In the CHW group on Facebook, we hear that many people suffer from considerable weight gain which has no apparent connection to calorie intake. There are good reasons for this.

Weight gain can result from the action of drugs on receptors in our brain. Long-term weight gain can be 40-60 pounds / 20 – 30 kg with some anti-depressants. Which, of course is depressing in itself!  Studies only tend to cover up to 12 weeks, so the reported weight gain will appear lower than it really is.

Cymbalta/duloxetine block histamine 1 receptors

There are 4 histamine receptors.  We are used to histamine reactions in the body, where allergic reactions can be treated. 

In the brain, histamine has different effects. The histamine 1 receptor is partly responsible for satiety – the feeling of being full. If it is blocked, we will get the urge to eat – the “munchies”.

Thermogenesis

The heat energy produced by burning fat – is also affected by blocking the H1 receptor, which can lead to a slow, steady increase in weight.

These drugs block the 5HT2C receptors

These are serotonin receptors. If you activate them, you lose weight, if you block them, you become obese. (At least, that’s what tests on mice show. The discussion about animal testing will have to take place somewhere else.)

How to manage the weight gain

Strict diet, vigorous exercise, resistance workouts. However – we know this is not possible for most people taking Cymbalta/duloxetine and possibly not a good idea for those who can manage it.

Other drugs…

We do NOT recommend any drugs to counter the negative effects of another drug.

At 5:20 on this video, we hear about drugs … side effects – diarrhea … greasy stools …

https://www.youtube.com/watch?v=S-NukJp_Nbs

We hope that helps you understand why you gain weight on antidepressants.

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