Diabetes medicines work in different ways. Metformin remains useful for many people with type 2 diabetes, but modern treatment may also include SGLT2 inhibitors, GLP-1-based therapies, dual GIP/GLP-1 treatment, DPP-4 inhibitors, sulfonylureas, thiazolidinediones or insulin.
In 2026, medication choice is based on much more than HbA1c alone. Heart disease, heart failure, kidney disease, body weight, liver health, hypoglycemia risk, side effects, cost and personal treatment goals can all influence which medicine is most appropriate.
When patients ask me, “What is the best diabetes medicine?”, my answer is that there is no single medicine that is best for everyone. The right treatment depends on what we are trying to achieve and what other health risks need attention.
A diabetes medicine may be prescribed to lower blood glucose, but some medications can also help protect the heart or kidneys, support weight management, reduce cardiovascular risk, or replace insulin that the body can no longer produce adequately.
Lifestyle measures—including balanced nutrition, physical activity, sleep, weight management and diabetes education—remain important. However, modern diabetes treatment does not require every patient to “fail lifestyle treatment” before useful medication can be considered. For some people, organ-protective medicines are appropriate early in the course of type 2 diabetes.
What changed in 2026? Diabetes treatment is increasingly chosen according to the whole person's health—not HbA1c alone. Cardiovascular disease, chronic kidney disease, heart failure, weight, liver health and hypoglycemia risk can all influence treatment selection.
For a broader patient-friendly explanation, see my guide to the ADA and EASD 2026 diabetes guidelines .
Modern diabetes treatment should be individualized. Before recommending a medicine, your clinician may consider:
This is why two people with a similar HbA1c may appropriately receive different medicines.
The following table gives a simplified overview. It is not a prescribing guide, and individual medicines within the same class may have different approved uses, benefits and precautions.
| Medication class | Main role | Possible advantages | Important considerations |
|---|---|---|---|
| Metformin | Reduces liver glucose production and improves insulin sensitivity | Effective, inexpensive, long experience of use, low hypoglycemia risk when used alone | Digestive side effects, vitamin B12 deficiency with long-term use in some people, kidney function must be considered |
| SGLT2 inhibitors | Increase glucose loss through the urine | Can provide important heart-failure and kidney benefits in appropriate patients | Genital infections, dehydration and rare ketoacidosis are among the safety issues that require education |
| GLP-1 receptor agonists | Increase glucose-dependent insulin response, reduce glucagon and slow digestion | Strong glucose lowering, weight loss and cardiovascular benefit with selected agents | Nausea, vomiting and other gastrointestinal effects can occur; suitability must be individualized |
| Dual GIP/GLP-1 therapy | Acts through both GIP and GLP-1 pathways | Strong glucose-lowering and weight-loss effects | Gastrointestinal effects and other prescribing precautions require individual review |
| DPP-4 inhibitors | Enhance the body's incretin response | Oral treatment, generally weight-neutral, relatively low hypoglycemia risk when used alone | Glucose-lowering effect is usually more modest than several newer options; drug-specific precautions apply |
| Sulfonylureas | Stimulate insulin release from the pancreas | Effective glucose lowering and generally lower cost | Can cause hypoglycemia and weight gain |
| Thiazolidinediones | Improve insulin sensitivity | Can provide effective glucose lowering in selected patients | Weight gain, fluid retention and other risks can limit their use |
| Insulin | Replaces or supplements the body's insulin | Essential in type 1 diabetes and highly effective at lowering glucose | Hypoglycemia, weight gain, dose errors and treatment burden require education and monitoring |
Metformin remains one of the most established medicines for type 2 diabetes. It mainly reduces unnecessary glucose production by the liver and improves the body's response to insulin.
When taken by itself, metformin usually has a low risk of causing hypoglycemia. It is generally weight-neutral and may be associated with modest weight loss in some people.
Common side effects include nausea, diarrhea, abdominal discomfort, bloating, reduced appetite and sometimes a metallic taste. These effects are often most noticeable when treatment begins or the dose is increased. Taking metformin with food when prescribed and increasing the dose gradually may improve tolerance.
Long-term metformin treatment can contribute to vitamin B12 deficiency in some patients. Kidney function also matters because severe impairment can allow metformin to accumulate and increase the risk of rare but serious lactic acidosis.
For detailed dosing principles, kidney considerations and safety information, see my metformin dosage guide .
Glucophage is a brand name for metformin. Therefore, when patients ask about Glucophage side effects, many of the same metformin precautions apply.
For a focused discussion, read Glucophage side effects and how to manage them .
Metformin may be used in selected people with insulin resistance, including many people with type 2 diabetes and some people with other metabolic conditions. However, insulin resistance alone does not mean that everyone automatically needs metformin.
Read more about metformin and insulin resistance .
Pregnancy requires a separate medication review because glucose targets, maternal health and fetal considerations differ from routine type 2 diabetes care.
Do not begin, stop or change metformin during pregnancy without professional guidance. See metformin and pregnancy: safety, risks and when to stop .
GLP-1 receptor agonists have become increasingly important in type 2 diabetes care. Depending on the specific medicine and patient, these therapies can provide substantial glucose lowering, support weight loss and provide cardiovascular benefits.
Dual GIP/GLP-1 therapy, such as tirzepatide, acts through two metabolic hormone pathways and can produce strong effects on glucose and weight.
These medicines are not simply “weight-loss injections.” In diabetes care, treatment selection depends on the person's glucose goals, cardiovascular status, kidney function, weight-related goals, other medical conditions and medication tolerance.
Common problems can include nausea, vomiting, diarrhea, constipation or reduced appetite, especially during dose escalation. The exact contraindications and precautions depend on the medicine.
Important: Do not obtain compounded, unapproved or “research” GLP-1 products from unreliable online sources. Use prescription medicines only through legitimate medical and pharmacy channels.
SGLT2 inhibitors lower glucose partly by causing the kidneys to remove more glucose through the urine.
Their importance now extends beyond glucose. For appropriate people with type 2 diabetes, these medicines may be selected because of demonstrated benefits in chronic kidney disease or heart failure, even when HbA1c is not the only concern.
Possible side effects include genital fungal infections, increased urination and dehydration. A rare but serious complication is diabetic ketoacidosis, which can sometimes occur without extremely high glucose.
Patients may need specific instructions about acute illness, fasting, surgery and dehydration. Do not stop or restart an SGLT2 inhibitor on your own; follow the sick-day or procedure plan provided by your clinician.
DPP-4 inhibitors help prolong the action of the body's incretin hormones. They are taken by mouth, are generally weight-neutral and have a low risk of hypoglycemia when used without insulin or medicines that directly stimulate insulin release.
Their glucose-lowering effect is usually more modest than that of GLP-1-based therapies. DPP-4 inhibitors are generally not combined with GLP-1 receptor agonists because they act on overlapping pathways without providing meaningful additional benefit.
Sulfonylureas stimulate the pancreas to release insulin. They can lower glucose effectively and are often relatively inexpensive, but they can cause hypoglycemia and weight gain.
Patients taking a sulfonylurea need to understand how missed meals, illness, alcohol and activity may affect the risk of low blood sugar.
Thiazolidinediones improve insulin sensitivity and can lower glucose in selected patients. However, fluid retention, weight gain and other adverse effects mean that they are not appropriate for everyone, particularly when heart-failure risk is a concern.
Insulin is essential for everyone with type 1 diabetes because the body cannot produce enough insulin to survive safely.
People with type 2 diabetes may also need insulin. This can happen when glucose is very high, symptoms of insulin deficiency are present, during certain illnesses or surgery, during pregnancy in selected situations, or when other treatments do not provide enough control.
The ADA 2026 Standards advise considering insulin in adults with type 2 diabetes when symptoms of hyperglycemia are present or glucose levels are very high—for example, an HbA1c above 10% or blood glucose of 300 mg/dL (16.7 mmol/L) or higher.
In adults with type 2 diabetes who do not have severe hyperglycemia or a hyperglycemic crisis, GLP-1-based therapy may often be considered before insulin for initial or additional injectable treatment.
For the complete overview, see insulin treatment: types, doses, pumps and safety .
Read my detailed guide to insulin side effects and hypoglycemia prevention .
| Topic | Metformin | Insulin |
|---|---|---|
| Type | Oral glucose-lowering medicine | Hormone given by injection or pump |
| Main action | Reduces liver glucose output and improves insulin sensitivity | Replaces or supplements the body's insulin |
| Hypoglycemia | Low risk when used alone | Important risk if dose, food and activity are not balanced |
| Weight | Usually weight-neutral; modest loss in some people | Weight gain can occur |
| Type 1 diabetes | Does not replace insulin | Essential |
| Type 2 diabetes | Commonly used | Used when clinically needed |
This comparison is intentionally simplified. The correct treatment depends on the full clinical situation rather than choosing one medicine from a table.
Some side effects can be reduced through careful dosing, timing, monitoring and regular follow-up. The appropriate strategy depends on the medicine.
For more detailed medication warnings, interactions and precautions, see our diabetes drug safety and side effects guide .
Contact your healthcare team if you develop:
Seek urgent medical help for severe hypoglycemia, loss of consciousness, seizure, severe confusion, difficulty breathing, persistent vomiting with dehydration, suspected diabetic ketoacidosis, severe weakness, chest pain, or another serious deterioration in your condition.
A diabetes medicine should have a purpose. Sometimes that purpose is lowering glucose. Sometimes it is also protecting the heart or kidneys, reducing heart-failure risk, supporting weight management, or replacing insulin the body cannot make.
I do not want patients to judge their treatment by whether they take “many” or “few” medicines. I want us to ask whether every medicine is still useful, safe, tolerated and appropriate for that person's current health.
There is no longer one universal first medicine for every person. Metformin remains an important and commonly used option, but SGLT2 inhibitors, GLP-1-based therapies or combinations may be prioritized when cardiovascular disease, heart failure, chronic kidney disease, obesity or other treatment goals are important.
Yes. Metformin remains effective, widely used and relatively inexpensive. What has changed is that doctors do not always need to wait for metformin to fail before considering medications that offer important heart, kidney or weight-related benefits.
No. GLP-1-based therapies were developed and studied as metabolic treatments, including for type 2 diabetes. Depending on the specific medicine and patient, they may lower glucose, support weight loss and provide cardiovascular or other benefits.
Selected SGLT2 inhibitors have demonstrated kidney and heart-failure benefits in appropriate patients. Their use depends on kidney function, other medical conditions and the exact indication.
No. Type 2 diabetes can change over time, and insulin may become the safest or most effective treatment in some situations. Needing insulin is a treatment decision—not a personal failure.
Not on your own. Normal readings may mean that the treatment is working. Some people can safely reduce medication after substantial lifestyle or weight changes, while others still need treatment for glucose or organ protection. Any reduction should be planned with the prescribing clinician.
1. American Diabetes Association Professional Practice Committee. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2026 . Diabetes Care. 2026;49(Suppl 1).
2. Davies MJ, Aroda VR, Bajaj M, et al. Management of type 2 diabetes, 2026: A consensus report by the American Diabetes Association and the European Association for the Study of Diabetes . Diabetologia. 2026.
3. National Institute of Diabetes and Digestive and Kidney Diseases. Insulin, Medicines, & Other Diabetes Treatments .
4. MedlinePlus. Metformin Drug Information .
5. NHS. About Metformin .
Medical disclaimer: This page provides general educational information and does not replace individualized medical advice, diagnosis or prescribing. Do not start, stop, increase, decrease or substitute a diabetes medicine without discussing the change with your doctor or qualified healthcare professional.