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Why You’re Not Losing Weight With Phentermine

why you're not losing weight on phentermine

Phentermine is undoubtedly an extremely effective weight loss medication, but for all of those who experience weight loss success, there are some who are left wondering why they’re not losing weight with phentermine. While it could be that phentermine has stopped working for you, if you can still feel the effects of appetite suppression and added energy, then it could be for one of these reasons.

1. Eating Too Much

Counting calories can be a pain, but it’s a good way to allot how much food you can have at each meal and for each snack. In addition, it’s also important to weigh your portions as you could be overestimating how much you’re meant to eat of certain foods; test how accurate your judgment is by portioning your food as you normally would and then weigh it out afterwards. If you’re consistently serving yourself generous portions then you could be consuming A LOT more than you think, therefore making losing weight with phentermine more difficult.

2. Not Eating Enough

Phentermine works by suppressing appetite, but sometimes this effect can be too strong, to the extent that people have zero appetite and can struggle to eat anything all day. You may think that less food = more weight loss, but as we explain here, that’s really not the case; there is an ideal amount of calories that you should be eating to successfully lose weight, and getting that balance right is the key to losing weight with phentermine. If you’re consuming too few calories each day, your body’s reaction is to think that there are lean times ahead, meaning that it will turn your metabolism right down and cling onto any fat that comes its way, i.e. you are less likely to lose weight.

3. Not Getting Enough Sleep

Establishing a healthy diet and becoming more active will help you to shed pounds, but lifestyle factors such as getting enough sleep also play an important part in your ability to lose weight with phentermine. When we lack sleep, our brains crave unhealthy easy foods, and our hormones tell us that we’re hungry when we’re not. This is clearly not a recipe for losing weight with phentermine, so make sure to make sleep a priority and get at least 7 hours every night.

4. An Undiagnosed Health Issue

Before prescribing phentermine, your doctor should check that you aren’t suffering from one of the many health issues that can cause weight gain or make it difficult to lose weight. These health issues can include a vitamin or mineral deficiency, such as anemia, Polycystic Ovary Syndrome (PCOS), diabetes, or an under-active thyroid, among others. If you haven’t been fully checked for these types of issues and losing weight with phentermine is proving to be difficult then ask your doctor for a full health check-up, even if just to eliminate these as potential reasons.

5. Not Getting Your Vitamins

Deficiencies in vitamins and minerals lead to a sluggish metabolism and slow bodily processes, meaning your body has to work extra hard to process the food you eat, and as a result, losing weight with phentermine is more difficult. So, make sure you get the recommended daily requirements of important weight loss nutrients to get better results. That said, it can be difficult to eat enough of a variety of foods to meet all these requirements, so we recommend Phen Vites, which contain all of these crucial vitamins plus added premium ingredients like 5-HTP to help boost your weight loss potential even more.

why you're not losing weight with phentermine

6. Too Stressed

Stress can be one of the underlying reasons for weight gain, so it makes sense that it’s something that needs to be addressed in order to lose weight. One study found that participants taught stress-management techniques were able to lose significantly more weight than the participants who weren’t taught these techniques, even though their diets and activity levels were the same.  Reducing stress balances out hormones and allows your body to function better, so you should aim to reduce your stress levels for success in losing weight with phentermine. Click here for some great ideas on how to manage stress.

7. Not Exercising

Many people rely solely on diet to lose weight, which can be effective to a certain extent, but it’s the combination of diet and exercise that really gets results. Unless you’re unable to exercise due to injury you should get moving every day, even if it’s just walking for half an hour. If you find it hard to get motivated to exercise, check out these ways to make exercise more fun. Exercise is a great stress reliever, adds to your phentermine energy boost, and, research into long term weight loss has consistently found that exercise is the key to losing weight with phentermine for good.

8. Eating Too Many Empty Calories

Losing weight with phentermine isn’t all about eating less, it’s more about eating better. And the same is true of your calorie allowance; just because two foods have the same amount of calories does not make them equally good for you. Furthermore, low calorie or low fat options aren’t always the way to go, so try to avoid light, low fat or specific diet foods as they often substitute healthy fats or calories for added sugar or salt and can be more processed than the regular foods they aim to replace. Instead, aim to get goodness from your diet by seeking out foods packed with vitamins, minerals and healthy fats, avoid anything overly processed, and fill up on fiber and protein to keep hunger at bay for longer. You should also watch the calories and sugar you consume in your drinks, as liquid calories can really add up without giving us any value for money as far as goodness goes.

9. Not Drinking Enough Water

Drinking water has so many benefits for those losing weight with phentermine; water suppresses your appetite by filling you up without the calories, it helps your body work better and boosts metabolism, maximizes the effects of phentermine, relieves side effects, and it helps you drop water weight. Make water the ONLY thing you drink and you’ll be sure to see a reduction in side effects, a healthier you and improved weight loss results. And, for an extra weight loss boost add the ultimate detox, Phen Drink to water to see even more success.

10. Not Challenging Yourself

If you’re starting from zero then phentermine will give you a huge burst at first, but too many people continue on automatic pilot and expect to see these great results all throughout their phentermine prescription. Instead you should see it as a learning process, where you expect to progress and improve in all aspects of your life, and not just as a means to an end. So, challenge yourself continuously to eat better and be more active by setting new targets and mini-goals to keep your interest up and you’ll be sure to enjoy more success losing weight with phentermine.

Could one of these reasons be why you’re not losing weight with phentermine? Let us know by commenting below!

122 thoughts on “Why You’re Not Losing Weight With Phentermine”

  1. Avatar

    I started Phen last week after my weight has really gone up in the past several years. My ideal weight is 120-125. I’m 151 lbs.now. 5’5 and 65 y.o. Even though I eat fresh vegs, fish & chicken, and little carbs, I keep gaining, Asked my doc to recommend something to jump start my metabolism. She prescribed Phentermine 37.5. After 4 days of the jitters, dizziness, dry mouth and headaches, I havent lost an ounce! It’s very discouraging to read these comment from Phen users who are religiously counting calories, exercising hours a day, eliminating carbs, giving up coffee, teas & soda, and still little to no weight loss! AND, if the AVERAGE monthly weight loss (as determined by several medical studies), is ONLY 3-6 lbs, why bother taking Phen? The cost ($40 for 30:pills) & side effects just aren’t worth the minimal (or no) results. VERY DISAPPOINTING.

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      Maura, I took Phentermine a few years back and went from 150 lbs to 119lbs, size 12 to size 4. Here’s what I did: When starting out taking Phentermine, take 1/2 a tablet for the first week, then increase to a full tablet, this helps your body adjust to it and jitters and dizziness go away. The dry mouth helped me drink more water, it was irritating but I kept taking the pills, the first month I only lost 3lbs, doctor said keep trying. I was exercising some, eating more chicken and fish, fruits and veggies but still not losing. I went back after another month and again I had only lost 2-3 lbs, again he suggested to keep trying. So I did. The third month, I changed nothing, still exercising a little, still eating the same, changed nothing I had done the 2 previous months. After my first week into the 3rd month I started dropping weight and dropping it fast. I lost all my weight within 5-6 months. I think everyone’s body chemistry is different and some start losing right away and others take a little more time. Oh and only weigh yourself once a month, your weight can fluctuate during this time and can be very frustrating. If you try again, Good luck, drink lot’s of water, take vitamins, walk, eat better.

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        Dante Mackenzie

        You have no idea how grateful I am you posted this reply. I’m in mother two and I’ve lost almost nothing. I was feeling so discouraged. Thank you.

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          Roseanna Morrison

          My dr will only prescribed it for 3 months I have lost 31lbs in 3 months I was disappointed as well I thought I should have lost more I watch calories only 1500 ad day walked a mile 3 times a week due to knee surgery but did 1/2 other days drank lots of water don’t give up keep working my first time I did it I lost 68lbs but walked 2 miles a a day and watch everything I ate went from 359 to to 288 so it can work dropped my account to 4 from 6 good luck

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            Thanks for the review. I started taking Phen 37.5 I think 5 days ago…prescribed by my PCP. The first 4 days was very weird due to headaches jitters and dizziness.

            Also the first 3 days i wasn’t hungry at all but i still force myself to eat a little…but since taking Phen i change my diet from the get go once i started, mainly eat salad with grilles chicken or bake chicken. I stop eating snacks or drinking any beverages the day i started the Phen medication.

            So my body is either confused or freaking out as to why the host immediately STOP feeding it all those delicious rubbish that it has been accustom to eating all these years.

            Well on day 4 i started to feel hungry just a very very very small bit, but also i was not craving the food so i was in no rush to eat. I also had this irritating headache and dizziness that just could leave me alone, so i felt to beat the hunger i had a salad and bake chicken. But that night i was still a little hungry so o had some more of the bake chicken.

            It is now day 5 and there’s no headaches jitters or dizziness, i don’t have the urge of not eating as i did 4 days ago, but am also not craving to eat. My PCP prescribed the first dose of Phen for 14 days and am on day 5. So i hope and pray that i get to lose weight just as you did.

            I currently weigh 357 pounds…i hope my weight loss journey goes smoothly.

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        Thank you for this post because I was getting discouraged because losing nothing, but feeling better. I need to just stay focused! You were a big help!

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      I was on the 30mg for 2 months – no weight loss – my Dr bumped me up to the 40mg – been on these for 16 days still no weight loss.. I’m 54 5ft 5in and 84kg – my weight is usually 66kg – 68kg – this weight gain has only taken place over the past 2 years and I am post menopause- had all my blood tests and my thyroid is normal.. I walk 3-4 times a week for 30-40 mins and I am GF and lactose intolerant so my diet is not a bad one.. these extra 16kg are killing me..

    3. Avatar
      Patrick A. NewPerson

      I hope you did not give up and something has worked out for you.

      My experience has been an “unqualified success”; words by my dr. I have dropped just shy of 40# in 3.5mo. It truly has been transforming. After 3.5 mo I am just 2# away from dead center average in all categories that matter; blood work is perfectly normal in all areas that matter too. The annoying side effects dissipated after a couple of weeks. I was neurotically consistent, taking within minutes each, under same conditions; kept a log using a lap timer.

      Surprisingly, It took nearly a month before my weight started drop, then at a rate of about 3-5# a week. I approached the whole problem “holistically”: a brutally honest assessment of what I consumed, and how much; type of exercise and how much. Water and lots of water. Counted every damn calorie that crossed my lips-weighing everything with a digital kitchen scale linked to a phone app. Phentermine allowed me to more easily discern whether I was standing in front of the fridge because I was hungry and “needed” a snack, or if I was bored. I started with taking any serving of anything and taking half away to save. I used the psychology trick of using a smaller plate.

      I then assessed the types of exercises I did. Previously, I was doing nearly exclusively cardio and got no where – in 4 mo I lost just 2 pounds (which I attribute to new sneakers.) Cardio is good, no argument there, but it alone will NOT get you weight loss.

      This time, in consultation with a dr., lots of reading, and a fitness trainer, I discovered what they’d all been saying all along: strength training. A strength training plan geared toward age & gender and goals is key.

      In frequent contact with my dr, we have began a slow and carefully planned process of ending the use of Phentermine.

      Even my sleep dr is thrilled; my sleep apnea numbers became so low, I was directed to stop using a PAP machine.

      I am stunned and elated at where I now at: replacing belts that are two big, replacing pants. The widest part of my waist has dropped almost 13”.

      I hope you have found that which works for you. My 6wk old, 1st grandchild gave me mine.

      Good luck.

    4. Avatar

      I lost about 60 pounds last year by eating in a calorie deficit but I was still considered extremely obese for my height. I started going to the gym consistently 5 days a week back in January but didn’t lose any weight. I met with a personal trainer weekly and still nothing. I could see a difference but the scale wasn’t moving. I figured I was just gaining muscle so thats why it wasnt showing on the scale. Finally I got irritated in July so my Dr recommended we try this medicine (failing to tell me that it is addicting and that its an amphetamine). So I took it every day like prescribed. I was so happy that I had lost 7 pounds but when I went to my dr appt last week, my dr said that I should have lost at least 20 pounds. So that shot my confidence down. I did lose 5 inches on my waist but he still expected me to lose more. So I will be on it for another 2 months. But the last 2 days, I’ve been experiencing painful muscle spasming lasting for 12+ hours. First my calf, then my arm and now my neck into my head. The urgent care sent me to the ER because they thought it was the start of a stroke. Come to find out it’s a side effect of this medicine. I guess it attacks your muscular system. The ER doctor is confident the effects on my muscles will go away when I stop the medicine but she recommended I get a 2nd opinion on taking this med. She said I weigh too little to be on it (I am 200 pounds) and said the less you weigh, the higher chance of having permanent neurological and cardiovascular damage. She was also concerned that I hadn’t lost more weight since this medicine is an amphetamine. So, I guess I’m getting a 2nd opinion. I’m so irritated with this medicine. I’m not losing weight, the damage it does to your body outweighs the little bit of weight you lose, its super freaking addicting and from what I’ve been told, people gain the weight right back when they stop the medicine. It’s not worth it to me.

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    I have been on Phentermine for 11 months now and when I first started I was all excited I was down 11 lbs. But I haven’t lost since but I haven’t gained anything either. This is very upsetting. I feel like I hit a wall. I can tell that the Phentermine is working just not in the weight loss area. I don’t know what to do.

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      You have to start and stop phentermine at 3 months once you stop ,its a break for 1 month and then you can continue for another 3 months . If you continue longer than 3 months it wont work at all ! in order to work you have to give it a break

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    Hi I got phentermine from a doctor and 6 days in I started craving bad foods again and wanting to binge as if the phentermine lost its touch. There is no way I built up a tolerance in 6 days that’s nuts! Help!

  4. Avatar

    Hi. I’ve been on phentermine 30mg for 8 weeks. Lost 12lbs total. I eat right, drink my water, exercise every day. They added amino acids, B12 and chromium. They upped my dosage to 37.5mg to see if that would help but doesn’t. In 4 days, i gained and haven’t changed anything. I am also post menopausal. Does Phentermine help us that are older? I have alot to lose.

  5. Avatar

    I have been on Duromine for 2 weeks now , 15mg , nothing is happening at all , actually just putting on more weight. I am 52yo , in full menopause !!!
    help i am so frustrated and disappointed !

  6. Avatar

    Hi I’m 30 years old, 5’4, and I weigh about 197 lbs. I started phentermine about two weeks ago. Dr adviced me to take half a pill the first week but when I notice that I hadn’t lost anything I went back and asked him to up my dose, he told me to go ahead and take the whole pill which is 37.5 mg. I’m on the second week and still see no weight loss yet. The appetite has decreased somewhat and I’ve been trying to eat lots of chicken and salads instead of the junk I was eating before. I must also say that I have high blood pressure and take Metoprolol twice a day. I also take tramadol 150mg 3 times a day because I’m addicted to it and dr is slowly weaning me off of tramadol, I used to take a whole lot more a few months ago and I’ve been addicted to it for about 10 years but recently I decided that I wanted to stop taking it for good.
    Anyways, I was also told by my dr that I’m very low on vitamin d. Could any of these be the reason why I’m not losing weight?? I have an appointment with my dr tomorrow to begin a weight loss program where they give you a shot twice a week, this shot is a fat burner with vitamin B12 and lipozene.
    They also give you a seven day supply of phentermine (which I already have) and a seven day supply of topamax. Will any of this help me lose weight any time soon?

    1. Avatar

      Hi Isa,

      In an effort to make phentermine work better, many patients look for supplements to take with phentermine. Learn more here: https://www.phentermine.com/phentermine-stopped-working/best-supplements-phentermine/

      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 we explain more: https://www.phentermine.com/phentermine-stopped-working/

      Hope that helps!

      Rebeca, Phentermine.com

      1. Avatar

        Hi. I’m on my third day of phentermine. I’m 20, male. The issue isn’t that I need faster results, I’m patient, the issue is that phentermine doesn’t give me energy, even though it’s a stimulant. in fact, it makes me tired and sluggish, but it does make me feel content and calm. This is a little concerning for me, as it’s the opposite of what I’m supposed to be feeling . Some doctors think I have ADD, others said I do not, so I’m wondering if it’s just that I have ADD and so phentermine is having a sedating effect on me. It’s just a little concerning to me, and I haven’t seen anyone else have this problem.

  7. Avatar

    Hi week 3 on duramine.30 mg have lost 5.5 kgs but am now at a standstill.i was 91 kg now 85.5 kg and have seemed to come to a stand still at 85.5.maybe not enough water and I went off my vitamins. I take 4 women’s vita gummies a day and 2 vitamin b.s. as I’m low in vit b.my diet is good.salad yogurt fruit 2 multi grains slices bread per day and lean cuisine frozen prepared meal for dinner.and only water and a 1 cup of tea in morning with 1 sugar tablet what do u think of that .thanku fiona

  8. Avatar

    I’ve been on phentermine for 2 months now, first month 15mg and now up to 30mg on my second month and i feel like my body juat wants to hold onto all my fat , i lost 2kgs in the first month but felt like it stopped so that’s when they upped my dose, i don’t have too much to loose but this has been a weigh battle for ongoing years that severe dieting and excerising just can’t fix… and it seems this won’t work either.. is there anything else i can try ???

  9. Avatar

    Hi I have been taking phentermine for 2 weeks I lost 4kg and am still eating the same and can’t loose any more it has been another week with no weight loss I’ve tried eating less but still no difference not sure what do as I am not eating much I don’t think I should cut down any more also have been getting dizzy every time I stand up

    1. Avatar

      YOu probably aren’t eating enough. Try adding in protein shakes or something along those lines. These provide a lot of needed proteins and vitamins, without the bulk.

  10. Avatar

    I’m on month 3..
    Lost 7 lbs , gained back 2 .
    Walking everyday and eating extremely clean . I get plenty of sleep.
    I just don’t get it 😭
    In my early thirties I did phen and only lost 19 lbs in 4 months . I also take topamax and 5htp . I do however have a neck injury and take gabapentin for nerve damage, accident was this year and I had neck surgery, I’m still in tons of pain 😐
    Could something else be going on? Should I just keep hanging in there?

    1. Avatar
      Lorraine Santiago

      I’m not sure why this medicine isn’t helping you? I started taking the medicine June 1, 2021, and I’ve lost 14 lbs already. The key to it working, is putting your body in ketosis. I did that the first 4 days of the diet, by eating meat, eggs, and shrimp only. I also get a weekly B12 shot. Haven’t started exercising yet, and I hardly drink enough water.

  11. Avatar

    I am on my 2nd month and my first month I lost 21 pounds so I was feeling great I am still doing what I was doing last month but I have not lost any weight this month I am bummed out but I am hoping that it will kick in on month 3. We will see I have a Dr. Apt this Friday

    1. Avatar

      Hi Joshua,

      A plateau is a temporary stall in weight loss. Most patients experience at least one phentermine plateau, often 1-2 months into treatment. Here we explain what you can do about it: https://www.phentermine.com/phentermine-stopped-working/

      You are welcome to join our brand new support group so you can connect with other phentermine users, share your experience and get some valuable advice: https://www.facebook.com/groups/1069871763087734/

      Rebeca, Phentermine.com

  12. Avatar

    Do not take this medication! Just for helpful feedback I would stop taking it. Or only take it for a short time and get off of it it’s bad for your heart. Causes problems in your heart for life. Please stop.

  13. Avatar

    I am on day 4 day the first 2 days the energy was great I drank lots of water due to dry mouth. I am 42 yrs old with a 3yr old and 1yr old I suffer from major depression since having my last babies so I figured that was my cause for weight gain but anyways I thought this was going to work but now I am very doubtful as to most energy is gone so I’d dry mouth I continue to drink water thou I gave up my coke zeros I am only on a half of pill for the first month. Any suggestions on what to do to help?

    1. Avatar

      Hi Danielle,

      It’s important to point out that many phentermine users report that this medication amplifies emotional reactions in all directions. As a result, people with a history of depression or other mental health problems may be more susceptible to phentermine psychological side effects. Please be aware and click here to learn more: https://www.phentermine.com/phentermine-side-effects/depression/

      In regards to your question, maybe this can help: https://www.phentermine.com/phentermine-side-effects/fatigue/ and this: https://www.phentermine.com/phentermine-stopped-working/

      You are also welcome to join our Facebook support group so you can connect with other phentermine users, share your experience and get some valuable advice: https://www.facebook.com/groups/1069871763087734/

      Rebeca, Phentermine.com

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