Comparison
Metformin vs Semaglutide
Side-by-side of Metformin and Semaglutide. 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.
Semaglutide
Semaglutide for weight loss: GLP-1 agonist (Ozempic, Wegovy) drives 15-17% mean loss at 2.4 mg/week in STEP trials. Watch lean-mass loss.
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
Semaglutide
- •Long-acting GLP-1 receptor agonist with a ~7-day half-life that supports once-weekly subcutaneous dosing
- •STEP trials reported ~15 to 17% mean body-weight loss at 2.4 mg/week over 68 weeks in adults with obesity
- •Lowers HbA1c by ~1.0 to 1.8 percentage points in type 2 diabetes versus placebo
- •SELECT trial showed reduced major cardiovascular events in adults with prior CVD and overweight or obesity
- •Up to 25 to 40% of weight lost can be lean mass; pairing with resistance training and protein intake mitigates this
- •GI effects (nausea, vomiting, constipation) drive most discontinuations and ease with slow titration
Side-by-side
| Attribute | Metformin | Semaglutide |
|---|---|---|
| Category | pharmaceutical | pharmaceutical |
| Also known as | Glucophage, Fortamet, Glumetza, dimethylbiguanide | Ozempic, Wegovy, Rybelsus |
| Half-life (hr) ↗ | 6 | 168 |
| Typical dose (mg) ↗ | 1500 | 2.4 |
| Dosing frequency | 1 to 3 times daily with meals; XR once daily | weekly (SC); daily (oral Rybelsus) |
| Routes | oral | subcutaneous, oral |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 2.5 | 72 |
| Molecular weight | 129.16 | 4113.58 |
| Molecular formula | C4H11N5 | - |
| Mechanism | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. | Long-acting GLP-1 receptor agonist; potentiates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic satiety centers. |
| Legal status | Prescription only (FDA approved for type 2 diabetes 1994) | Prescription only (FDA-approved, EMA-approved) |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance) | Rx only (not a controlled substance); FDA-approved for type 2 diabetes (2017) and chronic weight management (2021) |
| Pregnancy | Category B; used in gestational diabetes and PCOS per current guidance | Not recommended; discontinue 2 months before planned pregnancy |
| CAS | 657-24-9 | 910463-68-2 |
| PubChem CID | 4091 | 56843331 |
| Wikidata | Q19484 | Q27089394 |
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)
Semaglutide
Common side effects
- nausea
- vomiting
- diarrhea
- constipation
- decreased appetite
- injection-site reactions
- fatigue
Contraindications
- personal or family history of medullary thyroid carcinoma
- multiple endocrine neoplasia type 2
- pregnancy
- history of pancreatitis (use caution)
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)
- warfarin: monitor INR due to altered absorption(moderate)
Which Should You Take?
Metformin and Semaglutide 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 Semaglutide.
- → If your priority is metabolic health and glucose control, pick Metformin.
Edge case: Half-lives differ materially (Metformin ~6 hr vs Semaglutide ~168 hr). Semaglutide reaches steady state faster; Metformin is easier to dial in if tolerability is uncertain.
Default choice: either is defensible. Metformin edges out on goal breadth + legal accessibility; Semaglutide 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 Semaglutide?
Metformin and Semaglutide 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 Semaglutide?
Metformin half-life is 6 hours; Semaglutide half-life is 168 hours.
Can you stack Metformin with Semaglutide?
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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