Affiliate links on our site may earn us commissions. Learn More.

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy Policy.


Discover The Best Wellness Tips In Your Inbox

Subscribe to Health Reporter’s newsletter and get our health experts’ highlights and the latest news about healthy living.
The newsletters are spam-free and sent from our health experts and professionals.

Thank You!

You have successfully subscribed to our newsletter!
Home arrow Nutrition arrow Weight Management arrow How to Lose Weight on Phentermine Fast: Avoid These Mistakes

How to Lose Weight on Phentermine Fast: Avoid These Mistakes

Written by Dennis Njoroge
Fact checked by Rosmy Barrios, MD
Last update: April 7, 2023
8 min read 1488 Views 0 Comments
clock 8 eye 1488 comments 0

Millions of people struggle with weight loss. Learn all the tips and tricks on how to lose weight on phentermine fast.

how to lose weight on phentermine fast

There are endless diets, meal replacement plans, and supplements promising rapid weight loss, but most are unbacked by scientific evidence. 

However, some weight loss strategies are backed by research and considerably improve weight management.

Among these strategies is using phentermine, one of the most reliable weight loss prescription medications used to treat obesity for people who cannot lose weight by only working out and following a healthy diet.

Phentermine has been an FDA-approved drug since 1959 and is one of the safest and most effective prescribed medications for weight loss in the United States. 

This article will discuss how this weight loss medication works, show you how to lose weight on phentermine fast, and what mistakes to avoid when using this drug.

What Is Phentermine?

Phentermine is an FDA-approved weight-loss drug. Doctors prescribe phentermine for people with obesity to help weight loss. This drug is meant for short-term weight loss.

Phentermine accelerates weight loss by suppressing appetite, hence lowering your food intake and making a person feel full for longer. It works best as part of an overall weight loss plan combined with a healthy diet and exercise like other weight loss drugs.

Though this drug is among the common prescription weight loss medication drugs, taking phentermine is not suitable for you if you have underlying conditions like heart disease, glaucoma, or increased blood pressure. It is also unsuitable for people with a history of drug abuse, extreme agitation, or an overactive thyroid.

Pregnant and nursing mothers are also advised against taking phentermine. Taking phentermine for weight loss may sometimes cause addiction, especially for people with a substance disorder, and it is therefore classified as a controlled substance.

How to Intensify Phentermine?

It would be best to combine phentermine with lifestyle changes such as a workout routine and a dietary program to intensify it. Using phentermine correctly and combining it with lifestyle changes leads to noticeable changes in your weight.

Primarily, phentermine works as an appetite suppressant. It helps suppress appetite by increasing specific hormone levels such as dopamine and serotonin, which lead to reduced hunger levels and cravings.

Phentermine, therefore, helps reduce hunger levels among people with difficulties sticking to their recommended caloric intake hence allowing a person to lose weight gradually.

Though this drug won’t shred pounds by itself, it will significantly boost your weight loss rate if correctly used. Below are some tips to intensify phentermine’s effectiveness in your body.

#1 Make dietary changes

When planning to lose weight on phentermine fast, it will also benefit you to make permanent lifestyle and nutrition changes. 

Taking phentermine helps suppress appetite, and research suggests that phentermine users lost 3.3% more body weight than people on a meal plan alone.

Most people assume that phentermine makes it easier to starve themselves, but it is better to establish a healthy relationship with food instead.

Eat some healthy portions of nutrient-dense foods. Avoid foods with high sugar and salt content, preservatives, and saturated fats and replace them with a diet rich in healthy fats, protein, fiber, fruits, and vegetables.

Controlling your portions and sticking to a balanced diet keep you motivated throughout your weight loss journey. Planning for your body’s nutrition keeps you on the path to long-term success.

#2 Have an exercise plan

Adding an exercise plan to your weight loss program goes a long way and helps you lose weight on phentermine fast.

A workout routine is essential as phentermine’s influence declines over time, and the workouts prevent you from being drug-resistant or stagnating on a weight loss plateau. Lifting weights also helps you build muscle mass and increase your body’s metabolism.

#3 Do not skip meals

Your body’s metabolism is among the main factors determining whether you will maintain weight after losing it. Skipping meals slows down metabolism leading to weight gain or making it harder to lose more weight.

Episodic caloric restriction from skipping meals is unsustainable, and the best way to sustain calorie restriction is through eating regular low-calorie meals. One of the best ways to avoid skipping meals is to eat fiber-rich and high-protein foods that promote satiety.

On the other hand, phentermine boosts the effectiveness of calorie restriction as it increases your metabolism on a low-calorie diet and reduces your appetite, thus helping you reap more significant weight loss benefits.

#4 Drink plenty of water

If you want to lose weight on phentermine, it is essential to take water to boost the metabolic functions associated with weight loss. Water is a natural appetite suppressant, and drinking it can reduce unnecessary snacking and hunger levels.

Water also boosts calorie burning on phentermine as it increases the body’s energy expenditure while resting.

If the body is dehydrated, it fails to remove feces and urine, but water helps the kidneys filter waste and retain essential electrolytes. Dehydration leads to digestive problems such as constipation and diarrhea.

The waste build-up in the human body may cause bloating, which adds a few inches to the waist. Replacing sugary drinks and energy drinks with water also helps drastically reduce liquid calorie intake, which will help you lose weight.

Water is also crucial in lipolysis, the process of fat metabolism. Drinking enough water helps the body burn stored fat and break down fats from food.

Water also helps with workouts as it helps muscles, joints, and connective tissues work correctly as the activity ramps up during exercise. It also helps reduce the risk of muscle cramps and fatigue that can interfere with your workouts.

#5 Get a good night’s sleep

Sleep deprivation can interfere with your weight loss plan and overall health. Lack of sleep affects the body’s ghrelin and leptin concentrations, the hormones that regulate hunger. This will increase hunger levels and food cravings.

Adequate sleep also helps you avoid late-night snacking. Late-night snacking is often associated with less nutritious food options such as high-fat and high-calorie foods, making it harder to lose weight.

Lack of sleep makes you feel more fatigued, thus lowering your energy levels and motivation for more strenuous exercises. Experts recommend that a healthy person needs at least 7 hours of sleep every night for optimal body functioning.

Does Phentermine Suppress Appetite?

Consuming phentermine leads to a suppressed appetite, which causes you to eat fewer calories, leading to gradual weight loss.

Phentermine belongs to a group of drugs known as anorectics, commonly called appetite suppressants. This weight-loss drug causes weight loss by stimulating the central nervous system and increasing hormone levels of dopamine, serotonin, and norepinephrine.

An increase in these hormonal levels causes decreased hunger levels, thus making it easier for you to stick to a low-calorie diet. It is best to combine diet and exercise to avoid phentermine tolerance that builds up in some people in the first two weeks.

Is It Safe to Exercise While Using Phentermine?

Doctors say it is safe and encourage the use of phentermine when exercising. 

Most phentermine prescriptions are used to treat people with obesity experiencing high-risk diseases like diabetes and high blood pressure.

For successful weight loss, you need to combine phentermine with diet and exercise. Exercise helps combat chronic diseases, increase your energy levels, and improve your mood. 

Phentermine and Hormone Imbalance

When you take phentermine, it stimulates the sympathetic nervous system (part of the nervous system connecting the brain and spine), increasing hormonal levels of dopamine and serotonin and consequently suppressing appetite.

Since phentermine stimulates these hunger-suppressing hormones, it is best to discuss with your healthcare provider if you have any underlying conditions like thyroid disease, severe blood pressure, or a controlled substance like a diet pill.

How Much Water to Drink With Phentermine?

A study showed that you should drink at least 74 to 101 ounces of water (9 to 12 glasses) to maintain healthy body functions. Phentermine users lose weight quickly in the first weeks due to drinking water.

If you don’t take enough water or eat sodium-rich foods, the body holds on to the water it has to hydrate the body leading to higher numbers on the weight scale. However, when you drink lots of water, the body is used to having a continuous supply of water leading to weight loss.

Besides the associated benefits of water in weight loss, a constant water supply also relieves a dry mouth, which is among the common side effects of weight-loss drugs.

How Long Does It Take to Lose Weight on Phentermine?

It takes about 3 months for phentermine users to lose 3% of their body weight and 6 months to lose about 5–7%. Putting this in perspective, a 200-pound person would lose 10–14 pounds of body weight in 6 months.

However, people may respond differently to this weight loss medication. If you haven’t lost much weight after using it for more than 3 months, it would be best to see a healthcare professional for medical advice.

Your body mass index, proper nutrition, and a good exercise regimen also influence how much weight you can lose on phentermine.

Best Way to Take Phentermine

The best way to take phentermine is usually once a day, an hour before breakfast, on an empty stomach. Your doctor may adjust your dosage to up to three times a day if necessary.

It is paramount to follow your doctor’s instructions when taking phentermine. Taking this drug late in the day can cause insomnia. If you take sustained-release phentermine capsules, swallow the pills whole and avoid crushing or chewing them to reduce the risk of side effects.

This medication’s dosage and length of use depend on your response to treatment and overall medical condition. The doctor adjusts the dose depending on the body’s response. Like other medications, take the drug regularly for the best results.

The medication may stop working after a few weeks, and if this happens, your doctor may advise you to stop taking the medication.

A Word From Our Dietitian

The best way to get to your goal weight is to eat a nutritious, low-calorie diet and combine it with exercise.

However, taking prescription medication such as phentermine may help people with difficulties losing weight. However, when taking this drug, you have to be active and eat well; otherwise, you are putting yourself at risk.

As much as phentermine is an excellent tool for rapid weight loss, it is not recommended as the first line of treatment. There is no quick fix to weight loss other than prioritizing a healthy lifestyle.

Before taking phentermine for weight loss, it is best to first talk to a licensed medical doctor to assess whether the medicine is good for you.


Phentermine is an approved prescription-only drug used for short-term weight loss. With a doctor’s guidance, you can see long-term weight loss success when using phentermine.

It would help if you combined phentermine with a proper diet and workout routine for the best results.

Written by Dennis Njoroge
Dennis is a seasoned writer who focuses on writing health and wellness articles. His career goal is to educate people on how to reprogram their lives by breaking free from unhealthy eating habits and fostering new sustainable habits. Dennis tries to give easy-to-follow advice based on scientific research. He strongly believes that regardless of age, fitness level, a person can always learn something new and reach their health goals if they have a positive mindset.
The article was fact checked by Rosmy Barrios, MD
Was this article helpful?
Thank you! We received Your feedback

Leave a comment

Thank you for your comment!
We will review it as soon as possible.
Your Name
Missing required field
Your Comment
Missing required field