For individuals managing diabetes or seeking weight loss solutions, Wegovy and metformin emerge as potential options. Both prescription medications have demonstrated benefits in regulating blood sugar levels and reducing body weight. While they offer similar advantages, their active ingredients and mechanisms of action differ significantly. This article provides a detailed comparison of Wegovy and metformin to help you make an informed decision.
What are Wegovy and Metformin?
Wegovy is a brand-name drug containing the active ingredient semaglutide, while metformin is a generic drug known by brand names such as Glucophage, Fortamet, and Riomet. Wegovy, manufactured by Novo Nordisk, received FDA approval in 2021 and is classified as a glucagon-like peptide-1 (GLP-1) receptor agonist. Metformin belongs to the biguanide drug class.
How Do They Work?
Metformin: This oral medication is commonly prescribed to manage blood sugar levels in individuals with type 2 diabetes. It decreases glucose production in the liver, improves the body's sensitivity to insulin, and reduces the amount of sugar absorbed by the intestines. Metformin is often used as a first-line treatment due to its efficacy, safety profile, and additional benefits, such as weight stabilization and a low risk of low blood sugar.
Wegovy: This injectable medication contains semaglutide, a GLP-1 receptor agonist that mimics the hormone glucagon-like peptide-1. It acts on the brain to reduce appetite and slows gastric emptying. In other words, it helps users feel fuller longer. It also improves insulin response and lowers blood sugar by stimulating insulin secretion and reducing glucagon levels. Wegovy is primarily prescribed for chronic weight management and cardiovascular risk reduction in people with obesity.
Approved Uses
Metformin: As an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus. Metformin is sometimes used off-label for managing symptoms of polycystic ovary syndrome (PCOS), such as insulin resistance and irregular menstrual cycles.
Read also: Sustainable weight loss using Wegovy
Wegovy: FDA-approved for weight management in adults and children with obesity. It is also approved for adults who are overweight with at least one weight-related health condition, such as high blood pressure, diabetes, or high cholesterol. The active ingredient in Wegovy is available under a different brand name, Ozempic, which is approved to treat Type 2 diabetes.
Dosage and Administration
Metformin: Typically taken orally once, twice, or three times daily. It comes in 500 mg, 850 mg, and 1,000 mg tablets. The typical dosage for regular immediate-release tablets is 500 milligrams (mg) twice daily or 850 mg once daily with meals.
Wegovy: Typically taken as an injection once weekly. It comes in single-patient-use pens that deliver 0.25 mg, 0.5 mg, 1 mg, or 2 mg per injection. Wegovy (semaglutide) dosage starts at 0.25 mg per week and increases over time. The starting dose is 0.25 mg injected under the skin once weekly for 4 weeks. It then gradually increases to a target dosage of 2.4 or 1.7 mg once weekly.
Weight Loss Effectiveness: Wegovy vs. Metformin
Both Wegovy and metformin can aid in weight loss, but they operate through distinct mechanisms. Wegovy targets hunger and digestion, while metformin focuses on sugar control and metabolism. They can be used individually or in combination, depending on your health needs.
Wegovy for Weight Loss: Wegovy mimics the GLP-1 hormone, reducing appetite, slowing down digestion, and promoting insulin release. Studies suggest it may also lower the risk of heart disease.
Read also: Weekly Wegovy Progress
Metformin for Weight Loss: Metformin lowers blood sugar by reducing liver glucose production and improving insulin use. It may also reduce appetite through gut-brain signals. While not FDA-approved for weight loss, it can be prescribed off-label for this purpose.
Clinical Trial Results
Wegovy demonstrates more significant weight loss compared to metformin.
Wegovy: In clinical trials, participants using Wegovy experienced a 15-17% reduction in body weight over 68 weeks. In a clinical trial called the STEP 2 trial, people with Type 2 diabetes and obesity lost an average of 9.6% of their body weight using semaglutide 2.4 mg, compared to just 3.4% with a placebo over 68 weeks. This treatment also helped improve blood pressure and cholesterol levels.
Metformin: Metformin typically yields more modest results, with studies showing an average weight loss of 2% to 5%, especially when combined with a healthy diet and regular exercise. Some studies have shown that metformin can support weight management, though the effects are generally more modest than Wegovy’s. In a study involving people with prediabetes, participants taking metformin lost an average of 4.6 pounds (2.1 kg) within three years. Over time, they maintained an average weight loss of 5.5 pounds (2.5 kg).
Common Side Effects
Both metformin and Wegovy can cause side effects, particularly gastrointestinal issues.
Read also: Duration of Wegovy Treatment
Metformin: The most common adverse reactions (>5%) are diarrhea, nausea/vomiting, flatulence, weakness, indigestion, abdominal discomfort, and headache. Taste disturbances, diarrhea, and other stomach-related side effects are common side effects.
Wegovy: The most common adverse reactions, reported in ≥5% of patients, are nausea, vomiting, diarrhea, abdominal pain, and constipation.
Warnings and Precautions
Before starting either medication, consult with your doctor, especially if you have pre-existing health conditions or are taking other medications.
Metformin: Not suitable for individuals with severe kidney or liver issues. It can cause vitamin B₁₂ deficiency over time. Alcohol increases the risk of lactic acidosis, especially if you're sick or dehydrated. Metformin carries the risk of lactic acidosis, a condition characterised by high levels of lactic acid in the blood. Symptoms of lactic acidosis can include weakness, fatigue, muscle pain, and stomach discomfort. Contraindications include severe renal impairment (eGFR below 30 mL/min/1.73 m2), hypersensitivity to metformin, and acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
Wegovy: Do not take Wegovy if you or a family member has a history of medullary thyroid cancer or MEN 2. It can slow digestion, affecting medications like birth control or HRT. Watch for signs of pancreatitis, kidney problems, or mood changes. Wegovy can cause inflammation of the pancreas, gallbladder problems, kidney injury, and may worsen diabetic eye disease. Contraindications include a personal or family history of medullary thyroid carcinoma or in patients with multiple endocrine neoplasia syndrome type 2 and serious hypersensitivity reaction to semaglutide or any of the excipients in Ozempic.
Drug Interactions
Metformin: Drug interactions include carbonic anhydrase inhibitors and drugs that reduce metformin clearance (such as ranolazine, vandetanib, dolutegravir, and cimetidine).
Wegovy: Ozempic delays gastric emptying and may impact the absorption of concomitantly administered oral medications.
Taking Wegovy or metformin with insulin or insulin secretagogues, such as sulfonylureas, may increase the risk of low blood sugar (hypoglycemia). When metformin is taken with carbonic anhydrase inhibitors, it can increase the risk of a dangerous condition called lactic acidosis.
Cost and Insurance Coverage
Wegovy: Can be expensive without insurance, costing around $1,200-$1,350/month at retail pharmacies. Coverage depends on your plan, and many patients find it challenging to qualify. Currently, no generic version of Wegovy is available. Some insurance plans may cover Wegovy if it’s prescribed to reduce heart disease-related risks in people who are overweight with heart disease or have obesity and heart disease.
Metformin: Is budget-friendly as it is a generic drug that is covered by most, if not all, commercial insurance and Medicare plans. Unlike Wegovy, metformin is a generic drug that is covered by most, if not all, commercial insurance and Medicare plans. Without insurance, the cost can vary.
Combined Use of Wegovy and Metformin
It’s generally safe to use Wegovy and Metformin together. Wegovy helps control appetite, while Metformin improves how your body handles sugar. Studies show this combination can lead to more weight loss and better blood sugar control, especially for people with type 2 diabetes or obesity. According to Erika Gray, Pharm.D., cofounder of Toolbox Genomics, “Combined, they may help improve your blood sugar levels more than one drug alone, something that can translate to improved weight loss.” Doctors generally consider this combo safe, but it’s important to work with your medical provider to ensure it’s right for you.
Switching Between Medications
Some individuals switch to Wegovy for improved appetite control, while others add metformin to manage blood sugar and insulin levels. Combining the two can be effective but requires a well-planned approach under the guidance of a healthcare provider. You should never switch between Metformin and Wegovy, or take them together, without talking to your doctor first.
Metformin and the "Anti-Hunger" Molecule
A recent study in mice and humans revealed that metformin's weight loss effects are linked to an "anti-hunger" molecule produced after vigorous exercise, called lac-phe. This molecule plays a critical role in metabolism, exercise, and appetite. Metformin increases lac-phe levels, activating the same pathway as vigorous exercise to reduce hunger.