Withdrawal from Phentermine, How Long Does it Last?

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Certified cognitive-behavioral therapist, expert addiction and chemical dependency counselor, certified for more than twenty years of experience in adolescent, adult and family psychotherapy.
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Is Phentermine Addictive? Some rehab centers say “Yes” even when science has proven it is not addictive. Other programs recommend Phentermine withdrawal treatment. Which one is right?

What We Need to Know About Phentermine

This drug is the most prescribed weight loss medication in America. Phentermine is taken in a cycle for a short period of time (up to 12 weeks) to boost weight loss in obese people who are exercising and on a low-calorie diet. It is a member of a drug class called anorectics.

Phentermine is a stimulant that acts on the central nervous system. It works by increasing the release of neurotransmitters in the brain resulting in increased energy levels and suppressed hunger. Some people believe they can develop a dependency to it. Although science is still debating on this, different rehab centers maintain their stance on it.

Effects of Phentermine

The main effect of Phentermine is the reduction of appetite and the weight loss. In addition, some patients report improvements in their medical conditions (e.g. related illnesses to obesity).

Potential side effects of Phentermine can include:

  • Dry mouth 
  • A metallic taste in the mouth
  • Diarrhea
  • Constipation
  • Vomiting
  • Headache
  • Elevated blood pressure
  • Elevated heart rate
  • Anxiety

Phentermine is not an amphetamine, or stimulant, and is unlikely to cause dependence. Although it is a Schedule IV controlled substance, it is not considered highly addictive or habit-forming. 

Nevertheless, it holds the possibility of being misused and leading to addiction for certain individuals. Physical dependence may develop when the medication is used beyond the recommended duration or in excessive amounts. This could result in experiencing withdrawal symptoms if the medication is abruptly discontinued.

Following a doctor’s prescription for phentermine will reduce the chances of developing addiction.

Indications of Addiction to Phentermine

  • Exceeding the recommended amount consumed
  • Using the medication for a duration that exceeds the prescribed period.
  • Having trouble decreasing or discontinuing the medication.
  • Experiencing withdrawal symptoms while attempting to cease taking the medication.
  • Abusing the medication by using it for its stimulant effects, rather than for its intended purposes as directed by a doctor.

Withdrawal Symptoms – Myth or Reality?

Symptoms of withdrawal that have been recognized consist of:

  • Fatigue can occur as patients adjust to the absence of the stimulating effects of Phentermine, leading to feelings of drowsiness or tiredness.
  • Weight gain is common when discontinuing Phentermine due to the lack of appetite suppression provided by the drug. This is influenced by the person’s other lifestyle decisions, such as working out, following a low-calorie meal plan, and the medications they might be prescribed.
  • Low mood is a frequent occurrence. People might experience periods of sadness. Individuals who already have mental health conditions like depression may experience an increase in their depressive symptoms.
  • Cravings for drugs may occur when feeling tired and experiencing low mood, prompting a desire for the perceived benefits of Phentermine.

Opposing Scientific Evidence

A well-known scientific study has disproved the idea that Phentermine is addictive. The study found that patients being treated with phentermine for obesity do not develop abuse or psychological dependence. Also, they found that Phentermine does not cause cravings, which is a key indicator of addiction. 

Withdrawal symptoms similar to those experienced with amphetamines do not happen when treatment is stopped suddenly, even at doses well above the usual recommendations and after being treated for up to 21 years.

It should be noted that the main author operates a weight loss facility in California and could be influenced by this.

Timeline of Phentermine Withdrawal

  • Energy and mood decrease within 6-24 hours.
  • After 2-3 days: Feeling easily annoyed, tense, and down in spirits.
  • Withdrawal symptoms reach their highest point in 5-7 days. Weight gain might start to occur.
  • 10-12 days: Reduction in symptoms of withdrawal
  • Years can be spent still craving, for certain individuals.

Options for Treatment 

Combining different methods is necessary for effective treatment, including.

Some typical treatments that may be beneficial include:

Cognitive Behavioral Therapy (CBT)

CBT is a structured approach that helps people grasp how their thoughts, emotions, and actions are connected. CBT assists in building coping strategies to handle stress, anxiety, and emotional challenges by reframing and questioning negative beliefs, leading to a positive change in behavior.

Dialectical Behavior Therapy (DBT)

DBT is designed to help people create a life that is full of meaning and value. DBT focuses on maintaining a balance between acceptance and change, teaching people how to handle difficult emotions, and reducing conflict in relationships in order to promote healing.

Individual Therapy

In private therapy sessions, individuals have a secure and confidential environment to explore their emotions, beliefs, and actions, process difficult memories, and pinpoint areas for personal growth.

Family Therapy

Family plays a key role in the healing journey to repair damaged relationships and cultivate a nurturing atmosphere within the family.

Ongoing Support and Lifestyle Changes

Continual assistance and lifestyle adjustments are often necessary for maintaining sobriety and avoiding relapse during long-term recovery. Support groups play a vital role in the process of healing and reducing the chances of experiencing a setback. Typically, adjustments to one’s lifestyle are necessary in order to steer clear of situations, locations, and objects that could act as triggers.

At The Encino Recovery and Detox Center, we don’t just treat addiction; we nurture the spirit, heal the mind, and empower individuals to reclaim their lives. If you or a loved one is seeking assistance for Phentermine addiction, remember that help is just a call away. Your journey begins with that first step.


Phentermine. MedlinePlus.

Hendricks EJ, Srisurapanont M, Schmidt SL, Haggard M, Souter S, Mitchell CL, De Marco DG, Hendricks MJ, Istratiy Y, Greenway FL. Addiction potential of phentermine prescribed during long-term treatment of obesity. Int J Obes (Lond). 2014 Feb;38(2):292-8. doi: 10.1038/ijo.2013.74. Epub 2013 May 17. PMID: 23736363

Administrator / Chief Clinical Officer
Certified cognitive-behavioral therapist, expert addiction and chemical dependency counselor, certified for more than twenty years of experience in adolescent, adult and family psychotherapy.
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