Phentermine should only be taken for twelve weeks at a time.
This recommendation is related to the active ingredient’s strong potential for addiction and abuse, as well as a lack of research on the long-term effects of this medication (
Unfortunately, some people still experience withdrawal symptoms when they stop taking phentermine – even after a relatively short course of treatment.
Planning how to stop phentermine is important to help minimize phentermine withdrawal symptoms.
Phentermine is designed to be used alongside lifestyle modifications that promote weight loss (
A strong support system, whether in-person or online, can help you stay committed to your new, healthier lifestyle.
For some patients, it’s also beneficial to taper phentermine dosage in the final weeks of treatment. A taper allows the body to gradually adjust to a lower level of stimulant, which helps reduce the risk of phentermine withdrawal.
If possible, do not stop phentermine “cold turkey,” or very suddenly (
Read more here: Stopping Phentermine
Phentermine Withdrawal Symptoms
Phentermine withdrawal symptoms are similar to those associated with other stimulants.
Call your doctor or seek immediate medical attention if withdrawal symptoms are severe, worsening or interfering with daily life.
Take extra care to monitor for signs of depression and low mood, which are the typically the most dangerous side effects of stimulant withdrawal, even months after the last dose (
Read more here: Phentermine Withdrawal Symptoms
How Long Does Phentermine Withdrawal Last?
Duration of phentermine withdrawal varies from person-to-person. However, most people withdrawing from stimulants experience the most acute symptoms during the first four days, after which point they begin to feel better.
Lingering symptoms of stimulant withdrawal, such as low mood or fatigue, can last for weeks or months after stopping phentermine (
Read more here: Phentermine Withdrawal Time
Life After Phentermine
It’s critical that patients transition off phentermine with a plan for continued healthy living.
In fact, without a strong weight maintenance plan in-place, almost 80% of people who achieve major weight loss gain the pounds back within two years (
However, research shows that certain behaviors are highly-correlated with successful weight maintenance (
- Eating breakfast
- Weighing regularly
- Cooking at home
- Staying active
- Weintraub M, Hasday JD, Mushlin AI, Lockwood DH. (1984). A double-blind clinical trial in weight control. Use of fenfluramine and phentermine alone and in combination. Archives of Internal Medicine, 144(6):1143-1148.
- American College of Cardiology. (2011, November 21). Phentermine.
- Allina Health. (2013, June 12). Appetite suppressant, sympathomimetic.
- Drugs.com. (1999, April 26). Phentermine Hydrochloride Drug Information, Professional.
- Center for Substance Abuse Treatment. (1999). Chapter 5 – Medical Aspects of Stimulant Use Disorders. In Treatment Improvement Protocol (TIP) (Ser. 33).
- McGuire, MT, Wing, RR, & Hill, JO. (1999). The prevalence of weight loss maintenance among American adults. International Journal of Obesity and Related Metabolic Disorders, 23(12), 1314-1319.
- Wing, R. R., & Phelan, S. (2005). Long-term weight loss maintenance. The American Journal of Clinical Nutrition, 82(1), 222S-225S.