The product: Living Essentials’ Chaser – Freedom from Hangovers.

The claim: That taking this as you drink will keep a hangover at bay.

Key ingredients: Calcium carbonate and vegetable carbon.

Price: $2.99 for a four-capsule “sample pack.” Two capsules are said to last for up to three hours of drinking or as many as six drinks. – whichever comes first.

Other sources: Chaser is available at many GNC stores. A version that contains vitamin B is sold for wine headaches. Other companies also product hangover remedies. Unlike many of the other products on the market, however, Chaser does not contain aspirin or Tylenol, under the argument that these painkillers do little to prevent hangovers, only ease them.

How it works: According to company material, Chaser’s two active ingredients absorb the substances, known as congeners, that cause hangovers. Produced by fermentation – the same process that gives alcohol its kick – these congeners normally head straight for your bloodstream when you drink, prompting your body to respond with a surge of proteins that can lead to the signature pain of a hangover. Chaser’s vegetable carbons and the calcium carbonate sidetrack these congeners to your digestive tract, where they will do little harm.

Scientific evidence: The strongest evidence comes from a placebo-controlled study sponsored by Living Essentials and featured prominently on its web site, that asked participants to take Chaser or a sugar pill while consuming four to 12 drinks. The subjects given Chaser – the company did not specify how large a trial this was – all reported fewer hangover symptoms than their less fortunate compatriots. Although there’s been no independent research, experts do acknowledge that antacids such as calcium carbonate will tamp the production of acid and guard against stomach distress.

Possible dangers: Not many. Calcium carbonate may prevent the absorption not just of those congeners but other medications as well, including aspirin, tetracycline and iron. Experts recommend waiting a couple of hours in between taking these drugs and calcium carbonate.

Bottom line: Despite the limited scientific research to support its efficacy, Chaser has caught on fast among the college and club set. But Chaser is not the be all and end all. For starters, you have to remember to take it. Midway through a night of debauchery, that may be the last thing to cross your mind. Also, keep in mind that even if you do remember to take Chaser, it will not protect against any of the other effects of intoxication. So if you want a sure-fire way to make sure you wake up hangover-free without a red fact, as always, your best bet is not to imbibe at all.