2-minute questionnaire
Tell us your most recent A1C or fasting glucose, kidney history, and any prior metformin experience. We ask the same questions an endocrinologist would.
InstalabMetformin ER · 500mg · generic Glucophage XR®
Lower A1C. Better insulin sensitivity. Decades of data.
Metformin ER (generic Glucophage XR®) has decades of outcome data treating insulin resistance and diabetes, and is a leading molecule in longevity research. Physician-reviewed, delivered to your door, from $6/month.
500mgOnce daily
ADA first-lineFor type 2 diabetes
1.5%Avg A1C drop
Metformin ER 500mg · once daily · with dinner
Licensed US physician review
12,000+ patients treated
Available in all 50 states
Free shipping
How it works
From questionnaire to first dose.
A 2-minute questionnaire, physician review, and metformin ER shipped to your door. No appointments, no clinic visits.
Physician review
A licensed physician confirms metformin ER is appropriate for your glycemic profile and kidney function, usually within 1 business day.
Metformin ER delivered
Generic metformin ER 500mg ships same or next business day in tracked USPS packaging. Arrives in 3 to 5 business days.
A1C recheck at 3 months
Fasting glucose moves within days, but full A1C effect lands at about three months. Recheck then to see how 500mg is working for you.
Pricing
Pick your plan.
Subscribe for steady A1C control on metformin ER 500mg with automatic refills, or buy once to trial it. Physician review and shipping included.
Metformin ER 500mgGeneric for Glucophage XR®
Need more than 500mg?
Titrate up with physician oversight.
For patients who need their A1C below 6.5% — established type 2 diabetes, GLP-1 combination therapy, or aggressive prediabetes management. Membership includes the physician consults and lab follow-up that titration requires.
Step up to 750mg, 1000mg, or 2000mg as your 3-month A1C evolves. Same drug, same once-a-day routine — your physician adjusts based on response and tolerability, not yours alone.
Explore membership →Doses available
500mg ER is the standard starting dose.
It's the standard starting dose of metformin ER. Taking it with your evening meal minimizes the GI side effects that metformin is known for, while still delivering a meaningful A1C reduction for most people.
If your A1C at 3 months calls for more, our membership includes the physician oversight needed to titrate up safely.
500 mg ER Available to everyone
Starter dose · once daily with dinner · ~1.0 to 1.5% A1C reduction
$6/mo
starting price
Titration to higher doses benefits from physician follow-up to track A1C response, tolerability, and kidney function. That care belongs inside a membership.
About the medication
A simple daily routine, backed by data.
One tablet, once a day, with your evening meal. Most patients see fasting glucose drop within days, with the full A1C effect landing at about three months.
- Take once daily with your evening mealEvening dosing with food improves tolerability and smooths overnight glucose. Swallow the tablet whole. Do not crush, chew, or split.
- Recheck A1C at 3 monthsGlucose drops within days, but full A1C effect takes about three months. Kidney function is checked annually.
- B12 monitoring long-termAfter 4 or more years of use, metformin can lower B12. Your physician may check it annually.
Why metformin
The most proven diabetes pill.
Metformin activates AMPK in the liver, which suppresses hepatic glucose production. It also improves peripheral insulin sensitivity in muscle and fat. Because it doesn't stimulate insulin release, it doesn't cause hypoglycemia as monotherapy. Two landmark trials anchor the evidence: UKPDS 34 (Lancet 1998) found a 36% reduction in all-cause mortality in overweight T2D patients over a median 10.7 years. The Diabetes Prevention Program (NEJM 2002) showed metformin cut progression from prediabetes to T2D by 31% over 2.8 years.
- Decades of first-line use, proven in outcomes trialsMetformin has been a cornerstone T2D medication since the 1990s. UKPDS 34 showed a 36% reduction in all-cause mortality over 10+ year follow-up, establishing it as the baseline every other T2D drug is compared against. Recent guidelines favor GLP-1 or SGLT2 inhibitors for patients with cardiovascular or kidney disease, but metformin remains a standard starting point for many patients without those risk factors.
- No hypoglycemia, weight-neutralUnlike insulin or sulfonylureas, metformin doesn't cause low blood sugar as monotherapy. It tends to result in modest weight loss, typically 2 to 6 pounds, rather than the weight gain seen with most glucose-lowering drugs.
- ER means gentlerThe extended-release formulation dissolves gradually, which cuts through the diarrhea, nausea, and stomach upset that make immediate-release metformin hard to tolerate. Same glycemic efficacy, far better GI profile.
The UKPDS 34 trial
Published in The Lancet in 1998, UKPDS 34 randomized 1,704 overweight adults with newly diagnosed type 2 diabetes to metformin or conventional therapy and followed them for a median of 10.7 years. The metformin group had markedly lower all-cause mortality, diabetes-related mortality, and myocardial infarction. It established metformin as the baseline every newer T2D medication is compared against.
1,704
Overweight T2D patients randomized
36%
Reduction in all-cause mortality
10.7 yr
Median follow-up
Research context
Why aging researchers have studied this drug for two decades.
Metformin is FDA-approved for type 2 diabetes. It is not approved for longevity or anti-aging, and no human trial has proven it extends lifespan. The pathways below are why the research community keeps studying it, not reasons to take it. This section is educational context, not a treatment recommendation.
AMPK activation
Metformin activates the cell's master energy sensor, the same pathway that caloric restriction and exercise engage. AMPK activation is a central theme in almost every modern theory of aging.
Autophagy, cellular cleanup
Downstream of AMPK, metformin promotes autophagy, the process by which cells recycle damaged proteins and organelles. Cleaner cells age slower in animal models.
mTOR modulation
Metformin indirectly dampens mTOR signaling. Chronically elevated mTOR is linked to cellular senescence; modulating it is a mechanism shared with rapamycin and caloric restriction.
Mitochondrial effects
Metformin mildly inhibits mitochondrial complex I, which, counterintuitively, appears to trigger adaptive stress responses that support longer-term metabolic health (hormesis).
Lower chronic inflammation
Metformin reduces markers of systemic inflammation like CRP and IL-6. Chronic low-grade inflammation (“inflammaging”) tracks with cardiovascular, metabolic, and neurodegenerative disease.
Insulin / IGF-1 signaling
Metformin improves insulin sensitivity and normalizes IGF-1. Hyperinsulinemia and elevated IGF-1 are among the best-mapped drivers of accelerated aging across model organisms.
What the clinical record shows
Three pieces of evidence that keep researchers interested.
36%
Lower all-cause mortality
UKPDS 34 (Lancet 1998), 10.7-year median follow-up in overweight type 2 diabetics vs. conventional therapy.
31%
Lower T2D progression
Diabetes Prevention Program (NEJM 2002), 2.8-year follow-up in prediabetic adults. The 15-year DPP Outcomes Study showed the effect moderates to about 18% but persists.
TAME
Has not yet begun enrollment
Targeting Aging with Metformin, led by Dr. Nir Barzilai, is a proposed RCT designed to test whether metformin delays age-related disease in non-diabetic adults. As of early 2026 it has secured partial funding but has not yet started enrolling patients, and no human trial has shown metformin extends lifespan.
Metformin is FDA-approved for type 2 diabetes, not for longevity or aging. The research above is emerging.
Real results
What 500mg ER looks like in practice.
Three patients, three months in.
7.86.4A1C %12 weeks on 500mg ER
“My A1C was 7.8 when I got diagnosed. Three months on 500mg ER with dinner, down to 6.4. No stomach issues at all.”
7.36.6A1C %10 weeks on 500mg ER
“Regular metformin gave me daily diarrhea for weeks. Switched to ER and it's night and day, same A1C drop, no side effects.”
6.35.8A1C %16 weeks on 500mg ER
“Prediabetes ran in my family. I wanted to be proactive. A1C moved from 6.3 back into the normal range and I lost about 5 pounds.”
Metformin ER is a prescription medicine. Important safety information applies. Common side effects are gastrointestinal (diarrhea, nausea, metallic taste) and usually transient.
Common Questions
Everything people ask before starting.
Ready when you are
Lower A1C. Better insulin sensitivity.
Answer the questionnaire. A physician reviews your case, and if metformin ER is appropriate, your prescription goes out.
No commitment to treatment.