Botox for Weight Loss, What's the Skinny
In the quest for weight loss, some people are wondering if Botox may be the answer. After all, if Botox injections can get rid of wrinkles and pain (at least temporarily), excess pounds may not be far behind.
Is Botox a fix for overweight and obesity?
Over the past few years, a number of studies have examined whether Botox might be an answer for people who want to lose weight, and the results seemed promising. First, let’s look at a rat study.
The Turkish investigators examined the impact of Botox on weight loss and gastric emptying (how quickly food leaves the stomach) in obese rats. Previous experiments had shown that normal-weight rats lost weight after being injected with Botox.
A total of 37 rats were fed a high-calorie diet for 90 days and were treated with either Botox, saline, or nothing. While rats in the saline group lost some weight initially, they began to gain weight again.
Rats in the Botox group, however, reached significantly lower body weights than rats in the other two groups, and they also had significantly greater gastric emptying. These findings led the scientists to conclude that Botox given to obese rats can result in weight loss by increasing gastric emptying time.
But did this apply to people as well? To answer that question, investigators at Mayo Clinic conducted a human study in which they injected 100 or 300 units of Botox into a specific abdominal muscle in 10 healthy obese individuals. The researchers were interested in how Botox affected gastric emptying (how fast the stomach rids itself of food), body weight, and how full individuals felt.
After 16 weeks, this is what the researchers discovered:
- Individuals who received 300 units of Botox experienced a significant improvement in level of fullness (satiation) two weeks after the Botox injection
- Average weight loss for all individuals after 16 weeks was 11 pounds
- Gastric emptying was prolonged in the subjects who received 300 units of Botox, but it was not a significant improvement over baseline
Overall, the authors concluded that a dose of 300 units of Botox “significantly enhances satiation, is associated with weight loss, and may slow gastric emptying,” although they felt further research was necessary.
New study on Botox and weight loss
Now a new study, also from Mayo Clinic and from many of the same investigators as the previous study, has shed new light on the question of Botox and weight loss. This investigation involved 60 obese individuals who took part in the 24-week, double-blind, placebo-controlled trial.
Botox doses in this study were 100, 300, or 500 units, and a saline solution was the placebo. Injections were given using ultrasound for guidance, and the researchers measured body weight, calorie intake, satiation, symptoms, and eating behaviors.
Overall, the volunteers who received Botox experienced an increase in gastric emptying ranging from 14 to 24 minutes by the second week after the injection. Sixteen weeks after injection, the amount of weight loss was disappointing.
In fact, subjects in the placebo group lost more weight (4 lb, 13 oz) than did those who received 100 units of Botox (less than 1 lb). Weight loss among those who received 300 units and 500 units of Botox was 5 pounds and 6 pounds, 9 ounces, respectively.
In addition, Botox had no appreciable impact on satiation, calorie intake, symptoms, or eating behaviors. Based on these findings, Mark Topazian, lead author of the study and professor of medicine in the department of gastroenterology and hepatology at the Mayo Clinic in Rochester, stated that “I would not recommend gastric Botox injections to people who want to lose weight.”
Coskun H et al. Effect on gastric emptying and weight reduction of botulinum toxin-A injection into the gastric antral layer: an experimental study in the obese rat model. Obesity Surgery 2005 Sep; 15(8): 1137-43
Topazian M et al. Endoscopic ultrasound-guided gastric botulinum toxin injections in obese subjects: a pilot study. Obesity Surgery 2008 Apr; 18(4): 401-7
Topazian M et al. Gastric antral injections of botulinum toxin delay gastric emptying but do not reduce body weight. Clinical Gastroenterology and Hepatology 2013 Feb; 11(2): 145-50