The Second, Third, or Fourth Time Around With Phentermine

The Second, Third, or Fourth Time Around With Phentermine

Although phentermine is the most widely prescribed weight loss medication, something that those prescribed it will often encounter when they search the support group on Facebook, is that many people return to taking it after having taken it in the past, sometimes several times. 

This can lead to concern that phentermine is ineffective in the long term.

Still, as we explain here, there are many factors to consider when taking phentermine, and recognizing these is the key to ensuring that this is your more successful and final weight loss journey.

Returning to Phentermine Following a Break

It can be surprising for new phentermine users that, amidst the success stories, many people report returning to phentermine after their first, second, or third attempt.

However, that is not to say that their previous attempt or attempts were ‘failures’; one important thing to consider is that the majority of doctors will only prescribe phentermine for limited periods, often with breaks of at least one month in between periods of usage.

Sometimes, doctors or patients themselves prefer that the break be longer so that the patient can establish a healthy eating routine without reliance on phentermine.

Returning to taking phentermine may not mean that the patient gains weight during their time away from taking phentermine, but rather that they give themselves time to adjust and assess how to proceed with the remainder of their weight loss journey.

This second time on phentermine, therefore, comes with added insight into how to maintain their new weight or continue weight loss without phentermine and how making lifestyle changes while taking it can help to ensure long-term success following the end of their prescription.

Regaining the Weight

The same thread conversation does, however, include several phentermine users who gained back some or all of the weight that they had lost with phentermine before returning to taking the medication.

Still, as the entries show, this is intrinsically related to their expectations of phentermine and their attitude to weight loss while taking it.

One user talked about losing 50 lbs with phentermine in six months, but that’s because this was simply due to not eating very much due to a suppressed appetite and not due to learning new, healthier habits.

She went on to gain back the weight she had lost when she stopped taking phentermine, and her appetite came back.

One key phrase she uses is that she ‘leaned on the pill’, which is to say she expected that phentermine would do all the hard work for her, which may lead to weight loss but very rarely leads to maintaining this loss in the long term.

Phentermine should be seen as a tool to kick-start weight loss, not as a ‘cure’; to successfully lose weight and keep it off with phentermine, it is crucial that you use your time on phentermine as an opportunity to learn healthier habits such as drinking more water, exercising, eating healthier foods and avoiding processed foods.

Phentermine provides a decreased appetite and energy boost, making it easier for you to remain motivated and focused on weight loss success. With more energy, you can concentrate on eating healthily and incorporating more exercise into your daily life.

Then, with these new healthy habits established as part of your new lifestyle, it will be possible to continue without relying on phentermine.

How to Make This Time Your Last

How to Make This Time Your Last

If you’re someone who has taken phentermine in the past and gained weight following the end of your prescription, there are many crucial things to consider.

Perhaps the most important is that your first, second, or however many times before we’re not failures, but rather experiences to learn from. If you have successfully lost weight in the past, you can do it again, and the fact that you have since gained weight does not detract from this success.

However, you must change your way of thinking.

Many people embarking on a new healthy eating plan are serial offenders, whether it’s with phentermine or with a new diet.

So it is understandable to have an “If this doesn’t work, nothing will” attitude when you’ve been there before. However, this kind of negative thinking can really harm your best intentions.

Many studies have shown that a person’s belief in success makes it far more likely that they will achieve it. So, have faith that this is the start of a whole new you, and never underestimate the power of positive thinking.

The best way to achieve this success is to learn from the mistakes you may have made in the past.

Phentermine allows you to develop new healthy habits, so rather than relying on it to do all the hard work for you, you need to embrace this opportunity to establish healthier routines such as exercising, drinking water, and eating regular healthy meals.

With these healthy routines in place, the transition to finishing your phentermine prescription will be much smoother, and long-term success will be within your reach.

Another point raised by the phentermine users in these posts from the support group is that, often, their second time taking phentermine does not give them the same effects, whereby the energy-boosting properties and appetite suppression they experienced the first time around are not as apparent this time.

Although this can be frustrating, if you are also experiencing this, then a great way to help boost the effects of phentermine is to add PhenQ to your new healthy lifestyle.

PhenQ is a weight loss supplement that suppresses appetite and provides energy, just like phentermine.

Still, as they contain different ingredients, they can be used to complement your phentermine prescription and help make this time even more successful for you.

So, the good news is, with some positive thinking and a new approach to making this time on phentermine a success, whether it’s your first or your fifth time, long-term weight-loss success is within your reach!

If you’ve tried phentermine before and are starting again, we’d love to hear from you, so please leave your comments below!

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  1. This is my 2nd time taking the 37.5mg of phentermine. The first time the weight fell off and I lost almost 30lbs. This time it’s not as effective. The weight loss clinic that prescribed them stated that I can take a pill and a half, but I’ve read 37.5 should be the max you take a day. Has anyone ever took more than the 37.5 mg a day prescribed? Is this even safe?

    1. Hi Angel,

      Over time, the body adapts to phentermine and its effectiveness can decrease. Phentermine tolerance is an especially common problem for patients who have taken phentermine for a long time or are taking it for the second or third time. Here’s what you can do about it:

      You are also more than welcome to join our official Facebook support group so you can connect with other phentermine users today:

      Best regards,


      1. Hi Sarah- started Phen in August of 2022. Was on for 3 months lost 25-28 lbs- then it stopped working and I was finished with prescription not knowing that my Dr would keep me on . Started back in November but it was not the same – so 20 lbs have creeped up again due to bad eating choices. I’m on again- but have to get my mindset working
        Age- 63 Hashimoto (Hypothyroidism)
        5ft 6
        CW 181
        Whole Foods
        My one question since your dietician- is there a soluble fiber that really keeps a person satisfied. Not to have cravings
        Glucomannin or Chia seeds?
        Does L – glutamine work for cravings?
        Let me know if you have a website for nutrition that helps people with nutrition / supplements
        Much appreciated

        1. Hi Julie,

          To get an added boost of appetite suppression, we recommend adding Phen Caps, the leading phentermine alternative, to your daily phentermine. Phen Caps can be taken safely alongside your prescription to complement and support the effects of phentermine.

          To keep hunger at bay, you must focus on filling up foods high in protein and fiber, as this winning combination will leave you full for hours.

          So, be sure to eat lean meat, fish, eggs, and other healthy protein sources, as well as plenty of fiber-packed foods, such as whole grains, legumes, fruit, and veg.

          Hope that helps! You are also more than welcome to join our official Facebook support group so you can connect with other phentermine users today:

          Best regards,


  2. Hi there, I am 59 years old and was on phentermine 2 years ago. I had wonderful success losing 20 lbs. I kept it off, but the last few months, have gained 10lbs back. I also take bio identical for menopause and have for 9 years. I went back on the phentermine, but this time I feel nothing! No increase in energy, but mainly no decrease in appetite at all. I read some people have luck taking phen caps with the phentermine. Do they have to be purchased from a certain site,? What is the recommendation on this. I need to get this under control. I feel like I am always hungry. Thank you.

  3. I took my first round of Phen and lost 53 lbs in 9 mos.after changing my diet and reducing carbs and eliminating all soda and fast foods. I was extremely happy with the results and I felt GREAT! However, I took them for a very long stretch of time and got some pretty bad digestive issues which I believe ended with appendicitis. I do not blame the med for this, it was my mistake for taking it without a break. I have been off for 4 months and am just starting to put weight back on due to emotional eating that comes with my Bipolar disorder. Again, my problem not the meds. I am going to start my 2nd round and hope to get my mental state back in order. I read that if you take the Phen 2-3 x a week with intermittent fasting it can be very effective. Any comments on that?

  4. Hello, so last year I was considering bariatric surgery and my PCP asked why and of course I explained it to her. I’ve been fighting the blood pressure battle for years through medication. She says I can take that weight off you but ur blood pressure. Long story short she put me on but monitored my pressure monthly. Started me off with 15 mg then 30 and finally 37.5. I’ve lost 30 pounds in 6 months but am currently not taking Phentermine any more. How long of a break is needed before starting back? She only allowed 6 months.

    1. Hi Deedra, congrats on your success with phentermine! It depends on your individual case, but most doctors will consider a second round after a few months’ break. If you’re interested in going back on the medication, we would suggest bringing it up to your PCP. 🙂

  5. I started taking phentermine last year was on it for a few months and had no side effects lost 30 pounds. I had gained some back and wanted to go back on so I started last month. They recently upped my dosage to 37.5 since everything was fine and I wasn’t really seeing any results. I was also on 37.5 last year and had no side effects. The past two days i’ve had severe nausea, haven’t thrown up but i’m so nauseas wnd bloated that I don’t even want to eat. I started taking the 37.5 approximately 4 days ago. Is this a side effect that could occur? Or is it something else?

    1. Hi J! Yes, unfortunately nausea and bloating are common side effects of phentermine. Still, if the nausea or bloating gets worse, bothers you or isn’t going away, make sure to get in-touch with your prescribing doctor. He or she can best assess what’s causing the problem and help you treat it. Hope you start feeling better soon!

  6. I just had a baby 3 months ago and stopped breastfeeding two weeks ago. I tried Phentermine for the second time and I feel nothing. No energy and not curbing my appetite. Could it be my hormones affecting the drug? First time I used it two years ago worked great. Lost 40lbs in 4 months and kept it off till the baby. I only need to lose 30lbs this time

    1. Hi Amy! We’re actually not sure about this one, but it’s not out of the norm for people to experience a lack of effectiveness when they’re prescribed phentermine again. We’d recommend talking with your prescribing doctor about other medications and/or weight loss strategies. Best wishes!

  7. Hi was taking Duromine a few years ago with great success then stopped as I fell pregnant. Have started taking them again 6 months post baby but they are not working anymore. Im eating less but I’m not losing any weight. Any idea why this might be?

    1. Hi T! Could it be that you’re eating too little now? It seems counter-intuitive, but it actually slows weight loss when you don’t eat enough calories because your body thinks it’s in starvation mode and tries to hold onto the extra fat for energy. Unless your doctor specifically told you differently, aim for at least 1200 calories per day. You may be interested in these blog posts about calories for weight loss and eating enough on phentermine. Best wishes!

  8. If I stopped taking phentermine a month and a half ago can I start up again now? I lost 30 pounds being on it for six months and I’ve gained Almost all of it back.

    1. Hi Emily! Many people can take phentermine again after a break, but it’s ultimately dependent on your individual case and doctor. So, we’d recommend asking your prescribing physician if he/she thinks it would be okay for you to try phentermine again. Best wishes!

  9. I’m 63 and took phentermine over a 30 year time frame 10 times. I always had good results and minimal side affects until this last time. I began to have hard scary chest pains the almost made me double over. I had them for a couple of days and when they did not go away I went to the emergency room. I had stop taking the pills a week before the pains so I’m not sure if the pills had anything to do with the pain I experienced. Of course, I’ve began gaining the wait back and I’m trying so hard to keep it off. I just don’t want to undo what I almost lost my life trying to achieve. I might sound crazy but I think I want to try the pills again for about a week to get a handle on my eating. Fighting obesity is hard work, I just don’t want die trying to get it done.

    1. Hi!

      That sounds like it could definitely be a side-effect of taking phentermine. We strongly suggest consulting with your primary care physician and telling them all about that experience before embarking on the phentermine treatment again. Yes, fighting obesity is hard work, but not worth losing your life or permanently damaging your health over.



  10. I had taken phentermine back in 2013 and lost about 20 lbs. pretty much kept it off and only had been on it a month, the 20 lbs took about three months and stayed off! I just take it a month to get me back on track with eating habits and exercise. I recently gained it back and started taking it again 37.5 and I feel fantastic and finally not starving all the time! I would eat even when I was full before taking it. I use phentermine for only a month to get myself back on track. I also break it in half and take half after breakfast and other half later afternoon. Gives me enegery and curbs my appetite so I eat sensibly and have discipline. Stating weight was 150 and now 131. It helps me with fine tuning, losing the love handles and puffy belly.

  11. I’ve been on phentramine for the past 3 days now and I can already tell a difference in my appetite ..when can I expect to start losing weight?

    1. Hi Brittany,
      If you’re taking phenTRAmine as opposed to phentermine then we’re not sure about that product and success rates. However, with most weight loss supplements and medications then you should start to experience weight loss after a week or so if it is working as it should.

  12. I was prescribed 50mg of topimate. He actually asked me would I like to up it again. No way I am still experiencing hair loss in wads. Seems every time I shower I have a shower full of hair! Moody & gassy. ?

  13. I am restarting Phentermine for the 2nd time. I made some dumb choices and have been stress eating. I almost feel as if my hips are growing and so paranoid about weight gain because i hated myself when i was bigger. I made an appointment and will go in Friday and will start Phen Saturday morning again. This time on Phen though i will exercise as i lost weight too fast last time and had saggy skin. Has anyone ever taken more than 25mg of Toprimate? I am not sure if that quit working the last time as well.

  14. I have taken phentermine, probably, 5 times in the last 9 years. Each time it works, but each time comes with some stupid side effect. It never gave me energy or kept me up at night. When I got older and started school and gained some medical knowledge, I figured out that the reason I was always tired while taking the stuff is because my resting heart rate was about 140. I didn’t feel palpitations, so I had no clue until I took my vitals one day and put the puzzle pieces together. I was tired because my entire body was working overtime, especially my heart. The last round I took it (nearly 3 years ago), I was determined I would change my eating habits and workout. Well, it’s hard to work out when your heart rate shoots up to 220 with minimal activity. Finally I had an EKG one day that had some signs of old muscle injury ( which admittedly was probably non-specific) but scared the daylights out of me. I of course ballooned back up when I stopped taking it, and am at my heaviest now. But I refuse to take it again. My advice is to be careful on this medicine. It is not meant for long term use.

  15. I was prescribed Phentermine 37.5 mg at the end of 2010 and was on it for 5 mos. I lost 25 pds, going from 167 to 142 without much effort of diet and exercise. My heaviest was around 180 but got down to 167 before getting on the pill but I couldn’t get any lower. It was fantastic; I was so happy and felt so free and comfortable in my own skin. I could shop anywhere and clothes looked good on me! I was able to hang onto my weight loss for a few years before it started creeping back up to the 160s. I live in Ohio and the law only allows you to be on the pill for 3 mos at a time with a 6 mo wait to get back on. I went to a new dr that does weight and age management that did thorough blood tests for thyroid (showed it was high but not over limit), hormones, food intolerance and a 24hr urine hormone test that showed my cortisol wasn’t clearing. I cut out the food that showed intolerant and he put me back on the pill along with thyroid meds that brought my levels down to 1.2, DHEA, Progesterone and a bunch of other supplements to try to get my cortisol under control. I had little results and my weight crept back up to 170s. We then tried the other diet pills on the market Contrave which had terrible side effects that I couldn’t tolerate and Qysmia that had little effect other than losing a few pds. 2.5 months ago I started acupuncture, diet changes, and exercising 5 days a week for an hr each and gained 7 pds bringing me back up to 175, 35 pd from my lowest on the pill! Im trying to read up on cortisol and making changes to lower it but I am at my wits end working hard with no results. I may try to get back on the pill for the fifth time to see what happens. Glad to know I am not alone in this battle!

    1. When working out, did you try Interval training? Im also hypo. I started on Phentermine 4 months ago and have lost 32 pounds so far. I started out at 227 and now weigh 195. Im 65 years old and 5’1″. It’s awful because being hypothyroid makes it very difficult losing weight. I work out 4 days a week. I have a trainer 2 days a week. I ride the recumbent bike for 30 minutes, One minute fast, 20 seconds slow. It really made a difference, I had a trainer for 1.5 years before trying phentermine. I’m praying that once I get down my metabolism will reset and I can keep the weight off. I’m hopeful. I also have dinner before 4:40 PM. I eat nothing after 5:00.

  16. This is my 3rd time with Phentermine. The first time I lost 30 pounds, with no problem, no exercising and had to force myself to eat. I also had trouble sleeping. I was in my 30’s. The 2nd time around I was 43 and not sure how the weight crept up on me but I went back on them and again I lost 25 pounds, but it was a little harder this time and took longer but it worked. I am now 49 and have been struggling with my weight gain for over a year. My lowest was 143 and my heaviest was 178. I have hit 175 now, I started 3rd go round last year, and had no luck whatsoever. I had the headaches, but no sleeplessness – I slept too much and had no energy, was moody and I did get down to 155 but gained it back so quickly. I get a yearly wellness check at work – nice perk – and well the results of the blood test showed my thyroid was not working, I took it to my GP and was diagnosed with hypothyroidism. I am on synthroid, and taking the 30mg phen (i always took 37) I have added working out,careful eating and well watching everything – I have been back on Phen for 3 weeks (working out for 7), and only have 4 pounds to show in my loss. It’s frustrating that’s for sure – working out 5 days a week, eating better and now have cut out sodas. It may be a slow haul but I’m not giving up! I go back to the Dr in October and they said they may up the mg when i go back we will see how its going. I can tell you its hell getting older! 🙂 Other than that thyroid I am healthy and always have been very active. I am finally starting to feel normal again from taking the synthroid. So we will see what happens

    1. Oh wow this is my story too!!!! How did you go? I feel as though the phen isn’t working anymore because I’ve only lost 3kg in 8 weeks!! (I’m not sure how many pounds that is?) I am 5ft 4 inches and weighed 81kg now I weigh 78kg

  17. Hi What you wrote sounds exactly like my experience. I had alot of success and felt great while taking phentermine years ago, (the white and blue speckled ones) but now I have just started back and I am taking the 30 mg black Lancett 0957 pills and they are awful, I have no energy, stomach upset, nervous and jiterry they just make me feel completely different and not good like before. May I ask you which phentermine pill you are having the great results with now? Which manufacturer and what do they look like? Thanks so much and good luck with this time around! Kathy

  18. This is my third time on Phentermine. The first time I was 24 and me and my friend (who was overweight) decided to try them as she was scared to take them alone. I lost 20 lbs in 3 months with no diet or exercise and she lost 60 lbs and we were just so impressed with these pills and our results. A couple of years later (26) I had a baby and I wanted to get the weight off without exercising or dieting, so I started taking Phentermine again and I must say it was nothing like the first time! My appetite was suppressed, but I was still hungry with really bad headaches and at night when I was coming off the pill I was so irritated, so I decided not to continue! Well I am now 41 and I just had a baby 10 months ago and I have gained so much weight during and after the pregnancy and I just didn’t have the motivation to eat healthy or exercise due to me being so exhausted. I went to the doctor yesterday and my blood pressure is up (not to be concerned about just higher than usual) and I currently weigh 260 lbs!!! I have never been this big in my life and I literally cried after I got off the scale. Needless to say my doctor has put me back on Phentermine and has advised me that I must change my eating habits and exercise this time around because I am not as young as before and my metabolism is slow. With that being said, I took my first pill today and I felt wonderful!! I had energy again I even went walking for 15 mins (got to start somewhere) and 6 hrs later I’m still not hungry. I do have a very bad case of dry mouth but that’s more reason for me to drink water instead of my usual sodas. I really hope the pills work like they did when I was 24 because I am so unhealthy and unhappy right now and if I can get a jump start with these pills like before then I will definitely do my part. If the headaches come back I will discontinue use. I really want to be where I was when I was 24 which was 160 (before Phentermine) so I have 100 lbs to lose! Wish me luck and good luck to Bonnie I hope you lost the 22 lbs.!

  19. This is my second time doing Phentermine. The first time I just wanted to lose 25 pounds which I kept off for 3 years by exercising and eating healthy. December of 2013 I had a complete Hysterectomy and had to stay home for 6 weeks I then gained 22 pounds back fast. I am on Phentermine again hoping to lose the 22 pounds I had gained. Last time I had the capsules this time they gave me a tablet I asked the Doctor are these the same she said yes but to me they are not as strong as 3 years ago. I lost 5 pounds the first week and 2 the second which is good you don’t want to lose to fast. I see now you have Phen Caps do they work as good as Phentermine and does the same company as the prescription Phentermine make them? I watched the video on Phen Caps and the only thing I don’t agree on is she mentions Dr. Oz well all the products he shows on his show don’t work and those people sponsor his show thats why he endorses those products.

  20. Hello my name is nikkia I start taking them 3 years ago next week. .. I’ve lost 170 on them I look and feel so good thank u so much

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