Glucophage® (Metformin) Uses, Dosage, and Safety

What Metformin Is and How It Works

Metformin is a biguanide medicine used to manage type 2 diabetes. It helps lower blood sugar by reducing liver glucose production and improving insulin sensitivity in muscle and fat. It is available as immediate-release (IR) and extended-release (ER) tablets, and some markets offer an oral solution. Many start with metformin 500 mg and titrate based on response.

YouDrugstore is a licensed Canadian pharmacy headquartered in Manitoba, and all prescriptions are reviewed by licensed pharmacists before dispensing. We also partner with vetted international pharmacies to source authentic brands and generics across a wide range of strengths at affordable prices.

Metformin hydrochloride (metformin HCl) is taken by mouth with food. IR tablets are usually taken twice daily, and ER tablets are taken once daily, often with the evening meal. Metformin is first-line for metformin type 2 diabetes care and is sometimes used off-label for insulin resistance, prediabetes, and polycystic ovary syndrome (PCOS). Learn more in Metformin And Its Role In Type 2 Diabetes Care.

Dosage and Usage

• Typical IR start: 500 mg once daily with the largest meal for 1 week, then increase to 500 mg twice daily as tolerated.
• Alternative IR start: 850 mg once daily, then increase to 850 mg twice daily as tolerated.
• ER start: 500 mg to 1000 mg once daily with the evening meal; increase by 500 mg weekly as tolerated.
• Maintenance: 1500–2000 mg per day is common. Some patients on IR may use up to 2550 mg/day in divided doses.
• Take with meals to reduce gastrointestinal effects such as nausea or diarrhea.
• Swallow ER tablets whole; do not crush or chew.
• Missed dose: take the next scheduled dose; do not double up.
• Switching IR to ER: usually the same total daily dose, given once daily with the evening meal.
• Kidney function guides dosing. Many clinicians avoid starting therapy when eGFR is below 45 mL/min/1.73 m² and stop at eGFR below 30.

• Store tablets at 20–25°C (68–77°F) in a dry place away from moisture.
• Keep in the original, tightly closed bottle with the pharmacy label.
• Do not refrigerate or freeze. Protect from excessive heat.
• When traveling, keep medicine in your carry-on with a copy of your prescription.
• Use a pill organizer for short trips, and keep some tablets in the labeled bottle for security checks.
• If a dose schedule changes during travel, set reminders on your phone.

Benefits and Savings

Metformin improves fasting and post-meal blood glucose and lowers A1C by about 1–1.5% on average. It is weight-neutral for many people, and some see modest weight loss. It may improve lipid profiles and has long-term cardiovascular benefits in type 2 diabetes. ER tablets can reduce stomach upset and simplify dosing.

Ordering metformin online from our Canadian pharmacy can deliver 60–80% savings versus typical US prices. Many compare metformin price options by strength, such as metformin 500 mg or metformin 1000 mg, to match their prescription and budget. Per-month costs often decrease when larger quantities are purchased in one shipment.

Side Effects and Safety

• Common: nausea, diarrhea, stomach discomfort, gas, abdominal cramps.
• Less common: metallic taste, decreased appetite, headache, fatigue.
• Long-term: vitamin B12 levels may fall; periodic monitoring is often recommended.
• With other drugs: hypoglycemia risk rises when combined with insulin or a sulfonylurea.
• Alcohol: heavy or binge drinking increases lactic acidosis risk; limit or avoid.

Serious but rare lactic acidosis is more likely with severe kidney disease, significant liver disease, dehydration, heavy alcohol use, or conditions that reduce oxygen delivery (e.g., heart failure exacerbation, severe infection). Pause metformin before certain iodinated contrast procedures and during acute illness that can cause dehydration. For stomach issues, see Does Metformin Cause Diarrhea.

Onset Time

Some blood-glucose improvement can appear within a few days, especially in fasting values. Most people see meaningful changes after 1–2 weeks as the dose is titrated. A1C reflects average control over 3 months, so full A1C reduction takes about 8–12 weeks. Weight trends, if any, are gradual and often unfold over several months.

Compare With Alternatives

GLP-1 receptor agonists offer strong A1C lowering and weight loss benefits. Oral semaglutide is an option for those who prefer tablets; compare with Rybelsus® if a GLP-1 is being considered.

Injectable GLP-1 receptor agonists such as Victoza® Prefilled Pen are taken once daily and have proven glycemic and weight effects. They are often combined with metformin when A1C goals are not met.

DPP-4 inhibitor combinations can simplify therapy. One example is Janumet®, which pairs sitagliptin with metformin for patients needing dual therapy in a single tablet. SGLT2 inhibitors, sulfonylureas, and basal insulin are other common add-ons depending on goals and comorbidities.

Combination Therapy

• Metformin + GLP-1 receptor agonist: strong A1C lowering and weight benefit; low intrinsic hypoglycemia risk.
• Metformin + SGLT2 inhibitor: complementary effects on glucose, weight, and blood pressure; consider hydration status.
• Metformin + DPP-4 inhibitor: oral, weight-neutral option with modest A1C reduction.
• Metformin + sulfonylurea: effective but monitor for hypoglycemia; dose reductions may be needed.
• Metformin + basal insulin: effective for higher A1C; consider reducing insulin dose to limit hypoglycemia and weight gain.
• Fixed-dose combinations: can improve adherence; match strengths to prescribed metformin 500 mg, 850 mg, or 1000 mg bases.

Patient Suitability and Cost-Saving Tips

Metformin is indicated for adults with type 2 diabetes. It is not for type 1 diabetes or diabetic ketoacidosis. It may be used in insulin resistance, prediabetes, and metformin for PCOS where appropriate. Metformin classification is biguanide. Those with eGFR below 30 mL/min/1.73 m², metabolic acidosis, or severe liver disease generally should not receive it.

Use caution with unstable heart failure, severe dehydration, or heavy alcohol intake. Many avoid initiation when eGFR is between 30 and 45 and reassess risks and benefits regularly. Long-term therapy can lower vitamin B12 levels; screening may be suggested if anemia or neuropathy develops. Ask about metformin ER if stomach upset limits tolerance.

Smart ways to manage metformin cost include selecting larger fills when appropriate, which can lower the per-month price of metformin 500 mg or metformin 1000 mg. Turn on reorder reminders in your account so you never run out. Compare metformin price options across strengths and brands if a switch is clinically acceptable.

Authoritative Sources

Health Canada Drug Product Database: Metformin Hydrochloride

FDA/DailyMed: Metformin Hydrochloride Prescribing Information

Order Metformin from Youdrugstore: add to cart, upload your prescription, and we ship with prompt, express shipping.

This page is educational and does not replace advice from your healthcare professional. Always follow your prescriber’s directions and the supplied patient information.