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Diet Pills

Diet pills encompass a class of drugs with the goal of weight loss. Many of these drugs contain stimulants like Amphetamines and can be highly addictive.

Can You Become Addicted to Diet Pills?

Diet pills encompass a class of drugs with a similar goal (typically weight loss) but employ different methods in achieving that effect. Diet pill drugs may work by curbing appetite (Belviq®, Contrave®), increasing energy (phentermine, Didrex®) or blocking fat (Xenical®, Alli®). Because some diet pills contain Amphetamines, persistent use can lead to an addiction. Moreover, some people may suffer co-occurring disorders (such as depression or an eating disorder) and become dependent on the effects of diet pills.

Diet pills can essentially be sorted into three categories, defined by their chemical makeup and how they affect the body. The three types of diet pills include:

  • Stimulant – Affects the central nervous system to increase energy and a sense of well-being. Stimulants can also curb appetite.
  • Appetite suppressant – Effects specifically target serotonin and norepinephrine neurotransmitters in the brain to increase feelings of fullness and decrease appetite.
  • Fat Inhibitor – Activates in the gastrointestinal tract (i.e. stomach and intestines) to reduce fat absorption by a third.

The FDA has approved certain formulations in each type of diet pill, though not for everyone. Prescription weight loss aids are usually reserved for patients with a body mass index (BMI) over 30, or who have a BMI of at least 27 and a disorder that may be negatively affected by weight (such as Type 2 Diabetes). However, these medications can be fatal if misused or abused.

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Effects of Diet Pill Abuse

As a category of diet pill, stimulants carry a high risk of causing a dependence. Amphetamine-derived stimulants affect systems in our brain responsible for feeling happy or content (similar to other stimulants like Cocaine). Furthermore, many people become tolerant to the energy they get from their pills and eventually increase the amount they’re taking. Such behavior is among the common characteristics of addiction.

A diet pill overdose is similar to a Cocaine or Meth overdose and can include heart failure.

The short-term effects of stimulant-type diet pills include a rush of energy, increased blood pressure and heart rate, flushed skin, dizziness, and dry mouth. Continued use of these pills can lead to insomnia, constipation, pulmonary hypertension, heart valve diseases, and withdrawal symptoms if the person stops taking them. Persistent use of appetite suppressants commonly causes headaches, dizziness, and a range of bowel troubles. Likewise, fat inhibitors are known to cause unpleasant oily spotting, gas, and similar gastrointestinal issues.

Are Diet Pills Legal?

Diet pills have been on the market for over a hundred years, promising easy weight loss while hiding their high potential for dangerous side effects. The FDA continues to approve certain formulations for the purpose of losing weight but have also removed prescriptions from the market when they’ve proven deadly to public health. Additionally, some medications marketed as weight loss have not been approved by the FDA but are still available to the public.

Though they carry a risk of addiction, FDA-approved diet pills with stimulant-like effects include Adipex-P, Didrex, Bontril, Desoxyn, and Qsymia.

Most appetite suppressants (such as Contrave®) are considered at low risk for addiction, are FDA-approved, and are not mentioned in the Controlled Substances Act by the Drug Enforcement Administration (DEA). Other weight loss medications are Schedule IV substances (including Belviq® and Qsymia®), meaning they have a low potential for abuse in relation to Schedule III drugs. (Other Schedule IV substances include Benzodiazepines Xanax® and Valium®.)

Some diet pills have been banned by the FDA after causing unchecked addictions and overdose deaths. Fenfluramine (part of a combination with phentermine commonly known as fen-phen) was banned by the FDA in 1997. In 2010, the FDA did the same to Meridia® after it was proven to be the source of heart attacks and strokes.

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Are Herbal Diet Pills Dangerous?

While social media has made certain weight loss programs popular, these unverified and unstudied medications can be dangerous. “Herbal” weight loss pills, like other over-the-counter drugs, are not approved by the FDA as safe methods for weight loss. Any claims of significant weight loss in short periods of time should be a red flag – these pills can cause serious side effects or may simply be ineffective.

Weight loss supplements are removed from the market “almost every week” by the FDA. Many of these pills contain chemicals already banned by the government (such as Sibutramine, formerly sold under the brand name Merida) or dangerously high levels of NSAIDS (which can lead to stomach bleeding and strokes).

Common Diet Pills

Generic Name
Brand Name(s)
Common Side Effects
Benzphetamine Didrex® Stimulant Headaches, dizziness, nausea, insomnia, sweating, increased blood pressure and heart rate, restlessness, anxiety, and dependence.
Bupropion and Naltrexone


Contrave® Appetite Suppressant Headache, nausea, vomiting, dizziness, dry mouth, diarrhea, constipation, hot flashes, and unpleasant taste.


Tenuate®, Tepanil® Stimulant Constipation, restlessness, dry mouth, nervousness, insomnia, and dependence.


Pondimin® Stimulant Damages heart valves, primary pulmonary hypertension, increased heart rate and blood pressure, restlessness, insomnia, and anxiety.


Saxenda® Appetite Suppressant Nausea, vomiting, diarrhea, constipation, heartburn, fatigue, stomach pain, gas, and dry mouth.
Lorcaserin Belviq® Appetite Suppressant Headache, nausea, dizziness, dry mouth, fatigue, feelings of euphoria or dissociation can occur at high doses.
Methamphetamine Desoxyn® Stimulant Increased blood pressure and heart rate, restlessness, insomnia, nervousness, dependence, and withdrawal if stopped.
Orlistat Alli®, Xenical® Fat Inhibitor Softened stools, gas, fecal urgency, oily spotting, fecal incontinence, and risk of serious liver injury.
Phendimetrazine Bontril®, Prelu-2®, Plegine® Stimulant Headaches, dizziness, nausea, insomnia, sweating, increased blood pressure and heart rate, restlessness, anxiety, and dependence.
Phentermine Adipex®, Ionamin®, Suprenza® Stimulant Headaches, dizziness, nausea, insomnia, sweating, increased blood pressure and heart rate, restlessness, anxiety, and dependence.
Phentermine and topirate Qsymia®, Topamax Stimulant Tingling skin, dizziness, altered taste, insomnia, constipation, and dry mouth.
Sibutramine Meridia® Appetite Suppressant Headache, dry mouth, constipation, insomnia, runny nose, and sore throat.

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