12 months [4].
1.6 mg daily, then 1.6 mg twice weekly
Daily for an initial loading period, then twice weekly · 12+ weeks
Some immune-adjuvant and acute protocols front-load with daily dosing before settling to the standard twice-weekly schedule [4][6].
Vilon
Subcutaneous injection
200–500 mcg
Once daily · 5–10 day course
Common Khavinson-style introductory protocol for the KE (Lys-Glu) immune bioregulator; courses repeated 2–3 times yearly [6]. Research use only — no approved product.
500 mcg
Once daily · 10–12 day course
Typical full-course practice dose; cycle repeated every 3–6 months [6].
Intramuscular injection
500 mcg
Once daily · 10–12 day course
Intramuscular delivery is also documented for the injectable KE bioregulator; same per-course dosing as subcutaneous [6].
Best suited for
Thymosin Alpha-1
Chronic Hepatitis B or C Support
Thymosin Alpha-1 has its strongest clinical evidence here. Multiple trials show it helps clear viral loads and normalize liver enzymes, especially when combined with antiviral medications. It's approved in over 30 countries specifically for hepatitis treatment.
Cancer Treatment Support
When used alongside chemotherapy, Thymosin Alpha-1 may help maintain immune function that chemo tends to suppress. Research in lung cancer, melanoma, and liver cancer shows improved outcomes when added to standard treatments. It helps your immune system keep fighting even during tough treatments.
Age-Related Immune Decline
As you age, your thymus shrinks and produces less thymosin naturally—a process called immunosenescence. Supplementing with Thymosin Alpha-1 may help compensate, keeping your immune defenses more youthful and responsive. Think of it as replacing what your body makes less of over time.
Severe Infection Recovery
In sepsis and critical infections, Thymosin Alpha-1 has shown promise for reducing mortality by helping restore immune balance. It's particularly interesting because it modulates immunity rather than just boosting it—calming overreaction while enhancing pathogen-fighting ability.
Vilon
Immune system restoration in aging individuals with declining thymic function
Vilon is particularly well-suited for individuals focused on immune system restoration in aging individuals with declining thymic function. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Adjunctive immunomodulatory support during cancer treatment protocols
Vilon is particularly well-suited for individuals focused on adjunctive immunomodulatory support during cancer treatment protocols. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Geroprotective therapy targeting SIRT1/PARP pathways for cellular longevity
Vilon is particularly well-suited for individuals focused on geroprotective therapy targeting sirt1/parp pathways for cellular longevity. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Comprehensive Khavinson bioregulator protocols for anti-aging and immune support
Vilon is particularly well-suited for individuals focused on comprehensive khavinson bioregulator protocols for anti-aging and immune support. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Side effects
Thymosin Alpha-1
Common
- Injection site reactions
- Mild fatigue
- Flu-like symptoms
Uncommon
- Mild fever
- Lymph node awareness
Serious
- Allergic reaction
Vilon
Common
- Injection site reaction
- Mild fatigue
- Mild headache
- Digestive changes
Uncommon
- Flu-like symptoms
Serious
- No documented serious adverse effects
Safety & evidence
Thymosin Alpha-1
Evidence level
Moderate human trials (Phase 1-2)
FDA status
FDA approved for other use
Safety overview
Thymosin Alpha-1 has one of the most extensive safety records of any peptide, with decades of clinical use across multiple countries. Studies consistently report minimal side effects—mostly limited to mild injection site reactions. The 2-hour half-life means it doesn't accumulate in your system. It's been used safely in thousands of patients with hepatitis, cancer, and other serious conditions.
Contraindications
- Organ transplant recipients on immunosuppressants
- Active autoimmune disease flares
- Known allergy to thymosin peptides
- Pregnancy or breastfeeding
- Children under 18 without medical supervision
Vilon
Evidence level
Limited human trials
FDA status
Research compound
Safety overview
Vilon (immunomodulatory thymic peptide complex from bovine thymus) demonstrates favorable safety in Russian/Eastern European medical use over 20+ years with minimal documented serious adverse events in published literature. Bovine-derived peptide preparations carry theoretical prion disease risk (variant Creutzfeldt-Jakob disease) though processing methods and regulatory standards substantially reduce this risk. Common adverse effects are mild—local injection site reactions, transient fever, or lymphadenopathy—consistent with immune system stimulation rather than toxicity.
Contraindications
- Known hypersensitivity to peptide bioregulators or constituent amino acids (lysine, glutamic acid)
- Pregnancy and breastfeeding — insufficient reproductive safety data
- Active autoimmune disease in flare without medical supervision
- Organ transplant recipients on immunosuppression — potential interference with immunosuppressive regimens
Which is right for you?
Choose Thymosin Alpha-1 if...
- Immune system strengthening
- Chronic infection support
- Cancer adjunct therapy
- Healthy aging immune support
Choose Vilon if...
- Immune system restoration in aging individuals with declining thymic function
- Adjunctive immunomodulatory support during cancer treatment protocols
- Geroprotective therapy targeting SIRT1/PARP pathways for cellular longevity
- Comprehensive Khavinson bioregulator protocols for anti-aging and immune support