Thinking about trying Botox to relax frown lines, a filler to plump thinning lips or a laser treatment for stubborn skin blotches or acne scars? You’re not alone. More than 13 million Americans opted for age-erasing procedures like these in 2013, making minimally-invasive cosmetic procedures the largest and fastest-growing area of plastic surgery in the United States.

But exactly how safe are they? Until now, most reports about side effects have come from small studies on one procedure or a single practice. Now, the largest study ever to examine the safety of these procedures may reassure people who want to hold back time. Researchers at Northwestern University reviewed the outcomes of 20,399 minimally invasive procedures performed at eight medical centers across the U.S. by board-certified dermatologists — and found no significant health problems as a result.

What the research revealed

The researchers found just 48 “adverse events” — doctor speak for health problems. Most were skin discoloration, skin ulcers and other relatively minor problems “that would be expected to resolve with treatment over weeks or months,” the study authors wrote. “Significantly, no serious adverse events were reported.”

“The message for patients is that if you are thinking of getting one of these procedures, you are not indulging in something drastic or high risk,” noted lead study author Murad Alam, MD, professor of dermatology at Northwestern University Feinberg School of Medicine and a physician at Northwestern Memorial Hospital, in a university press release.

“The take home is these procedures are very safe and can be mixed and matched to give the individual a significant cosmetic benefit, rather than getting one big cosmetic procedure that might be risky."

However, the safety findings applied only to cosmetic surgery done by board-certified dermatologists, the researchers said.

Here are the main takeaways from the study:

Laser therapy

In laser therapy,high-energy beams of light (such as pulsed dye, Q-switched and fractional non-carbon dioxide lasers) are used to soften wrinkles around the eyes, mouth and other spots on the face and remove discolored areas caused by blemishes, spider veins, port wine stains and more. Lasers work by removing the top layers of skin and triggering the growth of collagen, protein fibers that support the skin from within.

Risk for minor problems: Low. The study found seven minor adverse events out of 7,991 procedures. Most were hyperpigmentation (permanent darkening of the skin, which is more of a risk for people with dark skin), but two had stubborn skin redness, one developed skin ulcers and one had purplish, bruise-like spots (“persistent purpura”).

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Intense Pulsed Light

In Intense, Pulsed Light, short, strong bursts of light are used for hair removal and to stimulate collagen growth in the skin, making skin look smoother.

Risk for minor problems: Low. In 596 procedures, the study found two adverse events: Burns and hyperpigmentation.

Radiofrequency procedures

In these procedures, mild electric current heats deep skin layer to tighten loose skin and reduce acne scars and cellulite.

Risk for minor problems: Low. In 461 procedures, the study found just one adverse event: skin burns.

Ultrasound

Sound waves (such as Ultherapy) tighten loose skin on the face and neck by stimulating collagen in deep skin layers.

Risk for minor problems: Zero. In 467 procedures, the study found no adverse events.

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Cryolipolysis

These procedures use “fat freezing” (such as CoolSculpting) that breaks up fat cells just below the skin without harming upper layers of skin.

Risk for problems: Low. In 254 procedures the study found one adverse event: unpleasant, lingering skin sensations (“persistent dysesthesia”).

Fillers

These “liquid face lifts” use injected forms of hyaluronic acid (such as Juvederm, Restylane, Sculptra, and Radiesse) or other compounds that add temporary fullness to lips and help even out scars and wrinkles.

Risk for problems: Low, but slightly higher than the other procedures. In 4,430 procedures there were 33 adverse events: Lumps (nodules) and beading (a ridge or line of swollen bumps where the filler was injected) were the most common.

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Neurotoxins

Also called neuromodulators, these injections of botulinum toxin (such as Botox Cosmetic or Dysport) relax wrinkles, frown lines and crow’s feet.

Risk for problems: Low. In 6,200 procedures there were two adverse events: bruising and eyelid drooping (ptosis).

Now, a couple of caveats. By research criteria, unsightly lumps in your lips after getting a filler, a drooping eyelid, and persistent, unpleasant sensations that feel like acid under the skin (a phrase often used to describe dysesthesia) may be classified as minor, but it’s unlikely that people hoping to look younger or to up their attractiveness are going to feel that way. If someone already has a body image problem, a cosmetic procedure that doesn’t turn out as planned may worsen it. And until a follow-up study is done, there's no way to know whether these problems actually did go away, as the researchers predicted, in the weeks or months after the procedure.


Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.