What it's used for
This medication is used alongside diet and exercise to help improve blood sugar control in adults with type 2 diabetes.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
Tablets must be swallowed whole without crushing or chewing, with a starting dose of 500 mg once daily with the evening meal that can be increased up to 2,000 mg daily.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Boxed warning / key safety info
This medication can cause a rare but serious condition called lactic acidosis, which can be fatal.
Common side effects
Common side effects include diarrhea, nausea, vomiting, abdominal pain, gas, heartburn, dizziness, and headache.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other diabetes medications covered at $0 with an active Tab membership.
Metformin cost without insurance
Cash prices for Metformin without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Metformin is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Metformin dosage and administration
Take ZITUVIMET orally twice daily with meals. ( 2.1 ) Individualize the dosage of ZITUVIMET on the basis of the patient's current regimen, effectiveness, and tolerability. ( 2.1 ) The maximum recommended daily dose is 100 mg of sitagliptin and 2,000 mg of metformin HCl. ( 2.1 ) The recommended starting dose in patients not currently treated with metformin is 50 mg sitagliptin and 500 mg metformin HCl twice daily, with gradual dose escalation recommended to reduce gastrointestinal side effects associated with metformin. ( 2.1 ) The starting dose in patients already treated with metformin should provide sitagliptin dosed as 50 mg twice daily (100 mg total daily dose) and the dose of metformin already being taken.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Metformin side effects
The following adverse reactions are also discussed elsewhere in the prescribing information: Lactic Acidosis [see Warnings and Precautions ( 5.1 )] Pancreatitis [see Warnings and Precautions ( 5.2 )] Heart Failure [see Warnings and Precautions ( 5.3 )] Acute Renal Failure [see Warnings and Precautions ( 5.4 )] Vitamin B12 Deficiency [see Warnings and Precautions ( 5.5 )] Hypoglycemia with Concomitant Use with Insulin or Insulin Secretagogues [see Warnings and Precautions ( 5.6 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.7 )] Severe and Disabling Arthralgia [see Warnings and Precautions ( 5.8 )] Bullous Pemphigoid [see Warnings and Precautions ( 5.9 )] Most common adverse reactions (incidence ≥5% of patients simultaneously started on sitagliptin and metformin and more commonly than in patients treated with placebo were diarrhea, upper respiratory tract infection, and headache.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Metformin drug interactions
Table 4 presents clinically significant drug interactions with ZITUVIMET: Table 4: Clinically Significant Drug Interactions with ZITUVIMET 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 ZITUVIMET may increase the risk for lactic acidosis. Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Tell your clinician and pharmacist about every medication, supplement and over-the-counter product you take.
Who should not take metformin
Severe renal impairment: (eGFR below 30 mL/min/1.73 m 2 ) ( 4) Metabolic acidosis, including diabetic ketoacidosis. ( 4 ) History of a serious hypersensitivity reaction to ZITUVIMET, sitagliptin, or metformin, such as anaphylaxis or angioedema. (4) ZITUVIMET is contraindicated in patients with: Severe renal impairment (eGFR below 30 mL/min/1.73 m 2 ) [see Warnings and Precautions ( 5.1 )]. Acute or chronic metabolic acidosis, including diabetic ketoacidosis. History of a serious hypersensitivity reaction to sitagliptin, metformin, or any of the excipients in ZITUVIMET. Serious hypersensitivity reactions including anaphylaxis or angioedema have been reported. [see Warnings and Precautions ( 5.7 ) and Adverse Reactions ( 6.2 )].
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is metformin covered at $0 with Tab?
Yes. Metformin is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get metformin through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get a metformin prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does metformin cost without insurance?
Without insurance, retail cash prices for metformin vary by pharmacy, strength and quantity. Metformin is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get metformin?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of metformin are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of metformin?
Take ZITUVIMET orally twice daily with meals. ( 2.1 ) Individualize the dosage of ZITUVIMET on the basis of the patient's current regimen, effectiveness, and tolerability. ( 2.1 ) The maximum recommended daily dose is 100 mg of sitagliptin and 2,000 mg of metformin HCl. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of metformin?
The following adverse reactions are also discussed elsewhere in the prescribing information: Lactic Acidosis [see Warnings and Precautions ( 5.1 )] Pancreatitis [see Warnings and Precautions ( 5.2 )] Heart Failure [see Warnings and Precautions ( 5.3 )] Acute Renal Failure [see Warnings and Precautions ( 5.4 )] Vitamin B12 Deficiency [see Warnings and Precautions ( 5.5 )] Hypoglycemia with Concomitant Use with Insulin or Insulin Secretagogues [see Warnings and Precautions ( 5.6 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.7 )] Severe and Disabling Arthralgia [see Warnings and Precautions ( 5.8 )] Bullous Pemphigoid [see Warnings and Precautions ( 5.9 )] Most common adverse reactions (incidence ≥5% of patients simultaneously started on sitagliptin and metformin and more commonly than in patients treated with placebo were diarrhea, upper respiratory tract infection, and headache. (FDA-approved label, retrieved 2026-09-15.)
What interacts with metformin?
Table 4 presents clinically significant drug interactions with ZITUVIMET: Table 4: Clinically Significant Drug Interactions with ZITUVIMET 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 ZITUVIMET may increase the risk for lactic acidosis. (FDA-approved label, retrieved 2026-09-15. Tell your clinician about every medication and supplement you take.)
Metformin is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
Solo $49/mo · Family $119/mo for up to 4 people · Family+ $149/mo for up to 8
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