Metformin and semaglutide both come up in weight loss conversations — but they're quite different medications arriving at the same question from very different directions. One costs $4 a month and has been prescribed for decades. The other costs hundreds, was approved for weight management in 2021, and has reshaped how clinicians and patients think about treating obesity.
This guide compares the two on the evidence that matters: how much weight each produces, what the side effects look like, who each is right for, and what you'll actually pay.
The Quick Comparison
| Metformin | Semaglutide | |
|---|---|---|
| Drug class | Biguanide | GLP-1 receptor agonist |
| Brand names | Glucophage (generic available) | Ozempic (diabetes), Wegovy (weight loss) |
| FDA-approved for | Type 2 diabetes | Type 2 diabetes (Ozempic); chronic weight management (Wegovy) |
| Weight loss (avg. trials) | ~2–3 kg | ~6 kg (Ozempic dose) to ~15% body weight (Wegovy) |
| Generic available? | Yes | Not yet (compounded available) |
| Cost without insurance | $4–$15/month | $99–$1,200/month depending on source |
| HSA/FSA eligible? | Yes | Yes |
| Off-label for weight? | Yes (common) | No (Wegovy is on-label) |
| Telehealth access | Widely available | Widely available |
What Each Drug Is
Metformin
Metformin is a biguanide — one of the oldest diabetes medications still in active use. It was approved by the FDA in 1994 for type 2 diabetes management and has since become the most-prescribed diabetes drug in the United States. It works primarily by reducing glucose production in the liver and improving insulin sensitivity in peripheral tissue, which together lower fasting blood sugar levels.
Metformin is not FDA-approved for weight loss, but its modest weight-reducing effect has made it a widely used off-label tool for patients with obesity, prediabetes, or insulin resistance. Some physicians also prescribe it for polycystic ovary syndrome (PCOS) to address insulin resistance alongside other metabolic concerns.
Key characteristics:
- Oral tablet (immediate release or extended release), taken once or twice daily
- Inexpensive — generic is available and widely covered by insurance
- Decades of safety data across diverse populations
- Weight effect is modest: typically 2–3 kg over 12–24 months in clinical trials
Semaglutide
Semaglutide is a GLP-1 receptor agonist developed by Novo Nordisk. It mimics the GLP-1 hormone produced naturally after eating, which stimulates insulin secretion, suppresses glucagon, slows gastric emptying, and — critically for weight loss — significantly reduces appetite and food intake via central nervous system pathways.
Semaglutide exists in two branded injectable forms:
- Ozempic (0.5–2.0mg weekly): FDA-approved for type 2 diabetes and cardiovascular risk reduction
- Wegovy (2.4mg weekly): FDA-approved for chronic weight management in adults with obesity or overweight with at least one weight-related condition
Compounded semaglutide — the same active ingredient — is also available through licensed telehealth providers, typically at $99–$450/month, making it significantly more affordable than brand options.
Weight Loss Evidence
Metformin: Modest, Steady Effect
Metformin's weight loss effect has been documented in clinical trials, but the numbers are modest compared to GLP-1 medications. The landmark Diabetes Prevention Program (DPP) found that participants on metformin lost an average of 2.1 kg over 2.8 years — compared to 5.6 kg in the lifestyle intervention group.
In studies focused on patients without diabetes, results are similar: average weight loss of 2–3 kg over 12–24 months. Metformin appears to work partly by reducing appetite, but the mechanism is less targeted than GLP-1 agonism, and the effect reaches a ceiling relatively quickly.
For patients who need modest weight reduction alongside blood sugar management, metformin is a reasonable, well-tolerated, inexpensive option. For patients with significant weight loss goals, it rarely gets them where they want to go on its own.
Semaglutide: Substantially Stronger Evidence
The data for semaglutide at weight management doses is in a different category. The STEP clinical trial program — a series of randomized controlled trials specifically examining semaglutide 2.4mg (Wegovy) for weight management — produced the following results:
| Trial | Population | Average Weight Loss |
|---|---|---|
| STEP 1 | Adults with obesity, no diabetes | −14.9% body weight |
| STEP 2 | Adults with obesity + type 2 diabetes | −9.6% body weight |
| STEP 3 | Obesity + intensive behavioral therapy | −16.0% body weight |
| STEP 4 (maintenance) | Continued vs. discontinued | Regain with discontinuation |
At the diabetes-dose level (Ozempic 1.0mg), the SUSTAIN trials showed average weight loss of approximately 4–6 kg — still substantially more than metformin.
For patients with obesity or significant overweight, semaglutide's clinical record is among the strongest in the weight loss medication landscape.
Cost Comparison
Metformin: Exceptionally Affordable
Generic metformin is one of the least expensive medications in the U.S. pharmacy system.
| Source | Typical Cost |
|---|---|
| Major pharmacy (generic, GoodRx) | $4–$10/month |
| Most insurance plans | $0–$15 copay |
| Extended-release generic | $10–$20/month |
Metformin is FSA and HSA eligible. For patients with insurance, it is often a $0 or $5 tier-1 formulary drug. This cost profile makes it accessible across virtually all income levels.
Semaglutide: Wide Range Based on Access Path
Semaglutide's cost depends heavily on how you access it.
Brand-name without insurance:
- Ozempic: ~$850–$1,000/month
- Wegovy: ~$1,300–$1,500/month
Compounded semaglutide through telehealth (most common path for out-of-pocket patients):
| Provider | Monthly Cost | Notes |
|---|---|---|
| Belle Health | $119/mo | Flat pricing across doses |
| Ro | $149/mo | Brand Wegovy also available |
| Henry Meds | $149/mo | No consultation fee |
| Ivim Health | $150/mo | Includes check-ins |
| Found | $159/mo | Includes coaching |
| Hims | $199/mo | Compounded semaglutide |
| Calibrate | $199/mo | Includes metabolic coaching |
| Hone Health | $299/mo | Labs included |
With insurance: Wegovy and Ozempic coverage varies significantly. Many commercial plans cover Ozempic for type 2 diabetes; fewer cover Wegovy for weight management (which requires specific BMI and comorbidity criteria). Prior authorization is common for both. Compounded semaglutide is typically not covered by insurance.
Both metformin and semaglutide are HSA/FSA eligible — an important consideration for patients using pre-tax accounts to offset healthcare costs.
Side Effects
Metformin
Metformin's most common side effects are gastrointestinal:
- Nausea, diarrhea, and stomach discomfort — particularly early in treatment or during dose increases
- Extended-release formulations reduce GI side effects significantly for most patients
- Vitamin B12 deficiency with long-term use — periodic monitoring is recommended
Rare but serious risks include lactic acidosis, primarily a concern in patients with severe kidney impairment. Metformin is generally not used in patients with eGFR below 30 mL/min/1.73m².
Semaglutide
Semaglutide's side effect profile is also predominantly gastrointestinal, though typically more pronounced than metformin during the titration phase:
- Nausea — the most common complaint, usually peaks during dose escalation
- Vomiting, diarrhea, constipation
- Decreased appetite (the intended mechanism; also listed as a side effect)
- Fatigue during early weeks
Most GI side effects resolve within 4–8 weeks as the body adjusts. Slow titration — the standard protocol at reputable telehealth providers — significantly reduces severity.
Serious risks include pancreatitis, gallbladder disease, and a boxed warning for thyroid C-cell tumors (established in rodent studies; not confirmed in humans). Semaglutide is not recommended during pregnancy.
GI comparison: Both medications cause GI discomfort, but semaglutide's effects tend to be more acute early on, while metformin's GI issues are often more persistent. Extended-release metformin significantly closes this gap.
Who Each Drug Is Right For
Choose Metformin If:
- You have type 2 diabetes or prediabetes and need blood sugar control
- Modest weight loss (2–5 kg) would be clinically meaningful alongside metabolic management
- Cost is a significant constraint — $4–$15/month is your ceiling
- You want an established, oral medication with decades of safety data
- You have PCOS with insulin resistance
Choose Semaglutide If:
- Your primary goal is significant weight loss (20+ lbs / 10+ kg)
- You have a BMI ≥30, or ≥27 with a weight-related condition (the Wegovy label criteria)
- You've tried lifestyle changes and/or metformin without achieving your weight goals
- You have type 2 diabetes and want both A1C control and meaningful weight reduction
- You're open to a weekly injection and the higher monthly cost
Consider Combination Therapy If:
Some providers prescribe both metformin and semaglutide together, particularly in patients with type 2 diabetes and obesity. The rationale is complementary mechanisms: metformin targets hepatic glucose production and insulin sensitivity, while semaglutide primarily reduces appetite and promotes weight loss through GLP-1 pathways. Clinical data supports this combination — the SUSTAIN-5 and STEP-2 trials both included patients on background metformin.
If you're already on metformin and interested in adding semaglutide for weight loss, this is a common clinical conversation. Discuss with your prescriber whether your current dose of metformin is working well enough to keep, or whether shifting fully to semaglutide makes more sense for your profile.
How to Access Semaglutide Through Telehealth
Semaglutide is the most widely available GLP-1 medication through telehealth platforms. Most providers offer:
- Asynchronous or video consultation with a licensed prescriber
- Compounded injectable semaglutide shipped to your door
- Ongoing dosage management and check-ins without in-person visits
- Shipping to most U.S. states
The typical telehealth process:
- Complete an intake form with health history, BMI, and goals
- Video or async consult with a prescriber
- Prescription filled by a licensed compounding pharmacy
- Monthly or quarterly shipments, with titration managed remotely
Use our provider comparison tool to filter by medication, state, cost, and included services to find the right match for your situation.
Frequently Asked Questions
Is semaglutide better than metformin for weight loss?
For weight loss specifically, yes — semaglutide produces significantly more weight reduction. STEP trial data shows average weight loss of 15% of body weight at the Wegovy dose (2.4mg weekly) over 68 weeks. Metformin typically produces 2–3 kg and is not FDA-approved for weight management. If weight loss is your primary goal, semaglutide has a substantially stronger clinical evidence base. That said, metformin remains a first-line medication for type 2 diabetes and prediabetes management, where weight loss is one benefit among several.
Can you take metformin and semaglutide together?
Yes. Combination therapy is common and well-established in type 2 diabetes management. Many of the landmark semaglutide trials included patients on background metformin, and the combination is safe. Some providers use both together for patients with obesity and insulin resistance who want maximized metabolic and weight management benefits. Always confirm the combination with your prescribing provider — dosing and monitoring may need adjustment.
How much does metformin cost compared to semaglutide?
Metformin generic costs $4–$15/month and is typically covered at low or zero cost by insurance. Semaglutide ranges from approximately $99–$450/month through telehealth (compounded) to $850–$1,500/month for brand-name Ozempic or Wegovy without insurance. The cost difference is substantial — on the order of 10x to 100x depending on the semaglutide access path you use.
Who should use metformin vs semaglutide for weight loss?
Metformin is most appropriate for patients with type 2 diabetes or prediabetes who need modest weight support alongside blood sugar control, particularly when cost is a constraint. Semaglutide is the better choice for patients with meaningful obesity, significant weight loss goals, or those who haven't achieved their targets with metformin or lifestyle changes alone. Patients with type 2 diabetes and significant obesity often benefit from both medications in combination. The right answer depends on your specific health profile, goals, and budget — which is exactly the conversation to have with a telehealth provider.
Ready to explore semaglutide through telehealth? Compare providers by price, medication, and state on our GLP-1 provider comparison page.