Comparison
Modafinil vs Thymosin Alpha-1
Side-by-side of Modafinil and Thymosin Alpha-1. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Modafinil
Modafinil cognitive enhancement profile: wakefulness-promoting agent, 100-200 mg dosing, 12-15 hour half-life, off-label nootropic use, Schedule IV status.
Thymosin Alpha-1
Thymosin alpha-1 peptide (Zadaxin, thymalfasin): 28-amino-acid TA1 immunomodulator. Dosing, T-cell effects, hepatitis B and HCV adjunct evidence.
Effects at a glance
Modafinil
- •FDA approved in 1998 for narcolepsy, with later additions for shift-work sleep disorder and OSA residual sleepiness
- •Schedule IV controlled substance in the US; prescription-only in EU, UK, Australia
- •Increases wakefulness via weak dopamine reuptake inhibition plus histaminergic, noradrenergic, and orexinergic activation
- •Long half-life of 12 to 15 hours requires morning dosing to avoid sleep disruption
- •Modest cognitive enhancement signal in non-sleep-deprived adults at 100 to 200 mg (Battleday meta-review 2015)
- •Substantial CYP3A4 induction reduces hormonal contraceptive efficacy; barrier methods recommended
Thymosin Alpha-1
- •28-amino-acid synthetic peptide identical to thymic-derived immunomodulator
- •Approved in over 35 countries as Zadaxin for hepatitis B, hepatitis C adjunct, and immune support
- •Not FDA approved in US; compounded by 503A/503B pharmacies for off-label immune support
- •Modulates T-cell maturation, NK activity, and Th1 polarization in immunocompromised states
- •Standard label dose: 1.6 mg subcutaneously twice weekly
- •Cleanest safety profile in the peptide class with hundreds of regulated trials behind it
Side-by-side
| Attribute | Modafinil | Thymosin Alpha-1 |
|---|---|---|
| Category | pharmaceutical | peptide |
| Also known as | Provigil, Modalert, Modvigil, diphenylmethylsulfinyl-acetamide | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 13 | 2 |
| Typical dose (mg) ↗ | 200 | 1.6 |
| Dosing frequency | daily, morning | 2x weekly |
| Routes | oral | subcutaneous, intramuscular |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 3 | 168 |
| Molecular weight | 273.35 | 3108.32 |
| Molecular formula | C15H15NO2S | C129H215N33O55 |
| Mechanism | Weak dopamine reuptake inhibition plus downstream activation of histaminergic, noradrenergic, and orexinergic wake-promoting systems. | Synthetic peptide modulator of innate and adaptive immunity. Promotes T-cell maturation and CD4/CD8 production, modulates Th1/Th2 balance, stimulates NK cell activity, and modulates TLR2/TLR9 signaling in dendritic cells. |
| Legal status | Schedule IV (US); prescription-only globally; not a supplement | Approved in 35+ countries as Zadaxin (hepatitis B, hepatitis C adjunct, immune support); not FDA approved in US; compounded by 503A/503B pharmacies for off-label use; not on WADA Prohibited List |
| WADA status | banned | unknown |
| DEA / Rx | Schedule IV | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Not recommended | Not recommended; insufficient data |
| CAS | 68693-11-8 | 62304-98-7 |
| PubChem CID | 4236 | 16130571 |
| Wikidata | Q422968 | Q913854 |
Safety profile
Modafinil
Common side effects
- headache
- nausea
- anxiety
- insomnia (with late-day dosing)
- dry mouth
- mild blood pressure elevation
Contraindications
- recent myocardial infarction
- unstable angina
- left ventricular hypertrophy
- significant arrhythmia
- history of Stevens-Johnson syndrome
- psychotic disorders
- pregnancy
- concurrent MAOI use
Interactions
- hormonal contraceptives: CYP3A4 induction reduces contraceptive efficacy; use barrier method(major)
- cyclosporine: reduced cyclosporine levels via CYP3A4 induction(major)
- warfarin: CYP2C9 inhibition raises INR(moderate)
- phenytoin: CYP2C19 inhibition raises phenytoin levels(moderate)
- MAOIs: potential hypertensive reaction(major)
- classical stimulants (amphetamine, methylphenidate): additive cardiovascular and sleep-disruption effects(moderate)
Thymosin Alpha-1
Common side effects
- mild injection-site irritation (rare)
- transient mild fatigue (rare)
- occasional headache (rare)
Contraindications
- pregnancy
- lactation
- active organ transplant rejection therapy
- systemic immunosuppression for autoimmune disease (relative)
- severe active autoimmune disease (caution)
Interactions
- interferon-alpha: additive immune effect; used clinically in approved combination protocols(minor)
- calcineurin inhibitors (cyclosporine, tacrolimus): theoretical destabilization of immunosuppression; avoid(major)
- antimetabolites (azathioprine, mycophenolate): theoretical destabilization of immunosuppression; avoid(major)
- vaccine administration: may augment vaccine response in elderly or immunocompromised; coordinate with clinician(minor)
Which Should You Take?
Modafinil comes out ahead for most readers on the criteria we weight: 3 catalogued goals, controlled substance, oral dosing, with a Tier-A outcome catalogued. Thymosin Alpha-1 is the right call when one of the conditionals below applies.
- → If your priority is wakefulness, pick Modafinil.
- → If your priority is focus or working memory, pick Modafinil.
- → If your priority is immune support, pick Thymosin Alpha-1.
- → If your priority is post-training recovery, pick Thymosin Alpha-1.
Edge case: If you cannot self-administer injections, Modafinil is the only oral option in this pair.
Default choice: Modafinil. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Thymosin Alpha-1 only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Modafinil and Thymosin Alpha-1?
Modafinil and Thymosin Alpha-1 differ in category (pharmaceutical vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Modafinil or Thymosin Alpha-1?
Modafinil half-life is 13 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack Modafinil with Thymosin Alpha-1?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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