Pheromones in your cologne? Good luck

The products: Pheromones are the true aphrodisiacs of the animal kingdom. Female pigs don’t respond to compliments or slow jazz, but the slightest whiff of androstenone -- a pheromone produced by randy boars -- will instantly put sows in a sexual mood. Hog farmers often use batches of androstenone, also known as “boar taint,” to fan barnyard desires.

Thanks to a wide array of pheromone-laced hair gels, colognes and body sprays, you can buy androstenone too. (If you do, it’s probably wise to stay clear of 4-H fairs or petting zoos for a while.) A quick Google search reveals thousands of sites selling pheromone products for humans. Many contain synthetic versions of androstenone, though others contain androstadienone, another pheromone that can cause sexual excitement in some animals.

A smattering of products are aimed at women, but men are clearly the main customers. You can pick up a $20 bottle of Realm pheromone cologne at a drugstore -- in fact, the Healthy Skeptic is wearing some right now. (It’s a spicy scent that, at least to the male nose, doesn’t seem any different from other inexpensive colognes.) Drugstores also sell tubes of Got2B Magnetik hair gel for men, containing androstadienone, for about $6. You can order a one-month supply of Nexus Pheromones, billed as “pure androstenone pheromone concentrate,” for about $50 via the Internet.

The claims: Whatever the product, the basic pitch is the same: Pheromones, we are told, can stir up sexual chemistry and make users practically irresistible. The Nexus Pheromones site claims users can “instantly arouse, attract, excite, intrigue, and seduce gorgeous women whenever you want.” Ads for Got2B Magnetik call pheromones “a man’s secret edge to make the ladies take notice.” Realm promises to awaken your “sixth sense,” a reference to a common claim that pheromones stimulate the vomeronasal organ in the nose, a structure that allegedly detects chemical signals that are too subtle to be smelled.

Bottom line: During the Healthy Skeptic’s four-day trial, splashes of Realm pheromone cologne failed to elicit a single response from nearby women, including coffee-shop baristas and the check-out person at the hardware store. (Mrs. Skeptic was out of the country and unavailable for comment.)

There are two possible explanations: The Healthy Skeptic is beyond help, or pheromone products are not what they’re touted to be. Fortunately, science points firmly to option No. 2. It’s highly unlikely that any compound could spur instant attraction in humans, according to Michael Meredith, a professor of neuroscience at Florida State University and an expert in mammalian pheromones.

In fact, Meredith says, there’s no convincing evidence that human pheromones even exist. Humans do release androstenone and androstadienone, but nobody knows if these compounds have any effect on other people. A study this year by researchers at UC Berkeley found that whiffs of androstadienone could boost stress hormones in women, but only at concentrations far higher than found in real life.

That’s not to say that humans aren’t closely attuned to chemical signals. Women are especially keen observers. Studies have found that moms can sniff out their baby’s apparel from a pile of identical T-shirts. Scents from a man’s underarm can also improve a woman’s mood, at least in the laboratory. The thing is, Meredith says, “You can’t necessarily apply this to a singles bar.”

Body odor does play an important role in human sexual attraction, says George Preti, a researcher with the Monell Chemical Senses Center in Philadelphia who specializes in human odors. Unfortunately, most natural odors work in the wrong direction. You aren’t likely to win a date on scent alone, he says, but you can lose one.

Smells are one thing, pheromones are another. The VNO -- the organ that supposedly senses pheromones -- doesn’t seem to have any function in humans, according to Charles Wysocki, a Monell neuroscientist. It’s just another thing that separates us from pigs. We don’t have an active VNO, and we don’t rely on pheromones to put us in the mood. No matter what marketers would have you believe, attraction is a little more mysterious and complicated outside of the barnyard.

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Is there a consumer product you’d like the Healthy Skeptic to examine? E-mail the details to health@latimes.com.