Diabetes Medications Compared: HbA1c Reduction, Cost & Side Effects Chart

Diabetes Medications · 5 · March 7, 2026

There are six major classes of Type 2 diabetes drugs. Your doctor will probably try them in a specific order. But most patients do not know why one is chosen over another, or what the alternatives are when the first choice does not work. Here is the comparison your endocrinologist would draw on a whiteboard if they had 30 minutes instead of 15.

The Ranking

Metformin: 1.0–1.5% HbA1c reduction. $4/month. GI side effects in 25%. No hypoglycemia risk. Heart attack reduction: 39%. First-line for everybody.

GLP-1 agonists (semaglutide/tirzepatide): 1.5–2.4% HbA1c reduction. $935–1,023/month. Nausea in 15–44%. Weight loss 12–15% body weight. Cardiovascular protection proven. Second-line for patients who need weight loss or have heart disease.

SGLT2 inhibitors (empagliflozin/dapagliflozin): 0.5–1.0% HbA1c reduction. $500/month. UTI and genital yeast infections. Heart failure reduction: 35%. Kidney protection: 32% reduction in kidney failure. Second-line for patients with heart failure or kidney disease.

DPP-4 inhibitors (sitagliptin/linagliptin): 0.5–0.8% HbA1c reduction. $350/month. Minimal side effects. Weight neutral. No cardiovascular benefit proven. Less exciting but well tolerated.

Sulfonylureas (glimepiride/glipizide): 1.0–1.5% HbA1c reduction. $10/month. Hypoglycemia risk. Weight gain 2–4 kg. No cardiovascular benefit. Cheap and effective but falling out of favour because they accelerate beta cell burnout.

Insulin: No ceiling on HbA1c reduction (dose-dependent). $100–700/month depending on type. Hypoglycemia risk. Weight gain 4–8 kg in first year. Required when beta cells cannot produce enough insulin regardless of other drugs.

The Decision Framework

Start with metformin (unless contraindicated). If HbA1c is still above target after 3 months, add a second drug based on your priorities: weight loss → GLP-1. Heart failure or kidney disease → SGLT2. Cost sensitivity → sulfonylurea. HbA1c above 10% → insulin.

Track every medication — dose, timing, side effects, adherence — at Medication Tracker. The platform shows allopathic and traditional medications side by side, flags potential interactions, and calculates adherence by time of day.