Are Appetite Suppressants Safe? (According to Science)

Isaac Robertson
Published by Isaac Robertson | Co-Founder & Chief Editor
Last updated: November 24, 2023
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Yes. FDA-approved appetite suppressants are safe for weight loss and treatment of obesity. When taken with a doctor's prescription and supervision, it can give your weight loss goals excellent, safe results.

According to studies, an average person eats between three and five pounds of food per day, depending on age, gender, metabolism, and habits.

And if you're like most people who need to eat doughnuts and cakes to feel satiated, losing weight can feel like a tough grind.

Appetite suppressants can work to help you cut your cravings short.

Quick Summary

  • Appetite suppressants are safe as they have been heavily examined by FDA before being declared fit for human consumption.
  • These suppressants control the central nervous system, helping suppress appetite.
  • Benzphetamine, phendimetrazine, and diethylpropion are some appetite suppressants that should be taken for up to 12 weeks.

How Do Appetite Suppressants Work For Weight Loss?

empty plate on a table and a person hand tied in a measuring tape

Appetite suppressants work as an anorectic drug [1] or prescription medication.

They act majorly in the satiety center of the central nervous system to help suppress appetite.

They also affect the digestive processes involving fat absorption, carbohydrate metabolism, and overall physical activity[2].

It's all-important to consider that appetite suppressants are just one part of a whole plan to lose weight along with diet and exercise.

An appetite suppressant reduces hunger and curbs food cravings, which helps lose weight.

By targeting the brain's appetite control center, they help your body feel full for longer periods, leading to a decrease in calorie intake.

They help your body to feel full longer and lessen calorie intake from food consumption. But it is not recommended to replace a healthy lifestyle.

How Long Should You Take Appetite Suppressants?

woman holding up a single yellow pill

Studies show that visible results were observed within six months of medication. However, some doctors who prescribe appetite suppressants advise taking them for 12 weeks or less.

Here are some appetite suppressants for up to 12 weeks of use:

  • Benzphetamine
  • Diethylpropion
  • Phendimetrazine

It's best to seek medical counsel about how long to take these medications for personal weight loss or other treatment plans.

What Is The Best and Safest Appetite Suppressant?

medical person holding up a pill bottle while thinking

When it comes to weight loss, appetite suppressants are one of the most sought-after products in the market today.

Guaranteed-to-work appetite suppressants with prescriptions or over-the-counter drugs work to curb hunger pangs for long-term and short-term use.

In addition, some, however, can potentially help improve high blood pressure, diabetes, and high cholesterol levels.

It is best to consult with a doctor about the best and safest appetite suppressant to avoid adverse reactions with other treatment drugs and current health conditions.

Prescription Appetite Suppressants

different pills in a pink background, and a doctor writing a prescription

Prescription appetite suppressants are doctors' prescribed drugs or diet pills for weight loss.

Here's a shortlist of prescription medications:

  • Lorcaserin (Belviq) - Belviq works to reduce appetite by acting on the 5-HT2C receptor for serotonin in the brain [3], which regulates feelings of fullness and hunger. It is recommended for people with a Body Mass Index (BMI) of 30 or 27 along with a weight-related condition.
  • Phentermine (Adipex-P, Lomaira, and Suprenza) - Phentermine helps lessen food intake and improves energy released by your body. However, its downsides may include fast heart rate, hypertension, sleeplessness, and mental instability [4].
  • Phentermine-Topiramate (Qsymia) - Qsymia is an extended-release capsule with two drugs, Phentermine which suppresses appetite, and Topiramate, which prevents seizures. It is advised for people with a BMI of over 27 or a weight-related condition to undergo a lifestyle change to lose weight.
  • Naltrexone-Bupropion (Contrave) - Contrave is an extended-release capsule and contains two medicines, Naltrexone and Bupropion. Its combination works on the hypothalamus and the brain's reward system to promote satiety to manage excess weight gain [5]. It is recommended along with a low-calorie diet and workout plan to lose weight.
  • Liraglutide (Saxenda) - Saxenda is an injectable drug that lessens hunger by producing an appetite hormone called Glucagon-Like Peptide (GLP-1), which slows stomach emptying. It is advised for people with a BMI of more than 27 along with a weight-related medical condition [6].  According to studies, you can continue using these drugs as long as they serve you well and offer no significant side effects [7].

Related Article: First Diet Pills

Over-The-Counter (OTC) Appetite Suppressants

giving money in exchange of medical pills

Along with doctors prescribed medications, OTC natural supplements may help control appetite for weight reduction and management.

Here are some OTC drugs and how they work: 

  • Fenugreek, Glucomannan, Acacia fiber, and Guar Gum lessen hunger by increasing fullness due to high soluble fiber content.
  • Yerba Mate, Coffee, Green Tea Extract, and Guarana supplement weight loss by boosting metabolism due to high caffeine content.
  • Garcinia Cambogia, Caralluma Fimbriata, and Griffonia simplicifolia are supplements known to control hunger pangs by increasing serotonin levels in the brain.
  • Conjugated linoleic acid (CLA), Bitter Orange, Forskolin, and Saffron Extract are known to lower appetite by increasing fat breakdown.

What Are The Potential Side Effects Of Appetite Suppressants?

woman holding her temple in pain, and a man hugging his upset stomach

Appetite suppressants, like any medications, may pose some harmful risks.

Here are the most commonly experienced side effects:

  • Restlessness
  • Dizziness
  • Sleeplessness
  • Dry mouth
  • Constipation
  • Loose Stools
  • Increased Heart Rate

Side effects with appetite suppressants can differ depending upon the type of drug and how it works [8]. However, they can be mild to moderate but are still considered safe when taken under a doctor's supervision.

Who Should Not Take Appetite Suppressants?

man holding his chest in pain and a close up image of a person's eyeball
  • People with Cardiovascular Problems. Research suggests that mild to moderate valvular heart disease showed one-third of the patients taking appetite suppressant drugs [9].
  • People with Glaucoma. Appetite suppressants may tend to raise blood pressure [10] that can add more stress to your eyes. It can lead to blurred vision and permanent damage.
  • People with Liver Disease. Some weight loss supplements may elevate liver enzymes in patients with existing liver damage, resulting in liver failure if not medically supervised [11].
  • People with hyperthyroidism. Some OTC appetite suppressants might contain significant thyroid hormone levels that may affect the hormonal responses of patients with overactive thyroid problems [12].
  • People who are taking antidepressant drugs. Some appetite suppressants tend to interfere and counter the effect of antidepressant drugs, which can cause serious side effects [13].

Are Natural Alternative Ways Better Than Diet Pills To Lose Weight Safely?

smiling bearded man holding up a salad bowl and a weighing scale

Natural alternative ways can create lifestyle modifications that can help you lose weight safely. But the results may take more time than taking weight loss pills along with exercise.

Here's a list of alternative ways to curb your appetite [14]:

  • Eat a reduced-calorie diet and protein-rich foods
  • Drink water before every meal
  • Exercise before a meal
  • Eat high fiber foods
  • Eat mindfully and avoid stress


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