Comparison
Alpha-GPC vs Thymosin Alpha-1
Side-by-side of Alpha-GPC 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.
Alpha-GPC
Alpha GPC supplement profile: 300 to 600 mg dosage, acetylcholine synthesis, attention and reaction-time evidence, side effects, and choline donor comparisons.
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
Alpha-GPC
- •Choline donor supplement, roughly 40% choline by weight; crosses blood-brain barrier efficiently
- •Replicated small gains in attention and reaction time at 300 to 600 mg in healthy adults
- •Standard prescription cognitive medication in much of Europe (Gliatilin) at 1,200 mg/day for vascular cognitive impairment
- •ASCOMALVA trial (n=210) showed cognitive preservation when added to donepezil over 24 months
- •Increases acute power output (~14%, single trial) and transient growth hormone secretion at 600 mg
- •TMAO production raises a contested cardiovascular concern at chronic high doses
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 | Alpha-GPC | Thymosin Alpha-1 |
|---|---|---|
| Category | supplement | peptide |
| Also known as | L-Alpha glycerylphosphorylcholine, choline alfoscerate, GPC, alpha-glyceryl phosphorylcholine | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 4 | 2 |
| Typical dose (mg) ↗ | 600 | 1.6 |
| Dosing frequency | 1 to 3 times daily | 2x weekly |
| Routes | oral | subcutaneous, intramuscular |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2 | 168 |
| Molecular weight | 257.22 | 3108.32 |
| Molecular formula | C8H20NO6P | C129H215N33O55 |
| Mechanism | Hydrolyzed to free choline and glycerophosphate after absorption; choline supports acetylcholine and phosphatidylcholine synthesis in CNS. | 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); prescription medication in much of Europe | 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 | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data; choline generally recommended in pregnancy | Not recommended; insufficient data |
| CAS | 28319-77-9 | 62304-98-7 |
| PubChem CID | 71920 | 16130571 |
| Wikidata | Q411478 | Q913854 |
Safety profile
Alpha-GPC
Common side effects
- mild GI upset
- headache
- dizziness
- occasional insomnia with evening dosing
Contraindications
- established cardiovascular disease (TMAO concern)
- concurrent strong anticholinergic therapy
Interactions
- anticholinergic medications: partial mutual antagonism(minor)
- cholinesterase inhibitors (donepezil): additive cholinergic effect, basis for ASCOMALVA protocol(minor)
- scopolamine: partial counteraction of anticholinergic effect(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?
Alpha-GPC 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 Alpha-GPC.
- → If your priority is athletic performance, pick Alpha-GPC.
- → 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, Alpha-GPC is the more accessible choice.
Default choice: Alpha-GPC. 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 Alpha-GPC and Thymosin Alpha-1?
Alpha-GPC 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, Alpha-GPC or Thymosin Alpha-1?
Alpha-GPC half-life is 4 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack Alpha-GPC 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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