Glipizide vs metformin for type 2 diabetes: compared
Metformin is the usual first medicine for type 2 diabetes; glipizide, a sulfonylurea, is often added when metformin alone is not enough. Metformin does not cause low blood sugar on its own and does not cause weight gain; glipizide works quickly but can cause both.
Updated October 4, 2026
At a glance
- How it works
- Glipizide
- Makes the pancreas release more insulin
- Metformin
- Reduces sugar made by the liver and improves insulin response
- Low blood sugar
- Glipizide
- Can cause it
- Metformin
- Not on its own
- Weight
- Glipizide
- Can increase
- Metformin
- Neutral or slight loss
- Common side effects
- Glipizide
- Low blood sugar
- Metformin
- Stomach upset and diarrhea, especially at first
- Generic
- Glipizide
- Yes, inexpensive
- Metformin
- Yes, inexpensive
Glipizide Glucotrol, a sulfonylurea | Metformin Glucophage | |
|---|---|---|
| How it works | Makes the pancreas release more insulin | Reduces sugar made by the liver and improves insulin response |
| Low blood sugar | Can cause it | Not on its own |
| Weight | Can increase | Neutral or slight loss |
| Common side effects | Low blood sugar | Stomach upset and diarrhea, especially at first |
| Generic | Yes, inexpensive | Yes, inexpensive |
Why metformin usually comes first
Metformin lowers blood sugar effectively, does not cause hypoglycemia by itself, and has decades of safety data. Its stomach side effects ease with time and are reduced by starting low, taking it with meals, or using the extended-release form. It is not used when kidney function is very low, and long-term use can lower vitamin B12.
Where glipizide fits
Glipizide lowers blood sugar quickly and costs little, so it is a common second medicine. Its main risk is low blood sugar, especially if meals are skipped, with alcohol, or in older adults, so it is taken with or before breakfast and skipped on days you will not eat. Keep fast-acting sugar with you and learn the warning signs.
Newer options
For people with heart disease, heart failure or chronic kidney disease, guidelines often recommend adding a GLP-1 medicine or an SGLT2 inhibitor rather than a sulfonylurea, because those also protect the heart and kidneys and do not cause low blood sugar on their own. Cost and coverage often shape the choice.
Taking them together
Metformin and glipizide are often combined, and combination tablets exist. When a sulfonylurea is added, home blood sugar checks help catch lows early.
Cost
Both are among the least expensive diabetes medicines, and 90-day supplies usually cost less per day.
Questions for your prescriber
- Is metformin alone enough, or do I need a second medicine?
- Would a GLP-1 or SGLT2 medicine protect my heart or kidneys?
- How should I handle a missed meal on glipizide?
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Sources
Written by the Script Unlock editorial team from the sources above. It is general information, not advice for you or your pet; your prescriber decides which medicine is right.
Script Unlock is a marketplace that lets licensed pharmacies quote a cash price on your prescription. It does not prescribe, dispense or sell medication, does not process patient payments, and does not give medical advice. Always follow the instructions of your prescriber and pharmacist and read the medication guide supplied with your medicine.