Comparison
Citicoline vs Thymosin Alpha-1
Side-by-side of Citicoline 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.
Citicoline
Citicoline supplement profile: CDP-choline as a phosphatidylcholine precursor, Cognizin dosing 250-2000 mg, cognition trials, stroke recovery evidence.
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
Citicoline
- •Choline donor and phosphatidylcholine precursor; oral bioavailability roughly 99%
- •Standard prescription medication for stroke recovery and vascular cognitive impairment in much of the world
- •Healthy-adult cognitive trials (Cognizin) report small gains in attention and working memory at 250 to 500 mg/day
- •ICTUS trial (n=2,298) was negative on stroke recovery in the modern thrombolysis era
- •Lower per-gram choline content than alpha-GPC (~18% vs ~40%), meaning smaller TMAO load at equivalent dose
- •Long uridine half-life (~56 hours) supports once or twice daily dosing
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 | Citicoline | Thymosin Alpha-1 |
|---|---|---|
| Category | supplement | peptide |
| Also known as | CDP-choline, cytidine 5'-diphosphocholine, Cognizin | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 56 | 2 |
| Typical dose (mg) ↗ | 500 | 1.6 |
| Dosing frequency | 1 to 2 times daily | 2x weekly |
| Routes | oral, intravenous | subcutaneous, intramuscular |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2 | 168 |
| Molecular weight | 488.32 | 3108.32 |
| Molecular formula | C14H26N4O11P2 | C129H215N33O55 |
| Mechanism | Hydrolyzed to cytidine and choline after absorption; both cross the blood-brain barrier and are recombined intracellularly to reform CDP-choline, supporting phosphatidylcholine synthesis and acetylcholine production. | 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 | Dietary supplement (US, Cognizin GRAS); prescription medication in most of the world | 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 | allowed | unknown |
| DEA / Rx | OTC supplement (US); Rx in most of the world | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data for routine use | Not recommended; insufficient data |
| CAS | 987-78-0 | 62304-98-7 |
| PubChem CID | 13804 | 16130571 |
| Wikidata | Q411470 | Q913854 |
Safety profile
Citicoline
Common side effects
- mild GI upset
- headache
- restlessness
- occasional insomnia with evening dosing
Contraindications
- concurrent strong anticholinergic therapy
- established cardiovascular disease (TMAO concern, smaller than alpha-GPC)
Interactions
- anticholinergic medications: partial mutual antagonism(minor)
- cholinesterase inhibitors: additive cholinergic effect(minor)
- antimetabolite chemotherapy (5-FU): theoretical cytidine pathway interaction(minor)
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?
Citicoline comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-B outcome catalogued. Thymosin Alpha-1 is the right call when one of the conditionals below applies.
- → If your priority is focus or working memory, pick Citicoline.
- → If your priority is stroke recovery, pick Citicoline.
- → 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 want to avoid 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, Citicoline is the more accessible choice.
Default choice: Citicoline. Lower friction to source, 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 Citicoline and Thymosin Alpha-1?
Citicoline and Thymosin Alpha-1 differ in category (supplement vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Citicoline or Thymosin Alpha-1?
Citicoline half-life is 56 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack Citicoline 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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