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Modafinil And Weight Loss: Understanding The Science Behind It

Modafinil And Weight Loss: Understanding The Science Behind It


Weight loss due to Modafinil is a common side effect requiring no medical attention. Even though the FDA does not approve its use for weight loss, studies show Modafinil 200 mg causes weight loss up to 0.84 kg after 8 weeks of use, with about an 18% decrease in calorie intake. 



Weight loss after taking Modafinil is something most people taking the Nootropic may experience. It is a common side effect of Modafinil and requires no immediate medical attention. 

However, Modafinil is a stimulant and not approved for weight loss aid, thus calling for the right product information. This blog investigates Modafinil's appetite suppression ability and scientific answers to whether Modafinil causes weight loss. 


Understanding Modafinil And Its Side Effects

Modafinil is a wake-promoting agent that has been approved by the FDA for the treatment of excessive daytime sleepiness. It is available under the brand names Modvigil, Provigil, and Modalert and works within 30 minutes of intake. 

The way our body manages body weight involves a complex mechanism. Thus, the intake of a few medications can cause weight loss, while others may cause weight gain. Modafinil, a stimulant, is thought to be a potential aid for weight loss. This is due to its similarities with other stimulants, such as amphetamines, which are known to cause weight loss. 

However, it is important to note that weight loss is a potential side effect of Modafinil and may not be seen in all users. 


How Does Modafinil Cause Weight Loss? 

According to the FDA, 

"No clinically significant differences in body weight are reported in patients treated with Provigil (Modafinil) compared to placebo."

However, user reports and testimonials suggest that most users often experience weight loss from Modafinil. 

It is crucial to understand Modafinil itself does not cause weight loss. However, it may induce certain behavioral changes that may lead to weight loss. 

Modafinil-induced weight loss does not happen in a day. It may take around 9 to 12 months to see a visible result. The key factors that cause weight loss from Modafinil include the following, which are discussed in detail in the section below. 

  • Reduced calorie intake due to appetite suppression. 

  • Increased metabolic rate.

  • Greater motivation. 


Modafinil Causes Appetite Suppression

One of the primary ways Modafinil causes weight loss is through its appetite-suppressing ability. This is supported by numerous studies that state loss of appetite and weight loss are some of the notable adverse effects of Modafinil [1]. 

As shown in the graph below, a 2008 study suggests that:

  • Modafinil decreases food intake by 18% for a dose of 200 mg. 

  • It decreases the total caloric intake by  38% for a dose of 400 mg.





The study further suggests that Modafinil significantly decreased hunger in the subjects. 

Modafinil’s appetite suppression is due to its ability to increase the production of numerous neurotransmitters [2]. 

Effects Of Modafinil On Dopamine - 

At the initial stage of taking Modafinil tablets, most users feel less hungry due to the secretion of the dopamine neurotransmitter. 

Dopamine is a neurotransmitter that regulates our mood, motivation, movement, and attention span. 

  • This inhibits certain centers in the brain that control hunger and appetite. 

  • It also leads to heightened motivation that helps people stick to their exercise and diet plans.

  • The increased level of dopamine also activates the reward centers in the brain. This leads to decreased enjoyment of various pleasures, including food. 


Modafinil Increases Metabolism

Metabolism is responsible for the breakdown of food, which helps flow energy. The extra energy is stored as fat when you overeat and indulge in less physical activity. 

Modafinil helps in weight loss by-

  • Enhancing the metabolic processes results in more calorie loss. 

  • The use of Modafinil helps increase the level of energy and improves physical activity. This helps avoid any additional storage of energy as body fat. 

This combination of lower calorie intake and higher calorie burn helps in effective weight loss. 


Influence On Motivation

Another explanation that supports why and how Modafinil causes weight loss is its ability to enhance focus and concentration. Modafinil results in 8 to 12 hours of improved attention and concentration, which can affect the dietary intake and calorie burn in two ways- 

  • The individual gets so engrossed in the task that they often forget to munch on snacks while working. 

  • Its impact on the dopamine level helps people engage in exercise and activities that aid in weight loss. 


Clinical Evidence On Modafinil And Weight Loss

Numerous clinical studies have found a relationship between Modafinil and weight loss. Some of the key scientific studies showcasing light into the use of Modafinil for weight loss are listed below. 

Clinical Trials On Modafinil's Weight Loss Effects

  • According to a 2012 study by Laura Christina Wittkampf et al., Modafinil (180 mg dosage) can cause a mean weight loss of 0.84 kg after 8 weeks of use. 

  • A study at the Weight and Eating Disorders Program at the University of Pennsylvania suggests that Modafinil is a good treatment for obesity. 

  • The ability of Modafinil to cause weight loss was also found in a 2006 study. It suggests that Modafinil is a well-tolerated drug and was associated with significant weight loss compared to a placebo [3]. 

Modafinil's Impact On Food Intake And Addiction-

  • An early clinical trial concluded that "similar to amphetamine, Modafinil reduces the amount of food consumed without altering the proportion of macronutrients consumed."

  • Another study conducted at Columbia University found that people taking Modafinil for shift work disorder had a significant reduction in food intake. 

  • Further, in a study published in the Personality and Individual Differences journal, researchers found that the use of Modafinil can help food addicts lose weight. 

  • "Modafinil has been shown to reduce impulsiveness in a variety of disorders such as alcohol dependence, schizophrenia, and ADHD. Food addicts suffer from the same neurobiological condition. This is why we believe it will help food addicts as well, and our initial tests have backed up that theory, says Professor Vlaev [4]. 


Is Modafinil For Weight Loss Medically Recommended?

No, the use of Modafinil is NOT medically approved for weight loss. Even though the FDA does not approve its use for weight management, it is still taken by many as a weight loss pill. 

It is essential to exercise caution while taking Modafinil for weight loss, as mentioned below.

  • Make sure to eat your breakfast before taking Modafinil dosage, as following its administration will cut down your appetite. 

  • The diuretic effect of Modafinil can cause dehydration, so ensure that you drink at least 2 liters of water while taking Modafinil. Diuretics are medications that cause dehydration by making you urinate more. 


Modafinil Vs Phentermine For Weight Loss

Phentermine is a prescription appetite suppressant medication that aids in weight loss. The medication is prescribed to people with a body mass index (BMI) of 30 or greater. 

So, which is a better weight loss aid? 

Both Phentermine and Modafinil function by acting as appetite suppressants. The findings from a phase IV clinical trial evaluating the effectiveness of Modafinil and Phentermine indicate the following [5]-


Drug Effectiveness 




Not At All

2.68 %

2.5 %


17.74 %

20.06 %


33.31 %

36.24 %


32.35 %

29.12 %

Very High

13.91 %

12.07 %


Even though studies show Modafinil to be a better weight-loss agent than Phentermine, the FDA has not approved its use for weight loss. It must be used only under the supervision of a doctor. 


Modafinil Weight Loss Stories

Modafinil caused a 40-lb weight loss (from 280 lbs to 240 lbs) over the course of one year. The individual also experienced a 5.08 kg reduction in body mass index (BMI) (from 35.52 Kg/m2 to 30.44 Kg/m2) [6]. Body mass index (BMI) is a number that helps in estimating body fat based on the weight and height of the person. 

Modafinil Weight Loss Reviews

  • A Reddit user (Cheesieblaster) claims to have lost 20 pounds (9.07 kg) after taking Modafinil. He further states that he experiences lower cravings for sweets and snacks. 

  • Another Reddit user (Masked Tyrant) reported the appetite-suppressing effect of Modafinil. The user says he had to force himself to sit down and eat a meal after taking Modafinil dosage. 

  • A Quora user (Vera Novak) taking Provigil, the brand name of Modafinil, notices losing weight without much effort. 


Modafinil And Weight Loss- Our Final Thoughts

Modafinil is NOT approved for weight loss, but it helps boost motivation and stay focused on lifestyle modification and diet plans that may help you lose weight. 

Even though weight loss is a common side effect of Modafinil, it is completely mild and is not associated with any serious underlying conditions. 

Modafinil and weight loss are indirectly connected due to its appetite-suppressing ability and ability to help you avoid food cravings.  

It is important to note that weight loss induced by Modafinil occurs during the course of the treatment and is often reserved after the completion or cessation of the medication.

Anybody wishing to lose weight from Modafinil intake should incorporate other lifestyle changes such as regular exercise and eating right for a better result.


Yes, using Modafinil can suppress appetite, thus aiding in weight loss. 


Yes, Modafinil causes appetite suppression, thus causing weight loss, and is considered a side effect of the Nootropic. 


Similar to Modafinil, Provigil can also cause weight loss. 


Anorexia is an eating disorder that causes weight loss. Modafinil can have an anorexic effect, thus causing appetite suppression. 


Yes, the use of Modafinil is very effective in boosting a person's energy. 


A few clinical studies suggest Modafinil weight gain. 


There are no studies supporting an increase in appetite from Modafinil. 


Yes, the use of Modafinil can increase metabolic rate, which helps with weight loss.

No, there are no reports of Modafinil causing weight gain in users.

Provigil can cause weight loss of up to 0.84 kg after 8 weeks of use.

Modafinil is a diuretic and does not cause water retention in the body.


  1. A review of modafinil film-coated tablets for attention-deficit/hyperactivity disorder in children and adolescents, Tandfonline. 

  2. How is it possible to lose weight with Modafinil, abouttimemagazine

  3. Modafinil for atypical depression: effects of open-label and double-blind discontinuation treatment, PubMed. 

  4. Drug for narcolepsy could help food addicts lose weight, ScienceDaily. 

  5. Modafinil vs. Phentermine, ehealthme.

  6. Modafinil-associated weight loss in a clozapine-treated schizoaffective disorder patient, PubMed.