Compare metformin vs. Humalog

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

Glucophage
(metformin)

Humalog
(insulin lispro)

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. Humalog is a fast-acting insulin that provides meal-time 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.
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 Humalog
64%
+1% better vs. metformin
50%
-4% worse vs. metformin
16%
Same vs. metformin
280 reviews
Have you used Humalog (insulin lispro)?
Worth itNot sureNot worth it
Side effects
metforminHumalog
  • Diarrhea 41%
  • Nausea/vomiting 18%
  • Gas 6%
  • Weakness 3%
  • Indigestion 3%
  • Stomach pain 1%
  • Headache 1%
More metformin side effects »
  • Flu syndrome 35%
  • Pharyngitis 33%
  • Headache 30%
  • Rhinitis 25%
  • Pain 20%
  • Cough increased 17%
  • Infection 14%
  • Accidental injury 9%
  • Diarrhea 9%
  • Asthenia 7%
More Humalog side effects »
How it works
metforminHumalog
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.Humalog is a short-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 after meals.
Type of medication
metforminHumalog
Prescription onlyPrescription only
Available as
metforminHumalog
  • Pill
  • Extended release pill
  • Liquid
  • Injection
Used for
metforminHumalog
Risk factors for serious side effects
metforminHumalog
  • 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 Humalog (insulin lispro) 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
metforminHumalog
  • 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
metforminHumalog
  • Always take it with food to lessen stomach upset.
  • Short-acting insulin good for blood sugar control around meal times.
Kidneys and liver
metforminHumalog
  • 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
metforminHumalog
  • 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
metforminHumalog
  • 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.
  • Humalog is a fast-acting insulin that provides sugar control after meals.
  • 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
metforminHumalog
  • 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 multiple times every day, usually before each meal.
  • 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
metforminHumalog
  • 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.
  • Short-acting insulin good for blood sugar control around meal times.
  • Take 5 to 10 minutes before a meal. Effects last for 2-4 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.
  • Make sure you understand how to give yourself the injections.
  • When mixing with another insulin (such as insulin NPH), draw this insulin into the syringe first.
  • Don't shake the vial. 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 HumalogSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Humalog (insulin lispro)?
Worth itNot sureNot worth it