Diabetes medications: every class, how each works, and where amylin drugs fit

The A1C, weight and hypoglycemia columns follow the grading the ADA uses to compare glucose-lowering medicines in Section 9 of its Standards ^[1]. A network meta-analysis of 453 randomised trials covering 21 treatments from 9 classes reached a consistent picture: insulin regimens and some GLP-1 receptor agonists added to metformin produced the largest A1C reductions, and in drug-naive people at low cardiovascular risk no treatment differed from another ^[2].

Pramlintide sits apart. Its FDA label approves it only for people with type 1 or type 2 diabetes who use mealtime insulin, and it carries a boxed warning for severe hypoglycemia when used with insulin ^[3]. Two older tablet classes, meglitinides (repaglinide, nateglinide) and alpha-glucosidase inhibitors (acarbose, miglitol), are still approved but rarely chosen; the hypoglycemic drugs classification guide covers them with the rest of the oral agents.

Type 2 diabetes combines two problems: the body responds less to insulin, and the pancreas cannot make enough extra insulin to compensate. The drug classes attack that from different directions:

• The liver. Metformin reduces the glucose the liver releases between meals, the main reason fasting glucose runs high.
• The pancreas. Sulfonylureas and meglitinides force insulin release at any glucose level. The incretin drugs (DPP-4 inhibitors, GLP-1 receptor agonists and tirzepatide) increase insulin only when glucose is raised, and also lower glucagon, the hormone that pushes glucose up.
• The kidney. SGLT2 inhibitors block glucose reabsorption so more leaves in the urine, which lowers glucose and also reduces strain on the heart and kidneys.
• The gut and the brain. GLP-1 drugs, tirzepatide and amylin analogues slow stomach emptying and reduce appetite, which is where most of their weight effect comes from. Alpha-glucosidase inhibitors slow carbohydrate digestion.
• Muscle and fat. Pioglitazone makes tissues more sensitive to insulin.

Because the routes are separate, the effects add up: a person on metformin plus an SGLT2 inhibitor plus a GLP-1 drug is using three different mechanisms. The two most-studied incretin drugs have their own evidence records on this site: semaglutide and tirzepatide. Insulin is different again: it replaces the hormone itself, so it works whatever the underlying cause, and its dose can be raised until glucose comes down, at the price of hypoglycemia and weight gain.

Oral diabetes medications (the searches for diabetes tablets names, type 2 diabetes pills and sugar pills for diabetics all mean these) are metformin, sulfonylureas, DPP-4 inhibitors, SGLT2 inhibitors, pioglitazone, the meglitinides, the alpha-glucosidase inhibitors and one oral GLP-1 receptor agonist, semaglutide tablets (Rybelsus). Many are sold as two-drug combination tablets, for example empagliflozin with metformin. The guide to glucose pills goes through the tablets one by one, and Jardiance for type 2 diabetes covers the best-known SGLT2 inhibitor in detail.

Injectable diabetes medicines are the GLP-1 receptor agonists, tirzepatide, insulin and pramlintide. GLP-1 drugs and tirzepatide are mostly once-weekly pens; the ADA prefers them to insulin when a person needs the stronger effect of an injectable, and recommends combining them with insulin when insulin is used ^[1]. The tirzepatide label tells prescribers to consider lowering the dose of a sulfonylurea or insulin when tirzepatide is started, because the combination raises the risk of hypoglycemia ^[4]. The type 2 diabetes treatments guide sets out when injections enter the sequence, and metformin vs insulin compares the oldest tablet with the oldest injection.

Over-the-counter diabetes medication does not exist in the sense people search for: every class in the table needs a prescription in the United States. Supplements sold for blood sugar are not approved to treat diabetes. Generic diabetes medications exist for the older classes, including metformin, glipizide, glimepiride, glyburide, pioglitazone and human insulin, which is one reason cost weighs on the choice.

The 2026 Standards frame the choice as shared decision-making between the person and their clinician, built around a few questions ^[1]:

• Heart disease or high cardiovascular risk: a GLP-1 receptor agonist or SGLT2 inhibitor with proven cardiovascular benefit, whatever the A1C ^[1].
• Heart failure: an SGLT2 inhibitor. New in 2026, semaglutide injection and tirzepatide are listed for people with obesity and heart failure with preserved ejection fraction ^[1].
• Chronic kidney disease: an SGLT2 inhibitor, with a GLP-1 receptor agonist now also an option ^[1].
• Weight: GLP-1 receptor agonists and dual GIP/GLP-1 agonists are the preferred agents when weight management is a goal ^[1].
• Hypoglycemia risk: sulfonylureas and insulin carry it; the other classes do not on their own.
• Cost and access: metformin, sulfonylureas and pioglitazone are generic and inexpensive; the newer classes are not.

Metformin remains the usual first tablet when none of those conditions applies, because it is effective, does not cause hypoglycemia and costs little ^[1]. The trial evidence fits that order: across 453 trials, specific GLP-1 receptor agonists and SGLT2 inhibitors reduced death and heart or kidney events only in people at increased cardiovascular risk, and SGLT2 inhibitors reduced heart failure hospitalisation and end-stage kidney disease ^[2]. So the best medicine for a diabetic patient depends on which of these conditions they have, which is why two people with the same A1C can end up on different drugs.

For the full sequence, from lifestyle to a second and third medicine, see type 2 diabetes treatments, step by step.

Low blood sugar is the side effect that most separates the classes: only insulin, sulfonylureas, meglitinides and pramlintide with insulin lower glucose regardless of how high it is. The hypoglycemic drugs guide lists which drugs cause lows and, the other way round, which common medicines raise blood sugar.

Pramlintide, approved in 2005, is the only amylin analogue on the market. It is injected before meals by people who already use mealtime insulin ^[3], which keeps it a niche drug. Cagrilintide is a long-acting amylin analogue given once a week, and its main use in trials is in a single injection with semaglutide called CagriSema. The how cagrilintide works guide covers the mechanism, and amylin analogs compares the class.

Two things follow from the table. The combination lowers A1C about as much as the strongest classes above, but against semaglutide alone the extra A1C effect was small; the larger difference was in body weight. The cagrilintide vs semaglutide comparison shows the arms side by side.

CagriSema is not approved for diabetes or anything else. Novo Nordisk filed it with the FDA in December 2025 for weight management in adults with obesity or overweight, not for diabetes ^[12]. If it is approved, it would sit in the injectable group of the table, next to the GLP-1 receptor agonists. The new weight-loss drugs guide follows that filing.

The newest approval in this space is orforglipron (Foundayo), a non-peptide GLP-1 pill that the FDA approved on April 1, 2026 for adults with obesity or overweight with weight-related problems ^[13]. That approval is for weight, not type 2 diabetes; diabetes trials have reported, and the new diabetes medications guide tracks where that filing stands, along with the other drugs in late trials.

Two related questions have their own guides. Prediabetes medication covers what is used before diabetes is diagnosed, and type 2 diabetes remission explains what the evidence shows about bringing A1C below the diabetes range without medicines, which is the term the research uses rather than cure.