There are currently five drugs approved by the FDA for the specific treatment of obesity. They are:

• Orlistat: This drug works by inhibiting the enzyme that breaks down dietary fat, thus reducing the absorption of fat and calories from the gut. It can help people lose about 3% of their body weight over a year, but it also causes gastrointestinal side effects, such as oily stools, flatulence, and diarrhea⁹.
• Lorcaserin: This drug works by activating the serotonin 2C receptor in the brain, which reduces appetite and increases satiety. It can help people lose about 5% of their body weight over a year, but it also carries a risk of cardiovascular and psychiatric adverse events, such as hypertension, headache, and depression⁹.
• Phentermine/Topiramate: This combination drug works by stimulating the sympathetic nervous system and modulating the activity of certain neurotransmitters, such as norepinephrine, dopamine, and glutamate, which affect appetite and energy expenditure. It can help people lose about 10% of their body weight over a year, but it also causes side effects, such as insomnia, dry mouth, constipation, and cognitive impairment⁹.
• Naltrexone/Bupropion: This combination drug works by blocking the opioid receptors and inhibiting the reuptake of dopamine and norepinephrine in the brain, which reduce food cravings and increase energy expenditure. It can help people lose about 6% of their body weight over a year, but it also causes side effects, such as nausea, vomiting, headache, and anxiety⁹.
• Liraglutide: This drug works by mimicking the action of glucagon-like peptide-1 (GLP-1), a hormone that is secreted by the gut after a meal and stimulates insulin secretion, inhibits glucagon secretion, and reduces appetite and gastric emptying. It can help people lose about 9% of their body weight over a year, but it also causes side effects, such as nausea, vomiting, diarrhea, and pancreatitis⁹.