Glucophage®
Metformin
Version 2025-04 · Last reviewed April 1, 2025 · Methodology
List Price
$30
With Insurance
$4
The Short Version
Plain-language summary
Glucophage (Metformin) lowers blood sugar by telling your liver to stop releasing so much glucose between meals. It also helps your muscles use insulin more efficiently.
How it works: Metformin works primarily by telling the liver to stop releasing glucose between meals. It also improves muscle cells' ability to respond to insulin, reducing the amount needed to clear glucose from the blood.
What people most commonly report
Usually improves after 2-4 weeks; take with meals
Studies include independent, publicly funded research, not just manufacturer data.
What Else the Evidence Supports
Non-drug options with clinical backing
Lifestyle intervention reduced T2D risk by 58% in a landmark NIH-funded trial (Diabetes Prevention Program, 2002)
Comparable A1C reduction to metformin.
-0.
Improves insulin sensitivity 48-72h per session.
Meta-analysis: equal to metformin in A1C reduction.
What This Really Costs
Long-term cost projection based on current pricing
Monthly
$15
$4 w/ insurance
without insurance
Annual
$180
$48 w/ insurance
without insurance
10 Years
$1.8K
$480 w/ insurance
without insurance
30 Years
$5.4K
$1.4K w/ insurance
without insurance
Lifestyle alternative: $0/month in prescriptions. Low-carb diet - Comparable A1C reduction to metformin.
The average American retiree spends $165,000 on healthcare after retirement (Fidelity, 2024). Informed choices today compound over decades.
Related Evidence
Explore related medications reviewed on EvidentMeds
Supplement Questions
Omega-3 Fatty Acids
Omega-3 may support cardiovascular health in diabetic patients alongside glucose-lowering therapy.
Magnesium
Long-term metformin use may reduce magnesium absorption. Deficiency can worsen insulin resistance, the condition metformin is treating.
Berberine
Berberine and metformin share the AMPK activation mechanism. Taking both together may cause blood glucose to drop more than expected. This combination requires physician supervision.
Metabolic & Lifestyle Alternatives
Dietary & Lifestyle Approaches to Blood Sugar Management
Lifestyle intervention reduced T2D risk by 58% in a landmark NIH-funded trial (Diabetes Prevention Program, 2002)
Important context: Evidence quality varies across these approaches. Some are well-studied with randomized controlled trial data; others are based on observational or smaller studies. These interventions are not guaranteed to replace medication for all patients. Discuss with your doctor whether any of these are appropriate for your clinical situation.
Global Prescribing & Pricing
Widely recommended as a first-line medication for type 2 diabetes across major guidelines globally
United States
$4–10 (generic)/mo
First-line per ADA guidelines; universally used
No lifestyle prerequisite; prescribed by any physician
Almost always covered
United Kingdom
~$2–4/mo
NICE first-line alongside lifestyle counseling
Lifestyle modification recommended but not a hard prerequisite
Fully covered by NHS
France
~$2–6/mo
Universal first-line in French diabetes guidelines
Lifestyle counseling included in standard care pathway at no extra cost
Fully covered by Sécurité Sociale
India
~$0.50–1/mo
Largest global generic producer; widely prescribed
Subsidized under national diabetes programs; exported globally
Subsidized or free at public clinics
WHO Essential Medicines
~$2–5 global/mo
On WHO Essential Medicines List since 1994
Required to be available in all countries' formularies per WHO mandate
Covered in most national formularies globally
Metformin is one of the only medications where US, European, and WHO guidelines fully agree, it's first-line everywhere. Generic production in India keeps global prices at $0.50–$5/month. The US generic costs $4–10, making this one of the few drugs where pricing parity is nearly achieved.
Clinical Trials & Funding
Understanding who funds research helps contextualize results. Industry-funded trials are not automatically invalid - they undergo the same FDA review - but declared conflicts and sponsor effects are worth knowing. All linked trials can be verified on ClinicalTrials.gov.
Key Efficacy Results
A1C -1.5%, weight neutral, possible longevity benefits
Referenced Studies
Each study shows its evidence level and Cochrane RoB-2 risk-of-bias rating - tap the bias badge for details.
Evidence & Transparency
Cochrane RoB-2 (Risk of Bias)
Badges reflect an editorial assessment using Cochrane's RoB-2 tool domains: randomization, intervention deviation, missing data, outcome measurement, and selective reporting. These are not certified Cochrane reviews. Learn more ↗
CMS Open Payments
Manufacturer payment disclosures are reported via the CMS Sunshine Act. Disclosure is legally required and does not imply bias or misconduct. Language uses "may," "suggests," or "appears", never definitive clinical claims. CMS Open Payments ↗
Live Clinical Trials
Live from ClinicalTrials.gov · refreshed every 4 hours
Currently enrolling, active, and recently completed studies involving Metformin. Data is pulled directly from the U.S. National Library of Medicine.
Recent Research
Live from PubMed · peer-reviewed literature · refreshed every 4 hours
Most recently indexed clinical trials and systematic reviews mentioning Metformin in PubMed.
Source Documentation
Structured citations for referenced clinical trials
Each referenced trial is listed with its registry ID, funding source, and bias assessment. Use the copy button to generate a formatted citation.
| Trial | Registry ID | Cite |
|---|---|---|
| DPP (NIH) | NCT00004992 | |
| MILES (Metformin Longevity) | NCT02432287 |
Bias ratings use Cochrane RoB-2 methodology. Editorial assessment - not a certified Cochrane review.
Our MethodologyCommon Side Effects
While taking this medication, you may experience the following common side effects. We've included tips on how to manage them.
Nausea
25%Always take with food; start with low dose
Diarrhea
28%Usually improves after 2-4 weeks; take with meals
Stomach upset / cramping
20%Extended-release version causes less GI trouble
Vomiting
7%Take with largest meal of the day
Metallic taste in mouth
15%Common; usually fades over time
Decreased appetite
10%Can be a benefit for weight management
Vitamin B12 deficiency (long-term)
20-30% with long useSupplement B12; have levels checked annually
Flatulence / bloating
12%Reduce dose temporarily; use extended-release
Weakness / fatigue
6%Check B12 levels if persistent
Headache
5%Usually mild and temporary
Serious Adverse Effects
- • Lactic acidosis (rare but potentially fatal)
- • Vitamin B12 deficiency (long-term)
- • Hypoglycemia (when combined with insulin/sulfonylureas)
- • Kidney problems (stop if eGFR <30)
Drug Interactions
Major Interactions (Avoid)
Moderate Interactions (Caution)
Food Interactions
When to Contact Your Doctor
This medication requires ongoing medical supervision. The following situations warrant a prompt conversation with your prescribing physician - do not wait for your next scheduled appointment.
Contact soon if you notice
- Lactic acidosis (rare but potentially fatal)
- Vitamin B12 deficiency (long-term)
- Hypoglycemia (when combined with insulin/sulfonylureas)
- Kidney problems (stop if eGFR <30)
- Fasting blood glucose rising above 130 mg/dL
Also discuss if you want to
- Review whether this medication is still appropriate for you
- Consider dosage adjustments based on response
- Explore lifestyle or non-drug alternatives
- Understand stopping or tapering options
- Plan monitoring labs and follow-up
In the US, call 911 or go to the nearest emergency room for severe symptoms. Poison Control: 1-800-222-1222.
Special Populations
Safety classifications for specific groups - discuss with your provider before use.
Used in gestational diabetes; discuss with OB.
Low levels in milk; generally acceptable.
Insulin resistance rises significantly after menopause due to the loss of estrogen's protective metabolic effects. Metformin is frequently started during this period. Some of this insulin resistance responds to hormone therapy. Lifestyle changes, especially reducing refined carbohydrates, often address post-menopause metabolic changes more effectively than medication alone.
Approved for type 2 diabetes in children ≥10.
Monitor kidney function; stop if eGFR <30.
Risk of lactic acidosis. Hold for contrast.
FDA Adverse Event Reports
Patient-filed reports from the FDA FAERS database · refreshed daily
Community Reports
User-reported experiences - anonymous & anecdotal
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Stopping This Medication Safely
Metformin has no physical withdrawal syndrome. However, blood sugar typically rises without lifestyle compensation, and abrupt stopping is not recommended for patients with poor glycemic control.
What Published Research Shows About Stopping This Medication
This summarizes what published research documents, it is not personal medical advice. Any changes to your medication require discussion with your prescribing physician.
- ·Research supports establishing a low-carbohydrate or Mediterranean diet before stopping
- ·Clinical guidelines describe 150 min/week of exercise as beneficial preparation before stopping
- ·Published approaches describe dose reduction of 50% for 2–4 weeks in patients on high doses (1500–2000mg)
- ·Research recommends monitoring fasting blood glucose daily for 4 weeks after stopping; HbA1c reassessment at 3 months is documented clinical practice
Warning Symptoms, Contact Your Doctor If You Experience:
- Fasting blood glucose rising above 130 mg/dL
- Increased thirst or urination
- Fatigue
- HbA1c above target at 3-month check
Never change or stop a medication without consulting your prescribing physician.
Questions for Your Doctor
$2.99, printable guide for your next appointment
Questions to Ask
- 1.Could I try lifestyle changes first?
- 2.Should I take B12 supplements?
- 3.Would extended-release reduce GI side effects?
- 4.What A1C should we target?
Lab Tests to Request
- HbA1c
- Kidney function (eGFR, creatinine)
- Vitamin B12
- Fasting glucose
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Common Questions About Glucophage®
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