Many people yearn for a better sex life, at least if the growing number of performance-boosting sex supplements and their ads is any measure.
Some of these remedies are marketed as "natural alternatives" to the widely used prescription drug Viagra to treat erectile dysfunction which is another name for impotence - the repeated inability to have and/or maintain an erection sufficient for sexual intercourse.
For other supplements, the vague claims about improving sexual performance ("on a scale of 1 to 10, before I was a 2, now I'm a 10!" the guys on the radio ads say) are the same claims made for aphrodisiacs for centuries. With names like Man Alive, NuMan, Enzyte, Herbal V, ArginMax, Rock Hard, Climagra and BetterMan, the great majority are aimed at men, though a few also claim to help women.
An erection depends upon many factors, including blood supply and nerve tissue in the penis, as well as hormones and psychological factors. Some ingredients commonly found in the supplements are supposed to affect these factors, and in a few cases there is a theoretical basis for such claims. But most of the supplements on the market today contain many ingredients, which range from promising to dubious to dangerous. One problem: The labels often don't tell you exactly what's inside, and rarely in what amounts. And even if they do tell you, they may not be accurate.
Here are four of the most common ingredients - two relatively new, two old - and what researchers have learned about them.
This amino acid, one of the building blocks of protein, is promoted to cure impotence, among many other things. It does boost levels of nitric oxide, which dilates blood vessels and increases blood flow - and this, in theory, may improve erections. This is similar to what Viagra does. But it's unknown whether enough of the supplemental arginine gets into the penis to make a difference. Indeed, at least two studies have found little or no improvement compared with a placebo.
Best known as the "athletic aid" used by Mark McGwire during his 70-home-run 1998 season, th hormone precursor Androstenedione is supposed to increase testosterone in the blood (and thus build muscle). One 2002 study found that andro, as it's called, does neither; another found that it does not increase libido. But it does raise levels of estrogen, which is dangerous for men. And it can increase the risk of certain cancers and heart disease (by lowering protective HDL cholesterol) and cause male breast enlargement.
Other testosterone-like proprohormone supplements also are promoted as "all natural" testosterone boosters. There is no evidence they do what's claimed. But if they did act like testosterone, they would probably carry all its risks. No one should try to self-prescribe hormones. And only a small number of men need to take testosterone, which is available only by prescription.
Made from bark of a West African tree, this has been used as an aphrodisiac for centuries and, in pre-Viagra days, was sometimes prescribed to treat erectile dysfunction (the extract is called yohimbine). It dilates blood vessels and increases blood flow, and thus, it's thought, may improve erections. It has been shown to increase sexual arousal in rats, but has had mixed results in human studies. Its side effects include a boost in blood pressure, abnormal heart rhythms, nausea, anxiety and sleeplessness. It is unsafe and ineffective, according to the Food and Drug Administration and the German commission that reviews herbal treatments. On top of that, an FDA test found that most yohimbe supplements contain little or none of it.
Regarded as an aphrodisiac (and a virtual cure-all) in Asia for centuries, this herb, too, is claimed to improve erections by dilating blood vessels, and by affecting nerves involved in erections. At least one study found that Korean red ginseng improves erections. But that doesn't mean that the types of ginseng commonly sold here (Asian and Siberian) would have similar benefits. A big problem with ginseng is its great variability. Not only are there several types, which have different compounds and biological properties, but different parts of the plants are used and these also contain varying chemical compounds. And there's no quality control. You have no idea what you're getting in the bottle or what it might do.
Countless other herbs and other ingredients - from ginkgo, DHEA, and deer horn to damiana, maka and an array of vitamins and Chinese herbs - are claimed to enhance sexual performance and sex drive. But there is little or no good scientific evidence for any of them. Manufacturers often say they have studies to support their claims, but these are unpublished, or involve rats, or are of poor quality. In addition, it is hard to evaluate the psychological effects of the supplements: the pills may cause no measurable improvement in erections, performance or sexual activity, yet some people may still report "better sex lives."
The side effects of all these compounds are largely unknown, especially when such compounds are combined and when taken by older men with existing medical conditions. Viagra and similar drugs won't help everyone, but at least its benefits and sides effects have been well studied. There are other medical/psychiatric treatments for erectile dysfunction and other sexual problems. Talk to your doctor, not the salesperson at the health food store.
Bottom line: The ingredients range from promising to dubious to dangerous. The side effects are largely unknown, especially when such compounds are combined and when taken by older men with existing medical conditions. Viagra and similar drugs won't help everyone, but at least their benefits and side effects have been well studied.