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Compare Wegovy vs. Phentermine

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

Wegovy (semaglutide)
Phentermine (Adipex-P)
Wegovy (semaglutide)
Phentermine (Adipex-P)

Summary of Wegovy vs. Phentermine

Summary for GLP-1 agonist
Prescription only

Wegovy (semaglutide) is used in addition to a lower-calorie diet and exercise plan to help with weight loss in certain adults and children 12 years of age and older. It's also proven to lower the risk for heart attack, stroke, and death due to heart problems in adults with a larger body size and heart disease. This medication belongs to the drug class called glucagon-like peptide-1 (GLP-1) receptor agonists. The dosing schedule for Wegovy (semaglutide) is once a week, and the medication is injected under your skin. Common side effects include nausea, diarrhea, and stomach pain.

Summary for Sympathomimetic
Prescription only

Phentermine (Adipex-P) is an appetite suppressant. It's a prescription weight loss pill for people ages 17 years and older. This medication works best when it's part of a treatment plan that involves healthy diet and regular exercise. Phentermine (Adipex-P) is taken by mouth once daily, typically in the morning. Some of the more common side effects of this medication include dry mouth, trouble sleeping, and headache.

Indications of Wegovy vs. Phentermine

Indications for
•Long-term treatment for weight management in:
•Adults with a body mass index (BMI) of 30 kg/m2 or greater; or BMI of 27 kg/m2 or greater and a weight-related condition (e.g., high blood pressure, Type 2 diabetes, high cholesterol)
•Children 12 years of age and older with a baseline BMI at the 95th percentile or greater
•Lowering the risk of heart attack, stroke, and death due to heart problems in adults with heart disease and a larger body size
Indications for

Short-term treatment for weight management in adults with a body mass index (BMI) of:

•30 kg/m2 or greater; or
•27 kg/m2 or greater, and with at least one other weight-related condition (e.g., high blood pressure, high blood sugar, high cholesterol)

Pros and Cons of Wegovy vs. Phentermine

Pros and Const for GLP-1 agonist
Pros
•Can help you lose weight when it's used along with a nutritious diet and regular exercise
•Approved for use for weight loss in certain children aged 12 years and older (BMI at or above the 95th percentile)
•Injected once a week
Cons
•Must inject under the skin
•Can cause stomach pain, nausea, and diarrhea
•Can't take with other semaglutide products (Ozempic, Rybelsus) or with other GLP-1 agonists
Pros and Const for Sympathomimetic
Pros
•Can help you lose 5% to 10% of body weight
•Usually taken by mouth once per day
•Available as a lower-cost generic
•Comes as tablets, capsules, and orally disintegrating tablets
Cons
•Most insurance companies don't cover the cost of phentermine (Adipex-P).
•Has a risk of misuse and dependence since it's a stimulant medication that's similar to amphetamines
•Might not be a good choice for people with high blood pressure
•Should be avoided in children 16 years of age and younger, pregnant and breastfeeding women, and people with serious heart problems

Common Side Effects of Wegovy vs. Phentermine

Common Side Effects for
•Nausea (44%)
•Diarrhea (30%)
•Vomiting (24%)
•Constipation (24%)
•Stomach pain (20%)
•Headache (14%)
•Tiredness (11%)
Common Side Effects for
•Dry mouth
•Headache
•Tremor
•Constipation
•Diarrhea
•High blood pressure
•Fast heart rate
•Difficulty sleeping

Warnings of Wegovy vs. Phentermine

Common Side Effects for
•Possible risk for thyroid cancer
•Inflammation of the pancreas (pancreatitis)
•Gallbladder problems
•Low blood sugar
•Kidney damage
•Allergic reactions
•Eye problems in people with Type 2 diabetes (diabetic retinopathy)
•Faster heart rate
•Possible risk for self-harm
Common Side Effects for
•Not safe to combined with other weight loss medications
•Phentermine not working well
•Risk of misuse and dependence
•Trouble concentrating or problem with coordination
•Heart and lung problems
•Risk of high blood pressure
•Risk of low blood sugar in people with diabetes

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