Compare metformin vs. Lantus

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

Glucophage
(metformin)

Lantus
(insulin glargine)

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 blood sugar. Lantus (Insulin Glargine) is a long-acting insulin that provides all-day sugar control. It can cause low blood sugar, so make sure you know what the symptoms are and always have a source of sugar nearby.
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Coupons for metformin
Best available price for 60 (500mg) tablets of metformin
Coupons for Lantus
Best available price for 15 (5 solostar pens of 3ml) cartons of lantus
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 Lantus
67%
-2% worse vs. metformin
51%
-5% worse vs. metformin
14%
-2% worse vs. metformin
584 reviews
Have you used Lantus (insulin glargine)?
Worth itNot sureNot worth it
Side effects
metforminLantus
  • Diarrhea 41%
  • Nausea/vomiting 18%
  • Gas 6%
  • Weakness 3%
  • Indigestion 3%
  • Stomach pain 1%
  • Headache 1%
More metformin side effects »
  • Ear, nose, or throat infection 22%
  • Infection 9%
  • Accidental injury 6%
  • Headache 6%
  • Ankle and leg swelling 20%
  • High blood pressure 20%
  • Sinus inflammation 19%
  • Flu 19%
  • Clouded eye lens 18%
  • Bronchitis 15%
More Lantus side effects »
How it works
metforminLantus
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.Lantus (Insulin Glargine) is a long-acting insulin medicine for diabetes. It acts like the insulin that your body normally makes to process sugars and fats, and it keeps your blood sugar stable throughout the day.
Type of medication
metforminLantus
Prescription onlyPrescription only
Available as
metforminLantus
  • Pill
  • Extended release pill
  • Liquid
  • Injection
Used for
metforminLantus
Risk factors for serious side effects
metforminLantus
  • Kidney problems
  • Liver problems
  • Congestive heart failure
  • Using contrast dye for procedures
  • Surgery
Detailed Glucophage (metformin) risks & warnings »
  • Insulin dose too high
  • Use of other blood sugar lowering medicines
  • Poor injection techniques
  • Unstable kidney functions
  • Unstable liver functions
Detailed Lantus (insulin glargine) 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 found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

Alcohol
metforminLantus
  • 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
metforminLantus
  • Always take it with food to lessen stomach upset.
No food related info.
Kidneys and liver
metforminLantus
  • 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.
  • Okay to use even if you have liver or kidney problems, unlike most other blood sugar-lowering medicines.
Weight
metforminLantus
  • Doesn't cause weight gain.
  • Can cause weight gain and low blood sugar.
  • Likely to cause moderate weight gain (around 4 to 6 pounds).
Upsides and benefits
metforminLantus
  • 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.
  • Insulin is the most effective blood sugar-lowering medicine. When used correctly, it'll lower blood sugar every time you use it and prevent the harmful effects of high sugar levels on your organs and blood vessels.
  • Lantus is a long-lasting insulin that provides consistent, all-day sugar control with less risk of low blood sugar.
  • Dose can be easily adjusted to make a customized regimen that's tailored to your body.
  • Starting insulin early in the treatment of Type 2 diabetes can maintain your body's insulin-producing cells and slow down disease progression.
  • Okay to use even if you have liver or kidney problems, unlike most other blood sugar-lowering medicines.
Downsides and risks
metforminLantus
  • 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.
  • You have to take insulin by injection.
  • You have to check your blood sugar every day.
  • Likely to cause moderate weight gain (around 4 to 6 pounds).
  • Higher risk of low blood sugar episodes than other kinds of diabetes medicines.
Tips from our pharmacists for people taking the medication
metforminLantus
  • 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.
  • Long-acting insulin good for baseline blood sugar control.
  • Works in 1 hour and lasts about 24 hours.
  • Can cause weight gain and low blood sugar.
  • Make sure you and your family know the symptoms of low blood sugar: sweating, shakiness, weakness, fast heartbeat, nervousness, headache, blurry vision, trouble thinking clearly, or passing out.
  • Always have a good source of sugar nearby for low blood sugar episodes.
  • Take it at the same time every day.
  • Make sure you understand how to give yourself the injections.
  • Don't shake the vial or mix with another insulin. Store unopened vials in the refrigerator. Opened vials are good at room temperature for 28 days.
  • Check your blood sugar levels every day.
Learn more
More about metforminSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Glucophage (metformin)?
Worth itNot sureNot worth it
More about LantusSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Lantus (insulin glargine)?
Worth itNot sureNot worth it