withdrawal symptoms

How To: Avoid Withdrawals with Phentermine

General Phentermine Questions?
Check out the ultimate guide to phentermine weight loss pills!

Phentermine is the most widely prescribed and frequently encountered diet pill on the market, however phentermine has the potential to become very addictive and should only be used on a short-term basis, along with exercise and a healthy eating plan. As phentermine can only be used for a limited amount of time, many of those prescribed it may find that they experience side effects following cessation of the medication. Trying to manage your weight without the help of phentermine while you are also experiencing withdrawal symptoms can make this a very difficult period for those who have recently stopped taking phentermine. Here, we explain why withdrawal occurs in the first place, what kinds of symptoms you may experience, ways to help you manage them whilst also working to maintain the weight you have lost with phentermine, so you can proactively avoid withdrawals with phentermine

Why Do Withdrawals Happen In The First Place?

Withdrawal symptoms occur when an individual stops taking a medication or recreational drug after having taken it for long enough to develop a mental or physical dependency. Phentermine is typically prescribed for no more than 12 weeks at a time, although it is highly possible to experience withdrawal symptoms after this period, since it is a very addictive medication.

The sustained use of many drugs causes adaptation within the body that tend to lessen the drug’s original effects over time, known as drug tolerance. Many phentermine users experience a reduction in effectiveness of the medication over time, which indicates that tolerance is occurring within the body. It is important to always follow the instructions of your doctor, so if you find that your phentermine prescription does not produce the same effects, you should not increase your dosage in an attempt to manage your increase in tolerance. Doing this will only lead to a greater dependency and therefore a greater chance of withdrawal symptoms once your prescription ends. This adaptation and tolerance to phentermine is the core reason for withdrawal symptoms, as strong medication can be highly reactive and addictive to the body.

What Are The Symptoms Of A Phentermine Withdrawal?

Most people use phentermine for a limited period, ideally until they have established a healthy routine that includes a balanced diet and regular exercise. However, if phentermine is misused or abused it can become habit forming, resulting in a greater chance of several withdrawal symptoms. These are some of the most common:


Phentermine acts as a stimulant on the central nervous system, which causes your blood pressure to rise and energy increases. Once the medication has been discontinued and the drug is no longer stimulating your body in this way, it is possible that you will experience feelings of weariness and fatigue. The best solution for this is to ensure that you are getting proper sleep, diet, and exercise, and the tiredness should diminish within a few days.

Weight Gain

Weight regain is common after quitting phentermine, which may be due to an increased appetite and lack of exercise from withdrawal symptoms, like fatigue. However, it is important to stress that phentermine is used as an aid for weight loss in obese patients and that relying on this medication to make you lose weight will only result in long-term disappointment. Phentermine is prescribed to suppress your appetite on a short-term basis, with three months of continuous use being the maximum advised. It is the patient’s responsibility to use this pill as a tool to help control appetite while following a sensible diet and exercise program. If phentermine is taken without any effort to change the lifestyle in other ways, then it is to be expected that weight gain is high on the list of side effects once the medication is no longer being taken.



Insomnia, or the inability to fall asleep or stay asleep, has been linked to phentermine, both as a side effect of taking the drug and as a withdrawal symptom. As phentermine stimulates the nervous system, most patients recognize the insomnia while taking the medication. However, insomnia can also be related to depression, which is a dangerous side effect that dieters may face after finishing their prescription. If you continue to suffer from insomnia for more than a few days, speak to your doctor to determine if further action is needed.

Low Mood

Phentermine helps suppress appetite and cravings by altering the levels of the mood-regulating neurotransmitters norepinephrine and dopamine. After quitting the drug, it often takes time for the brain to return to its normal state of functioning. Due to this, depression symptoms like sadness, low mood and fatigue are common symptoms of phentermine withdrawal, and for people with an underlying mental illness such as depression, these symptoms can be particularly harmful. Exercise and proper nutrition can alleviate some symptoms, and your doctor may prescribe appropriate medication if the problem persists.

How Can I Avoid Withdrawal Symptoms?

While withdrawal itself is not always avoidable, there are ways to help minimize symptoms. You should follow the prescription instructions as set out by your doctor, and you should also consult your doctor before attempting to discontinue phentermine so that you can discuss together how to manage and minimize any potential withdrawal symptoms. In many cases, gradually tapering down to a lower dose can reduce the severity of withdrawal, and as phentermine is available in doses ranging from 37.5mg down to 15mg, you should be able to taper down your dosage before stopping it. If you want to reduce your dosage before stopping it entirely, you should always check with your doctor before deciding to do so yourself, in order to ensure that this is an appropriate course of action for you.

While still taking phentermine, you should build yourself up towards the inevitable end of your prescription by using phentermine as a tool to help you achieve a maintainable healthy lifestyle. As well as eating healthily and exercising, it is important to establish a good sleeping routine and to take time to relax and look after your own well-being and emotional needs. This balanced routine will help you adjust to life without phentermine, both in terms of maintaining the weight loss you have achieved and in terms of managing any withdrawal symptoms you may experience.

A great way to continue this balanced routine is to use a weight loss supplement such as Phen Caps to manage the end of your phentermine prescription. Like phentermine, Phen Caps suppresses appetite/cravings and increases energy, meaning that the withdrawal symptoms of fatigue, low mood and weight gain are all less likely. Furthermore, you will benefit from further assistance with weight loss management, therefore extending the likelihood of successfully reaching your weight loss goals.

If you’ve experienced withdrawal symptoms following the end of your phentermine prescription, or if you have any great tips for how to minimize these symptoms, we’d love to hear from you! Please get in touch by commenting below!


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101 Responses

  1. I have been taking Phetemine 37.5 for about 3 weeks now and I feel like crap. I started out with horrible hot flashes and sweating horribly then it went to being really jittery. Which I can handle those side effects but now this week for about 5 days now I have had the worst headaches of my life. I have tried ibuprofen and Tylenol and home remedies of rubbing Vicksburg vapor rub on my temples and sleeping with an ice pack on my face and NOTHING helps it. I am so miserable I just want to quit them cold turkey, but I\’m scared of the withdrawls. But I can\’t take these horrific headaches any longer, they make me cry and very irritable. To top.it off I am very constipated which I never am and I am extremely tired but can\’t sleep at night. And if I do sleep it\’s only a couple hours.
    What do I do?
    I hate this drug!

    Sincerely headache that won\’t go away

    • Hi Heather,
      We’re sorry to hear you’re having such a miserable time on phentermine! We would definitely recommend getting in-touch with your doctor right away. While mild side effects are common, you should speak with your doctor ASAP if they are so bad it’s interfering with your daily life (like yours are). If you’d like to know more about side effects, you may be interested in this page: https://www.phentermine.com/phentermine-side-effects.htm
      Hope you feel better soon!
      Rachel, phentermine.com

  2. Hi my name is Tonya I been on this drug since feb 1 2017 I just threw my last two pills away today! I been moody snappy to my family not sleeping head aches jidery feeling rapid heart rate my blood pressure been a little higher and my heart rate was super high today well I went to the doc today for a weigh in and like I said my blood pressure was a little up and my heart rate was super high I told the doc I haven\’t been feeling right and I been experiencing chest pain well they done an ekg on me which was ok thank god but she wants to do a complete blood work on me in the morn. But I also noticed I been loosing some hair recently not in clumps but a small handful of stands I take out of my comb or brush or I find a small handful in my tub! And I find same amount on my pillows I don\’t know why I\’m having this?? Iforgot to ask the doc! I know my side effects were bad but I wanted to loose weight and nothing else worked even though I was told horror stories on this drug and read the same! Well I felt so bad since I been on this drug I am so scared of the withdrawls now! If anyone could help please send me a message back.. I have three kids and I stopped taking this drug because I want to be here to see them grow up! The reason I took this drug to loose weight is because my husband needs a kidney transplant and he\’s on dialysis well I asked the the people who was doing his transplant papers if I could be a living donor and the guy litterely told me I couldn\’t because I am too fat that killed me I couldn\’t help save my husbands life and like I said we have three kids ages 17-14-& 10 well I went from 235 lbs the first year and I wanted to loose more weight because it wasn\’t coming off any more so I told my doc I need help can I have the phentermine well I went from 210 to 175 my first goal I lost the 35 lbs since feb 1st. Now I need to know how to keep loosing weight with out this drug????? And how to not get the withdrawls so any advice please comment!

    • Hi Tonya, thanks for your comment! You might find this blog post about hair loss on phentermine helpful. Also consider checking out our Facebook support group for your questions about weight loss after phentermine. There’s lots of other people that have transitioned off phentermine, and they may be able to offer you some helpful tips and advice. Best of luck on your continued journey!
      Rachel, phentermine.com

  3. My name is Lori,
    I have been blessed, I am off and was on for three months. My doctor gave them to me to assist with slow weight loss, and yes I have suffered some of the side effects to a minor degree.
    Today, after being off for two days, I am tired and needed to take a nap. I also recognize having had drymouth and some insomnia during the 3 month course of the medication, but I had already been on a weight loss regiment.
    Most likely I won\’t go back on the medication because I was doing it before, it did assist, but did not speed up the already occurring weight loss.
    I researched the medication for weeks before I started, and had been on a proven systematic weight loss regime then and now; just be thoughtful, listen to your body, and use good judgement.

    • Hi Lori, I\’ve been on Phentermine for 5 weeks and have another week to go. I want to get off of them but after reading all these comments, I\’m scared. Did you just stop the medication cold turkey? I just started a new job recently and don\’t want the side effects to mess me up. I\’m tired of the dry mouth and feeling like my heart is racing. Also, I have insomnia occasionally.


  4. It depends what you are on exactly. If you are on Qsymia (phentemrine plus another drug), you can\’t go off cold turkey. It can cause seizures. You must talk to a doctor about how to properly ween off these drugs. If any of you are foolish enough to buy drugs from the internet or illegally….taking one every other day for couple weeks may be better than cold-turkey if the drugs you are given are even what they are supposed to be. These are questions that can only be answered by a real doctor with a real medical degree and not some flunky or fraudster. Your life is at stake.

  5. I\’ve been taking phentermine for about a year. Started with one dose 37.5) then increased to an additional half dose at midday per my doctors advice.
    I wanted to come off the pills, tried to last month. Experienced terrible side effects and gained about 10 pounds (in less than a month). After looking online I now see that side effects are experienced and considered withdrawal.
    I started taking my prescription again because I couldn\’t handle the side effects.
    Any suggestions on how to get off phentermine without the hellish side effects? (sleepy, depressed, eating everything in sight, can\’t focus or think, weight gain).


    • Hi Nicole! We’re sorry to hear about the terrible side effects you’ve had while coming off phentermine 🙁 Did you try to stop cold turkey, or gradually decrease the dose? If you’d tried to stop all of a sudden the first time, it may help if you tried to come off it a little more gradually. We would recommend talking with your prescribing doctor about your desire to get off phentermine and the withdrawal symptoms you’ve experienced, and then raising the idea of decreasing your dose little by little. Never adjust your dosage without first speaking to your doctor. Best wishes!!
      Rachel, phentermine.com

    • HI Nicole,

      I just have been 7 days on Phentermine and I suffer the same.
      I am kind of relieved that you also can\’t think and focus, which is my main trouble.

      I already have been to different doctors and they say my vital stats, nerval system and everything is ok.

      Are you over it? Are the side effects gone now?


  6. I have been on phentermine for about 7 weeks now. The last 4 days I have been so dizzy, headaches, forgot fullness, really tired and just confused all the time. I want to stop taking them but after reading the comments I’m scared to. Do you think it would be okay if I didn’t take one tomorrow but take one the next day? Then wait two days to take the next one. That way I just slowly come off of it?

    • Hi Dani 🙂 If you’re experiencing a lot of side effects from phentermine and want to stop taking it, it’s best to schedule an appointment with your doctor if at all possible. He/she can help you address your symptoms and work with you going forward. Best wishes!
      Rachel, phentermine.com

  7. In 2014 I used Qsymia going through all the steps. During the first few months the weight loss was great. I continued this for 6 months with a weight loss of 35 lbs. My Dr. slowly backed me down and off the drugs. I kept the weight off until I had foot surgery that put me down for 2 months of no weight on the foot. Went back on it about a month ago at 3.75 lost a few lbs. Stepped up to 7.5 and have lost nothing. However I have constant stomach pain and no real desire to eat but I do. This drug regimen worked so well before but now nothing. I\’ve currently stopped after taking one month of the 7.5 dose. Any suggestions??? HELP!!!

    • Hi Judy! Sorry to hear that Qsymia isn’t working as well this time around. We would suggest talking to your doctor about the stomach pain and lack of weight loss to see what he or she suggests. He/she may adjust your treatment plan, bring up other options for weight loss meds and/or discuss non-pharmaceutical weight loss options. Either way, hope you feel better and find something that works soon! Best wishes!!
      Rachel, phentermine.com

  8. I have been on phentermine for about 5 years trusted my doctor knew what he was doing i was up to 37.5 mg now DEA has his license on hold he can\’t write a prescription for my med. he is also on vacation so I am out of phentermine which means I just had to suddenly stop taking them I can\’t sleep, my body hurts I just want to know how long does the withdrawals last?

    • Anita,
      I\’m sorry to hear you are in such a bad situation and a victem of circumstances. I know I can only speak from my own experience, but it might help since it also comes from my knowledge working in pharmacy for the past 17 years. What seems to help some individuals with the chemical signals controlling your described symptoms, might be 5-HTP. Sold in most store like Walmart and natural food stores. 100mg at first each day before bed. Ideally, 200mg each night (after 2 days of 100mg being tolerated well). 5-HTP is the precursor to melatonin and it is much better for your body to have instead of taking just melatonin right off the bat because it allows you to naturally cycle into the production of melatonin. Over the counter melatonin is not as bioidentical as what your own body produces and is a hormone that will keep derailing the full natural cycle. This will help with mood, neurotransmitters, etc which are all the root of symptoms you might be experiencing.
      The only other thing I might add is a good *Raw* vitamin B complex. Brands like vitamin code are great for providing your body with better absorbable and usable B vitamins (bioavailability). Vitamon B is very important to metabolic rate and feeling energy naturally. I hope this helps. I asked Phentermine representatives about their take on 5-HTP two months ago so I could be aware of any post market contraindications 5-HTP and Phentermine might have displayed in individuals (would illustrate the combo might only trigger underlying issues that not all people may have, but might want to be aware if). They confirmed that their side has also seen great benefits of 5-HTP and Phentermine.

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