Naltrexone- FDA Approved Drug Assists Weight Loss by Stopping  Cravings for Alcohol and Carbs

Naltrexone reduces craving for alcohol  and desires  for sweets by blocking the pleasure centers in your brain that respond to alcohol as well as sweet  and salty foods. These are called opiate receptors since they also involved with opiate drugs. When these areas of the brain are blocked, a person feels less need for “one more drink,” two scoops of ice cream or a full bag of Stacy’s Chips. FDA-approved since 1994 for the treatment of alcohol and opiates, Naltrexone is safe, without significant side effects and has recently shown great promise in the treatment of weight gain especially when complicated by too much alcohol.

How Many  Calories in Alcohol Drinks?- How  Blocking Alcohol Effects Can Reduce Weight

Naltrexone  reduces alcohol intake producing weight loss. Alcoholic drinks have many more calories than is realized by most  people. A single shot(1.5 oz) of straight alcohol  is 85 to 105 calories. A glass of wine( 4oz) about 90-98 calories and 8 oz of beer from 70 to 200-300 calories. There are minor differences between brands and types of straight alcohol.  A mixed drink such a margarita or gin and tonic may contain 250-350 calories or more and contain 30 grams of carbs.  The added calories are due to the sugar. Not only are these “empty” calories, they cause hunger, loss of sleep and inactivity.  The is a chart on calories in alcohol below. However, there are significant effect of  alcohol on metabolism.  Its estimated that the actually effective calories may be 200- 300 calories  or more for the final drink. 

A single alcohol drink( 100 calories)  7 days a week can add about 12 lb weight gain in a year. This is the minimum, it does not take into account mixed drinks, high calorie craft beers and the sugar in many mixes. In addition the metabolism, inactivity, increased appetite and poor sleep associated with alcohol is not included. 

How Naltrexone Blocks Receptors in Brain, Reducing Desire for Alcohol

Naltexone’s blockade of alcohol-opiate receptors in the brain is seen in the graph below. On the left, alcohol is stimulating the receptors(called opiod receptors) to release large amounts of dopamine, serotonin and other pleasure producing chemicals in the brain. In many people this results in the need for more and more alcohol and often alcohol related medical problems and unwanted weight gain. On the right, naltrexone(blue  circles) circulates around the brain and occupy the same receptors involved with alcohol. When a person drinks alcohol and takes naltrexone  since  the   alcohol receptors are already occupied by the naltrexone,  the alcohol can not attach to the receptors resulting in reduction in dopamine and serotonin release. This leads to a reduction in calories as as the secondary effects of the alcohol.

Naltrexone blocks alcohol effects in brain

How Naltrexone Exerts its Weight Loss Effect Beyond Alcohol Reduction

In addition to the calories, alcohol exerts its effects on metabolism and many other factors.

Alcohol Calories

Drinking alcohol has many effects on weight loss. Besides lowing control levels and causing poor sleeping, it  slows metabolism, increases hunger and impairs judgment regarding healthy food choices. Naltrexone decreases desire for alcohol which directly reduces caloric intake, especially for carbohydrate laden alcohol drinks like margaritas, mojitos, rum and coke.

• Appetite reduction: Many people notice a reduction in appetite and cravings which result in less food. Reduction in the hunger promoting hormone, ghrelin may be the source of this observation. Observations have been positive in reducing “binge” eating.

• Cognitive function: Treatment with naltrexone is capable of improving mental clarity and reducing brain fog leading to better food choices.

• Decision making: The decision to take immediate gratification over a delayed reward is mediated by the orbitofrontal cortex (OFC) of the brain. Naltrexone helps people to resist unhealthy foods and/or only eat when necessary by its effect on the OFC.

• Decreased food cravings: Certain individuals are more susceptible to food cravings than others, Regular administration of naltrexone decreases food cravings for high-fat and/or high-sugar foods that often contain huge amounts of calories. This is seen often in the evening snacks of cookers, candy, ice cream as well as salty chips and crackers.

• Energy increase: Some naltrexone users will experience an increase in energy levels leading to more overall physical activity, thereby burning calories and speeding up metabolism for weight loss.

• Hormonal modulation: Hormones such as leptin, ghrelin, and thyroid can significantly affect satiety, hunger, and metabolism. Naltrexone may increase concentrations of leptin, a satiety-signalling hormone that tells the brain you are full. Conversely, naltrexone may reduce concentrations of the hunger-signalling hormone ghrelin resulting in less hunger.

• Insulin reduction: Naltrexone reduces basal concentrations of insulin among obese individuals. Decreasing the secretion of insulin is associated with improved insulin sensitivity, body mass index (BMI) changes, decreased caloric intake, and increased leptin – all of which can promote weight loss. (Source:

• Mood improvement: A subset of individuals tends to eat unhealthy, overeat, or binge eat in an effort to cope with depression or low mood. If you are among the individuals that overeat when depressed, naltrexone may help.

How to Use  Naltrexone for Weight Loss:

Since naltrexone has been in use for more than 23 years and is extremely safe, research is concentrated on  how to achieve the maximum effect while avoiding the self limited common  side effects of nausea and headaches. Since every individual has a great variability in brain responses to alcohol and rewarding foods and also to side effects,  the use of naltrexone has to be individualized for each user. Major efforts have involved:

1. Titrating the dose:   Naltrexone is almost always taken in a single dose. Start with 25 mg of naltrexone(1/2 of the 50 mg standard dosage.) Then slowly increase dose depending on the side effects and the response.  You will not get sick if you do drink on naltrexone. You will experience less desire and can easily stop after one drink.  If even 1/2 of the standard 25 mg dose is too much, then you can purchase doses as low as 6 mg/pill

2. Taking the dose at bedtime for a week since the nausea lasts only 3-4 hours and is mostly mild.

3. How do you know you are at the “right” dose: The end point for titrating the dose is when the desire for  alcohol and some of the food cravings diminish to acceptable levels.

Naltrexone (Standard Dose vs. Low Dose Naltrexone (LDN):

• Note: There has been extensive research on using low dose naltrexone(LDN naltrexone) for many diseases other than alcohol, opiates and weight loss. LDN is not for alcohol or diet since it involves a tiny dose of  3-4 to  5 mg as  single dose at bedtime. It can be very confusing. For weight loss the most effective dose has been at least 50 mg/day.

Commonly Reported Side effects of Naltrexone:

Most Common Side Effects: streptococcal pharyngitis, syncope, anxiety, arthralgia, arthritis, dizziness, drowsiness, fatigue, frequent headaches, headache, joint stiffness, nasopharyngitis, nausea, nervousness, obsessive compulsive disorder, panic attack, pharyngitis, posttraumatic stress disorder, sedated state, sinus headache, vomiting, induration at injection site, malaise, pain at injection site, and tenderness at injection site.–all of these are rare, self limiting.

Other side effects include: muscle cramps, muscle rigidity, muscle spasm, stiffness, depression, and twitching. See below for a comprehensive list of adverse effects