Certain weight loss medications may be recommended for individuals when they are not having success with their weight loss goals from lifestyle change alone. The efforts in making behavior changes to lose weight look very different from person to person. Success generally increases with the help and guidance of a specialized care team, which may include a nutritionist or dietitian. Even when a weight loss medication is prescribed, it is still recommended to maintain a dedication to lifestyle change and have additional guidance and support for changing behaviors (more on that later).
For adults, there are currently 7 FDA-approved medications for weight loss, or more recently being discussed as anti-obesity medications.
- Stimulants – reduce appetite by increasing norepinephrine levels in the central nervous system
- Phentermine (Adipex-P, Lomaira)
- Phentermine/topiramate ER (Qsymia)
- Side effects include increased heart rate/jitters, headache, insomnia, dry mouth
- Gastrointestinal agents – prevent fat absorption in the gut
- Orlistat (Alli, Xenical)
- Side effects include GI discomfort, fecal incontinence, loose stools, vomiting, constipation
- Second-generation medications, also known as Incretin-based therapy (GLP-1 and GIP mimickers) – slow down how quickly your stomach empties. This reduces your hunger cues by decreasing appetite and promoting satiety. These medications can reduce your caloric intake, promoting weight loss and blood sugar balance.
- Liraglutide 3.0 mg (Saxenda)
- Semaglutide 2.4 mg (Wegovy)
- Tirzepatide (Zepbound)
- Side effects include nausea, diarrhea, constipation, indigestion, abdominal pain
Research on Weight Loss Medications: Effectiveness, Side Effects, and Long-Term Weight Management
Research varies greatly on the effectiveness of these weight loss medications due to differences in medication dosing, study population differences, and study design. Short-term data does reveal a promising influence on weight change (between 5-23% total body weight loss over various time frames). However, long-term data is limited for many of these medications as the majority of them were approved only in the last decade. This means that we simply do not know how well the addition of these medications will support long-term weight management and behavior change beyond the data that is being collected in real time.
Additionally, we know that even the best study design with positive outcomes can be hard to recreate in a real-world setting. One review summarized results from 41 different studies done within a real-world setting. They found that successful weight loss, defined as greater than or equal to 5% total body weight loss in 3-6 months, was observed in 14-58.6% of patients. The use of these medications was associated with mild to moderate side effects that influenced long-term use. It was estimated that less than 43% of participants were still taking liraglutide (Saxenda) by 6 months, meaning more than half of participants ended up stopping their medication at that time (1). Another review, including data from 10 separate studies for Tirzepatide (Zepbound), showed that the incidence of gastrointestinal side effects increased with each increase in medication dose. This occurred in 39-49% of patients, with 10% of them discontinuing their medications due to the side effects they were experiencing (4).
Weight Loss Medications: Short-Term vs. Long-Term Use and Potential Risks
It is important to note that some of these medications are prescribed for short-term use only (like Phentermine), whereas more recent, second-generation medications (Saxenda, Wegovy, Zepbound) are currently prescribed for lifelong weight management. What happens if you can’t tolerate the side effects of these medications or your insurance coverage stops? One study showed that one year after stopping semaglutide (Wegovy), participants, on average, gained back ⅔ of the weight they had lost initially, along with the reversal of other cardiometabolic improvements originally seen (2).
Overall Approach to Weight Management with or Without Medication
These medications for weight loss are not going away anytime soon. The reality is that with or without these medications, there is no magic bullet for successful behavior change leading to weight loss. You are looking at a good 6-12 months of working hard to make sustainable and healthy lifestyle changes. When done with a trained behavior change expert, like a dietitian, for at least 14 visits over 6 months, your success rate is higher (3). If you choose to take medication for the purpose of losing weight, it is important to let your doctor and anyone else on your care team know.
The Role of Dietitians and Nutritionists in Sustainable Weight Management
It is possible to lose weight too quickly. For reference, rapid weight loss defined as greater than 10% total body weight loss within 3-6 months or for certain people or a loss of more than 2 lbs per week over a prolonged time period, can have consequences. Many of these medications can influence your appetite or desire to eat, which can put you at risk for malnutrition if you are not eating enough. Being malnourished from prolonged inadequate nutritional intake can cause nutrient deficiencies and promote loss of healthy muscle tissue. You also have a higher risk of developing gallbladder disease or impairing your immune function if you are experiencing malnutrition. A dietitian can make you a personalized nutrition plan to help ensure proper nourishment while decreasing the risk of losing muscle tissue during your journey to lose weight.
Medication-Assisted Weight Loss and Expert Guidance for Success
In summary, it is a very personal decision between you and your doctor to include a weight loss medication to assist in weight loss. With any medication, it is important to ask questions to help you decide what is best for you. Some have been included below for reference. Behavior change is not easy and takes time and diligence. Working with an expert who can help support you in your journey is crucial for long-term success and motivation. There is no magic bullet, but working with a guided care team can increase your chances of success.
Possible Questions to Ask Your Doctor Regarding Medications to Assist with Weight Loss
- How do these medications work?
- What happens if I stop taking this?
- How long do I need to take this medication?
- What side effects can I expect?
Kelly Myers
MS, RD, LDN
Kelly is a Licensed and Registered Dietitian Nutritionist with a passion for helping individuals and families. She completed her Bachelor’s Degree in Food Science and Human Nutrition…. READ MORE
References
- Ahmad NN, Robinson S, Kennedy-Martin T, Poon JL, Kan H. Clinical outcomes associated with anti-obesity medications in real-world practice: A systematic literature review. Obes Rev. 2021;22(11):e13326. doi:10.1111/obr.13326
- Mishra R, Raj R, Elshimy G, et al. Adverse Events Related to Tirzepatide. J Endocr Soc. 2023;7(4):bvad016. Published 2023 Jan 26. doi:10.1210/jendso/bvad016
- Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564. doi:10.1111/dom.14725
- Wadden TA, Tronieri JS, Butryn ML. Lifestyle modification approaches for the treatment of obesity in adults. Am Psychol. 2020;75(2):235-251. doi:10.1037/amp0000517