Appetite suppressants: how they work, side effects, and natural alternatives

A combination of diet, exercise, and other healthy lifestyle choices is typically touted as the best way to lose weight and keep it off. But, when you’ve tried again and again to lose weight “naturally,” it’s easy to get discouraged and consider adding something new to your regimen. With a huge range of prescription and non-prescription appetite suppressants available, you may be wondering if they’re the secret to helping you shed stubborn pounds and get your weight back on track. Keep reading to learn about appetite suppressants, how they work, and whether they’re a good choice for you.

The U.S. Food and Drug Administration (FDA) has approved several prescription medications designed to suppress your appetite. Some are approved for long-term use, while others are meant to be taken for a short time, usually less than 12 weeks. 

Short-term appetite suppressants authorized by the FDA include:

• Phentermine (brand names Adipex P, Lomaira)

• Benzphetamine (brand names Didrex, Regimex) 

• Phendimetrazine (brand name Bontril PDM) 

• Diethylpropion

• Naltrexone-bupropion (brand name Contrave)

Long-term options for weight loss include:

• Phentermine-topiramate (brand name Qsymia) 

• Semaglutide (brand name Wegovy)

• Liraglutide (brand name Saxenda)

• Tirzepatide (brand name Zepbound)

Other weight loss medications like Orlistat (brand names Xenical and Alli) work by preventing fat absorption in your digestive system rather than by suppressing your appetite.

For a long time, research has shown that weight loss drugs can help you shed pounds, but in some cases, the weight loss is modest. A review of five appetite suppressants found that participants who were overweight or obese lost an average of 5% of their body weight over one year on medication. Because most of those treatments were not intended for long-term use, significant and drastic lifestyle changes were always crucial to keep the weight off long-term.

That was until GLP-1 medications like Wegovy (semaglutide) and Zepbound (tirzepatide) showed up. These medications have shown an average of 20% weight loss over the first year of use, making them a game changer for patients with overweight or obesity.

Weight loss medications are usually prescribed to people with a body mass index (BMI) of at least 30. 

While BMI is classically used by healthcare providers and researchers to estimate your body fat percentage, the calculation isn’t always accurate. BMI has been criticized for failing to take body fat distribution, gender, or ethnicity into account. Your healthcare provider will decide if these treatments are right for you.

You may receive a prescription for one of these treatments if you have a condition that is associated with excess body weight, such as type 2 diabetes, heart disease, or obstructive sleep apnea. 

If you take certain medications, including antidepressants and anti-anxiety drugs, appetite suppressants may cause a dangerous interaction. They can also worsen certain health conditions–You should inform your healthcare provider if you have:

• Glaucoma

• Heart disease

• Hyperthyroidism (overactive thyroid)

• Liver disease

People who are pregnant or breastfeeding should not take appetite suppressants.

Side effects of appetite suppressants vary depending on the medication. Common side effects may include:

• Increased blood pressure

• Trouble sleeping (insomnia)

• Headache

• Nervousness

• Nausea

• Constipation

• Dry mouth

• Depression

Some dietary supplements claim to suppress your appetite naturally––without medication. While more research is needed, these supplements may help you lose weight: 

1. Green tea extract

Green tea has long been touted as a weight loss tool. While drinking more liquids can help you lose weight (enter green tea), the evidence that green tea specifically does the heavy lifting isn’t very strong. Your best bet? Drink a cup or two of green tea a day, but skip the pills and potions that claim to contain it. 

2. Garcinia cambogia 

This fruit naturally grows in India and other parts of South Asia. It contains a chemical similar to citric acid called hydroxycitric acid (AHC), which may decrease appetite and help with weight control.

3. Glucomannan 

This fiber is taken from the Amorphophallus konjac plant. Since glucomannan can absorb 50 times its weight in water, researchers suggest that it can fill up your stomach and make you feel full.

4. Capsaicin

There are some claims that capsaicin–a fiery derivative of cayenne peppers–can help with everything from reducing high blood sugar to weight loss. Some claim that capsaicin can help reduce your appetite by helping you feel full. But that doesn’t mean you should be shoveling fistfuls of hot peppers. One small study of a combination of capsaicin, ginger, and green tea extracts found a slight increase in weight loss among participants who used these treatments compared to the placebo.

5. Yerba mate 

This plant is native to subtropical areas, especially in South America. Many people in this part of the world use its leaves to make beverages. Studies on mice show positive weight loss results, but research has yet to be conducted on humans.

6. Dietary fiber 

Foods high in fiber––like fruit, vegetables, oats, and legumes––slow the absorption and digestion of carbohydrates and help you to feel fuller for longer, which can aid in weight management.

If you’re trying to make healthy diet choices, you may want to cut back on sugar. Sugar spikes trigger hormone release from your pancreas, which can boost your appetite and make you feel hungrier.

Keep in mind that the FDA has not given the green light to any over-the-counter weight loss or appetite suppressant supplements. More research is needed to understand the safety and efficacy of weight loss supplements.

If you’re trying to lose weight, make an appointment with your healthcare provider. They can help you develop a treatment plan to safely reach your healthy goals.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

December 07, 2023

Written by

Alyson Powell Key

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.