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Orlistat Side Effects - Is it Safe to Take?

Orlistat Side Effects - Is it Safe to Take?
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 8 min read

If you have been wondering if Orlistat is safe, look no further. While there may be some side effects of this medication, it is generally safe and beneficial. 


Orlistat is an anti-obesity drug. It is sold as the prescription medication Xenical or the over the counter pills Alli. It is a lipase inhibitor, meaning that it blocks your body's ability to absorb diety fats, which helps reduce the number of calories your body takes in. This medication is most commonly used under the guidance of a health care provider while you are on a very-low-calorie diet. This does not mean that you need a prescription for Orlistat. It is available to purchase over the counter. Generic versions are also available for those who want cheaper medications. 

It is taken from your body's natural lipase inhibitors. Being a natural chemical in your body means that it is very stable. It also means that it is effective. When you combine it with a healthy diet and exercise routine, you can boost your weight loss quite a bit. You may also notice that you have lower blood pressure and are less likely to develop type 2 diabetes from extreme weight loss while taking this medication. Just remember that this is not a type 2 diabetes pill. 

However, all people seem to be able to talk about are Orlistat side effects. While diarrhea the most common, these decrease as you take the medication. 

The Science

Orlistat works by preventing the lipases in your pancreas and intestines from doing their job. When these enzymes cannot work, your body does not digest and absorb the fat you eat. These undigested fats will pass through your body. This medication does not get absorbed into your body, so you have to take it before eating a meal. If you take it properly, it can help block over one-quarter of the fat you eat from being absorbed. Taking higher doses does not increase the amount of fat your body passes. 

Additionally, Orlistat was recently found to inhibit fatty acid synthase, preventing cancer cells from growing in your body. Some studies have even been conducted on its potential use to stop tumors from growing. However, one of the common Orlistat side effects, the inhibition of off-target cells, may prevent this medication from being used as an anti-tumor medication. It also shows potential as a cure for other issues and parasites. 


Orlistat is most commonly used to treat obesity. This is because it can help promote weight loss. Many people who take it will experience at least a five percent reduction in body mass. Some can even reach more than ten percent if taken under the surveillance of medical professionals, like the ones at Nu Image Medical. However, one of the Orlistat side effects is that after you stop taking your medication, you may regain some weight. 

This medication is also useful for reducing type 2 diabetes in people who undertake a challenging weight loss journey. Some people have also prescribed Orlistat as a way to lower blood pressure. 


This medication has been proven to lower the amount of fat absorbed through your diet and lower blood pressure. It also works to improve insulin sensitivity and help prevent the onset of type 2 diabetes due to a drastic weight change. Because it lowers the amount of fat you absorb, it can help you lose weight and gain a healthy body composition. When paired with a healthy diet and exercise routine, the amount of weight you lose will be significantly more. 

Side Effects

The primary side effects you may experience on this medication are diarrhea, involuntary bowel movements, and frequent bowel movements. However, the majority of Orlistat side effects can be avoided if you do not eat foods with a lot of fat in them or a tremendous amount of calories. Diarrhea and gas can be minimized by eating only a few grams of fat with each meal. Over-the-counter Alli even notes that people on this medication will begin to associate Orlistat with the uncomfortable side effects of eating fat. These side effects will worsen when you start your course and lessen over time as your body gets used to the medication and the very-low-calorie diet. Seek the opinion of weight-loss professionals, like the ones at Nu Image Medical, to make sure that you are doing your very-low-calorie diet safely. 

In rare cases, some people have noted liver injury after using this medication. Similarly, some people have claimed that this medication causes kidney damage. These side effects may stem from your body, absorbing too much sodium, which is sometimes a side effect of your body not absorbing enough fat. Numerous studies have been done on the potential for severe or mild organ damage. However, there has been no concrete evidence supporting the theory that Orlistat damages your liver or kidneys. Researchers noted that the damage to a patient's liver or kidneys was often evident before starting Orlistat. This led researchers to believe that lifestyle habits caused damage to the liver and kidneys people experience before patients' weight loss journeys. 

Additionally, people who use Orlistat for long periods have claimed that it caused breast cancer, although these claims were false. Researchers have even pointed out that studies suggest Orlistat can kill breast cancer cells rather than encourage them. Long-term use can also cause colon carcinogenesis and lesions due to your body excreting undigested fat. Lesions and carcinogenesis are thought to be the first signs of colon cancer. However, this only happens if you eat high-fat foods while taking this medication. 

Your body will also not absorb vitamins that you get from fat while on this medication. Therefore, you should take a multivitamin before bed for as long as you are on Orlistat. 

Combination Treatments

Another popular method for weight loss is combination treatments that use Orlistat and other medications, such as Acarbose. This is because Acarbose and Orlistat work together to block fat and carb absorption, cause a caloric deficit, and suppress your appetite. They also help reduce post-meal blood sugar spikes, which helps your body fight against insulin resistance. Additionally, Acarbose can help relieve some of the gastrointestinal side effects related to Orlistat. These combination treatments are the perfect way to fight obesity and the side effects you may experience while losing weight. 

Generic Versions

Originally, Orlistat was only available in its name-brand form, Xenical. However, you now have more options when purchasing this medication. Now you can get generic Orlistat, which is often available in different dosage options. Using the generic formula is often what doctors choose if their patients experience many Orlistat side effects. Getting the generic brand is also one way to help lower the cost of your weight loss journey. 

Counterfeit Pills

Over-the-counter Orlistat was given a bad name after counterfeit pills were made that contained sibutramine was marketed as Alli and sold over the internet. These pills had dangerous doses of this medication. This is another reason why many people believe the Orlistat side effects are more severe than they are. 

Although Orlistat may have several side effects, it is generally safe to use as a weight-loss drug. Don't be afraid to try it and boost your weight loss success today. 

Nu Image Medical® offers a new and futuristic approach to achieving optimal health and wellness. The company has been a weight loss, anti-aging and wellness provider since 2004 and offers medically supervised programs for medical weight losspeptideserectile dysfunctionscream cream, and hair loss (NuDew) 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.