Metformin Dosage Chart: A Complete Reference for Every Strength, Schedule, and Use

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> Reviewed by FormBlends Medical Team · Last updated April 2026 · 8 sources cited

Key Takeaways

• Metformin is dosed from 500 mg to 2,550 mg per day, taken with meals to minimize GI side effects. Most adults reach a maintenance dose of 1,500 to 2,000 mg over 4 to 6 weeks of titration.
• Immediate-release (IR) tablets are taken 2 to 3 times daily. Extended-release (XR or ER) is once daily, usually with dinner. The total daily dose is similar; XR has lower GI side effects.
• Available tablet strengths: IR 500 mg, 850 mg, 1,000 mg. XR 500 mg, 750 mg, 1,000 mg. Liquid concentration: 500 mg per 5 mL.
• The FDA maximum daily dose is 2,550 mg for IR and 2,000 mg for XR. Doses above 2,000 mg add modest A1c benefit and more GI side effects.
• Dose adjustments are required for kidney impairment (eGFR 30 to 45 mL/min) and for patients on interacting medications.

Direct answer (40-60 words)

The standard metformin dosage chart starts at 500 mg once daily, titrates up by 500 mg per week to a maintenance dose of 1,500 to 2,000 mg per day. Maximum FDA-approved doses are 2,550 mg for immediate-release and 2,000 mg for extended-release. Always take with meals to limit GI side effects.

Table of contents

1. The 30-second answer
2. Standard adult metformin dosage chart
3. Immediate-release vs extended-release: side-by-side
4. Available tablet strengths and forms
5. Titration schedule from start to maintenance
6. Dosing for specific conditions (diabetes, PCOS, weight loss, prediabetes)
7. Dose adjustments for kidney function
8. Pediatric and adolescent dosing
9. Drug interactions that change dosing
10. FAQ
11. Sources
12. Footer disclaimers

Standard adult metformin dosage chart

The complete adult immediate-release dosing chart, per the FDA-approved labeling and the 2024 American Diabetes Association Standards of Care:

Step	Dose	Schedule	Total daily dose	Use case
Starting	500 mg	Once daily with dinner	500 mg	Week 1 of titration
Step 2	500 mg	Twice daily (breakfast, dinner)	1,000 mg	Week 2
Step 3	500 mg	Three times daily, or 750 mg twice daily	1,500 mg	Week 3
Step 4	1,000 mg	Twice daily	2,000 mg	Week 4 to maintenance
Maximum	850 mg	Three times daily	2,550 mg	Reserved for additional A1c need

Extended-release dosing:

Step	Dose	Schedule	Total daily dose
Starting	500 mg	Once daily with dinner	500 mg
Step 2	1,000 mg	Once daily with dinner	1,000 mg
Step 3	1,500 mg	Once daily with dinner	1,500 mg
Step 4	2,000 mg	Once daily with dinner	2,000 mg (FDA max for XR)

Both formulations should be taken with food. Skipping food increases nausea and diarrhea sharply.

Immediate-release vs extended-release: side-by-side

Variable	Immediate-release (IR)	Extended-release (XR)
Brand names	Glucophage	Glucophage XR, Fortamet, Glumetza
Dosing frequency	2 to 3 times daily	Once daily
Time to peak	2 to 3 hours	4 to 8 hours
GI side effect rate (full dose)	30 to 50% in titration	18 to 30% in titration
Cost (generic, 30 days)	$4 to $20	$10 to $40
FDA max daily dose	2,550 mg	2,000 mg
Available strengths	500, 850, 1,000 mg	500, 750, 1,000 mg
Crushable	Yes	No (destroys ER coating)
Liquid form available	Yes (Riomet, 500 mg per 5 mL)	No

For weight loss and prediabetes, extended-release is usually preferred because once-daily dosing improves adherence over months and the GI side effect rate is lower at the same total daily dose.

For acute diabetes management requiring fine-grained dose titration, immediate-release is sometimes preferred because the dosing flexibility (2 or 3 times daily, varying amounts at each meal) lets providers tune more precisely.

Available tablet strengths and forms

Immediate-release tablets:

• 500 mg (most common, used for titration)
• 850 mg (used for 1,700 mg or 2,550 mg total daily dosing)
• 1,000 mg (used for 2,000 mg twice-daily maintenance)

Extended-release tablets:

• 500 mg
• 750 mg
• 1,000 mg

Liquid (oral solution):

• Riomet, 500 mg per 5 mL (100 mg/mL)
• Used in patients who cannot swallow tablets, including some pediatric and elderly patients

Combination tablets (metformin plus another drug):

• Metformin / sitagliptin (Janumet, Janumet XR)
• Metformin / saxagliptin (Kombiglyze XR)
• Metformin / linagliptin (Jentadueto, Jentadueto XR)
• Metformin / empagliflozin (Synjardy, Synjardy XR)
• Metformin / dapagliflozin (Xigduo XR)

Combination products simplify the regimen for patients on multiple medications. The metformin dose in combination products is usually 500 mg or 1,000 mg per tablet.

Titration schedule from start to maintenance

The full week-by-week plan most providers follow:

Week 1: 500 mg once daily.

• Take with dinner.
• Watch for early GI symptoms (mild nausea, loose stools are common in week 1; usually resolve by day 5 to 7).

Week 2: 1,000 mg per day.

• Add a 500 mg dose with breakfast (IR) or single 1,000 mg with dinner (XR).
• If GI symptoms persist, stay at 500 mg for an extra week.

Week 3: 1,500 mg per day.

• Add 500 mg with lunch (IR) or increase XR to 1,500 mg with dinner.
• Expect mild GI symptoms for 2 to 3 days after each step-up.

Week 4 to 6: 2,000 mg per day.

• IR: 1,000 mg twice daily with breakfast and dinner.
• XR: 2,000 mg once daily with dinner.
• This is the standard maintenance dose for diabetes and weight loss.

Optional Week 6+: 2,550 mg per day (IR only).

• 850 mg three times daily.
• Reserved for patients who need additional A1c reduction beyond what 2,000 mg provides.

If GI symptoms appear at any step, stay at the current dose for an additional 1 to 2 weeks before advancing. The titration is patient-paced. There is no penalty for going slower.

For more on the titration mechanics, see our is 500 mg metformin a low dose guide.

Dosing for specific conditions

Type 2 diabetes: 1,500 to 2,000 mg per day, titrated to A1c target. Max 2,550 mg per day (IR) or 2,000 mg per day (XR). Reduce dose for eGFR 30 to 45 mL/min/1.73 m². Stop for eGFR under 30.

Prediabetes (off-label): 1,500 to 1,700 mg per day. The Diabetes Prevention Program (Knowler et al., NEJM 2002) used 1,700 mg per day in prediabetic adults and reduced progression to type 2 diabetes by 31% over 2.8 years.

Weight loss in non-diabetic adults (off-label): 1,500 to 2,000 mg per day. Average loss of 4 to 7 lb over 6 months. Lower doses produce minimal effect.

Polycystic ovary syndrome (PCOS): 1,500 to 2,000 mg per day for cycle regularity, ovulation support, and androgen reduction. Some lean PCOS patients use 1,000 mg per day.

Gestational diabetes (off-label, provider-directed): 500 to 2,500 mg per day. Some providers use insulin instead. Consult an obstetric specialist.

Geriatric patients (over 80 years): start at 500 mg per day and titrate slowly. Maximum dose often capped at 1,500 mg due to age-related kidney function decline.

The reason 1,500 to 2,000 mg appears across most use cases is that this is the dose range where metformin's effects (reduced hepatic glucose production, improved insulin sensitivity, mild appetite reduction) become clinically meaningful. Below 1,500 mg, the effect is small in most patients.

Dose adjustments for kidney function

Metformin is renally cleared. Reduced kidney function means accumulation, which raises the rare but serious risk of lactic acidosis. The 2024 ADA guidance:

eGFR (mL/min/1.73 m²)	Recommendation
60 or above	Standard dosing, no adjustment
45 to 59	Standard dosing; monitor renal function every 3 to 6 months
30 to 44	Reduce maximum dose to 1,000 mg per day; do not initiate metformin in metformin-naive patients
Under 30	Contraindicated; stop metformin

Acute kidney function changes also matter. Pause metformin 48 hours before:

• Surgery requiring general anesthesia
• IV iodinated contrast imaging (CT scans, angiography)
• Acute illness with risk of dehydration (severe vomiting, severe diarrhea)

Restart 48 hours after, once kidney function is verified normal. The pause prevents accumulation during temporary kidney function dips.

Pediatric and adolescent dosing

Metformin is FDA-approved for type 2 diabetes in patients 10 years and older.

Initial dose: 500 mg twice daily with meals. Titration: increase by 500 mg per week as tolerated. Maximum: 2,000 mg per day in patients 10 to 16 years old.

Extended-release formulation is approved for patients 17 and older. Below 17, immediate-release is the default.

Pediatric dosing for off-label uses (PCOS in adolescents, obesity adjunct) is provider-directed. Most pediatric endocrinologists follow adult titration patterns adjusted for body weight, capping at 2,000 mg per day.

Drug interactions that change dosing

Several common medications affect metformin levels or share side-effect pathways. Notable interactions:

Drug	Effect	Adjustment
Cimetidine	Raises metformin levels	Reduce metformin dose by 25 to 50%
Dolutegravir (HIV)	Raises metformin levels	Reduce dose; max 1,000 mg per day
Iodinated contrast	Acute kidney function dip	Pause 48 hours before and after
Topiramate	Raises lactic acidosis risk	Use caution; monitor labs
Heavy alcohol	Raises lactic acidosis risk	Avoid heavy or binge drinking
Insulin or sulfonylureas	Hypoglycemia risk	Adjust other diabetes medications
Diuretics (loop, thiazide)	Volume depletion raises kidney risk	Monitor eGFR more frequently

If you start any of the above on top of stable metformin therapy, ask your provider whether the metformin dose should change.

FAQ

What is the standard metformin dosage?

The standard maintenance dose for adults is 1,500 to 2,000 mg per day, divided into 2 to 3 doses with meals (immediate-release) or once daily with dinner (extended-release). Most patients titrate from 500 mg to 2,000 mg over 4 to 6 weeks.

What is the maximum dose of metformin?

2,550 mg per day for immediate-release, 2,000 mg per day for extended-release. Doses above 2,000 mg add modest A1c benefit at the cost of more GI side effects. Most adults are maintained at 2,000 mg.

Should I take metformin with food?

Yes. Taking metformin with meals cuts GI side effects (diarrhea, nausea, cramps) sharply. The largest dose should align with the largest meal. For extended-release, dinner is the most common timing.

What is the difference between metformin IR and XR?

Immediate-release is taken 2 to 3 times daily and reaches peak blood levels in 2 to 3 hours. Extended-release is taken once daily and releases over 8 to 12 hours. XR has 30 to 40% lower GI side effect rates at the same total daily dose.

Can I cut metformin tablets in half?

Immediate-release: yes, if needed for dose adjustment. Extended-release: no. Cutting XR tablets destroys the time-release coating and converts the medication to immediate-release, which causes the GI side effects you were trying to avoid.

What happens if I miss a metformin dose?

Take it with food as soon as you remember, unless it is close to the next scheduled dose. Do not double up. Missing a dose occasionally has minimal impact on overall control. Frequent missed doses reduce A1c benefit.

Can I take metformin once a day?

Extended-release is designed for once-daily dosing. Immediate-release works better divided into 2 or 3 doses. If you have trouble with twice-daily dosing, ask your provider about switching to extended-release.

Is 1,500 mg of metformin a high dose?

1,500 mg is a low-end therapeutic dose. The FDA maximum is 2,550 mg, so 1,500 mg is roughly 60% of maximum. It is the entry point into clinically effective dosing for most adults.

How long does it take metformin to work?

For glycemic effect: A1c drops measurably within 4 to 6 weeks at a stable dose. For weight loss: gradual loss of 1 to 2 lb per month, with most loss occurring in the first 3 to 6 months.

Can I take metformin while pregnant?

Some providers continue metformin for women with PCOS or gestational diabetes. Others switch to insulin. Metformin crosses the placenta. The decision is individualized. Stop metformin and contact your provider if you become pregnant on the medication.

What is the metformin dose for weight loss?

1,500 to 2,000 mg per day. Average loss in non-diabetic adults is 4 to 7 lb over 6 months at this dose. Doses below 1,500 mg produce minimal weight effect. For more, see our dosage of metformin to lose weight guide.

Can metformin be taken with GLP-1 medications?

Yes. Metformin is commonly combined with semaglutide or tirzepatide for additional glycemic protection in patients with prediabetes or type 2 diabetes. Both medications cause GI side effects, so titrate slowly and avoid starting both at the same time.

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• Tool: dosage calculator

Sources

1. American Diabetes Association. Standards of Care in Diabetes 2024. Diabetes Care. 2024;47(Suppl 1).
2. Knowler WC, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin (DPP). N Engl J Med. 2002;346(6):393-403.
3. Apolzan JW, et al. Long-term weight loss with metformin or lifestyle intervention. Ann Intern Med. 2019;170(10):682-690.
4. Blonde L, et al. Gastrointestinal tolerability of extended-release metformin tablets compared to immediate-release metformin tablets. Curr Med Res Opin. 2004;20(4):565-572.
5. Aroda VR, et al. Long-term metformin use and vitamin B12 deficiency in the DPP Outcomes Study. J Clin Endocrinol Metab. 2016;101(4):1754-1761.
6. Inzucchi SE, et al. Metformin in patients with type 2 diabetes and kidney disease: a systematic review. JAMA. 2014;312(24):2668-2675.
7. American Academy of Family Physicians. Practice Guideline on Metformin in Adults. 2022 update.
8. FDA Prescribing Information, Glucophage and Glucophage XR. Updated 2023.

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Platform Disclaimer. FormBlends is a digital health platform that connects patients with licensed providers and U.S.-based pharmacies. We do not manufacture, prescribe, or dispense medication directly. All clinical decisions are made by independent licensed providers.

Compounded Medication Notice. Compounded semaglutide and tirzepatide are not FDA-approved. They are prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded medications have not undergone the same review process as FDA-approved drugs and are not interchangeable with brand-name products.

Results Disclaimer. Individual results vary. Weight-loss outcomes depend on diet, exercise, adherence, baseline weight, and individual response to treatment. Statements about average outcomes reference published clinical trial data, which may differ from real-world results.

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