Comparison
MOTS-c vs Thymosin Alpha-1
Side-by-side of MOTS-c 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.
MOTS-c
MOTS-c peptide is a 16-amino-acid mitochondrial-derived peptide. Preclinical signals for insulin sensitivity, exercise capacity, dosage notes.
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
MOTS-c
- •16-amino-acid peptide encoded in mitochondrial DNA (12S rRNA region); discovered 2015
- •Activates AMPK in skeletal muscle and liver; improves insulin sensitivity in rodent models
- •Circulating endogenous levels decline with age, motivating the longevity-restoration hypothesis
- •CohBar's MOTS-c analog CB4211 discontinued after phase 1b NASH readout did not meet endpoints
- •Anecdotal protocols use 5 to 10 mg subcutaneously 2 to 3 times weekly
- •Not on the WADA Prohibited List as of 2026; future scrutiny likely given exercise-mimetic mechanism
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 | MOTS-c | Thymosin Alpha-1 |
|---|---|---|
| Category | peptide | peptide |
| Also known as | Mitochondrial Open Reading Frame of the Twelve S rRNA-c, MOTSc | Talpha1, Ta1, Zadaxin, Thymalfasin |
| Half-life (hr) ↗ | 0.5 | 2 |
| Typical dose (mg) ↗ | 5 | 1.6 |
| Dosing frequency | 2-3x weekly | 2x weekly |
| Routes | subcutaneous | subcutaneous, intramuscular |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 4 | 168 |
| Molecular weight | 1880.18 | 3108.32 |
| Molecular formula | C82H132N22O25S2 | C129H215N33O55 |
| Mechanism | Mitochondrial-derived peptide that activates AMPK in skeletal muscle and liver, improves insulin sensitivity, and translocates to the nucleus under metabolic stress to modulate nuclear gene expression in retrograde mitochondrial signaling. | 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 | Not FDA approved; research-use-only grey market; not currently on WADA Prohibited List | 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 | unknown | unknown |
| DEA / Rx | Not scheduled (research chemical) | Rx only via international approval or US compounding (no controlled-substance schedule) |
| Pregnancy | Insufficient data; not recommended | Not recommended; insufficient data |
| CAS | 1627580-64-6 | 62304-98-7 |
| PubChem CID | 139599184 | 16130571 |
| Wikidata | Q24832108 | Q913854 |
Safety profile
MOTS-c
Common side effects
- injection-site irritation
- transient fatigue
- headache (anecdotal)
Contraindications
- pregnancy
- lactation
- active malignancy (theoretical)
- severe hypoglycemia risk on concurrent insulin or sulfonylurea
Interactions
- insulin: additive insulin sensitization may increase hypoglycemia risk(moderate)
- metformin: both activate AMPK; theoretical additive metabolic effect, no controlled data(minor)
- sulfonylureas: increased hypoglycemia risk via additive insulin sensitization(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?
Thymosin Alpha-1 comes out ahead for most readers on the criteria we weight: 3 catalogued goals, 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, with a Tier-A outcome catalogued. MOTS-c is the right call when one of the conditionals below applies.
- → If your priority is healthspan extension, pick MOTS-c.
- → If your priority is metabolic health and glucose control, pick MOTS-c.
- → If your priority is immune support, pick Thymosin Alpha-1.
- → If your priority is post-training recovery, pick Thymosin Alpha-1.
Edge case: Half-lives differ materially (MOTS-c ~0.5 hr vs Thymosin Alpha-1 ~2 hr). Thymosin Alpha-1 reaches steady state faster; MOTS-c is easier to dial in if tolerability is uncertain.
Default choice: Thymosin Alpha-1. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for MOTS-c 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 MOTS-c and Thymosin Alpha-1?
MOTS-c and Thymosin Alpha-1 differ in category (peptide vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, MOTS-c or Thymosin Alpha-1?
MOTS-c half-life is 0.5 hours; Thymosin Alpha-1 half-life is 2 hours.
Can you stack MOTS-c 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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