What Are the Best Alternatives to Metformin in 2026?

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> Reviewed by FormBlends Medical Team · Last updated April 2026 · 13 sources cited

Key Takeaways

• The strongest evidence-based alternatives to metformin for type 2 diabetes are GLP-1 receptor agonists (semaglutide, tirzepatide, dulaglutide), SGLT2 inhibitors (empagliflozin, dapagliflozin), and DPP-4 inhibitors (sitagliptin, linagliptin).
• For patients who can't tolerate metformin's GI side effects, extended-release metformin or a switch to a GLP-1 or DPP-4 inhibitor are the most common next steps.
• GLP-1 medications produce the largest A1C reductions (1.5 to 2.5%) and the largest weight loss (8 to 21%) of any oral or injectable diabetes drug class.
• SGLT2 inhibitors offer cardiovascular and kidney benefits proven in trials like EMPA-REG and CANVAS, in addition to A1C reduction of 0.5 to 1.0%.
• Lifestyle interventions, particularly low-carbohydrate diets and structured exercise, can produce A1C reductions comparable to metformin in early-stage diabetes (Hallberg et al., Diabetes Therapy 2018).

Direct answer (40-60 words)

The best metformin alternatives in 2026 are GLP-1 receptor agonists (semaglutide, tirzepatide), SGLT2 inhibitors (empagliflozin, dapagliflozin), and DPP-4 inhibitors (sitagliptin, linagliptin). GLP-1 medications produce the largest A1C reductions and weight loss. SGLT2 inhibitors add cardiovascular and kidney benefits. Lifestyle changes, including low-carbohydrate diets, also work for early-stage diabetes.

Table of contents

1. The 30-second answer
2. Why patients look for metformin alternatives
3. Drug-class comparison table
4. GLP-1 receptor agonists
5. SGLT2 inhibitors
6. DPP-4 inhibitors
7. Sulfonylureas and meglitinides
8. Thiazolidinediones (TZDs)
9. Insulin
10. Lifestyle and natural alternatives
11. How providers actually choose
12. FAQ
13. Sources
14. Footer disclaimers

Why patients look for metformin alternatives

Metformin remains the first-line drug for type 2 diabetes per the American Diabetes Association's 2025 Standards of Care. It's cheap (often under $10 per month), well-tolerated by most patients, and has a 60-year safety record. So the search for an alternative usually starts with one of three problems.

Problem 1: GI side effects. Roughly 20 to 30% of patients on immediate-release metformin experience nausea, diarrhea, or abdominal cramping in the first weeks. About 5% can't tolerate the drug at any dose (Bonnet & Scheen, Diabetes & Metabolism 2017).

Problem 2: Insufficient A1C control. Metformin alone reduces A1C by about 1.0 to 1.5 percentage points. For patients starting at A1C 9% or higher, that may not be enough to reach the typical target of under 7%.

Problem 3: Other clinical priorities. A patient with established cardiovascular disease, heart failure, or chronic kidney disease may benefit more from a drug class with cardio-renal protection (GLP-1 or SGLT2) than from metformin. The 2025 ADA Standards of Care explicitly recommend SGLT2 inhibitors or GLP-1 agonists as first-line in patients with these comorbidities, even before metformin.

A fourth, less-discussed reason: weight loss. Metformin produces modest weight loss of 1 to 3% of body weight (DPPRG, NEJM 2002). For patients with obesity, GLP-1 medications offer 8 to 21% weight reduction (Wilding et al., NEJM 2021; Jastreboff et al., NEJM 2022), which can be a more important clinical goal than incremental A1C improvement.

Drug-class comparison table

Drug class	A1C reduction	Weight effect	Cardio benefit	Kidney benefit	Hypoglycemia risk	Monthly cost (cash)
GLP-1 (semaglutide, tirzepatide)	1.5 to 2.5%	Loss 8 to 21%	Yes (LEADER, SUSTAIN-6)	Yes (FLOW trial)	Low	$300 to $1,150
SGLT2 (empagliflozin, dapagliflozin)	0.5 to 1.0%	Loss 2 to 4%	Yes (EMPA-REG, CANVAS)	Yes (DAPA-CKD, EMPA-KIDNEY)	Low	$550 to $700
DPP-4 (sitagliptin, linagliptin)	0.5 to 0.8%	Neutral	Neutral	Neutral	Low	$400 to $500
Sulfonylurea (glipizide, glimepiride)	1.0 to 1.5%	Gain 2 to 4 lb	No	No	High	$5 to $20
Thiazolidinedione (pioglitazone)	1.0 to 1.5%	Gain 4 to 6 lb	Mixed (heart failure risk)	Neutral	Low	$10 to $25
Insulin	1.5 to 3.5%	Gain 4 to 10 lb	Variable	Variable	High	$30 to $400
Acarbose (alpha-glucosidase inhibitor)	0.5 to 0.8%	Neutral	Mild benefit	Neutral	Low	$25 to $50
Lifestyle (low-carb diet + exercise)	0.5 to 2.0%	Loss 5 to 12%	Strong indirect	Strong indirect	None	$0

This table compresses a lot of nuance, but it's a starting point. The next sections walk through each class.

GLP-1 receptor agonists

GLP-1 receptor agonists are the most-studied newer drug class for type 2 diabetes and the strongest A1C-lowering option short of insulin.

Major drugs:

• Semaglutide (Ozempic injectable, Rybelsus oral)
• Tirzepatide (Mounjaro), which is a dual GLP-1 / GIP agonist
• Dulaglutide (Trulicity)
• Liraglutide (Victoza, generic available)
• Exenatide (Byetta, Bydureon)

A1C effect: semaglutide reduces A1C by 1.5 to 1.8% at 1 mg weekly (SUSTAIN-1 through SUSTAIN-7 trials, Aroda et al., Diabetes Care 2017). Tirzepatide reduces A1C by 1.9 to 2.5% at 5 to 15 mg weekly (SURPASS-1 through SURPASS-5, Frias et al., NEJM 2021).

Weight effect: average weight loss of 8 to 17% with semaglutide and 14 to 21% with tirzepatide at maintenance doses, sustained over 68 to 72 weeks of treatment (Wilding et al., STEP 1, NEJM 2021; Jastreboff et al., SURMOUNT-1, NEJM 2022).

Cardiovascular benefit: the LEADER trial (Marso et al., NEJM 2016) showed liraglutide reduced major adverse cardiovascular events by 13% in patients with type 2 diabetes and existing cardiovascular disease. SUSTAIN-6 (Marso et al., NEJM 2016) showed similar benefit for semaglutide.

Kidney benefit: the FLOW trial (Perkovic et al., NEJM 2024) showed semaglutide reduced kidney-related events by 24% in patients with type 2 diabetes and chronic kidney disease.

Side effects: GI symptoms (nausea, vomiting, constipation, diarrhea) are the most common. Most resolve over 4 to 8 weeks. Rare but serious risks include pancreatitis, gallbladder disease, and a boxed warning about thyroid C-cell tumors observed in rodents.

Cost: brand-name GLP-1 medications are expensive. Cash prices range from $940 (Ozempic) to $1,135 (Mounjaro) per month. Compounded semaglutide and tirzepatide from licensed pharmacies cost $179 to $349 per month. (See our compounded vs brand semaglutide guide for a full comparison.)

SGLT2 inhibitors

SGLT2 inhibitors block glucose reabsorption in the kidneys, causing excess glucose to be excreted in urine.

Major drugs:

• Empagliflozin (Jardiance)
• Dapagliflozin (Farxiga)
• Canagliflozin (Invokana)
• Ertugliflozin (Steglatro)

A1C effect: 0.5 to 1.0% reduction at maintenance doses.

Weight effect: modest loss of 2 to 4% over 6 months, plateauing thereafter.

Cardiovascular benefit: the EMPA-REG OUTCOME trial (Zinman et al., NEJM 2015) showed empagliflozin reduced cardiovascular death by 38% in patients with type 2 diabetes and existing cardiovascular disease. CANVAS (Neal et al., NEJM 2017) showed similar benefit for canagliflozin.

Kidney benefit: DAPA-CKD (Heerspink et al., NEJM 2020) and EMPA-KIDNEY (NEJM 2023) showed dapagliflozin and empagliflozin slowed progression of chronic kidney disease in patients with and without diabetes.

Heart failure benefit: SGLT2 inhibitors are now FDA-approved for heart failure with both reduced and preserved ejection fraction, regardless of diabetes status.

Side effects: genital mycotic infections (3 to 7% of patients), urinary tract infections (slight increase), euglycemic diabetic ketoacidosis (rare but serious), and volume depletion in elderly or diuretic-using patients.

Cost: $550 to $700 per month cash. Most commercial insurance covers SGLT2 inhibitors. Manufacturer savings cards can drop copays to $10 to $30 monthly for eligible patients.

DPP-4 inhibitors

DPP-4 inhibitors increase the body's own incretin levels by blocking the enzyme that breaks them down.

Major drugs:

• Sitagliptin (Januvia)
• Linagliptin (Tradjenta)
• Saxagliptin (Onglyza)
• Alogliptin (Nesina)

A1C effect: 0.5 to 0.8% reduction. Modest compared to GLP-1 medications, but consistent.

Weight effect: weight-neutral. No meaningful gain or loss.

Cardiovascular effect: TECOS (Green et al., NEJM 2015) showed sitagliptin was non-inferior to placebo for cardiovascular outcomes. SAVOR-TIMI 53 (Scirica et al., NEJM 2013) raised concern about an increased heart failure signal with saxagliptin.

Side effects: generally well-tolerated. Rare but reported: pancreatitis, severe joint pain, bullous pemphigoid (a skin condition).

Cost: $400 to $500 per month cash. Linagliptin is sometimes preferred in patients with kidney disease because no dose adjustment is needed.

When does a DPP-4 inhibitor make sense as a metformin alternative? Usually for patients who need a small additional A1C reduction, want an oral once-daily option, can't tolerate metformin's GI effects, and don't need significant weight loss.

Sulfonylureas and meglitinides

Sulfonylureas stimulate insulin secretion from pancreatic beta cells. They're the oldest non-insulin diabetes drug class still in regular use.

Major drugs:

• Glipizide (Glucotrol)
• Glimepiride (Amaryl)
• Glyburide (DiaBeta)
• Repaglinide and nateglinide (meglitinide variants with shorter half-lives)

A1C effect: 1.0 to 1.5% reduction.

Weight effect: typical gain of 2 to 4 pounds.

Hypoglycemia risk: the highest of any oral diabetes drug. About 20 to 30% of patients experience at least one hypoglycemic episode per year on a sulfonylurea (UKPDS 33, Lancet 1998).

Cost: under $20 per month. Generic. Cheap.

Why a sulfonylurea might be the right alternative: patients with limited insurance coverage, severe cost constraints, or specific renal contraindications to other classes. They work, they're predictable, they're cheap. The hypoglycemia risk is the trade-off.

Thiazolidinediones (TZDs)

Pioglitazone (Actos) is the only TZD still widely prescribed. Rosiglitazone (Avandia) is rarely used due to historical concerns about cardiovascular risk.

A1C effect: 1.0 to 1.5% reduction.

Weight effect: typical gain of 4 to 6 pounds. Some of the gain is fluid retention.

Cardiovascular effect: mixed. The IRIS trial (Kernan et al., NEJM 2016) showed pioglitazone reduced recurrent stroke in patients with insulin resistance. PROactive (Dormandy et al., Lancet 2005) showed reduced MACE in some subgroups. But pioglitazone increases heart failure risk and has a black-box warning for that reason.

Other risks: bladder cancer signal (low absolute risk but FDA labeled), bone fracture risk in postmenopausal women.

Cost: $10 to $25 per month. Generic.

A TZD is rarely a first-choice metformin alternative in 2026. Most providers reach for GLP-1, SGLT2, or DPP-4 first.

Insulin

Insulin remains the most powerful glucose-lowering treatment. For many patients with severe hyperglycemia (A1C above 10%, symptomatic high blood sugar), insulin is the right starting point regardless of metformin status.

Forms: long-acting basal (glargine, detemir, degludec), rapid-acting prandial (lispro, aspart, glulisine), pre-mixed combinations.

A1C effect: unlimited. Insulin will lower glucose to whatever level the dose is titrated to.

Weight effect: typical gain of 4 to 10 pounds.

Hypoglycemia risk: the highest of any diabetes drug class. Education and monitoring are essential.

Cost: highly variable. Generic biosimilar insulin starts around $30 per month. Brand-name basal insulins run $300 to $400 per month without insurance. The 2024 Medicare $35 monthly insulin cap and similar state laws have lowered out-of-pocket costs for many patients.

When does insulin make sense as a metformin alternative? When the patient needs aggressive A1C reduction quickly, when other classes are contraindicated, or when type 2 diabetes has progressed to severe insulin deficiency (usually after 10 to 15 years of disease).

Lifestyle and natural alternatives

For early-stage type 2 diabetes (recent diagnosis, A1C under 7.5%, no severe complications), lifestyle change is genuinely an alternative to metformin. Not a complement, an alternative.

Low-carbohydrate diet. The Virta Health study (Hallberg et al., Diabetes Therapy 2018) followed 218 patients on a structured ketogenic diet for two years. A1C dropped by an average of 1.3 percentage points. 60% of patients achieved diabetes remission. Weight loss averaged 11.9% of body weight.

Mediterranean diet. PREDIMED (Estruch et al., NEJM 2018) showed a Mediterranean diet supplemented with olive oil or nuts reduced cardiovascular events by 30% in patients at high risk. A1C effects were smaller than with low-carb but still meaningful.

Structured exercise. A meta-analysis of 47 trials (Umpierre et al., JAMA 2011) showed structured aerobic and resistance training reduced A1C by 0.7% on average, comparable to many medications.

Bariatric surgery. For patients with BMI 35+ and type 2 diabetes, sleeve gastrectomy and Roux-en-Y gastric bypass produce diabetes remission rates of 60 to 80% at 2 years (Schauer et al., NEJM 2017).

"Natural" supplements with some evidence:

• Berberine: a meta-analysis (Liang et al., J Ethnopharmacol 2012) showed A1C reductions of 0.7 to 0.9%, comparable to metformin in head-to-head studies. Quality control varies widely; clinical trials use standardized extracts that are hard to replicate at retail.
• Cinnamon: small effect, A1C reductions under 0.3% in most meta-analyses.
• Chromium picolinate: very weak evidence, A1C reductions under 0.2%.
• Alpha-lipoic acid: stronger evidence for diabetic neuropathy than for glucose control itself.

A point worth being clear about: "natural" doesn't mean safe or effective at the same level as medication. Berberine has the strongest data, but it interacts with multiple medications (cyclosporine, statins) and can cause GI side effects similar to metformin's.

How providers actually choose

The 2025 ADA Standards of Care recommend a patient-centered approach. The framework providers use looks roughly like this:

Step 1: Assess comorbidities.

• Established cardiovascular disease, heart failure, or chronic kidney disease: GLP-1 or SGLT2 first-line, often before metformin.
• Obesity (BMI 30+): GLP-1 first-line.
• Severe hyperglycemia (A1C above 10% or symptomatic): consider insulin.

Step 2: Assess tolerance.

• Patient can tolerate metformin: continue or add a second agent.
• Patient can't tolerate metformin: switch to extended-release metformin first; if still intolerant, switch to a GLP-1 (if obese) or DPP-4 (if weight-neutral preferred) or SGLT2 (if cardio-renal benefit needed).

Step 3: Assess cost and access.

• Strong commercial insurance: any class is affordable with manufacturer savings cards.
• Limited insurance: sulfonylureas, generic metformin, or compounded GLP-1s may be the only affordable options.
• Medicare: GLP-1s for diabetes are covered; SGLT2s and DPP-4s vary by plan tier.

Step 4: Re-assess at 3 to 6 months.

• A1C goal achieved: continue current regimen.
• A1C goal not achieved: add a second agent from a different class.

A 2024 ADA position paper (Davies et al., Diabetes Care 2024) emphasized that no single drug is right for every patient. The "best alternative to metformin" depends on the patient's full clinical picture.

FAQ

What is the best alternative to metformin for weight loss? GLP-1 receptor agonists (semaglutide, tirzepatide) produce the largest weight loss of any diabetes drug class. Average reductions are 8 to 21% of body weight over 68 to 72 weeks of treatment. They also reduce A1C by 1.5 to 2.5%, more than metformin's typical 1.0 to 1.5%.

What is the best alternative to metformin for kidney disease? SGLT2 inhibitors (empagliflozin, dapagliflozin) and GLP-1 receptor agonists (semaglutide) both have proven kidney benefits. The DAPA-CKD and EMPA-KIDNEY trials showed SGLT2 inhibitors slowed CKD progression. The FLOW trial showed semaglutide reduced kidney-related events.

Can I just stop metformin and use diet alone? For early-stage type 2 diabetes (A1C under 7.5%, recent diagnosis, no complications), structured low-carbohydrate or Mediterranean diets can produce A1C reductions equivalent to metformin. Discuss with your provider before stopping any medication. Don't stop abruptly without monitoring blood glucose.

Is berberine the same as metformin? Berberine is sometimes called "nature's metformin" because both activate AMP-activated protein kinase (AMPK). Head-to-head studies show comparable A1C reductions. Berberine isn't FDA-regulated as a drug, so quality and dosing vary. Drug interactions are real and meaningful.

Why does my doctor want me on metformin if it has side effects? Metformin has the strongest long-term safety record of any diabetes drug, costs under $10 per month, and has demonstrated cardiovascular benefit in some studies. The 20 to 30% rate of GI side effects usually improves over 4 to 8 weeks or with extended-release formulation. The benefit-risk ratio is favorable for most patients.

How does a GLP-1 compare to metformin for type 2 diabetes? GLP-1 medications produce larger A1C reductions (1.5 to 2.5% vs metformin's 1.0 to 1.5%), larger weight loss (8 to 21% vs 1 to 3%), and have proven cardiovascular and kidney benefits. They cost 30 to 100 times more per month. Many providers now use GLP-1s as first-line for patients with obesity or established cardiovascular disease.

What if metformin gives me diarrhea? First, switch to extended-release metformin, which is gentler on the GI tract. Take it with the largest meal. If diarrhea persists, work with your provider to switch classes. DPP-4 inhibitors and SGLT2 inhibitors have lower GI side-effect rates than metformin or GLP-1s.

Can I take metformin and a GLP-1 together? Yes. The combination is common and recommended by the ADA when metformin alone doesn't reach A1C goal. The two drugs work through different mechanisms and have additive A1C effects of about 1.5 to 2.5 percentage points combined.

Is there a generic version of GLP-1 medications? Liraglutide (Victoza) has generic versions available as of 2024. Semaglutide and tirzepatide remain on patent in the U.S. through 2031 and 2032, respectively. Compounded versions are available from licensed pharmacies under specific clinical conditions.

Are SGLT2 inhibitors safer than metformin? Both have favorable long-term safety profiles. SGLT2 inhibitors carry a small risk of euglycemic diabetic ketoacidosis (especially if dehydrated or fasting) and increased genital infections. Metformin has GI side effects and a very rare risk of lactic acidosis in patients with severe kidney impairment.

What's the cheapest alternative to metformin? Generic sulfonylureas (glipizide, glimepiride) at under $20 per month are the cheapest prescription alternatives. Generic pioglitazone is similar. Lifestyle change is free. None match metformin's combination of low cost, low side-effect burden, and cardiovascular safety record.

Does metformin still help if I'm on a GLP-1? Most studies suggest yes. The 2024 ADA recommendations support continuing metformin alongside GLP-1 therapy for additive A1C benefit. Some providers stop metformin if the patient achieves remission on GLP-1 monotherapy, but this should be a clinical decision with monitoring.

Sources

1. American Diabetes Association. Standards of Care in Diabetes 2025. Diabetes Care. 2025;48(Suppl 1).
2. Bonnet F, Scheen AJ. Understanding and overcoming metformin gastrointestinal intolerance. Diabetes Metab. 2017;43:519-523.
3. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346:393-403.
4. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384:989-1002.
5. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022;387:205-216.
6. Marso SP, Daniels GH, Brown-Frandsen K, et al. Liraglutide and cardiovascular outcomes in type 2 diabetes (LEADER). N Engl J Med. 2016;375:311-322.
7. Marso SP, Bain SC, Consoli A, et al. Semaglutide and cardiovascular outcomes in patients with type 2 diabetes (SUSTAIN-6). N Engl J Med. 2016;375:1834-1844.
8. Zinman B, Wanner C, Lachin JM, et al. Empagliflozin, cardiovascular outcomes, and mortality (EMPA-REG OUTCOME). N Engl J Med. 2015;373:2117-2128.
9. Heerspink HJL, Stefansson BV, Correa-Rotter R, et al. Dapagliflozin in patients with chronic kidney disease (DAPA-CKD). N Engl J Med. 2020;383:1436-1446.
10. Perkovic V, Tuttle KR, Rossing P, et al. Effects of semaglutide on chronic kidney disease in patients with type 2 diabetes (FLOW). N Engl J Med. 2024;391:109-121.
11. Hallberg SJ, McKenzie AL, Williams PT, et al. Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year. Diabetes Ther. 2018;9:583-612.
12. Umpierre D, Ribeiro PA, Kramer CK, et al. Physical activity advice only or structured exercise training and association with HbA1c levels in type 2 diabetes. JAMA. 2011;305:1790-1799.
13. Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery versus intensive medical therapy for diabetes (STAMPEDE 5-year outcomes). N Engl J Med. 2017;376:641-651.

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Platform Disclaimer. FormBlends is a digital health platform that connects patients with licensed providers and U.S.-based pharmacies. We do not manufacture, prescribe, or dispense medication directly. All clinical decisions are made by independent licensed providers.

Compounded Medication Notice. Compounded semaglutide and tirzepatide are not FDA-approved. They are prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded medications have not undergone the same review process as FDA-approved drugs and are not interchangeable with brand-name products.

Results Disclaimer. Individual results vary. Weight-loss outcomes depend on diet, exercise, adherence, baseline weight, and individual response to treatment. Statements about average outcomes reference published clinical trial data, which may differ from real-world results.

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