Over-the-Counter Drugs and Dietary Supplements for Weight Loss

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Lifestyle changes like a healthy diet and regular exercise are essential for long-term weight management. But some people may seek additional support through over-the-counter (OTC) drugs and weight loss supplements.1

OTC drugs and dietary supplements are easy to get without a prescription. They can be found in most drugstores and pharmacies around the country. There are many kinds, and they are marketed as aids to achieve weight loss.1

How do over-the-counter drugs and dietary supplements work for weight loss?

Several OTC drugs and dietary supplements claim to promote weight loss by:1,2

  • Burning fat
  • Suppressing appetite
  • Increasing metabolism
  • Reducing the absorption of fat

Research has not yet confirmed that these claims are true. It is also worth noting that most of these products have not been approved by the US Food and Drug Administration (FDA). Some also can be dangerous and harmful. For example, some OTC ingredients can interact or interfere with certain medicines and prescription drugs.1

What are the ingredients of over-the-counter drugs and dietary supplements?

OTC drugs and dietary supplements often contain a lot of ingredients. In fact, there are some diet products that contain more than 90 ingredients! The most common ingredients used include:1,2

  • Herbs and plant extracts
  • Caffeine
  • Fiber
  • Minerals

Examples of OTC drugs

OTC drugs and diet supplements come in many forms, including:1

  • Capsules
  • Pills
  • Powders
  • Liquid

Examples of OTC weight loss drugs include:1,2

  • Herbs and plant extracts
  • Appetite suppressants
  • Fat absorption blockers

Herbs and plant extracts

Some herbs and plants have naturally occurring substances that may have an effect on weight loss. Examples of herbs and plant extracts that have been studied for weight loss include:1

  • Bitter orange – Components of bitter oranges may suppress appetite and increase fat burning.
  • Caffeine – This naturally derived substance is found in coffee beans, tea leaves, kola nuts, and many other plants. Caffeine may boost metabolism and stimulate the central nervous system.
  • Capsaicin – This component of chili peppers may increase calorie burning and feelings of fullness.
  • Chromium – This mineral that affects insulin may reduce hunger.
  • Green tea extract – This substance taken from the Camellia sinensis plant may increase fat burning and reduce fat absorption.
  • Glucomannan – This fiber derived from the konjac plant may increase feelings of fullness and slow down digestion. This can leave you fuller for longer.
  • Raspberry ketones – This compound found in raspberries may increase metabolism.

Appetite suppressants

Some OTC drugs and diet supplements also work by suppressing the appetite. Most OTC appetite suppressants combine a variety of plant-based components like caffeine or green tea extract. These may help reduce hunger, thereby helping you to eat less.1,2

Fat absorption blockers

Blocking the body’s ability to absorb fat is another way that OTC drugs may help people lose weight. These drugs block fat from being absorbed in the intestines. The unabsorbed fat is then passed through your stool.3,4

Orlistat is an OTC drug that stops the absorption of fat in the intestines. Orlistat is currently the only FDA-approved OTC weight loss drug.3,4

When used together with a reduced-calorie diet and exercise, Orlistat has been shown to help people lose modest amounts of weight. But it may cause gastrointestinal side effects like:3,4

  • Oily stools
  • Increased bowel movements
  • Bathroom urgency
  • Gas (flatulence) with oily discharge
  • Stomach pain

Are over-the-counter drugs and diet supplements safe?

When considering the safety of OTC weight loss drugs and diet supplements, there are several factors you will want to consider.1

Limited efficacy

There is very limited research on how well these drugs and supplements work in humans. Because they often contain so many different ingredients, it can be hard to understand which ingredients have the most effective results and at what dosage.1

OTC weight loss drugs may provide modest benefits in terms of weight loss. But they may not be right for everyone. They are most effective when used as part of a comprehensive weight management plan that includes dietary changes and increased physical activity.1

Individual variations

Every person’s response to OTC weight loss drugs will be different. What works for 1 person may not work for another. Approach these drugs with caution. Set realistic expectations, and closely monitor their effects on your body.1

Lack of regulation

Many OTC weight loss drugs and supplements – with the exception of Orlistat – are not regulated by the FDA the same way other drugs are. This means that no outside agency confirms the ingredients or suggested dose.1

For example, a fish oil supplement may have more or less fish oil than listed on the label. A supplement may also contain ingredients that are not labeled correctly or at all. This can be dangerous. It can lead to taking too much or taking unwanted ingredients.

The FDA created good manufacturing practices (GMPs) to help this situation. GMPs are guidelines for companies to follow when making supplements. The FDA rarely inspects facilities making supplements in the United States. Companies outside the United States do not have these inspections. But many more supplements are sold than are tested.5

If you are considering OTC drugs to help with weight loss goals, talk with your healthcare provider first. They can assess whether it is safe and appropriate for you.1

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking. Many OTC weight loss drugs can cause side effects such as:1,2

  • Anxiety
  • Changes in bowel movements (loose stools, oily stools, gas, and bathroom urgency)
  • Headache
  • High blood pressure
  • Increased heart rate
  • Insomnia

These are not all the possible side effects of OTC weight loss drugs. Talk to your healthcare provider about what to expect when taking OTC weight loss drugs. You also should call your healthcare provider if you have any changes that concern you when taking OTC weight loss drugs.

Other things to know

OTC drugs and weight loss supplements are often expensive. You may need to take cost into account when choosing OTC drugs.1

Be sure to read labels carefully, follow dosage instructions, and be aware of potential interactions with other medicines you take.

Do not take OTC weight loss drugs before talking with your healthcare provider. This is especially true if you have any of the following health conditions:1

  • Diabetes
  • Heart disease
  • High blood pressure
  • Liver problems or liver disease

While OTC drugs can seem like a convenient solution for weight loss and obesity treatment, their effectiveness and safety must be carefully considered. Before beginning obesity treatment, tell your healthcare provider about all your health conditions and any other drugs, vitamins, or supplements you currently take. This includes over-the-counter drugs.

Ultimately, the key to long-term weight management lies in adopting a healthy lifestyle that includes a balanced diet, regular exercise, and sustainable habits. OTC drugs may provide temporary support, but they should always be used with caution and under medical guidance.

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