Compare metformin vs. Januvia

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Glucophage
(metformin)

Januvia
(sitagliptin)

Lowers blood sugar. Glucophage (metformin) is the first choice medicine to control your blood sugar and lower the risk of death from diabetes, although a few people may not tolerate the stomach side effects.Lowers your blood sugar. Januvia (sitagliptin) is a good add-on treatment if your blood sugars are not controlled and you don't want to use an injectable medicine.
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.01metformin
Reviews for metformin
65%
of people (All ages) say metformin is worth it
46%
say it works well
16%
say it's a big hassle
938 reviews
Have you used Glucophage (metformin)?
Worth itNot sureNot worth it
Reviews for Januvia
44%
+21% better vs. metformin
34%
+12% better vs. metformin
17%
+1% better vs. metformin
143 reviews
Have you used Januvia (sitagliptin)?
Worth itNot sureNot worth it
Side effects
metforminJanuvia
  • Diarrhea 41%
  • Nausea/vomiting 18%
  • Gas 6%
  • Weakness 3%
  • Indigestion 3%
  • Stomach pain 1%
  • Headache 1%
More metformin side effects »
  • Common cold 2%
  • Diarrhea 1%
  • Upper respiratory infection 3%
  • Headache 1%
More Januvia side effects »
How it works
metforminJanuvia
Glucophage (metformin) is an anti-diabetic drug. It lowers the amount of sugar your body makes or absorbs, and allows your body use the existing insulin better.Januvia (sitagliptin) is an anti-diabetic drug that enhances your body's release of insulin.
Type of medication
metforminJanuvia
Prescription onlyPrescription only
Available as
metforminJanuvia
  • Pill
  • Extended release pill
  • Liquid
  • Pill
Used for
metforminJanuvia
Risk factors for serious side effects
metforminJanuvia
  • Kidney problems
  • Liver problems
  • Congestive heart failure
  • Using contrast dye for procedures
  • Surgery
Detailed Glucophage (metformin) risks & warnings »
  • History of pancreatitis
  • High blood triglyceride levels
  • Gallstones (stones in gallbladder)
  • History of alchoholism
  • Kidney problems
Detailed Januvia (sitagliptin) risks & warnings »
Pregnancy

Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

Alcohol
metforminJanuvia
  • Limit or avoid alcohol when taking this medicine.
  • Excessive or chronic alcohol use can increase the risk of a dangerous side effect.
No alcohol related info.
Food
metforminJanuvia
  • Always take it with food to lessen stomach upset.
  • Take once a day in the morning with or without food.
Kidneys and liver
metforminJanuvia
  • Glucophage (metformin) can cause this rare life-threatening condition. Your doctor will check your kidneys and liver before you start. Symptoms include deep and rapid breathing, nausea, vomiting, and stomach pain. This is a medical emergency and you should get help right away. You're more likely to get this if you already have kidney problems. Glucophage (metformin) should be stopped 48 hours before and after surgery or any imaging procedure needing contrast dye.
  • Usually not a good choice for people with kidney problems. Your doctor will tell you if Glucophage (metformin) is right for you to take.
  • Januvia (sitagliptin) can worsen kidney problems. Your doctor may check your kidney function before and during treatment. Your doctor may have to adjust the dose or stop this medicine based on changes in kidney function.
Pain
metforminJanuvia
No pain related info.
  • Tell your doctor right away if you have severe stomach pain, nausea, and/or vomiting. These are symptoms of pancreatitis.
Weight
metforminJanuvia
  • Doesn't cause weight gain.
  • It is less likely to cause weight gain and low blood sugar compared to other diabetes medicines.
Upsides and benefits
metforminJanuvia
  • Improves sugar control and lowers A1c levels as much as 2%.
  • One of the few diabetes medicines that lowers the risk of death from diabetes-related complications.
  • Doesn't cause weight gain.
  • Rarely causes low blood sugar.
  • Oral blood sugar-lowering medicine.
  • Januvia (sitagliptin) is not linked to worsening heart failure like other medicines in its class.
  • Uses the hormones naturally produced by your body to affect how sugar is processed.
  • It is less likely to cause weight gain and low blood sugar compared to other diabetes medicines.
Downsides and risks
metforminJanuvia
  • Often causes stomach upset, like diarrhea, nausea, gas, or stomach cramping.
  • Usually not a good choice for people with kidney problems. Your doctor will tell you if Glucophage (metformin) is right for you to take.
  • Excessive or chronic alcohol use can increase the risk of a dangerous side effect.
  • Lowers A1c (average blood sugar over time) by less than 1%.
  • Available as brand version only.
  • Some people might get frequent cold-like symptoms.
  • Rare but serious side effects include pancreatitis and severe joint pain.
Tips from our pharmacists for people taking the medication
metforminJanuvia
  • Can cause upset stomach with nausea and especially diarrhea in the first couple of weeks.
  • Always take it with food to lessen stomach upset.
  • Stay hydrated.
  • Limit or avoid alcohol when taking this medicine.
  • Tell your doctor about any deep or rapid breathing, or persistent nausea, vomiting, and stomach pain.
  • Check your blood sugar regularly.
  • Take once a day in the morning with or without food.
  • Can cause headache and cold-like symptoms.
  • Tell your doctor right away if you have severe stomach pain, nausea, and/or vomiting. These are symptoms of pancreatitis.
  • Tell your doctor right away if you are experiencing severe joint pain.
  • Check your blood sugar regularly to check for low blood sugar.
Learn more
More about metforminSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Glucophage (metformin)?
Worth itNot sureNot worth it
More about JanuviaSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Januvia (sitagliptin)?
Worth itNot sureNot worth it