Comparison
Metformin vs Nicotinamide Riboside
Side-by-side of Metformin and Nicotinamide Riboside. 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.
Nicotinamide Riboside
Nicotinamide riboside (NR) is the most-studied NAD+ precursor in humans. Sold as Niagen by Chromadex; raises plasma NAD+ 30-60% at 250-1,000 mg/day.
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
Nicotinamide Riboside
- •Most-studied NAD+ precursor in human trials; the original Niagen formulation by Chromadex
- •Plasma NAD+ rises 30-60% at 250-1,000 mg/day across multiple human PK trials
- •Martens 2018 reported reduced BP and arterial stiffness at 500 mg/day for 6 weeks
- •Dollerup 2018 found no insulin sensitivity change despite plasma NAD+ rise
- •Tissue NAD+ rise inconsistent; hard clinical endpoints not yet measured
- •Larger human safety database than NMN; comparable mechanistic effects
Side-by-side
| Attribute | Metformin | Nicotinamide Riboside |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | NR, Niagen, nicotinamide riboside chloride |
| Half-life (hr) ↗ | 6 | 8 |
| Typical dose (mg) ↗ | 1500 | 500 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | daily, typically morning |
| Routes | oral | oral |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2.5 | 4 |
| Molecular weight | 129.16 | 255.25 |
| Molecular formula | C4H11N5 | C11H15N2O5 |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | NAD+ precursor via salvage pathway. Phosphorylated to NMN by nicotinamide riboside kinase (NRK), then converted to NAD+. Substrate for sirtuins, PARPs, and CD38. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | OTC dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | OTC supplement |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Insufficient data at supplement doses |
| CAS | 657-24-9 | 1341-23-7 |
| PubChem CID | 4091 | 439924 |
| Wikidata | Q19484 | Q3343054 |
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)
Nicotinamide Riboside
Common side effects
- mild GI upset (rare)
- headache (rare)
Contraindications
- pregnancy / lactation (insufficient data)
- active cancer (theoretical, no contraindicating data)
Interactions
- pterostilbene: complementary sirtuin pathway (Basis combination)(minor)
- TMG (trimethylglycine): methylation support during high NAD+ precursor dosing(minor)
Which Should You Take?
Nicotinamide Riboside 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. Metformin is the right call when one of the conditionals below applies.
- → If your priority is energy and stamina, pick Nicotinamide Riboside.
- → If your priority is metabolic health and glucose control, pick Nicotinamide Riboside.
- → If your priority is healthspan extension, pick Nicotinamide Riboside.
Edge case: If you want to avoid prescription-only, Nicotinamide Riboside is the more accessible choice.
Default choice: Nicotinamide Riboside. 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 Nicotinamide Riboside?
Metformin and Nicotinamide Riboside 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 Nicotinamide Riboside?
Metformin half-life is 6 hours; Nicotinamide Riboside half-life is 8 hours.
Can you stack Metformin with Nicotinamide Riboside?
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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