Comparison
Metformin vs Tirzepatide
Side-by-side of Metformin and Tirzepatide. 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.
Tirzepatide
Tirzepatide for weight loss: dual GIP/GLP-1 agonist sold as Mounjaro and Zepbound. SURMOUNT-1 showed 22.5% mean body-weight loss at 15 mg over 72 weeks.
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
Tirzepatide
- •Dual GIP plus GLP-1 receptor agonist with a ~5-day half-life supporting once-weekly subcutaneous dosing
- •SURMOUNT-1 reported ~22.5% mean body-weight loss at 15 mg over 72 weeks versus 2.4% on placebo
- •Lowers HbA1c by ~1.9 to 2.6 percentage points in type 2 diabetes across SURPASS trials
- •Outperformed semaglutide 1.0 mg head-to-head on weight loss and HbA1c in SURPASS-2
- •GI effects (nausea, diarrhea, vomiting) drive most discontinuations and ease with slow titration
- •Lean-mass loss observed in body-composition substudies; resistance training and protein intake mitigate this
Side-by-side
| Attribute | Metformin | Tirzepatide |
|---|---|---|
| Category | pharmaceutical | pharmaceutical |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | Mounjaro, Zepbound, LY3298176 |
| Half-life (hr) ↗ | 6 | 120 |
| Typical dose (mg) ↗ | 1500 | 10 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | weekly |
| Routes | oral | subcutaneous |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2.5 | 72 |
| Molecular weight | 129.16 | 4813.45 |
| Molecular formula | C4H11N5 | C225H348N48O68 |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | Synthetic 39-amino-acid peptide that activates both GIP and GLP-1 receptors. Potentiates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic and brainstem satiety circuits. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | Prescription only; FDA-approved 2022 (T2DM, Mounjaro) and 2023 (chronic weight management, Zepbound) |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | Rx only (not a controlled substance) |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Not recommended; discontinue 2 months before planned pregnancy |
| CAS | 657-24-9 | 2023788-19-2 |
| PubChem CID | 4091 | 156588324 |
| Wikidata | Q19484 | Q105099794 |
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)
Tirzepatide
Common side effects
- nausea
- diarrhea
- vomiting
- constipation
- decreased appetite
- injection-site reactions
- fatigue
- abdominal pain
Contraindications
- personal or family history of medullary thyroid carcinoma
- multiple endocrine neoplasia type 2
- pregnancy
- history of pancreatitis (use caution)
- severe gastroparesis
Interactions
- insulin: additive hypoglycemia risk; insulin dose typically reduced(major)
- sulfonylureas (glipizide, glyburide): hypoglycemia risk, sulfonylurea dose often reduced(major)
- oral medications (general): delayed gastric emptying can alter absorption kinetics(moderate)
- oral contraceptives: reduced exposure after first dose; backup contraception recommended for 4 weeks after initiation and each dose escalation(moderate)
- warfarin: monitor INR due to altered absorption(moderate)
Which Should You Take?
Metformin and Tirzepatide score evenly on the criteria we weight (goal breadth, legal accessibility, evidence depth). The conditionals below should drive the decision more than any aggregate score.
- → If your priority is healthspan extension, pick Metformin.
- → If your priority is fat loss, pick Tirzepatide.
- → If your priority is glycemic control, pick Tirzepatide.
Edge case: If you cannot self-administer injections, Metformin is the only oral option in this pair.
Default choice: either is defensible. Metformin edges out on goal breadth + legal accessibility; Tirzepatide is the right call if your priority sits in the goals listed 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 Tirzepatide?
Metformin and Tirzepatide differ in category (pharmaceutical vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Metformin or Tirzepatide?
Metformin half-life is 6 hours; Tirzepatide half-life is 120 hours.
Can you stack Metformin with Tirzepatide?
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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