Should I Use Diabetes Pills or Insulin?

Medically reviewed by Alan Carter, PharmD on May 27, 2016Written by Ann Pietrangelo on May 27, 2016

Treating diabetes

Diabetes affects the way your body breaks down food. Treatment depends on which type of diabetes you have.

In type 1 diabetes, your pancreas stops producing insulin. Insulin is a hormone that helps regulate glucose, or sugar, in your blood. Type 2 diabetes starts with insulin resistance. Your pancreas no longer produces enough insulin or doesn’t use it efficiently.

Every cell in your body uses glucose for energy. If insulin isn’t doing its job, glucose builds up in your blood. This causes a condition called hyperglycemia. Low blood glucose is called hypoglycemia. Both can lead to serious complications.

What pills are available to treat diabetes?

A variety of pills are available to treat diabetes, but they can’t help everyone. They only work if your pancreas still produces some insulin. They can’t treat type 1 diabetes. They aren’t effective in people with type 2 diabetes when the pancreas has stopped making insulin.

Some people with type 2 diabetes can benefit from using both pills and insulin. Some pills to treat diabetes include:


Metformin (Glucophage, Fortamet, Riomet, Glumetza) is a biguanide. It lowers the amount of glucose in your liver and boosts insulin sensitivity. It may also improve cholesterol levels and might help you lose a little weight. People normally take it twice per day with meals. You can take the extended-release version once per day.

Potential side effects include:

  • upset stomach
  • nausea
  • bloating
  • gas
  • diarrhea
  • a temporary loss of appetite

It may also cause lactic acidosis in people with kidney failure, but this is rare.


Sulfonylureas are fast-acting medications that help the pancreas release insulin after meals. They include:

People usually take these medications once per day with a meal.

Potential side effects include:

  • irritability
  • low blood glucose
  • upset stomach
  • skin rash
  • weight gain


Repaglinide (Prandin) is a meglitinide. Meglitinides quickly stimulate the pancreas to release insulin after eating. You should always take repaglinide with a meal.

Potential side effects include:

  • low blood glucose
  • nausea
  • vomiting
  • a headache
  • weight gain

D-phenylalanine derivatives

Nateglinide (Starlix) is a D-phenylalanine derivative. People take it with meals. It helps the pancreas release insulin after you eat.

Low blood glucose is a potential side effect.


Rosiglitazone (Avandia) and pioglitazone (Actos) are thiazolidinediones. Taken at the same time each day, they make your body more sensitive to insulin. It may also increase your HDL cholesterol.

Potential side effects include:

  • fluid retention
  • swelling
  • fractures

These drugs also increase your risk of heart attack or heart failure, especially if you’re already at risk.

Dipeptidyl-peptidase 4 (DPP-4) inhibitors

DPP-4 inhibitors include:

They help stabilize insulin levels and lower how much glucose your body makes. People take them once per day.

Potential side effects include:

  • a sore throat
  • a stuffy nose
  • a headache
  • an upper respiratory tract infection
  • an upset stomach
  • diarrhea

Alpha-glucosidase inhibitors

Acarbose (Precose) and miglitol (Glyset) are alpha-glucosidase inhibitors. They slow the breakdown of carbohydrates into the bloodstream. People take them at the beginning of a meal.

Potential side effects include:

  • upset stomach
  • gas
  • diarrhea
  • abdominal pain

Bile acid sequestrants

Colesevelam (Welchol) is a bile acid sequestrant. It lowers blood glucose and cholesterol levels. People use it with other diabetes medications.

Potential side effects include:

  • a headache
  • nausea
  • gas
  • heartburn
  • diarrhea
  • constipation

This drug may also interact with birth control pills.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors

SGLT2 inhibitors include:

They work by stopping the kidneys from reabsorbing glucose. They may also help lower blood pressure and help you lose weight.

Potential side effects may include urinary tract or yeast infections.

Some of these medications are combined into a single pill.

Read more: Diabetes: New drug treatment options »

How is insulin used to treat diabetes?

You need insulin to live. If you have type 1 diabetes, you’ll need to take insulin every day. You’ll also need to take it if you have type 2 diabetes and your body doesn’t produce enough on its own.

Fast- or long-acting insulin is available. It’s likely you’ll need both types to keep your blood glucose under control.

You can take insulin several ways:

  • You can take injections using a standard needle and syringe by loading the insulin into the syringe. Then, you inject it just under your skin, rotating the site each time.
  • Insulin pens are a bit more convenient than a regular needle. They’re prefilled and less painful to use than a regular needle.
  • The insulin jet injector looks like a pen. It sends a spray of insulin into your skin using high-pressure air instead of a needle.

Insulin infuser or port

An insulin infuser or port is a small tube that you insert just under your skin and hold in place with adhesive or dressing, where it can remain for a few days. It’s a good alternative if you want to avoid needles. You inject insulin into the tube instead of directly into your skin.

Insulin pump

An insulin pump is a small, lightweight device that you wear on your belt or carry in your pocket. The insulin in the vial enters your body through a tiny needle just under your skin. You can program it to deliver an insulin surge or a steady dose throughout the day.

Diabetes pills vs. insulin

It’s usually not a case of either pills or insulin. Your doctor will make a recommendation based on the type of diabetes you have, how long you’ve had it, and how much insulin you’re making naturally.

Pills may be easier to take than insulin, but each kind comes with potential side effects. It may take a little trial and error to find the one that works best for you. Pills can stop working even if they’ve been effective for some time.

If you start out with only pills and your type 2 diabetes worsens, you may need to use insulin as well.

Insulin also has risks. Too much or too little can cause serious problems. You’ll have to learn how to monitor your diabetes and make adjustments as necessary.


  • Pills can be easier to take than insulin.


  • You may experience side effects when taking diabetes pills.

Questions to ask your doctor

If you have type 1 diabetes or if you must take insulin, you already know you’ll have to monitor your blood glucose levels carefully and adjust your insulin accordingly. Ask your doctor about the various methods of delivering insulin and be sure to report lumps, bumps, and rashes on your skin to your doctor.

If your doctor is prescribing a pill, here are a few questions you might want to ask:

  • What is the purpose of this medication?
  • How should I store it?
  • How should I take it?
  • What are the potential side effects and what can be done about them?
  • How often should I check my glucose levels?
  • How will I know if the medication is working?

These medications are intended to be part of an overall treatment plan that includes exercise and careful dietary choices.

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