We love the idea of losing weight with less effort. Perhaps that is why people seem to embrace new diet drugs when they become trendy. Although all the attention these last several months has been on semaglutide (Wegovy and Ozempic), older medications are still available. One reader is curious about whether to take Alli for the long term.
Is It Safe to Take Alli for a Year?
Q. I have been taking Alli in an attempt to lose weight and reduce my cholesterol. For the last six months, I have taken it continuously, and I plan to keep on until my next cholesterol testing. Usually I do not suffer the stated side effects from this medication. Is it safe to use this medication long term?
A. The FDA intially approved orlistat in 1999 as the prescription drug Xenical. An over-the-counter form called Alli got the green light in 2007. It works by blocking the absorption of fat from the intestinal tract.
This drug does lower both total cholesterol and LDL cholesterol. One large clinical trial showed that weight loss is modest, but the drug reduces the risk of type 2 diabetes and blood pressure (Current Obesity Reports, Jan. 6, 2021). In theory, these effects should lead to lower cardiovascular mortality.
However, the investigators report:
“However, the long-term safety of orlistat, naltrexone/bupropion, and phentermine/topiramate on cardiovascular morbidity and mortality have not been established.”
Most clinical trials were fairly short, on the order of six months. Some lasted twice that long with no undue effects appearing other than digestive distress (International Journal of Obesity and Related Metabolic Disorders, Nov. 2001).
Because Alli blocks absorption of fat, it may also reduce the absorption of fat soluble vitamins such as E, D and K as well as beta-carotene. A daily multiple vitamin might be a good idea to reduce this potential complication. In addition, Alli can interfere with certain pills taken at the same time, particularly cyclosporine, levothyroxine, warfarin and amiodarone. Such medicines should be taken at least two hours before or after you take Alli.
Liver Safety Questions:
If you notice any symptoms such as itching, yellow eyes or skin, fever, weakness, vomiting, fatigue, dark urine, light-colored stools or loss of appetite, contact your doctor immediately. About a decade ago, the FDA received reports of liver injury associated with orlistat. Upon investigation, however, the agency concluded that this was not a reason to tell people not to take Alli. We wish that FDA would do a better job monitoring long-term safety in both over-the-counter and prescription drugs.
According to expert consensus, Alli works best when taken in conjunction with physical activity and diet. To find out more about these approaches, you may wish to listen to our interviews with Dr. Robert Lustig (Show 1332: What Everyone Gets Wrong About Weight Loss); Drs. David Ludwig and Walter Willett (Show 1279: Challenging Dietary Dogma on Weight Gain); or Dr. Will Bulsiewicz (Show 1312: Fiber, Phytonutrients and Healthy Soil).