Why Does Wellbutrin Cause Weight Loss?

July 20, 2007 2:10 PM

Why does Wellbutrin cause weight loss? Even my doctor doesn't seem to know for sure. Are there unproven medical hypotheses or studies amongst doctors or pharmacists or anyone else that lean towards an as-yet-unofficial answer? (Feel free to get technical. If I don't understand, I'll Google.)
posted by WCityMike to health & fitness (10 comments total)

Wellbutrin is well known as also being a stimulant. Stimulants help weight loss by making people more active and upping their metabolism.
posted by damn dirty ape at 2:13 PM on July 20, 2007

For some people, Wellbutrin can also cause weight *gain*. The short answer is that the don't really know for sure how it works and what effect it will have.
posted by SpecialK at 2:14 PM on July 20, 2007 [1 favorite]

I think it depends on the person, as SpecialK intimated, and here's how:

Some people eat more when they are depressed, because food=comfort. Take wellbutrin, stop being depressed, eat less, exercise more as a result (and, by the way, have more sex--wellbutrin is good for that, too), and you lose weight.

Some people gain weight on wellbutrin because these are the people who DON'T eat comfort food when they are depressed, the people who instead sleep a lot, or just don't eat. Once they feel better, they go back to their usual habits.
posted by misha at 2:21 PM on July 20, 2007

I think that Wellbutrin has a tendency to reduce addictive cravings in people, which is why it is also marketed as Zyban to help people stop smoking.

It also is one of the few ad's that perks people up, whereas most of the common antidepressants make people kind of sleepy or lethargic. Being perky burns more calories than laying in bed staring at the ceilinig.
posted by tastybrains at 2:25 PM on July 20, 2007

When I was on Wellbutrin, it gave me lots of energy and dampened my appetite. This wore off after a few months, but it was nice to actually feel peppy after a year of depression.
posted by lychee at 2:55 PM on July 20, 2007

The true reason is not known, but bupropion is obviously known to inhibit DA reuptake. It has been speculated that elevating synaptic DA levels or agonizing DA receptors can cause weight loss.

The physiology of how DA is associated with weight loss is only partially understood, but there may be links to leptin and insulin, among many other factors.
posted by NucleophilicAttack at 3:10 PM on July 20, 2007

You might be interested in this:

"Bupropion is a norepinephrine and dopamine uptake inhibitor that has been available for several years for the treatment of depression and aiding smokers to quit. Although bupropion is not approved for treating obesity, three randomized clinical trials have shown some degree of efficacy for this drug in promoting weight loss in obese patients. The present drug profile provides a review of the pharmacology of bupropion, clinical evidence of efficacy with regard to weight reduction, tolerability and risks, and the current and future role of this drug in the management of obesity."

Email me if you're interested in the full article.
posted by docgonzo at 3:23 PM on July 20, 2007

Weight loss obviously isn't perfectly well understood, or we'd've solved the problem of obesity by now. (Which we haven't, in case that wasn't obvious.)

There's a splendid color plate by Frank Netter illustrating the effect of hypothalamic lesions in the cat. Basically if you lesion in a pair of tiny nuclei (extreme lateral) in the hypothalamus, cats become anemic and placid; in the ventromedial area, however, lesions make the cat voracious and rageful. The hypothalamus exerts control, not only of mood and the appetitive functions in terms of behavior, but also influences metabolism by its connections with the pituitary; thyroid, cortisol and other steroids, insulin and insulin-like growth factors and growth hormones are all under direct regulatory control by the hypothalamus.

Unlike the "average" brain cell (neuron) that runs on glutamate or GABA, cells involved in these functions (loosely termed "limbic" functions) often use monoamines, which as far as you are concerned means dopamine, norepinephrine, or serotonin as neurotransmitters. The hypothalamus receives innervation from higher structures and itself contributes innervation to other brain structures in the various monoamine networks.

I wish I could show this plate and the other Netter hypothalamus illustrations to you as it would help clear this question up. If you chose to go to the library, you would find it in the last pages, as a supplement, to his spectacular CIBA-Geigy illustrations of the anatomy of the nervous system.

This is necessarily a gloss; it would not be useful for me to start lecturing you, for example, on the functions of the ventral tegmental area and its connections to the basal forebrain nuclei because you have no context to place either of those brain structures. Also, I have only a rudimentary understanding of the knowledge in the field; as is probably unsurprising to you, there are people who make understanding the reasons for the answer to your question their life's work.
posted by ikkyu2 at 6:20 PM on July 20, 2007 [1 favorite]

I lost a good 15 pounds on Wellbutrin. It killed my appetite so I rarely ate. The weight loss leveled out after a bit.
posted by Serena at 7:26 PM on July 21, 2007

For me, it absolutely killed my appetite. It didn't even occur to me to eat for an entire weekend.
posted by happyturtle at 11:09 AM on July 22, 2007