Weight-Loss Medications

Weight-loss medications are drugs used to suppress appetite, increase the feeling of fullness, affect how dietary fat is absorbed, or otherwise change how people eat and absorb food. Their purpose is to support diet and exercise as methods of losing weight. They require a prescription from a physician and are generally prescribed only for people with a great deal of weight to lose and/or additional health problems caused by excess weight. Some of these medications are designed to be used for weight loss; others were originally approved for other conditions but have weight loss as a side effect. Some cause side effects and are not appropriate for everyone.

Background

In some times and cultures of the past, being overweight was seen as a sign of wealth. However, during the late nineteenth century, people began to see a slim figure as more desirable. At this time, medications were not strictly controlled, and people began creating weight-loss pills from an extract of the thyroid gland. The thyroid regulates metabolism, or the process by which food is turned into fuel for the body. The theory behind these pills was that they would increase metabolism, enabling the body to burn more fat.

They worked to a certain extent but had many dangerous, and sometimes fatal, side effects. Nevertheless, the pills continued to be available to the public. It was also discovered that some drugs used for other purposes, such as amphetamines, a stimulant prescribed for several conditions, also suppressed appetite.

Beginning in the 1940s, many people took popular pills called "rainbow drugs." They included thyroid extracts, amphetamines, diuretics to stimulate urination, laxatives to speed food through the digestive system, antidepressants, and other medications. They also proved to be dangerous and caused deaths and other health problems. Drugs like these were among those that encouraged governments around the world to create agencies such as the Food and Drug Administration (FDA) in the United States. These agencies review medications prior to sale, monitor their safety and effectiveness, and make decisions about whether they can remain on the market.

Overview

Weight-loss medications are generally intended for people who are significantly overweight. This is determined by a measurement known as a body mass index (BMI), which is computed by dividing a person’s weight in kilograms by the square of their height in meters. This measurement is an indication of how much body fat a person has. People with a BMI of 30 are considered obese; those with a BMI between 27 and 30 are considered overweight. Physicians generally consider prescribing weight-loss medications for people who have a BMI greater than 30 or who have a BMI of 27–30 and another medical condition that is affected by being overweight, such as high blood pressure or diabetes. Weight-loss medications are not intended for people whose health is not at risk because of their weight. They are also not for use by people who are pregnant or who have certain health conditions that could be worsened by the ingredients in the drugs.

These medications are almost always prescribed in addition to diet and exercise programs, not in place of them. They support diet and exercise plans in several ways, most commonly by helping to reduce hunger. In theory, being less hungry helps a person stay on a calorie-restricted diet better, increasing the likelihood they will lose weight. Some weight-loss drugs also reduce cravings for high-sugar, high-fat foods that contribute to weight gain. Others change how the body metabolizes fat, reducing the amount of dietary fat that turns into body fat.

Weight-loss drugs can be beneficial because they can result in a reduction of body weight by 3 to 12 percent more than diet and exercise alone. Improvements to health, such as reduced blood pressure and blood sugar levels, can be seen with a 5 to 10 percent weight loss. Being overweight also contributes to a number of other health problems, including joint pain and arthritis, reduced muscle mass, and a greater risk of complications during surgery. Experts note that these drugs also do not work for everyone. They explain that the reasons that people are overweight are complex, as are the factors that contribute to appetite. This makes it very difficult to find a medication that works consistently for everyone.

Modern weight-loss drugs also have some side effects, though not as many as the earliest versions. They can cause nausea, diarrhea, or constipation. They can take several weeks to work, but most people lose one to two pounds per week while on them. However, incorporating diet and exercise is also important. Weight-loss medications are not meant to be taken indefinitely, and many people will regain weight if they do not make lifestyle changes. In addition, the medications can be very expensive and may not be covered by health insurance.

Kinds of Weight-Loss Medications

Several different weight-loss medications are available, though different countries have their own lists of approved drugs. In the United States, the FDA has approved several, some of which are single-drug products and others that are combinations. Phentermine, sold as Adipex and Lomaira, is a single-drug product; it is an amphetamine that suppresses appetite. Other single-drug products include lorcaserin, sold as Belviq, which helps by making people feel fuller; orlistat, sold as Alli or Xenical, which blocks the absorption of some dietary fat; and liraglutide, an injection sold as either Victoza or Saxenda, which suppresses appetite and cravings. Combination weight-loss drugs available include Qsymia, a combination of phentermine and the anticonvulsant drug topiramate ER, which together help control appetite and binge eating, and Contrave, which combines the antidepressant buproprion HCL and Naltrexone, which is used to treat opioid addiction, to reduce appetite.

Sometimes medications prescribed for one condition are found to help with another. Using a drug for a condition other than the one for which it is approved is called off-label use. For example, physicians observed that many patients on certain medications to treat diabetes were losing weight and began prescribing them off-label for weight loss. Two such medications include semaglutide, sold as Ozempic, and tirzepatide, sold as Mounjaro. Both are injections used to treat type 2 diabetes; a higher dose of semaglutide sold as Wegovy is approved for weight loss. The company selling Mounjaro is also seeking FDA approval for its use for weight loss.

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