The first lime Vivian* tried laser hair removal, she made an appointment with a prominent New York City dermatologist. "I was nervous about the whole thing, so I did a lot of research and found out that this guy was a real pioneer in the field," recalls the 35-year-old book publicist, "But his reception area was kind of depressing, and he kept emphasizing that the procedure wasn't permanent." While Vivian was happy that the zaps on her bikini line weren't as painful as she feared, she was less thrilled with the bill for several hundred dollars. "There was no way I was going to keep paying that much for something the doctor couldn't guarantee would even work," she says. Not long afterward, however, she found a place that reassured her: a downtown med spa with a stylishly appointed lounge and a receptionist who sold her a package of six sessions at a reduced price. "They used the same laser the doctor did for half the price," she says. "Plus, the clients and staff were fun and cute, like people you'd want to have a drink with," she says. "I remember thinking, why on earth would anyone go to a dermatologist when they could come here?"

Thanks to people like Vivian, the med-spa business is booming, with the number of locations nationwide jumping from about 450 in 2004 to about 2,500 today, according to the International Medical Spa Association. For women already accustomed to going to the spa for massages and facials, signing up for a chemical peel or a little Botox can feel like a perfectly logical next step (especially when the treatments are attractively priced and easy to schedule). What they don't realize is that the safety of these quasi-medical facilities varies wildly—and that there is little to no governmental oversight of what goes on within their impeccably decorated waiting rooms. Some med spas are totally legitimate, with a dermatologist or plastic surgeon always hovering nearby to provide scrupulous supervision of every procedure. But others are staffed by former manicurists and cosmetologists now wielding swabs of acid for face peels, or inexperienced laser operators who "burn as they learn"—an expression Min-Wei Christine lee, an assistant clinical professor of dermatological surgery at the University of California, San Francisco, read in one med spa's training manual and later testified about in a California court case and medical-board hearing. There isn't a central reporting agency for complaints related to the industry, but "every time we ask member doctors if they see bad results from med spas, the number of yeses increases," says Roy Geronemus, clinical professor of dermatology at New York University and former president of the American Society for Dermatologic Surgery.

Of course, most dermatologists, and plastic surgeons would be perfectly happy to see their lower-cost competitors put out of business entirely. A few will admit (grudgingly) that some procedures offered at med spas are safer than others. But they can all agree on one point: that it's up to the client to do her homework. Here's how to figure out whether and how to book that spa session—or run back to the safety of the dermatologist's office.

1. ASK ABOUT THE DOCTOR
Just because a spa has a medical director doesn't mean you'll ever lay eyes on her—or that she'll be available if there's all emergency. "There is no data on how many med spas have a doctor in the house, but we estimate it to be between 10 and 20 percent," says Karla Keene, a vice president of MedResults, a spa consultancy company. Since state regulations vary considerably (for example, Kentucky requires a doctor to be in the room any time a laser is used; in Georgia the physician can be up to 50 miles away), it's imperative that you do your own investigation long before you change into a med spa's Egyptian cotton robe, (A national study of med-spa complications from 2004 to 2006 by San Francisco dermatologist Vic A. Narurkar and colleagues found that 82 percent of them occurred when there was no doctor on site.)

Four key questions will yield quite a bit of information right over the phone. Start by asking the receptionist, "Is the spa affiliated with a doctor?" (If she answers no, you might want to hang up.) Second, what kind of doctor is she? Seems obvious, but it's actually common for the consulting physician to be a podiatrist, an anesthesiologist—or anything but a board-certified dermatologist or plastic surgeon. (According to Narurkar's study, 57 percent of complications happened at facilities where a medical director had limited or no background in dermatology or plastic surgery.) "Don't let the doctor get away with saying, 'I'm board-certified' and 'I specialize in dermatology or cosmetic surgery,'" Lee says. "The doctor could be board-certified in family practice and have taken a weekend course on the procedure." She advises calling your state medical board to confirm that the doctor's board certification is indeed in dermatology or plastic surgery, and to also check on any complaints against her.

Next, it's critical to find out if the doctor will be performing the treatment, or at least be in the building during it. If the answer is no, that isn't necessarily a deal breaker—but be sure to ask how many days a week the doctor is at the spa and how closely she supervises the technicians, aestheticians, and nurses (because a doctor who's located 50 miles away can't exactly zip in to handle emergencies). If the receptionist can't answer with specifics, the spa's medical director may be what is known as a "rent-a-doc" who just lends his name to the organization for a fee.

2. ASSESS THE RISKS
If you learn that a doctor will not be performing the actual treatments, you need to decide which appointments—if any—you're comfortable booking. New York City dermatologist Bruce Katz, founder and director of the well-respected Juva Skin & Laser Center/MediSpa and the chairman of the medical advisory board of the Medical Spa Society, says the following procedures are the least risky: mild peels ("no more than 20 percent glycolic acid, or 10 to 15 percent trichloroacetic acid") and microdermabrasion (it's hard to mess that up"). Katz is also comfortable with nurses or aestheticians wielding an Intense Pulsed Light wand as long as a doctor is on the premises. However, his personal list of procedures that should never be performed by anyone other than a dermatologist or plastic surgeon is considerably longer. "No laser or injection treatments for spider veins; no stronger peels; no tattoo removal; no lasers like the Fraxel or pulsed-dye lasers for treating broken blood vessels, redness, or scars—these are all more invasive." So, what if the treatment you're considering isn't on either list? Read on.

3. DON'T GET BURNED
Laser treatments are among the most popular procedures at med spas—and, according to Narurkar's study, they also have the highest rate of complications. Here's just one example: A dark-skinned patient came to him with blisters all over her legs (which turned to dark and light spots) thanks to laser hair reduction. "She had already had a treatment (that went fine, but one day the laser for dark skin was already in use," he says. "So, rather than reschedule her, they used a different laser that wasn't safe for dark skin." If, like Vivian, you are still tempted to sign up, it's imperative to find a technician who has logged significant time using the devices—not just completed whatever training your state requires. Katz offers the following analogy: "My daughter just took a weekend course in motorboat operation and passed the test, but she hasn't even driven a boat yet. The better question to ask is, 'How many days a week does the person perform these procedures?'" If the nurse or aesthetician is licensed according to state regulations and has been treating clients full-time for three to four days a week for three months, that's the bare minimum of familiarity Katz considers necessary to be able to recognize—and prevent—adverse reactions. Another key question: Does the spa own its lasers? "If they rent, that's a bad sign," Katz says. "That may mean there's not enough volume" for a technician to get the necessary experience. And whenever possible, try to at least have a consultation with the spa's doctor to make sure your skin and the laser in question are a good march, even if she won't be doing the zapping. "There are at least ten devices for hair removal alone," notes Geronomus. "Many are excellent—but often the right one just isn't used."

4. BE AFRAID OF NEEDLES
There aren't any hard numbers on complications from injectable treatments at med spas, but just consider the worst-case scenarios for a moment. If Botox is injected into the wrong spot, if too much is used, or if it's diluted (a common cost-cutting measure), the toxin can travel, causing a droopy eye or blurred vision that lasts for up to four months. Fillers like Restylane and Sculptra can produce lumps if injected incorrectly, and if the needle hits a blood vessel it can cause a whole area of skin to die, leading to disfigurement—and even blindness. When we asked Katz point-blank if such injections should only be administered by a doctor, he replied, "In my opinion, yes," but noted that state regulations vary considerably. Then he pointed out a factor that even the most safety-conscious client might never consider: the importance of aesthetic training. "A nurse who doesn't have a sense of what looks natural may overdo it and freeze all the muscles. This frozen look is why so many patients are afraid of Botox," he says. Bottom line: Are any of the above scenarios worth a savings of a few hundred bucks? Only you can answer that, but you get our drift.

5. WATCH THE HARD SELL (AND THE FINE PRINT)
With all their specials and discounts and prepaid packages, it can sometimes feel like the med-spa equivalent of the Hippocratic Oath must be "first, get a credit-card imprint." The Sleek MedSpa chain, for example, looks for aestheticians who can "meet weekly sales goals" and "promote additional services to current patients and ask for referrals" (according to a recent job posting on the spa's website). Keep this profit motive in mind when a technician starts aggressively pushing new treatment. Plus, while it's often cheaper to buy med-spa sessions in bulk, be sure to check the spa's refund policy before committing to a whole series (especially if the spa is part of a chain). Consider one med-spa chain that went bankrupt and was bought out and renamed twice—with each change, clients lost their prepayments. (Often in such situations, new owners are not legally obligated to give refunds.) If the location you're considering seems at all sketchy, contact the Better Business Bureau in your area and your state medical board, and ask whether there have been any complaints or disciplinary actions against the spa, its medical director, or its technicians. You can also search realself.com, an independent clearinghouse of doctor and spa reviews posted by clients, for any mention of your spa—positive or negative.

Finally, if something sounds too good to be true, listen to your instincts. The spa staff may sometimes swear to have gotten amazing results from the treatment you're interested in—whether or not they've actually had it. And be wary of grandiose claims, such as a chemical peel being "better than a face-lift," or guarantees of any kind. Remember Vivian, who was all too happy to ditch her dermatologist for the sleek downtown chain? Four years later, she's still trooping in every few months for treatments. "They said it would take six sessions, but I've been at least 20 times now," she admits. "They offer a nice discount, but I don't even want to do the math at this point."

*This name has been changed.