Compare metformin vs. Lantus

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

ADVERTISEMENT

Glucophage (metformin)

Prescription only

Lantus (insulin glargine)

Prescription only
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.

3.7/ 5 average rating with 938 reviewsformetformin
Lowers blood sugar.

Lantus (insulin glargine) is an effective, long-acting insulin that provides all-day blood sugar control, but it can cause low blood sugar levels, so be sure to have a source of sugar nearby.

3.7/ 5 average rating with 584 reviewsforLantus
Upsides
  • 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 one of the most effective blood sugar-lowering medication and can lower your A1c (average blood sugar over time) by up to 2-3%.
  • Lantus (insulin glargine) is a long-lasting insulin that provides consistent, all-day sugar control with just once or twice daily dosing.
  • Dose can be easily adjusted to make a customized regimen that's tailored to your body's needs.
  • Lantus (insulin glargine) can be used with liver or kidney problems.
Downsides
  • 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 regularly to assure your medications are working.
  • You may gain some weight, around 4-6 pounds.
  • You have to maintain a consistent schedule to avoid low blood sugar episodes. Dramatic changes in weight or meal patterns will require dose adjustments.
ADVERTISEMENT
Used for
Dosage forms
  • Pill
  • Extended release pill
  • Liquid
  • Injection
Price
Want to save even more money?
Sign up now for a 30-day trial and save up to 95% at CVS, Kroger, Albertsons, and other pharmacies.
Learn more
Reviews
938 reviews so far
65%
saidit'sworth it
46%
saiditworked well
16%
saidit'sa big hassle

Have you used Glucophage (metformin)?

Leave a review
584 reviews so far
67%
saidit'sworth it
51%
saiditworked well
14%
saidit'sa big hassle

Have you used Lantus (insulin glargine)?

Leave a review
Side effects
7possible side effects
  • Diarrhea
    53%
  • Nausea/vomiting
    26%
  • Gas
    12%
  • Weakness
    9%
  • Indigestion
    7%
  • Stomach pain
    6%
  • Headache
    6%
See more detailed side effects
19possible side effects
  • Upper respiratory tract infection
    28%
  • Swelling in the limbs
    20%
  • High blood pressure
    20%
  • Flu
    19%
  • Sinus infection
    19%
  • Cataracts
    18%
  • Inflammation of the airways
    15%
  • Joint pain
    14%
  • Pain in extremity
    13%
  • Back pain
    13%
  • Cough
    12%
  • Urinary tract infection
    11%
  • Diarrhea
    11%
  • Depression
    11%
  • Infection
    10%
  • Headache
    10%
  • Blood vessel disease
    7%
  • Retinal vein disorder
    6%
  • Injection site pain
    3%
See more detailed side effects
Risks and risk factors
  • Excess lactic acid in the blood
    • Kidney problems
    • Liver problems
    • Congestive heart failure
    • Using contrast dye for procedures
    • Surgery
    • Alcohol use
  • Low vitamin B12 levels
See more detailed risks and warnings
  • Life-threatening low blood sugar (Hypoglycemia)
    • Insulin dose too high
    • Use of other blood sugar lowering medicines
    • Poor injection techniques
  • Complications due to low potassium
    • Use of other medicine that lower potassium
    • Current electrolyte imbalance
  • Severe allergic reactions
    • Allergy to insulin
See more detailed risks and warnings