Phentermine Tablets vs. Phentermine Capsules

Phentermine Tablets vs Phentermine Capsules

Since phentermine is manufactured by various pharmaceutical companies, it comes in many different shapes and sizes, including both capsules and tablets.

You may wonder what the difference is between tablets and capsules and which is better regarding phentermine.

Here we run through why companies choose between the two and what the advantages and disadvantages of each are when it comes to your phentermine prescription.

Phentermine Tablets

The most commonly known form of phentermine is the white tablet with blue speckles, although there are also plain white tablets made by certain manufacturers, all of which can be seen here.

Adipex-P, the most popular phentermine brand, comes in the form of white tablets with blue speckles, and it is thought that manufacturers such as Actavis Pharmaceuticals and Qualitest Pharmaceuticals copied this widely recognized design for their phentermine tablets to maximize their selling potential, as people often incorrectly believe that the blue speckles are the active phentermine ingredient.

To be effective for their intended use, tablets must be designed according to the required release time, which can be either quick, delayed, or extended-release.

As phentermine must be released throughout the day to be effective, manufacturers design the phentermine tablets with the appropriate extended release dissolution control.

This is achieved by including inactive ingredients in the tablet, such as the coating, which controls how the active phentermine ingredient is absorbed by the body.

However, one disadvantage of tablets is that they can pass through the body without being completely absorbed, meaning that it is possible that some of the phentermine fails to enter your bloodstream.

Tablets are cheaper to make, and so patients often find that their prescription is cheaper to fill.

Tablets can also be notched for splitting, which is an advantage that patients taking phentermine tablets have mentioned in the support group on Facebook.

If you find that your dosage is too strong and that the side effects are difficult to manage, as long as your doctor is in agreement, splitting your dosage by breaking your pill in half can be a good solution.

Some doctors may also advise patients to begin by taking half a tablet and then working up to a whole tablet. With tablets, there is also the option of taking half in the morning and then half before lunch, which can be particularly useful for people who experience an energy slump after lunch, as this is a key time of day when people are more susceptible to unhealthy cravings for sweet or fatty foods.

Another disadvantage of phentermine tablets is that they are only available in the maximum dosage of 37.5mg, so if your doctor feels that a lower dose is more suitable for you, then it is likely you will be prescribed capsules, as these are available in doses of 15mg, 30mg, and 37.5mg.

Phentermine Capsules

Phentermine Capsules

Phentermine capsules come in various colors and include the popular phentermine brand Adipex-P, the FDA-approved phentermine and topiramate combination Qsymia, and various dosages of generic phentermine.

Adipex-P capsules are available in the 37.5mg dosage, as shown here, while generic phentermine capsules are available in either 30mg or 15mg, as shown here.

Qsymia is available in four different dosages, ranging from 3.75mg of phentermine and 23mg of topiramate to 15mg of phentermine and 92mg of topiramate, all of which are shown here.

One major advantage of capsules is that they have a much better absorption rate than tablets as they begin to dissolve immediately in the stomach.

There is little to no chance that any of the contents will fail to be absorbed by the body.  Capsules enter the bloodstream immediately, so phentermine in capsule form contains slow-release ingredients to ensure that the effects are released throughout the day.

Capsules have the added advantage of providing an immediate boost of energy in addition to the extended-release of effects, an advantage mentioned on the support group on Facebook, as patients report feeling the initial boost of energy that is then sustained for longer throughout the day.


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Furthermore, unique mixes and ingredients are more achievable with capsules, which is why Qsymia is produced in capsule form.

Qsymia provides prolonged appetite suppression and energy-boosting effects by combining topiramate with low doses of phentermine, which would be difficult to produce as a tablet.

One disadvantage of capsules is that they are more expensive to produce. Therefore, a prescription for phentermine capsules can sometimes be more costly for patients.

Although capsules cannot be split like tablets can, as they are available with lower dosages of phentermine, there is more chance for your doctor to prescribe an appropriate dosage rather than just 37.5mg, and therefore there is less need for patients to have to split their dosage.

As capsules are coated, they are often easier to swallow than tablets.  

If you still find it difficult to swallow the capsule, you may want to take the contents of the capsule out and mix it with liquid, but this is not advisable.

Capsules are specially designed to be taken whole, including the case usually containing time-release technology in the coating.

By taking just the inner ingredients, you could cause the phentermine to become less effective, especially later in the day, or the medication could be released into your bloodstream too quickly, which might worsen side effects.

You should speak to your doctor if you continue to have difficulty swallowing your medication. He or she may recommend that you take Suprenza, a brand of phentermine that dissolves on the tongue.

With phentermine, the decision to prescribe capsules or tablets will depend on your doctor and which of the two they believe to be a better option for you.

The main advantages of tablets are that they are cheaper and can be split in two, both of which can be preferable to you as the patient.

However, capsules are absorbed better by the body and, in the case of phentermine, they are available in a wider variety of dosages and brands, including Qsymia, the phentermine and topiramate combination, due to capsules being better suited to more complex and unique ingredient mixes.

Have you taken phentermine in capsule form or tablet form? If you’ve taken both, which do you prefer? Let us know by commenting below.

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  1. I originally was prescribed phentermine 37.5 that was a blue tablet. I had previously taken the generic Adipex, the white tablet with blue specs, and was miserable daily with a horrible headache. The last time I received my prescription, the pharmacy had changed vendors/suppliers for this medication, and it was the white tablet with blue specs. I’ve been taking those for almost two weeks now, and I’ve had a headache about everyday. Do you know the name of the light blue oval pull? Is this a normal side effect? Does the light blue tablet have toparimate in it, as well, so that can help with preventing headaches? I am only 15 lbs away from my goal and want to continue, but I can’t stand the daily headaches.

    1. I started taking phentermine 37.5….I have horrible head aches. I stopped taking the pills. Years ago I was on phentermine and had no head aches . Wish I was able to take them.

  2. Hi Victoria,
    You could try at the pharmacy to see if they will swap them or if not then request your script back. It’s strange that they have given you capsules when your prescription was for pills. This can be a huge difference for some people – the cost isn’t the only factor to consider when it comes to certain meds, which a pharmacist should know.

  3. Hi. I recently went to the doctor and was out on 15 mg capsules twice a day. I was still hungry after taking them so when I went back the next time he doubled my dose. So now I take 2 15mg capsules in the morning and 2 more in the afternoon. I’ve read a lot of reviews and I’m afraid my dosage is too high… What do you think???

    1. Hi Brittany,
      This dosage is very high – 60 mg total per day is almost twice the typical maximum of 37.5 mg. We obviously don’t have the medical training and knowledge of your doctor but this doesn’t seem like a good idea to us. Is it possible to get a second opinion?

  4. I know it’s not recommended to crush the tablets, but I’m wondering why. Does it change the effectiveness of the pill?

    1. Hi Kay,
      It’s because the tablet is set and coated, which allows it to pass to your stomach without the ingredients dissolving before it reaches there, and also helps the ingredients to be released gradually so that it is effective for you throughout the day. By crushing it, the ingredients start to dissolve on the way, which can result in a lower dosage of phentermine and a shorter period of effectiveness. If you find it hard to swallow tablets then there is the brand Suprenza, which is a dissolving pill:

  5. I have been on the 37.5 tablet for 2 plus weeks now and so has my sister. She feels very good and energetic. I, on the other hand feel absolutely nothing! I have been doing everything Dr told me such as journaling all my intake daily, drinking lots of water but I just have no energy at all. My sister can’t believe I don’t have the same results as her. What can possibly be going on with me? I can feel a little appetite control but zero energy which I need very much to work out, walk etc. Do you guys think I should try the capsules? I need more energy badly. Also I take vitamin supplements and follow my diet very well. I’m disappointed in myself.

    1. Hi Kim,
      This is nothing you’ve done wrong so you shouldn’t be disappointed in yourself. This is simply a demonstration of how phentermine (and all medications and supplements) affect people in different ways. We think you should ask your doctor about changing to a different brand or switching to capsules as these could work better for you.
      Good luck!

  6. I was originally given the white tablet with blue specs. It was not for me. Heart felt like it was going to pop out my chest and extreme dizziness. After 5 days the doctor gave me 30mg yellow capsules. Only side effect dry mouth which is good causing me to drink more water. Lost 50 lb in 11 months. I stopped losing weight and appetite increased so i was told to start taking 2 in the morning. Still no more weight loss actually gained 7 lbs. now im taking 1 capsule 30 mg along with 1 75mg tenuate. Been 1 week not sure if lost any weight but started having bowel issues resulting in bloody stool. Not sure if its related. Will be contacting doctor today since I’ve been taking phentermine for 17 months and the blood has only been since adding the new pill

  7. I have been prescribed 15 mg capsules which I take twice a day. I do feel like hunger is more under control than normal but I am NOT experiencing the boost of energy everyone keeps talking about! In fact, after I take, I feel sleepier or more sluggish. Two years ago I did take phentermine tablets and did experience that energy boost. I wonder why I am not experiencing it now?

    I do have pcos and gained about 30 lbs after having my baby. He’s now one and I have been trying desperately to get the weight down. I am also on metformin and occasional hydrochlorthyzade for water retention. I wonder if my dosage is too low? Do I need the full 37.5 for the energy?

  8. I have been prescribed 15 mg capsules which I take twice a day. I do feel like hunger is more under control than normal but I am NOT experiencing the boost of energy everyone keeps talking about! In fact, after I take, I feel sleepier or more sluggish. Two years ago I did take phentermine tablets and did experience that energy boost. I wonder why I am not experiencing it now?

    I do have pcos and gained about 30 lbs after having my baby. He’s now one and I have been trying desperately to get the weight down. I am also on metformin and occasional hydrochlorthyzade for water retention. I wonder if my dosage is too low? Do I need the full 37.5 for the energy?

  9. I picked up my script today and will start taking the capsules tomorrow morning. I’m really hoping to see the results that I’ve read about online. My goal is 40 pounds. I do take sleeping pills so I’m really hoping that will help with the insomnia that I’ve read so much about. Anything else I should be prepared for?

  10. I am taking the 30MG capsules. However, I am finding that even when I take them at 6:30AM I have a hard time getting to sleep until about 4AM the next morning. Do you think this may be from too high of a dose?

    1. Hi Joann,
      From what you say I think that it could be a little too high, at least to start with. As it’s a capsule it shouldn’t be broken in half or anything so perhaps you could ask your doctor for a smaller dosage to build up more resistance and then move up to the 30mg if and when you need more effect.

  11. I went to a diet doctor who gave me Phen 30 mg capsules, red & black. I guess I’m just wondering if they are really phen as I can never find pictures of my capsules and lately they don’t seem to be working as far as weight loss – just insane dry mouth that I can’t get rid of.

  12. Hi I’m on phentermine – 45mg capsules, yellow and white…it’s been 4 days and I’ve only seen 2lbs lost and I’m in the treadmill mornings for 15mins then by 11am another 10mins and at 11pm for 15mins. And I’ve cut soda down…I was drinking 5-7 cans a day….lately I’ve had half of one to one whole can a day depends…..& 4 days later only 2lbs……back in 2011 I was on phentermine 37.5mg capsules blue and white now these helped me but I only took 15 pills and lost almost 10lbs but I stop taking them bc I felt jittery and was not hungry at all….I was not eating at all just drank water and my husband was worried…
    So is anyone taking or is on phentermine 45mg yellow and white capsule? Any ideas for me to lose weight faster….I also got 4 b12 shots that day I was given these pills…

    Thanks !

  13. I have always taken the 37.5 mg capsules and I love them. Recently my prescription got screwed up and I received the tablets instead of the capsules. I do not like the tablets. They do not suppress my appetite and they make me feel sick to my stomach terribly. Has anybody else noticed this?


  14. I was currently taking phentermine 30 mg capsule – the black ones. The dr said he was going to put me on a stronger dosage and now it’s phentermine bc 30 mg capsule – it’s a white and blue capsule with small beads in it. Can you tell me the difference between the 2?

    1. Hi Brittany,
      The two sound very similar as they are both capsules and both a 30 mg dosage, so there is no difference in strength. The two capsules are probably made by different pharmaceutical companies and may have different inactive ingredients but are otherwise very similar. If you want any more information it would be best to ask your doctor as he will know more about different manufacturers.
      Hope that helps!

  15. I started taking the phentermine capsules November 5th and I’ve lost 20 pounds in one month. So the capsules are working for me, and I feel I have more energy and not as tired anymore! Here’s to hoping to more weight loss.

  16. I’m a gastric bypass patient. I require immediate release medications because extended arent properly absorbed. However, other medication that I’ve been on for other things, i.e. Seroquel etcetera, have cause me to gain fifty pounds so my GP prescribed Fastin (no longer available) and they gave me a capsule made by Sandoz E5000 that is ER … does Adipex P get released immediately by capsule or tablet?

    1. Hi Gerard,
      Tablets are more likely to be immediate release than capsules, although I’m not sure if they would count as immediate release as all phentermine is designed to incorporate some kind of extended release in order to keep the appetite suppression and energy boost going throughout the day. It’s best to ask your doctor which would be most suitable for you.

      1. Thank you. I know that Adipex P is the most prescribed. Because, as I mentioned, I require an IR mechanism I wasn’t certain to ask the doctor for Adipex P in tablet or capsule. Last month he prescribed Fastin* (no longer produced) and the pharmacy gave me extended release which hasn’t helped. Just want to know what to ask for. Thanks, again. Happy Thanksgiving.

    1. Hi , I’m going to start taking the capsule 30mg do u think what time u should take them, and can u eat before u take them or after?

  17. I previously took the capsules and my doctor said my body would adapt to taking the capsules and they would become ineffective. I refilled my script and was now given the white and blue tablets. Will my body adapt to these too?

    1. Hi Jennifer,
      Yes because your body is adapting to the phentermine, which is the active ingredient in both the capsules and pills. You may find the pills work better for you, or you may find that they don’t work as well, as people respond differently to the two types of phentermine. Hopefully they’ll work great for you!

  18. Lost 18 lbs. on 37.5 and it’s been over a year but I had to sacrifice sleep to stay on the pills. So, I stopped for awhile, and Dr. Suggested 30 mg. capsules. Still, I’m never tired!! So, I drink Extra Sleeptime tea which contains some Valerian root and it helps a little. I can get about 4-5 hrs. Sleep now. Is the tea safe with Phentermine? I still need to lose 20 more lbs. I’m 5’1 and 155.

  19. I am on amitripiline and was prescribed 15 mgs of phentermine capsules… Yellow & grey… Is it safe to take together?

    1. Hi Dawn,
      You should only take medications alongside phentermine if it’s been specifically approved by your doctor. Before you take the two together you should ask your doctor if it’s safe to combine these two medications.