Why Does My Phentermine / Adipex Not Work?

Phentermine can be called a miracle drug when it comes to weight loss. It is considered the first line, the standard treatment of overweight or obesity.

However, we should realize that the same drug can act differently for patients, because all people are different. Phentermine may not show the same effects or its effectiveness may be reduced under the influence of various factors. And, sometimes, even the best diet pills are not the best answer for some people.

In this article, we will discuss the causes of why Phentermine, Adipex, Duromine or any other Phentermine-containing drug does not work, and tell you what to do about it...

How does Phentermine work?

Let's first briefly discuss the action mechanism of Phentermine, and then explain why the drug does not work for some people and when it usually doesn’t work. This is a really important point. After all, you should not have illusions about what to expect from the treatment.

  • Phentermine stimulates certain centers in the brain and suppresses appetite;
  • The drug does NOT do anything else (even though assumptions were made about its thermogenic effect, not a single trial has confirmed it).

Phentermine does not burn fat and does not destroy fat tissue. This is how other products work, which can you can buy on YourBody.Expert. Read our articles, if you are interested.

While using the drug, you will not feel hunger (severe hunger) all day long. This is not simply our opinion. These are the conclusions of such serious organizations, like the FDA.

Phentermine does really work, and you should not deny it! Yes, of course, we are talking about most people, and not every single person individually. However, this fact can become a starting point in your journey to a healthy weight.

Appetite is not suppressed

The essence of Phentermine use is to lower your appetite and cravings. If this does not happen after several days of treatment, you have a reason to say that the drug does not work. You may think or say it, but this is not a reason to stop the treatment, at least, not right away.

OUR ADVICE: Give it 5-10 days.

There have been reported cases, when Phentermine did not exert its action immediately. Therefore, you should not rush to conclusions. Give your body some time to adapt to the action of the drug, and perhaps you will find the answer to your problems.

Do not fight with nature, fight the excess weight

You might have decided that Phentermine is a miraculous drug and began using very low-calorie diets. It is worthy of respect, but, perhaps, not the best way to act.

What happens if you limit your daily menu to a very small amount of food?

The drug will partially suppress hunger. However, if your body receives very few calories, you will feel hungry. There is no drug to fight this.

OUR ADVICE: Avoid very low-calorie diets, or keep to them for a very limited time – just to shock your body a little and make the weight move.

Your weight (fat deposits) are the balance between the energy you put into your body and the energy you use. To lose weight, you need to spend more energy than you consume with food and drinks during the day.

The appetite is suppressed, and the weight still does not decrease

We researched a lot of reviews about Phentermine. People say that they have less craving for food, yet the scales indicator remains at the same level. Therefore, they claim that Phentermine does not work.

OUR ADVICE: Change your lifestyle.

The diet pills are not the problem! Phentermine does reduce the appetite, but it does not guarantee fat loss. This is something that you and your body should do. If you still have no idea how it’s done, let us enlighten you. You must:

  • Be physically active;
  • Consume less calories than your body needs.

Of course, you probably made some efforts to lose weight, and you don’t rely on Phentermine action only. Most likely, this is not enough. You need more dramatic lifestyle changes.

You can keep to a really good diet, and not the best training plan (or vice versa). Do not be afraid to experiment. Ready weight management programs are not always the perfect choice for you.

It was good... but below my expectations

When people have really serious problems, it’s very easy to force yourself to believe in something, which is actually not true. Logic conclusions and evidence simply stop working.

What happens when people read the following:

  • “I lost 25 kilograms in 5 weeks”
  • “7 ways to reduce weight by 30 kg in one month”
  • “Half an hour a day is all you need to lose weight”

People start to believe that such quick and easy weight loss without a single effort truly is possible. Self-deception is not the best assistant on your way to a healthy weight.

OUR ADVICE: Set realistic goals.

We will not say that a fast weight loss is impossible. It can happen, and there are thousands of examples. But let's base our assumptions on the facts and results of clinical studies.

Phentermine is, perhaps, the most effective appetite suppressant. Want to know what can you expect? We will gladly provide you with this information (official sources) in different versions:

  • Weight loss of 5-10% in 12 weeks;
  • Loss of 6.4 kg in 12 weeks.

NOTE: these are average results, they can vary depending on many factors.

The results may indeed seem modest. But wait! We will tell you something interesting and really important. If you have class 1 obesity:

  • A weight loss of 5–10% will lead to a decrease in the amount of body fat by 20–31%;
  • After a course of treatment, the diagnosis of "obesity" may be replaced by the diagnosis of "overweight".

In addition, weight loss should not be quick. This is what doctors say, even though we dream of something else.

Repeated use of Phentermine

In your weight loss program, you can use:

Once you have completed the first treatment course (12 weeks) and finished the recommended break between the courses (1-2 weeks), you can repeat the course of treatment. Many people say that the effectiveness of the second and subsequent courses is not always satisfying.

OUR ADVICE: Try changing the type of Phentermine-containing medicine.

If you used Adipex 75 (a.k.a Adipex Retard), try replacing it with Phentermine, or vice versa. The body will respond to the release rate of the active substance from the capsule in a different way. The treatment effect may be the same as you felt during the first course of treatment.

This advice may help in other situations, as well.


You've probably heard something about severe drug interactions. This may sound quite serious and even frightening, right?

Interaction does not always mean that you will feel something like the side effects. It’s just that one certain drug may interfere with the action of Phentermine, and you will not even guess about it. As a result, you think that Phentermine is not effective, though it is simply the result of its interaction with another medication that you use.

OUR ADVICE: Do not combine Phentermine with other drugs.

Before you start using Phentermine, ask your doctor or pharmacist questions about the drug interactions. Find out if you should avoid certain drinks, food and medicines.

Proper use of Phentermine

In order for the obesity drug to work properly, it should be used CORRECTLY.

OUR ADVICE: Follow the recommended dosing schedule.

It means that:

  • You should take Phentermine in the morning with or without food;
  • You have to alter your lifestyle for the better;
  • You should NOT double the dose in an attempt to increase the treatment effectiveness.

These are basic, yet not all recommendations for use. Read our articles for more information.

Why is Phentermine not always the answer?

Phentermine might work perfectly well for your friend, and not work for you at all. This can really happen, even if you use our advice or other tips.

OUR ADVICE: Do not stop.

Phentermine is a truly unique drug that stands out from other weight loss pills. However, it is not the only obesity-fighting game plan.

Do not wait until the weight turns into a serious medical problem. Look for a solution, and you will definitely find it.

A Final word

As you can see from the above, there are many reasons why Phentermine does not work as you expected. Depending on the reason, there are solutions, which might help you.

Scroll the text up and down again.

Our advice should help you on your difficult journey. We hope that you will find the long-awaited answer to all your questions.

We kindly ask you to share your comments on how to improve Phentermine, if you have any. Write your recommendations and we will gladly study them. Your experience can help other people get the most out of Phentermine use.

To the main pageNext article
Blog Search
Blog categories