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Can a hormonal nasal spray help with weight loss?

Wesley Bedrosian/credit Wesley Bedrosian love spr

Ever wonder why it seems that a new romance often helps people drop a few pounds?

It turns out that taking a sniff of a nasal spray containing the “love” hormone oxytocin could be an effective appetite suppressant and a potential new weight-loss therapy, according to new research from Massachusetts General Hospital. In a study funded by the Boston Nutrition and Obesity Research Center, researchers tested a single dose of the spray on 25 healthy men — about half of whom were overweight — an hour before breakfast and found that they ate 122 fewer calories and
9 grams less fat at the meal compared to when they received a placebo spray.


“We found the men ate less, seemed to burn more fat, and seemed to handle their insulin better” after receiving the oxytocin spray, said study leader Dr. Elizabeth Lawson, director of the interdisciplinary oxytocin research unit at Massachusetts General Hospital. “We’re still in the early stages, but we’re hoping to research this further to see if it could be a potential treatment for obesity.”

The results were presented at the Endocrine Society’s annual meeting in San Diego last Sunday and have not yet been published in a peer-reviewed medical journal.

Oxytocin — a hormone that surges every time we hug or kiss a loved one — acts as a chemical in the brain to transmit nerve signals. Lawson and her colleagues believe the nasal spray crosses the blood-brain barrier and interferes with those regions that control appetite, but further research will need to confirm how it works — and whether it works as well in women, who weren’t included in the study. In animal tests, at least, oxytocin has proved both safe and effective.

An oxytocin nasal spray made by Novartis is already available for commercial use in Europe to trigger milk letdown in nursing mothers who are having lactation problems. (Oxytocin spikes when women breast-feed, which appears to be nature’s way of helping them bond with their new babies.) The dose used for that purpose is 4 international units of the hormone; the dose used in the study was 24 IUs.


“I think it is fair to say that the safety data thus far is reassuring, but it will be important to study the safety and efficacy of daily intranasal oxytocin,” said Lawson, who has not received financial funding from Novartis.

Dr. Caroline Apovian, director of nutrition and weight management at Boston Medical Center, called the new research “fascinating” but added that obesity experts need to see how long the spray actually controls appetite over the course of a day. Spray users might compensate by eating more calories at, say, lunch or dinner, which wouldn’t help them shed any excess pounds.