Watermelon Is Like Viagra? Really?

The last thing I thought I would be writing about when I returned from our sex educator conference in New Orleans was watermelons. Or if I did, I figured it would be in response to an email I received from a young man in Georgia, who said his favorite way of masturbating is by using sun-baked watermelons after he cuts an entry-portal through the rind. (Hmmm... Would the watermelon still be seedless after he's done?)

Instead, I find myself fielding questions about the recent media feeding frenzy that occurred after some fruit and vegetable expert from Texas claimed that watermelons "may work like Viagra." Sure, he might have qualified it by saying "may," but you don't make a statement like that to the press unless you are implying "does."

Scientifically speaking, there's about as much evidence that watermelons work like Viagra as there is for watermelons being the ultimate masturbation device. Worse yet, I'm not so sure that eating vast amounts of watermelon is all that good for you, unless you count the exercise you'll get from going to the bathroom umpteen extra times after wolfing down the copious amount of melon that you'd need to get any penis firming effect, assuming there is an effect.

The big to-do about the alleged watermelon-Viagra connection is because watermelons contain citrulline, which can be transformed into the amino acid arginine by way of a citrulline-NO or arginine-citrulline pathway. Arginine is involved with nitric oxide synthesis, and nitric oxide is an important player in the sexually excited crotch. Unfortunately, it's not nearly as simple as the "eat some melon, get a woody" formula that the journalism geniuses who write these stories might want you to think.

One of the many things missing in the recent news stories is that drugs like Viagra work on the penis by blocking the tear-down of a messenger molecule called cGMP. Viagra does this by inhibiting an enzyme called phosphodiesterase-5, which is fairly specific to the penis as opposed to your armpit or upper lip. (There are 11 different phosphodiesterase families, of which phosphodiesterase-5 is just one.)

So, does the citrulline in watermelon inhibit phosphodiesterase-5 like Viagra does? Funny how the fruit and vegetable people in Texas didn't bother to address this little matter. Nor did they bother to mention a single study that links watermelon consumption to a decrease in erectile dysfunction.

What does seem to be the case is that you'd need to eat about six cups of watermelon before you would even begin to consume enough citrulline to boost the amount of arginine in your body, and this assumes that boosting the amount of arginine can help a guy get a better erection. (While "Citrullus" may be Latin for watermelon, I can assure you it isn't Latin for "miracle in your pants" or "trouble under your toga." Otherwise, the seven hills of Rome would have been covered with watermelon vines instead of grapes and olive trees.)

While there is some evidence that taking arginine in combination with yohimbine can have a positive impact on the ability to get an erection in men with mild-to-moderate ED, arginine by itself won't put a tent in anyone's trousers. And while some health food people will tell you that amino acids like arginine can help fix everything from depression and alcoholism to herpes and heart disease, they sometimes forget to mention the clinical trial of L-arginine that was stopped early, because more people taking the L-arginine died than people who were taking a placebo.

I could go on about how citrullinated antigens are used as serologic markers in rheumatoid arthritis, not that the citrulline in watermelon has any connection with or impact on rheumatoid arthritis. Let's just say that while I hope you enjoy watermelon as much as I do, eating it in moderation is probably best.

And most important of all, if you are looking for something to help with your erection, seeing your physician rather than your grocer is by far the better way to go.