medicationPrescription only (US)Metformin extended-release tablets are FDA-approved as an adjunct to diet and exercise for glycemic control in adults with type 2 diabetesThe systematic review of long-acting vs. immediate-release metformin reported comparable glycemic efficacy with fewer gastrointestinal complaints for the ER form
Metformin ERBenefits, Dosage & Interactions
Also known as: Glucophage XR
Metformin extended-release (ER), also known by its brand name Glucophage XR, is an oral medication primarily used to manage blood glucose levels in adults and some children with type 2 diabetes. It belongs to a class of drugs called biguanides.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Strong — 1 human randomized trial and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
1 human randomized trial and regulatory approval on file.
Plasma half-life
~6.2 h
Typical timing
bedtime
Food rule
with food
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- Metformin ER trials in these cohorts used total daily doses from about 500 mg up to 2000–2550 mg, titrated over weeks[1][2][3]
- Frequency
- Once daily, taken with the evening meal in the cited comparative and combination trials[1][2][3]
Reported for Metformin ER in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Metformin ER entry is written from. Each number matches an inline marker above.
- [1]Long-Acting Metformin Vs. Metformin Immediate Release in Patients With Type 2 Diabetes: A Systematic ReviewTan J, Wang Y, Liu S, Shi Q, Zhou X, Zhou Y, Yang X, Chen P, Li S · Frontiers in Pharmacology · 2021 · Peer-reviewed · PMID 34079464
- [2]Gastrointestinal adverse events of metformin treatment in patients with type 2 diabetes mellitus: A systematic review, meta-analysis and meta-regression of randomized controlled trialsNabrdalik K, Skonieczna-Żydecka K, Irlik K, Hendel M, Kwiendacz H, Łoniewski I, Januszkiewicz K, Gumprecht J, Lip GYH · Frontiers in Endocrinology (Lausanne) · 2022 · Peer-reviewed · PMID 36187122
- [3]Fixed-Dose Combination of Dapagliflozin + Sitagliptin + Metformin in Patients with Type 2 Diabetes Poorly Controlled with Metformin: Phase 3, Randomized Comparison with Dual CombinationsSahay RK, Giri R, Shembalkar JV, Gupta SK, Mohan B, Kurmi P, Kumar SR, Sawardekar VM, Mishra A, Murthy LS, Arya VV, Sonawane AR, Soni PN, Gofne SK, Karnawat SR, Rajurkar MN, Patel PM, Lakhwani LK, Mehta SC, Joglekar SJ · Advances in Therapy · 2023 · Peer-reviewed · PMID 37258803
How to track Metformin ER doses
Tracking Metformin ER well takes four fields and a habit. Here is what to record so the log is still useful in three months.
- 1
Add the dose and unit
Log Metformin ER with its dose in mg so totals stay comparable over time — including days when you split the dose or skip it.
- 2
Set the time of day and food rule
Typical timing is bedtime. Take it with food, and record it that way so absorption stays consistent. Reminders fire at that time and can export to your calendar.
- 3
Check it against the rest of the stack
Run Metformin ER through the interaction checker against everything else in the routine — supplements, peptides, hormones and prescriptions — before it becomes a daily habit.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
With a reported half-life around 6.2 h, effects and timing shifts show up over days rather than instantly. Review Metformin ER alongside your logged metrics and any relevant blood work every few weeks before changing the dose.
What to log each time
- Dose in mg
- Time of day and whether it was taken with food
- Taken / skipped / delayed
- Any side effects or notable changes
References & Evidence
Sources on this page that document Metformin ER dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Metformin ER?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Metformin extended-release (ER), also known by its brand name Glucophage XR, is an oral medication primarily used to manage blood glucose levels in adults and some children with type 2 diabetes. It belongs to a class of drugs called biguanides. Unlike some other diabetes medications, Metformin ER does not typically cause hypoglycemia (low blood sugar) when used alone. It works by improving how the body handles insulin and reducing the production of glucose by the liver. Beyond its primary use for diabetes, Metformin ER is also being investigated for its potential role in longevity and weight management due to its metabolic effects. The extended-release formulation allows for once-daily dosing, which can improve patient adherence compared to the immediate-release version. (NIH ODS, FDA label)
What does the research say about Metformin ER?
Tap a section to expand.
Metformin's primary mechanism of action involves reducing hepatic (liver) glucose production. It achieves this mainly by activating adenosine monophosphate-activated protein kinase (AMPK) in the liver. Activation of AMPK leads to several downstream effects: it suppresses gluconeogenesis (the production of glucose from non-carbohydrate sources) and glycogenolysis (the breakdown of glycogen into glucose). Additionally, metformin improves insulin sensitivity in peripheral tissues, such as muscle and fat cells, allowing these cells to absorb and utilize glucose more effectively from the bloodstream. It also moderately decreases glucose absorption from the gastrointestinal tract. Unlike sulfonylureas, metformin does not stimulate insulin secretion from the pancreatic beta cells, which is why it rarely causes hypoglycemia on its own. The extended-release formulation is designed to release the active drug substance slowly over a period, maintaining more consistent plasma concentrations and potentially reducing gastrointestinal side effects. (DrugBank, FDA label)
Source for this section: Sources for How does Metformin ER work?: Jumps to this entry in the sources and references list at the end of the page.
The primary benefit of Metformin ER is its efficacy in **managing type 2 diabetes**. It helps to lower both fasting and post-meal blood glucose levels, contributing to better glycemic control and reducing the risk of diabetes-related complications. For individuals with type 2 diabetes, Metformin ER has been shown to reduce A1C levels, a key indicator of long-term blood sugar control. (NIH ODS)
Beyond glucose control, Metformin ER may offer **weight loss** benefits. While not approved specifically as a weight-loss drug, some studies and clinical observations suggest that it can lead to modest weight reduction, particularly in individuals who are overweight or obese and have type 2 diabetes. This effect is thought to be related to its impact on appetite, fat metabolism, and insulin sensitivity. (MedlinePlus)
There is growing interest in Metformin ER's **longevity** potential. Through its effects on metabolic pathways, particularly AMPK activation, metformin has been hypothesized to mimic some of the beneficial effects of caloric restriction, which is known to extend lifespan in various organisms. Research is ongoing to determine if these effects translate to human longevity or healthy aging. (PubChem, Cochrane reviews on metformin and aging research)
Other potential benefits under investigation include its use in treating polycystic ovary syndrome (PCOS) by improving insulin resistance and reducing androgen levels, and its potential role in cancer prevention, particularly in individuals with diabetes. (NIH ODS)
The efficacy of Metformin ER in treating type 2 diabetes is well-established and supported by extensive clinical trials and long-term observational studies. For instance, the UK Prospective Diabetes Study (UKPDS) provided significant evidence for metformin's role in reducing cardiovascular events and mortality in overweight patients with type 2 diabetes. (Cochrane review, UKPDS)
Evidence for Metformin ER's effects on weight loss is primarily derived from clinical trials in diabetic patients, which show a modest weight reduction. While often not the primary endpoint, weight changes are frequently observed. (MedlinePlus, clinical trial data).
Regarding longevity, evidence is currently in its early stages. Animal studies have shown metformin to extend lifespan in various organisms, including *C. elegans* and mice. Human studies are largely observational or exploring surrogate markers of aging. Large-scale clinical trials, such as the Targeting Aging with Metformin (TAME) study, are underway to investigate if metformin can prevent age-related diseases in non-diabetic older adults, thereby indicating a longevity benefit. (NIH ODS on TAME study, scientific literature on gerontology). This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Common side effects of Metformin ER often include gastrointestinal disturbances like nausea, vomiting, diarrhea, abdominal pain, and loss of appetite. These are often transient and can be mitigated by starting with a low dose and gradually increasing it, as well as taking the medication with food. The extended-release formulation is specifically designed to reduce the incidence of these gastrointestinal issues compared to the immediate-release version.
Less common side effects can include a metallic taste in the mouth. A rare but serious side effect is lactic acidosis, which is an accumulation of lactic acid in the blood. Symptoms can include unusual muscle pain, difficulty breathing, unusual stomach discomfort, dizziness, or lightheadedness. This risk is higher in individuals with kidney problems, congestive heart failure, or those who consume excessive alcohol.
Long-term use of metformin can lead to vitamin B12 deficiency. Periodic monitoring of vitamin B12 levels may be recommended, especially in patients with neuropathic symptoms or anemia. (FDA label, MedlinePlus). This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Individuals should be aware of the risk of lactic acidosis, a rare but serious metabolic complication associated with metformin accumulation. Risk factors include renal impairment, concomitant use of certain drugs, advanced age, surgical procedures, hepatic impairment, and excessive alcohol intake. Discontinue metformin immediately if symptoms of lactic acidosis occur and seek prompt medical attention. Renal function should be assessed before initiating Metformin ER and annually thereafter. (FDA label)
Metformin ER should be temporarily discontinued before or at the time of an iodinated contrast imaging procedure in patients with impaired renal function, or those at risk for renal impairment. It can be restarted 48 hours after the procedure if renal function is stable. (FDA label)
It is important to discuss all medical conditions, especially kidney or liver disease, heart failure, or a history of alcohol abuse, with your healthcare provider before starting Metformin ER. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Metformin ER is contraindicated in patients with severe renal impairment (e.g., eGFR <30 mL/min/1.73 m²), known hypersensitivity to metformin hydrochloride, acute or chronic metabolic acidosis (including diabetic ketoacidosis, with or without coma), and individuals undergoing radiological studies involving intravascular administration of iodinated contrast materials (for a period around the procedure due to potential acute renal function alteration). (FDA label). This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Combining Metformin ER with certain medications can increase the risk of adverse effects or alter its efficacy. Drugs that can worsen glycemic control or predispose to lactic acidosis include topiramate, zonisamide, oral contraceptives, phenothiazines, and certain diuretics. Alcohol consumption, especially excessive intake, severely increases the risk of lactic acidosis due to its effects on lactate metabolism. (FDA label, DrugBank)
Cationic drugs that are eliminated by renal tubular secretion (e.g., cimetidine, ranolazine, dolutegravir, trimethoprim) may increase metformin exposure by competing for common renal tubular transport systems, potentially increasing the risk of lactic acidosis. (FDA label)
Consult your healthcare provider and pharmacist about potential drug interactions before combining Metformin ER with any other medications, supplements, or herbal products. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Metformin ER is typically taken once daily with food. To optimize absorption and minimize gastrointestinal side effects, it is often recommended to take it with the evening meal or at bedtime. Your clinician will direct the specific dose and timing for your individual needs. (FDA label)
Source for this section: Sources for When should you take Metformin ER?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with Metformin ER?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pending | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
| Any vitamin + medication | Note | Category ruleConfidence: theoretical | Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source pending | Specific pairs are checked against a licensed source; confirm with your provider. |
| Vitamin B12 | Note | Compound pairConfidence: theoretical | Long-term metformin use is associated with reduced B12 absorption.Source pending | Monitor B12 annually; supplement if low. |
Frequently asked questions about Metformin ER
Metformin ER is a medication. It is also known as Glucophage XR. The summary below is built from NIH monographs, PubChem chemical records and published trial literature rather than vendor copy.
Metformin ER is commonly discussed in the context of the goals discussed on its profile page. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Metformin ER, it is typically taken in the evening, it is usually taken with food, and its approximate half-life is 6.2 hours, which influences dosing frequency. Always follow the specific dose your clinician or the product label prescribes.
Metformin ER carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
Interaction risk for Metformin ER comes from the rest of the stack: other medications, prescription medicines, hormone therapy and peptides. Because Metformin ER is usually taken in the evening, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 6.2 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Metformin ER with no sign-up.
There is no single answer for Metformin ER plus TRT. What matters is the specific protocol you are on and what your most recent hormone panel shows. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Pairing Metformin ER with peptides has to be assessed one peptide at a time, because GLP-1 agonists, secretagogues, healing peptides and melanocortins do not share an interaction profile. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
With a plasma half-life near 6.2 hours, once-daily dosing is the usual pattern for Metformin ER. It is typically taken in the evening. Most protocols have it taken with food. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
With a plasma half-life near 6.2 hours, a single missed dose of Metformin ER usually has a smaller effect on overall exposure than an irregular pattern of missed doses does. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Metformin ER the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Metformin ER?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Fixed-Dose Combination of Dapagliflozin + Sitagliptin + Metformin in Patients with Type 2 Diabetes Poorly Controlled with Metformin: Phase 3, Randomized Comparison with Dual Combinations(opens PubMed in a new tab)Adv Ther · 2023 · PMID 37258803 · https://pubmed.ncbi.nlm.nih.gov/37258803/
- 2.Pharmacokinetics and pharmacodynamics of metformin in healthy subjects and patients with noninsulin-dependent diabetes mellitus.(opens PubMed in a new tab)Journal of clinical pharmacology · 1996 · PMID 8973990 · https://pubmed.ncbi.nlm.nih.gov/8973990/
- 3.Canagliflozin + metformin ER for the treatment of type 2 diabetes: the evidence to date(opens PubMed in a new tab)Expert Opin Pharmacother · 2023 · PMID 37881952 · https://pubmed.ncbi.nlm.nih.gov/37881952/
- 4.Efficacy and Safety of Glimepiride, Voglibose, and Metformin ER in Type 2 Diabetes: A Randomized, Active-Controlled Study(opens PubMed in a new tab)J Diabetes · 2026 · PMID 41979234 · https://pubmed.ncbi.nlm.nih.gov/41979234/
- 5.Metformin extended release for the treatment of type 2 diabetes mellitus(opens PubMed in a new tab)Expert Opin Pharmacother · 2006 · PMID 16556094 · https://pubmed.ncbi.nlm.nih.gov/16556094/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 14219(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/14219
Verify at
Publisher search links for Metformin ER. These are places to check the information — they are not citations, so they are not numbered.
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Metformin ER?
Plain-text summary, safe to quote verbatim:
Metformin extended-release (ER), also known by its brand name Glucophage XR, is an oral medication primarily used to manage blood glucose levels in adults and some children with type 2 diabetes. It belongs to a class of drugs called biguanides.
Source: DoseRoutine — https://doseroutine.com/library/metformin-er
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Metformin ER — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/metformin-er
What compounds are similar to Metformin ER?
Others in the medication category or studied for the same goals.