Comparison
Metformin vs NMN
Side-by-side of Metformin and NMN. 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.
NMN
NMN supplements are oral nicotinamide mononucleotide capsules sold for longevity, energy, and metabolic health. They raise plasma NAD+ 30-90% at 250-1000.
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
NMN
- •Plasma NAD+ rises 30-90% at 250-1000 mg/day across human PK studies
- •Tissue NAD+ rise is inconsistent across human trials (Yoshino 2021, Igarashi 2022)
- •No human trials measure hard endpoints (mortality, CV events, cancer); evidence is biomarker-only
- •Most trials cluster at 250-500 mg/day; dose-response above 250 mg/day is poorly characterized
- •FDA position contested; widely sold as supplement but with regulatory uncertainty
- •Marketing claims for fertility and longevity outrun the human trial evidence substantially
Side-by-side
| Attribute | Metformin | NMN |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | nicotinamide mononucleotide, beta-NMN |
| Half-life (hr) ↗ | 6 | 4 |
| Typical dose (mg) ↗ | 1500 | 250 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | 1x daily, often morning |
| Routes | oral | oral, sublingual |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2.5 | 3 |
| Molecular weight | 129.16 | 334.22 |
| Molecular formula | C4H11N5 | C11H15N2O8P |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | Direct precursor in the NAD+ salvage pathway; converted to NAD+ by NMNAT enzymes in essentially every tissue. Raised NAD+ supports sirtuin and PARP enzyme activity. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | Not scheduled |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Insufficient data; precautionary avoidance |
| CAS | 657-24-9 | 1094-61-7 |
| PubChem CID | 4091 | 14180 |
| Wikidata | Q19484 | Q418972 |
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)
NMN
Common side effects
- mild GI upset (rare)
- occasional headache
- flushing (rare)
Contraindications
- pregnancy and lactation (precautionary, no data)
- active cancer (theoretical concern, not evidence-based)
Interactions
- metformin: no clinically significant interaction documented; both modulate metabolism through different mechanisms(minor)
- chemotherapy agents: theoretical concern about supporting cancer cell proliferation; coordinate with oncology team(moderate)
- CD38 inhibitors: would amplify NMN-induced NAD+ rise; not clinically relevant for most users(minor)
Which Should You Take?
NMN comes out ahead for most readers on the criteria we weight: 3 catalogued goals, Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia, oral dosing, with a Tier-A outcome catalogued. Metformin is the right call when one of the conditionals below applies.
- → If your priority is energy and stamina, pick NMN.
- → If your priority is metabolic health and glucose control, pick NMN.
- → If your priority is healthspan extension, pick NMN.
Default choice: NMN. Wider use case, 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 NMN?
Metformin and NMN 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 NMN?
Metformin half-life is 6 hours; NMN half-life is 4 hours.
Can you stack Metformin with NMN?
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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