Comparison
Metformin vs N-Acetyl Cysteine
Side-by-side of Metformin and N-Acetyl Cysteine. 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.
N-Acetyl Cysteine
NAC supplement benefits cover glutathione synthesis, liver and antioxidant support, and hangover recovery. Evidence strongest at 1200-2400 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
N-Acetyl Cysteine
- •Replenishes intracellular glutathione by supplying cysteine, the rate-limiting amino acid for synthesis
- •First-line antidote for acetaminophen toxicity, restoring hepatic glutathione before fulminant injury occurs
- •Reduces sputum viscosity in chronic bronchitis and COPD at 600 to 1200 mg/day over months
- •Modest symptom reductions in OCD and trichotillomania at 1200 to 2400 mg/day across small RCTs
- •Mixed evidence for psychiatric adjunct use in bipolar depression and schizophrenia negative symptoms
- •Inhaled forms can trigger bronchospasm in active asthma; oral use is the standard biohacker route
Side-by-side
| Attribute | Metformin | N-Acetyl Cysteine |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | NAC |
| Half-life (hr) ↗ | 6 | 5.6 |
| Typical dose (mg) ↗ | 1500 | 1200 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | 1 to 3 times daily, split dosing preferred |
| Routes | oral | oral, iv |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2.5 | 2 |
| Molecular weight | 129.16 | 163.19 |
| Molecular formula | C4H11N5 | C5H9NO3S |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | Deacetylated to cysteine, the rate-limiting precursor for glutathione synthesis; also directly scavenges reactive oxygen species and modulates glutamate signaling. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | OTC in most jurisdictions; restricted periods in US history (FDA reclassified 2022) |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | OTC supplement (US, post-2022); Rx indications also exist (acetaminophen overdose, mucolytic) |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Used clinically in pregnancy for specific indications; consult clinician |
| CAS | 657-24-9 | 616-91-1 |
| PubChem CID | 4091 | 12035 |
| Wikidata | Q19484 | Q413299 |
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)
N-Acetyl Cysteine
Common side effects
- sulfur-like taste or odor
- nausea
- flatulence
- diarrhea
Contraindications
- active asthma attack (inhaled form can trigger bronchospasm)
- known NAC hypersensitivity
Interactions
- nitroglycerin: potentiates vasodilation, risk of hypotension and headache(moderate)
- activated charcoal: reduces NAC absorption when used for acetaminophen overdose(moderate)
- anticoagulants: theoretical additive antiplatelet effect at high doses(minor)
Which Should You Take?
N-Acetyl Cysteine comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC, 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 post-training recovery, pick N-Acetyl Cysteine.
- → If your priority is liver function, pick N-Acetyl Cysteine.
Edge case: If you want to avoid prescription-only, N-Acetyl Cysteine is the more accessible choice.
Default choice: N-Acetyl Cysteine. 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 N-Acetyl Cysteine?
Metformin and N-Acetyl Cysteine 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 N-Acetyl Cysteine?
Metformin half-life is 6 hours; N-Acetyl Cysteine half-life is 5.6 hours.
Can you stack Metformin with N-Acetyl Cysteine?
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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