Comparison
Metformin vs Spermidine
Side-by-side of Metformin and Spermidine. 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.
Metformin
Metformin for longevity: biguanide mechanism of action, TAME trial status, anti-aging dosage, weight loss data, life extension evidence in non-diabetics.
Spermidine
Spermidine supplement benefits cover autophagy induction, longevity signals, and cognition. Wheat germ extract data, doses, and human trials reviewed.
Effects at a glance
Metformin
- •Reduces HbA1c by ~1.0 to 1.5 percentage points in type 2 diabetes; first-line agent in major guidelines
- •DPP trial: 31% reduction in T2DM incidence in adults with prediabetes over 2.8 years
- •Suppresses hepatic gluconeogenesis via AMPK activation and complex I inhibition
- •Long-term use depletes B12; annual monitoring recommended after year 2
- •Lifespan extension in non-diabetic humans is not established; TAME trial pending
- •MASTERS trial reported blunted resistance-training hypertrophy in older adults
Spermidine
- •Endogenous polyamine that induces autophagy via EP300 acetyltransferase inhibition and TFEB activation
- •Concentrated in wheat germ, soybeans, aged cheese, and mushrooms; ~10 to 15 mg/day in Mediterranean diets
- •Eisenberg 2016 reported dietary spermidine extended mouse lifespan and improved cardiac function
- •Wirth 2018 pilot (n=28) reported cognitive signal at 0.9 mg/day in older adults at risk for dementia
- •Larger Wirth 2019 follow-up (n=85) did not replicate the memory benefit at 12 months
- •Generally regarded as safe at supplemental doses; food-source position is reassuring
Side-by-side
| Attribute | Metformin | Spermidine |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | spermidine trihydrochloride, wheat-germ-extract spermidine |
| Half-life (hr) ↗ | 6 | 6 |
| Typical dose (mg) ↗ | 1500 | 1.2 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | daily, typically morning with food |
| Routes | oral | oral |
| Onset (hr) | 1 | 2 |
| Peak (hr) | 2.5 | 4 |
| Molecular weight | 129.16 | 145.25 |
| Molecular formula | C4H11N5 | C7H19N3 |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | Induces macroautophagy via inhibition of EP300 histone acetyltransferase and activation of TFEB-mediated lysosomal biogenesis. Substrate for hypusination of eIF5A, required for translation of mitochondrial respiration proteins. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | OTC dietary supplement (wheat-germ extract has GRAS status in US) |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | OTC supplement (not scheduled) |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Insufficient data; not routinely recommended at supplemental doses |
| CAS | 657-24-9 | 124-20-9 |
| PubChem CID | 4091 | 1102 |
| Wikidata | Q19484 | Q411089 |
Safety profile
Metformin
Common side effects
- nausea
- diarrhea
- abdominal discomfort
- metallic taste
- decreased appetite
- B12 depletion (long-term)
Contraindications
- eGFR below 30 mL/min/1.73m2
- acute or chronic metabolic acidosis
- severe hepatic impairment
- acute heart failure
- iodinated contrast within 48 hours
Interactions
- iodinated contrast media: renal injury risk; hold 48 hours peri-imaging(major)
- alcohol (heavy use): elevated lactic acidosis risk(major)
- cimetidine: raises metformin plasma levels via OCT2 inhibition(moderate)
- insulin and sulfonylureas: additive hypoglycemia risk in combination(moderate)
- dolutegravir: raises metformin exposure via OCT2(moderate)
Spermidine
Common side effects
- mild GI upset (rare)
- headache (rare)
Contraindications
- wheat-germ allergy or celiac disease (for wheat-germ-extract products)
- active cancer (theoretical)
- pregnancy and lactation (insufficient data)
Interactions
- DFMO (difluoromethylornithine): competing polyamine metabolism; do not combine without oncology guidance(moderate)
Which Should You Take?
Spermidine comes out ahead for most readers on the criteria we weight: 2 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. Metformin is the right call when one of the conditionals below applies.
- → If your priority is metabolic health and glucose control, pick Metformin.
- → If your priority is focus or working memory, pick Spermidine.
- → If your priority is healthspan extension, pick Spermidine.
Edge case: If you want to avoid prescription-only, Spermidine is the more accessible choice.
Default choice: Spermidine. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Metformin 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 Metformin and Spermidine?
Metformin and Spermidine differ in category (pharmaceutical vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Metformin or Spermidine?
Metformin half-life is 6 hours; Spermidine half-life is 6 hours.
Can you stack Metformin with Spermidine?
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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