Can Viagra help you lose weight?

  • A few days ago several newspapers reported about a new trial taking place in China which aims to investigate if PDE5 inhibitors, such as Viagra and Cialis, can help you lose weight by burning more fat.
  • The rationale behind the study is that a protein called cGMP can stimulate the conversion of white fat (white adipose tissue or WAT) into brown fat (brown adipose tissue or BAT). The converted tissue is aptly called "beige" fat. Now, there are two things to consider here:
    • Phosphodiesterase-5 (PDE5) inhibitors work by boosting levels of cGMP in the body
    • In contrast to white fat tissue (which stores fat in the body), brown and beige fat tissues actually burn fat, which is used to produce heat. This process is called thermogenesis.
  • By boosting levels of cGMP - and consequently the growth of brown adipose tissue - scientists hope that PDE5 inhibitors (Viagra, Cialis, Levitra etc.) can help you burn your body fat with no effort.
  • Life's easy, right? You fly in bed and you get to lose weight too. Well, hold your horses, don't get too excited just yet! I hate to be a spoilsport but this sounds too fishy, for three good reasons:
    • Brown fat may work well in mice and rats, but it does not work well in humans. Humans have so little brown / beige adipose tissue and they are so resistant to it's growth, that very strong stimulation is needed to turn white fat into beige / brown fat. Which brings us to the second point.
    • PDE5 inhibitors have so many side effects on the eyes, cardiovascular system and other body tissues, that the high dosages that will probably be required to stimulate oxidation (burning) of large amounts of fat, would be way too dangerous for you. Or, vice versa, for a normal dosage of Viagra don't expect  to lose more than a couple of pounds of fat. SImply put, I don't think it will be worth the effort to flood your body with Viagra for months on end, just to pound a kilo or two of fat. Cutting down on muffins will accomplish that much faster and and much more safely too.
    • And this brings us to the third point to consider. When you stop taking your Cialis / Viagra etc, your cGMP levels will go down, your beige fat will revert back to white fat and all will be lost. Are you prepared to take PDE5 inhibitors for ever, just to be a couple of pounds lighter?
  • And if you are a woman and think that your daily Viagra fix will do wonders in your sex life, well, think again. The PDE5 protein is not expressed in female genital tissues (as the clitoris) in significant amounts. This is the reason Viagra never worked for women.
  • Of course, if you are a man things look more upwards (excuse the pan), but again I don't think it is wise to medicate with PDE5 inhibitors day-in, day-out for years, just to be a little bit slimmer. The gym can do a much better job, without the side effects of medication...
  • In summary, I am still excited about the future potential of brown fat thermogenesis, but I believe that we will find a much smarter way to turn all our white fat into brown fat (and stay slim forever despite eating chocolate cookies all day...). But I don't think the way forward is to gulp down lots of Viagra with all its side effects.
  • Source: It's not just good for your sex life. Viagra may keep you slim, too!, http://www.dailymail.co.uk/health/article-3252612/It-s-not-just-good-sex-life-Viagra-slim-too.html