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Is Ozempic better than metformin?

Medically reviewed by Kristianne Hannemann, PharmD. Last updated on March 6, 2025.

Official answer

by Drugs.com

Key Points

  • Ozempic (semaglutide) and metformin are both used to treat type 2 diabetes, but they have not been directly compared in clinical trials.
  • Both medications lower hemoglobin A1C levels by a similar percentage in separate studies.
  • The choice between Ozempic and metformin depends on factors such as administration method, side effects, and cost.
  • Ozempic is brand-name only, while metformin is available in generic versions, making it more affordable.

How do metformin and Ozempic work?

Ozempic (semaglutide) and metformin both help manage blood sugar levels but work in different ways:

Metformin

Metformin is a biguanide that is taken by mouth up to a few times daily. It works in different ways to manage blood glucose levels:

  • Reduces glucose production in the liver
  • Improves insulin sensitivity
  • Slows down absorption of glucose from the intestines

Ozempic

Ozempic is glucagon-like peptide 1 (GLP-1) receptor agonist that is injected under the skin once a week. It works by:

  • Stimulating insulin release to lower blood sugar
  • Slowing digestion, increasing fullness and reducing appetite

How Effective Are Metformin and Ozempic?

Though no direct comparison studies exist, separate trials show both medications effectively lower hemoglobin A1C (HbA1c) levels:

  • Ozempic lowered HbA1c by 1.4-1.6% over 30 weeks (study of 388 patients).
  • Metformin lowered HbA1c by 1.4% over 29 weeks (study of 286 patients).

Individual responses vary based on dose, lifestyle, and concurrent medications.

Metformin vs. Ozempic for Weight Loss

Neither Ozempic nor metformin are FDA-approved for weight loss, but both have been associated with modest weight reduction.

Metformin and Weight Loss

Experts classify metformin as a weight-neutral treatment option for patients with type 2 diabetes. It has the potential to cause a small amount of weight loss in some patients.

  • Patients lost 0.6 kg (1.4 lbs) in a 29-week clinical trial.
  • Another study showed a 2.9 kg (6.4 lbs) loss over five years.

Ozempic and Weight Loss

Because Ozempic slows down how fast food moves through your digestive tract, it can decrease your appetite and result in lower calorie consumption. This can lead to weight loss in some patients.

In a 30-week study:

  • Ozempic 0.5 mg users lost 3.8 kg (8.3 lbs).
  • Ozempic 1 mg users lost 4.7 kg (10.3 lbs).
  • Placebo users lost 1.2 kg (2.6 lbs).

Related questions

Can You Take Metformin and Ozempic Together?

Yes. Studies show no interaction between the two medications. Since they work differently, they are often prescribed together for better blood sugar control.

During clinical studies submitted to the FDA for approval, some patients with type 2 diabetes took both Ozempic and metformin. If your blood sugar is not well controlled with one medication alone, your healthcare provider may recommend adding on another medication.

Side Effects of Metformin and Ozempic

Both medications commonly cause gastrointestinal side effects. Additionally, metformin can raise the risk for lactic acidosis. Some patients have reported pancreatitis while taking Ozempic.

Common Side Effects of Metformin (>5%)

  • Diarrhea
  • Nausea/vomiting
  • Excessive gas
  • Feeling weak
  • Indigestion
  • Stomach discomfort
  • Headache

Common Side Effects of Ozempic (≥5%)

  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach pain
  • Constipation

Serious Risks

  • Metformin: Risk of lactic acidosis (rare but serious condition).
  • Ozempic: Reports of pancreatitis and ileus in some users.

Key Takeaways

Ozempic and metformin are both effective for type 2 diabetes, but they work differently. Metformin is usually the first-line treatment due to its long-standing safety profile and affordability, while Ozempic may be considered when additional blood sugar or weight management is needed.

This is not all the information you need to know about metformin and Ozempic for safe and effective use and does not take the place of talking to your doctor about your treatment. Review the full product information here, and discuss this information and any questions you have with your doctor or other health care provider.

References

Hausner, H., et. al. (2017). Effect of Semaglutide on the Pharmacokinetics of Metformin, Warfarin, Atorvastatin and Digoxin in Healthy Subjects. In: Clinical Pharmacokinetics. DOI: https://doi.org/10.1007%2Fs40262-017-0532-6

Kahn, S. E., et. al. (2006). Glycemic Durability of Rosiglitazone, Metformin, or Glyburide Monotherapy. In: The New England Journal of Medicine. DOI: https://doi.org/10.1056/nejmoa066224

Metformin [package insert]. (Updated 01/2023). ScieGen Pharmaceuticals Inc. Accessed 07/04/2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4e4c4ba9-65c6-4273-8f6b-2423ab521dad

Ozempic [package insert]. (Updated 09/2023). Novo Nordisk. Accessed 07/04/2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=adec4fd2-6858-4c99-91d4-531f5f2a2d79

Van Gaal, L., et. al. (2015). Weight Management in Type 2 Diabetes: Current and Emerging Approaches to Treatment. In: Diabetes Care. DOI: https://doi.org/10.2337/dc14-1630

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How long does it take for Ozempic to work?

Your blood glucose (sugar) levels should start to fully decline within the first week after you start using Ozempic (semaglutide) at your regular dose. However, the full effect can take 8 weeks or longer, as this is a long-acting medication that is injected only once per week. Continue reading

What are the long-term side effects of Ozempic?

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