Metformin hydrochloride
Biguanide. Sold as Metformin hydrochloride.
Metformin is a first-line medication for type 2 diabetes and one of the most widely prescribed medicines in the world. It is often mentioned in discussions of weight, but its FDA label does not list weight loss among the approved uses, and no metformin product has been approved for it.
Brands and what each one is approved for
One active ingredient can hold several separate FDA approvals. They are different documents with different approved uses, and mixing them up is the most common mistake made about these medications.
| Brand | Status for this use | Supply | Label version |
|---|---|---|---|
| Metformin hydrochlorideREMEDYREPACK INC. | Approved for another condition | Prescription | 19 May 2026 |
WARNING: LACTIC ACIDOSIS Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypote
In the Metformin hydrochloride label
- nsion, and resistant bradyarrhythmias. The onset of metformin-associated lactic acidosis is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, somnolence, and abdominal pain. Metformin-associated lactic acidosis was characterized by elevated blood lactate levels (>5 mmol/Liter), anion gap acidosis (without evidence of ketonuria or ketonemia), an increased lactate/pyruvate ratio; and metformin plasma levels generally >5 mcg/mL.
A boxed warning is the most serious warning the FDA requires. This text is reproduced from the label.
How it works
Written by us
The label describes a reduction in glucose production by the liver, a reduction in intestinal glucose absorption, and improved insulin sensitivity. None of these are described in the label as a mechanism for weight reduction.
From the mechanism of action section of the Metformin hydrochloride label
Metformin is an antihyperglycemic agent which improves glucose tolerance in patients with type 2 diabetes mellitus, lowering both basal and postprandial plasma glucose. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization.
What the FDA approved it for
The approved uses, as worded in the label.
From the FDA label
- Metformin hydrochloride tablets are indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus.
- Metformin hydrochloride tablets is a biguanide indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus.
Forms and strengths
The presentations and strengths listed in the label.
From the FDA label
Metformin Hydrochloride Tablets USP, 500 mg: White, biconvex, circular shaped film coated tablets with 'A' debossed on one side and '12' debossed on the other side Metformin hydrochloride tablets:...
How the label says it is taken
What the label states about administration. It is not a dosing instruction for any individual.
From the FDA label
- Adult Dosage for Metformin Hydrochloride Tablets: Starting dose: 500 mg orally twice a day or 850 mg once a day, with meals
- Increase the dose in increments of 500 mg weekly or 850 mg every 2 weeks, up to a maximum dose of 2550 mg per day, given in divided doses
- Doses above 2000 mg may be better tolerated given 3 times a day with meals
- Pediatric Dosage for Metformin Hydrochloride Tablets: Starting dose: 500 mg orally twice a day, with meals
- Increase dosage in increments of 500 mg weekly up to a maximum of 2000 mg per day, given in divided doses twice daily
- Renal Impairment: Prior to initiation, assess renal function with estimated glomerular filtration rate (eGFR)
Most common adverse reactions
The adverse reactions the label reports as most common.
From the FDA label
most common adverse reactions (>5.0%) are diarrhea, nausea/vomiting, flatulence, asthenia, indigestion, abdominal discomfort, and headache. (6.
Warnings and precautions
The warnings and precautions section of the label.
From the FDA label
- Lactic Acidosis: See boxed warning.
- Vitamin B 12 Deficiency: Metformin may lower vitamin B 12 levels. Measure hematological parameters annually and vitamin B 12 at 2 to 3 year intervals and manage any abnormalities.
- Hypoglycemia with Concomitant Use with Insulin and Insulin Secretagogues: Increased risk of hypoglycemia when used in combination with insulin and/or an insulin secretagogue. Lower dose of insulin or insulin secretagogue may be required
Contraindications
Situations in which the label states the medication must not be used.
From the FDA label
- Metformin hydrochloride tablets are contraindicated in patients with: Severe renal impairment (eGFR below 30 mL/min/1.73 m 2).
- Hypersensitivity to metformin.
- Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
- Severe renal impairment (eGFR below 30 mL/min/1.73 m 2) Hypersensitivity to metformin Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
Drug interactions
Interactions the label singles out.
From the FDA label
- Table 3 presents clinically significant drug interactions with metformin hydrochloride.
- Table 3: Clinically Significant Drug Interactions with Metformin Hydrochloride Carbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis.
- Concomitant use of these drugs with metformin hydrochloride may increase the risk for lactic acidosis.
- Intervention: Consider more frequent monitoring of these patients.
Pregnancy and breastfeeding
The opening of the pregnancy section of the label. The full section is longer and is in the source document.
From the FDA label
Limited data with metformin hydrochloride in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. Published studies with metformin use during pregnancy have not reported a clear association with metformin and major birth defect or miscarriage risk. There are risks to the mother and fetus associated with poorly controlled diabetes mellitus in pregnancy.
Generic or brand
Written by us
Metformin is available as a generic in immediate-release and extended-release forms and is among the least expensive prescription medicines available.
The FDA label database lists 67 approved generic applications for this ingredient.
What affects the cost
Written by us
Cost is the reason metformin comes up in weight discussions at all: it is inexpensive and long established. That does not change what it is approved for. This site does not track prices and does not link to sellers.
Common questions
- Is metformin approved for weight loss?
- No. The FDA label covers glycaemic control in type 2 diabetes. Any use for weight is outside the approved indications, and this page does not describe what such use involves.
- Why is metformin in a weight loss category then?
- Because people look for it here. Leaving it out would not answer the question; stating plainly what the label does and does not cover does. Every page in this category marks whether the medication carries an approval for weight management.
Sources
Every fact above comes from one of these documents. The date is the effective date of the label version this page was built from.
FDA prescribing information for Metformin hydrochloride
REMEDYREPACK INC.. Label version 14, effective 19 May 2026.
Page last updated: 29 July 2026
Compiled by the HealthyStudy editorial team from FDA source documents. No medical reviewer is credited on this page, because none reviewed it.