A New Age Fertility Aid?

A company claims to have a dietary supplement that may improve a man's sperm quality, citing European studies that have some fertility specialists cautiously intrigued.

But the same doctors who plan to experiment with the product, called proXeed, warn that there's no proof yet that it works -- and are urging Americans to see a doctor before trying it on their own. There are many causes of male infertility, occasionally life-threatening ones, that proXeed can't help but that regular medicine can.

"I'm anxious and excited to see how it works, but I'd not at this point tell patients it's going to work," said Dr. Larry Lipshultz, a Baylor College of Medicine urologist and president of the American Society for Reproductive Medicine.

But proXeed isn't thought to cause side effects, so "the only thing you have to lose is the $100 a month you're going to spend" trying it, added Lipshultz, who is giving it to patients.

Other options such as in vitro fertilization can cost thousands.

Up to 40 percent of conception difficulties are believed caused, at least partly, by poor sperm. That means 2.5 million American couples potentially could try proXeed, said Sigma-Tau Consumer Products, which begins marketing the citrus-flavored drink mix Wednesday.

ProXeed contains two types of L-carnitine, a compound naturally present in the body important for cellular metabolism. People absorb L-carnitine mostly from red meat and dairy products.

Scientists know L-carnitine is highly concentrated in sperm-related tissues. The theory: Perhaps men with low sperm counts or poor sperm quality -- such as sperm that don't swim well -- lack L-carnitine. Small European studies suggest taking specific amounts of L-carnitine and a metabolite, acetylcarnitine, for three to six months gave subfertile men more normal sperm.

It won't create super fertility.

"ProXeed's not a miracle drug. It does one thing: It optimizes sperm quality, and it does that very well," said Brad Stewart of Sigma-Tau, an Italian-based company that also sells prescription drug versions of L-carnitine, including one sold in the United States to treat a rare metabolic disease.

The European research is promising, but "it's not all that firm, in all honesty," cautioned Dr. Jon Pryor of the University of Minnesota.

He will perform the first U.S. study this summer, giving up to 80 men at his clinic and Brown University either proXeed or a dummy pill.

Doctors are reassured about trying proXeed because the Food and Drug Administration says the prescription L-carnitine that treats metabolic disease has proved safe.

But L-carnitine also is sold as a dietary supplement, and dietary supplements are largely unregulated. The FDA cracks down only on dangerous ones, or those claiming to treat disease like a drug. FDA officials could not say if "optimizing sperm quality" would cross that line.

Consumers, however, can buy supplements without consulting a octor.

Don't do that, Pryor urged infertile men. Much male infertility is caused by something treatable such as a hormone imbalance that proXeed won't affect, and a few men even may have testicular cancer or another serious condition.

Sigma-Tau promised to pass that message to customers, and says it is working closely with fertility specialists "to develop the science" behind proXeed.

So why not seek FDA approval as a fertility drug rather than sell it as a supplement? It would take about $100 million more research and wouldn't prevent unregulated competitors sold in health food stores from claiming to work as well, said Stewart, who will sell proXeed on the Internet and by phone.

Other L-carnitine supplements are sold mostly for weight loss, something Sigma-Tau's testing shows doesn't work, he said.

Written By Lauran Neergaard