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!


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25 Responses

  1. I just started using phentermine and I don’t have mood problem. I’m still have and appetite I exercise before I go to work.I eat breakfast lunch and dinner. One thingi notice is im very tired. I mean my metabolism is very low.my questions is can I take and energy drink to boost it.

    • Hi Jay,
      If you’re tired it could be a side effect of the phentermine. We would advise you to try more natural methods to increase energy first, such as drinking water, sleeping at least 7 hours each night, and continuing with the exercise as this will help to increase energy levels. We would not recommend that you drink energy drinks as these are made up of chemicals and sugar, both of which will make phentermine less effective and will not help your weight loss efforts either. If your lack of energy continues then you could try the weight loss supplement Phen Caps which we recommend for added energy and appetite suppression to boost your phentermine. Here is a link to find out more: http://www.phen.com/phencaps
      Hope that helps!
      Sally, phentermine.com

  2. I’m taking Phentermine 37.5 mg. For almost 2 months now I started last month & I have not felt anything no weight loss, I have had the gastric by pass surgery done, I really can’t do any exercises, my knees prevent me I have severe arthritis in my left knee but it’s in both knees, I do diet I always buy fish tikapua, frozen veggies, fruits usually bananas, grapes, cantaloupes, honeydew melons, so my question is why am I not losing but gaining it all back, I was on belviq for a month my INS wouldn’t cover it; it’s too expensive for me, so help me out here what am I doing wrong, little today bit I do lack sleep I’m Lucky to get at least 3-4 hrs of sleep; I chew ice cubs cause I retain fluids

    • Hi Donna,
      The lack of sleep could be a factor, and retaining fluids would mean that you’re less likely to see a drop on the scale even when you have actually lost fat. You could try upper body exercises which would help to build muscle, and swimming is usually a safe exercise even for people with injuries. Do you feel the effects of phentermine, such as a suppressed appetite and more energy? If not then it may not be working for you like it should.
      Sally, phentermine.com

  3. Which are better? The pills or the caps

  4. Menstrual bleeding ever since I started taking phentermine x16 days ago?

    • Hi Shelley,
      This is not a typical side effect of phentermine – you should talk to your doctor straight away.
      Sally, phentermine.com

  5. I’ve been on adipex/phentermine for 2 weeks.. I know not a long time. I have lost 4 pounds.. the problem is, is I keep gaining weight back. I started at 240, I went down to 233, then I’ll gain back 2-3. I eat 1000-1200 calories a day. And I exercise. Could the problem be my thyroid? I am on synthroid and getting half my thyroid removed. Once I get it removed will my weight loss from phentermine get better? I need this to work, I feel like I’m out of options.

  6. Hi, I started taking phentermine and am on my 2nd week. I lost 7 pounds but on Monday when I started my 3rd week I gaind 5 pound it just doesn’t makes sense – I exercise 5 days a week and drink 80 ounces of water a day. For breakfast I eat 2 eggs with spinach, for lunch I have a chicken salad, and I hardly ever eat dinner maybe a cereal once in awhile. Can someone tell me what I’m doing wrong I’m so disappointed

    • That was posted last month, have you lost any yet? I’m in the same boat. I exercise 5 times a week and I eat 1200-1300 calories a day. No weight loss in 2weeks

  7. Only lose 5 lbs a month
    I still feel sluggish during the day and can sleep but can’t sleep at night I’ve been on adipex 2 months – cravings don’t deminish as I am a extreme binge eater of 16 yrs not by choice but by habit. I try to eat three small meals but find myself getting sick so I got stuck 160 weight after kids and can’t get back down 🙁 why isn’t it working for me like it does my friend who is a nurse?

    • And I am very active I push 5miles every other day drink only water and eat veggies raw yum I love my veggies just thought I add

  8. I started Phentermine on 4-28-2016. So far I’ve lost 18 LBS! I drink half my body weight of water, eat healthy and exercise daily. I burn almost 800 calories every day. I do a lot of the incline on the treadmill and elliptical, even cardio! But I still fit in my same pants size. I started off at 260, to 242. I have two more months left with phentermine..

    • I also started the same same day 4/28/16 on the first month i lost 16lbs im already on my 3rd month feeling great havent weighed my self though till i go back on August 11th…… 🙂

  9. I started this 8/6/16 weighing in at 223 at the doctors office but then I weighed myself with my own scale on 8/9/16 and weighed 211 so I really don’t know which scale number is correct because it is impossible to lose that much weight in like 2-3 days and I don’t feel the difference, but it’s probably the 223 lbs that I probably weigh, so I probably still weigh the same. Anyways, ever since starting this I’m even hungrier than before starting this pill, I eat a normal meal and then start to get full, but after like a half hour I get really hungry and nauseous, and my stomach feels empty. Today I kind of felt a little dizzy that I thought I was going to pass out, but I didn’t since I rushed to the kitchen to eat something. I also feel weak and sluggish but not tired, and it is really hard to go to sleep at night and go back to sleep because I take this pill at 6 am and then go back to sleep since I normally wake up at 11 am or around noon, but I’ve basically been sleeping for like 3-4 hours ever since. I don\’t know but ever since starting this I feel like sh!!!t but very wide awake which I didn’t before because I always felt tired before taking this pill. Maybe I need to lose weight the normal weigh… (haha get it? lol ill stop.)

    • Sorry I meant to say I weighed myself on Sunday August 7th, not today.

      • Sorry forgot to add more…

        I have a gym membership that I haven’t used in months and I would love to go back or at least go to the nearest trail and walk but I’m afraid that I’m gonna pass out since I feel weak-ish and feel heavier and sometimes I feel like my eyes want to go dizzy but I don’t end up stumbling or anything.
        I don’t know, I probably need to stop taking this.

  10. Lost 5lbs first week, one lbs the second week. I’m on my third week but my husband threw my pills away so I’m not on them this week and I feel bloated!! 🙁 my Dr won’t Rx them until next week bc they only allow 7 pills a week. I weighed on my home scale and it looks like I’ve gained back almost all the weight I’ve lost!! 🙁 how and why I don’t know, I sleep enough, I walk a mile every day twice a day, I eat one cup of food per meal as directed by my Dr and only what’s on the plan and have my three snacks which of course is veggies or a fruit, also only approved items on the list and even got my shots to boost energy. I take b12 and b complex and iron for my anemia. What could be wrong that I’m gaining ??? 🙁

    • Hi!
      The weight gain might be related to the bloating you’re experiencing. It could be related to your menstrual cycle, not drinking enough water, a food intolerance, or if you’re suffering from constipation as a side effect of phentermine. It’s not possible to gain that much weight in a week so it’s more likely to be water weight. If both you and your doctor think that this plan is the best way for you to lose weight then it shouldn’t matter if you are taking phentermine or not – phentermine does not directly cause weight loss, it just helps you to stick to your plan, which you seem to be able to do without phentermine. Just keep doing what you’re doing and stay strong! 😀
      Sally, phentermine.com

  11. I am currently taking phentermine. I still feel the energy but I do feel hungry during the day. Does that mean its stopped working for me?? Also, I weighed myself this morning and weighed in at 164. I got back on the scale when I got home from work and I weighed 165. Why?! I’m taking birth control so maybe that’s interacting with it and causing my weight loss to slow down??

    • Hi Jessica,
      This is the problem with weighing yourself too often. Your weight increases throughout the day due to the food you’ve consumed, liquid levels in the body, salt etc. You also get shorter throughout the day but then at night your body is still running, using the fuel consumed throughout the day while also stretching out your limbs and muscles, so that you wake up taller and lighter than you were when you went to bed. You should only weigh yourself in the morning before any food or liquid and ideally just once a week as that’s when you notice the overall difference, rather than becoming preoccupied with these ups and downs of a pound or two here and there which happen constantly throughout the day. Contraceptive pills haven’t been found to interact with phentermine so these are unlikely to affect your weight loss. And, with respect to still feeling hungry, only you know if this hunger is more or less than you used to experience. But, it is normal and correct to still feel hungry on phentermine – it isn’t designed to completely remove hunger. These tips on how to suppress appetite should give you some advice about the types of foods which will keep hunger at bay for longer: http://www.phentermine.com/blog/10-tips-suppress-appetite-phentermine/
      Sally, phentermine.com

  12. I am not sure if anyone still uses this blog but I have been on phen since Aug 9th. I have lost 15lbs but over the last week I haven’t lost anything at all. I eat oatmeal for breakfast, yogurt and a fiber one bar for lunch, and usually chicken breast and a veggie for dinner. I am also working out 5 days a week. I cant seem to lose anymore although I am nowhere close to a normal BMI. Is anyone else having this issue?

    • Hi Shaunte,
      The blog is where we post articles about phentermine and the comments on them are usually questions for us to answer. You might find it better to post in the forum to share your experiences with other phentermine users and to ask for advice. Here is the link to sign up if you’re not a member: http://www.phentermine.com/forum/register.php.
      In answer to your questions though, I have a couple of suggestions. Firstly, losing 15lbs in less then 3 weeks is really great and something to be celebrated. However, weight loss is not always linear – it is not typical to lose consistently every week, so this stall isn’t permanent, your body just has to adjust itself to take your losses into account. Secondly, it doesn’t sound like you are eating very much. I don’t know if you’ve just outlined a few of the things you eat, but you should be eating at least 1200 calories a day – oatmeal is great for breakfast but adding some fruit would be better, lunch should be around 300 calories and should incorporate some vegetables or legumes for fiber, protein and nutrients, and then your dinner seems fine. The fiber bar and yogurt would work better as snacks, and maybe add some sources of healthy fats to your diet such as oily fish, avocado, nuts or olive oil, as well as more whole grains, such as brown rice, quinoa or whole grain pasta. Hope that helps!
      Sally, phentermine.com

      • Thanks Sally. As far as my diet thats all i have been eating every day since i don’t have much of an appetite.

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