Comparison
Thymosin Alpha-1 vs Urolithin A
Side-by-side of Thymosin Alpha-1 and Urolithin A. 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.
Thymosin Alpha-1
Thymosin alpha-1 peptide (Zadaxin, thymalfasin): 28-amino-acid TA1 immunomodulator. Dosing, T-cell effects, hepatitis B and HCV adjunct evidence.
Urolithin A
Urolithin A supplement guide: pomegranate-derived metabolite, 500-1000 mg Mitopure dosing, mitophagy and muscle endurance evidence.
Effects at a glance
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
Urolithin A
- •Gut-microbiome-derived metabolite of pomegranate and walnut ellagitannins
- •Roughly 40% of adults are 'urolithin producers' from dietary intake; ~60% are non-producers
- •Ryu 2016 (Nature Medicine) reported lifespan extension in C. elegans and muscle benefits in aged rodents
- •Andreux 2019 first-in-human trial (n=60) established safety and mitochondrial gene-expression upregulation
- •Singh 2022 (n=66, 4 months, 1000 mg/day) reported improved muscle endurance in older adults
- •Most human trial portfolio is Amazentis-funded; independent replication is thin
Side-by-side
| Attribute | Thymosin Alpha-1 | Urolithin A |
|---|---|---|
| Category | peptide | supplement |
| Also known as | Talpha1, Ta1, Zadaxin, Thymalfasin | UA, Mitopure, ellagitannin metabolite |
| Half-life (hr) ↗ | 2 | 17 |
| Typical dose (mg) ↗ | 1.6 | 500 |
| Dosing frequency | 2x weekly | daily, morning with food |
| Routes | subcutaneous, intramuscular | oral |
| Onset (hr) | 24 | 2 |
| Peak (hr) | 168 | 4 |
| Molecular weight | 3108.32 | 228.2 |
| Molecular formula | C129H215N33O55 | C13H8O4 |
| Mechanism | 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. | Induces mitophagy via potentiation of PINK1/Parkin signaling, leading to selective degradation of damaged mitochondria. Secondary anti-inflammatory effects via NF-kB modulation. |
| Legal status | 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 | OTC dietary supplement (US GRAS 2018; EFSA Novel Food 2021) |
| WADA status | unknown | allowed |
| DEA / Rx | Rx only via international approval or US compounding (no controlled-substance schedule) | OTC supplement (not scheduled) |
| Pregnancy | Not recommended; insufficient data | Insufficient data; not routinely recommended |
| CAS | 62304-98-7 | 1143-70-0 |
| PubChem CID | 16130571 | 5488186 |
| Wikidata | Q913854 | Q27101321 |
Safety profile
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)
Urolithin A
Common side effects
- mild GI upset (rare)
- soft stools (rare)
Contraindications
- pregnancy and lactation (insufficient data)
- active chemotherapy (consult oncology)
Interactions
- chemotherapy agents: theoretical interaction with mitochondrial-targeting agents; consult oncologist(moderate)
Which Should You Take?
Urolithin A comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, 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 immune support, pick Thymosin Alpha-1.
- → If your priority is post-training recovery, pick Thymosin Alpha-1.
- → If your priority is healthspan extension, pick Urolithin A.
- → If your priority is muscle hypertrophy, pick Urolithin A.
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, Urolithin A is the more accessible choice.
Default choice: Urolithin A. Lower friction to source, 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 Thymosin Alpha-1 and Urolithin A?
Thymosin Alpha-1 and Urolithin A differ in category (peptide vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Thymosin Alpha-1 or Urolithin A?
Thymosin Alpha-1 half-life is 2 hours; Urolithin A half-life is 17 hours.
Can you stack Thymosin Alpha-1 with Urolithin A?
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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