The principal difference between the two types of lasers is the extent to which superficial skin layers are affected. The ablative laser causes the destruction of this top layer while the non-ablative laser leaves it intact. This key difference accounts for the greater skin resurfacing results possible with ablative laser, but also greater downtime and risk of unwanted side effects. For some conditions, repeated treatment with a non-ablative laser may achieve the same results as a single skin rejuvenation treatment with an ablative laser. This approach may be preferable for patients who are unable or unwilling to weather the downtime associated with ablative laser.

The use of cosmetic lasers has ballooned over the last decade with the global cosmetic laser market expected to reach 5.5 billion by 2026. The first cosmetic application of laser was in 1963, but it was the development of selective thermolysis in 1982 that gave physicians the ability to target specific tissue, thus spurring the rapid growth in the field that has continued to the current day.

Non-ablative laser was first introduced to the market in the late 1990s and the technology and uses for non-ablative laser has grown ever since.² Although a bit simplistic, a helpful way to explore the world of non-ablative laser is by separating them into fractionated and non-fractionated lasers.

A fractionated laser divides the light into thousands of microscopic treatment zones without affecting the surrounding skin, allowing for shorter recovery times and decreased risk. Fractional, non-ablative laser is used to treat a wide range of skin irregularities and concerns of photoaging.

Non fractionated and non-ablative laser creates uniform thermal damage to the dermis while sparing the epidermis. This procedure is generally used for vascular lesions containing haemoglobin, mild-to-moderate photodamage and early signs of skin ageing.

The primary benefits of a non-ablative laser are minimal downtime and fast recovery. Although the skin may appear pink or flaky following laser resurfacing, because the non-ablative laser does not damage the top layer of skin, makeup can generally be applied immediately after treatment. Any edema or redness is generally resolved within three days and the use of cold compresses may help alleviate discomfort after a skin rejuvenation laser treatment.

Although the skin begins to renew within 24 hours, patients are encouraged to keep the treated area well moisturized and apply sunscreen to avoid post inflammatory hyperpigmentation. Darker skin types may be prescribed creams containing pigment inhibitors such as hydroquinone. Results of a laser skin resurfacing are generally seen very quickly but will continue to evolve over several months after a non-ablative laser treatment.³

Both ablative and non-ablative lasers work on the principle of “controlled wounding,” whereby the induction of trauma within the skin initiates the natural healing response resulting in collagen remodelling, dermal repair and the production of new collagen. The energy produced by the non-ablative laser is absorbed by intradermal water at the target wavelength raising the intradermal temperature and delivering a thermal injury capable of denaturing collagen and initiating the wound response. The reduction in fine lines and wrinkles, overall improvement in skin texture, and skin tightening seen after skin rejuvenation with a non-ablative laser are due to this new collagen formation and subsequent dermal thickening^4,5

Unlike the ablative laser which vaporizes or “ablates” a fraction or all of the epidermis, the non-ablative laser does not physically damage the epidermis. This difference accounts for the minimal downtime and reduced risks associated with non-ablative laser.

The light energy of a non-ablative laser may be delivered in a non-continuous pulse action or via a wave divided into a grid of microscopic columns, otherwise known as a fractional laser. The fractional non-ablative laser delivers heat into the skin through thousands of tiny, deep columns known as microthermal treatment zones. All of this occurs without affecting the surrounding skin, allowing for a much faster recovery after laser resurfacing and a reduced likelihood of post- treatment complications.⁶

Because the non-ablative laser does not remove the top layer of the skin, it may not be as effective for skin resurfacing as an ablative laser. However, non-ablative lasers offer multiple approaches to skin rejuvenation without the downtime and complications associated with the more powerful ablative laser. This makes it the preferred method of skin rejuvenation for mild photoaging in patients 30 to 50 years of age.

Of all the types of laser treatment for the face, the non-ablative laser may not show the same dramatic results achieved with ablative laser, but the non-ablative laser does have a place in corrective treatments for the skin. Non-ablative laser delivered fractionally at 1550 nm was approved by the FDA since 2005 for the treatment of melasma⁷, and the newer picosecond non-ablative laser technology is effective for pigmentation concerns in some skin.⁸
New uses for non-ablative laser continue to be developed as technology and experimentation allows. For example, recent studies have explored the use of non-ablative laser in lieu of dermal fillers for lip rejuvenation⁹ as well as promising results for the treatment of under-eye bags.¹⁰

There are many options of non-ablative laser, each representing different wavelengths, pulse durations and fluence (the energy delivered per unit area) of the light beam. Each of these factors will affect the function of the non-ablative laser.
The main wavelength for non-ablative lasers is a long pulse of 1064 nm with target chromophores being melanin, hemoglobin and water.¹¹ This means that some non-ablative lasers can reach a depth of around 3 mm in the skin, into the dermis.¹² The desired depth of a non-ablative laser is determined by the location of the target. In this way, deeper is not always better as some conditions, such as photo-induced pigment, may lie in higher levels of the skin. Conversely, a laser treatment for acne scars may require more intensity.
Thankfully, non-ablative laser units offer adjustable depths by enabling the physician to change the pulse duration and fluence of the beam for customisable rejuvenation and non-ablative laser resurfacing.

The discomfort during any types of laser treatment for face or body will vary depending on the area being treated, the type of laser used, the duration of exposure and the patient’s personal pain threshold. For some devices, a patient must communicate the sensations of discomfort to the provider in order to avoid unwanted epidermal injury. In these cases, the use of anesthesia during laser resurfacing is not advised.

In general, a non-fractional, non-ablative laser will include a topical anesthesia before the skin rejuvenation treatment. A device to blow cool air or the use of ice packs may also be used to relieve discomfort and minimize edema immediately following the non-ablative laser skin resurfacing.

In general, a non-fractional non-ablative laser may create more discomfort than a fractional non-ablative laser. However, innovations within the field of laser skin resurfacing and skin rejuvenation have significantly improved the patient experience both during and after laser resurfacing and, in general, the procedure now includes only minimal discomfort.

The body represents a complete biological ecosystem that is constantly evolving and responding to external input. For this reason, lifestyle choices such as healthy eating, exercise and safe sun exposure can dramatically impact the longevity of results after non-ablative laser resurfacing.
While the most effective laser for skin rejuvenation is an ablative laser, repeated non-ablative laser treatments have been shown to produce good results with limited downtime. This presents the broad versatility of non-ablative laser as, unlike the ablative laser, each treatment with a non-ablative laser may be without any significant downtime or patient discomfort.¹³
Once the desired outcome has been achieved, the results of a series of non-ablative laser skin rejuvenation treatments will be more gradual and progressive, but may last 3-5 years depending upon the factors discussed above.¹⁴

Provided the patient is a good candidate for non-ablative laser treatments, the procedure is very safe and statistically represents fewer risks for post-treatment complications when compared with the stronger ablative lasers. In addition, because non-ablative laser may be performed in a series, wonderful results of skin rejuvenation can be achieved over time with little downtime and minimal risk. Precautions after any laser treatment can aid recovery and prolong the procedure’s results.

*Always consult your medical professional before undergoing this procedure.