Compare Lantus vs. metformin

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

Lantus (insulin glargine)

Prescription only

Glucophage (metformin)

Prescription only
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
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
Upsides
  • 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.
  • 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.
Downsides
  • 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.
  • 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.
Used for
Dosage forms
  • Injection
  • Pill
  • Extended release pill
  • Liquid
Price
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Reviews
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
938 reviews so far
65%
saidit'sworth it
46%
saiditworked well
16%
saidit'sa big hassle

Have you used Glucophage (metformin)?

Leave a review
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
7possible side effects
  • Diarrhea
    53%
  • Nausea/vomiting
    26%
  • Gas
    12%
  • Weakness
    9%
  • Indigestion
    7%
  • Stomach pain
    6%
  • Headache
    6%
See more detailed side effects
Risks and risk factors
  • 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
  • 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