Laser resurfacing & rejuvenation 101

Learn all about laser resurfacing from how it works, what it does, the results, the different types of cosmetic laser, skin tone considerations and clinical evidence.
WeAreBodyBeautiful shares everything your need to know about laser resurfacing & rejuvenation anti-aging treatments both professional & at-home
By Laura Gladman
May 23, 2020

Laser resurfacing is a very popular professional cosmetic procedure for face, neck, hands, and chest. It encourages fresh, new, supple skin to grow. The laser beams selectively target then heat, or sometimes destroy, parts of your skin. This kick-starts collagen synthesis to repair these injuries. Fresh new collagen rejuvenates your skin, smoothing out lines and wrinkles, fading wrinkles and areas of discolouration, and tightening your skin for a younger appearance. 

Although not as drastic as cosmetic surgeries, you’ll still need a few weeks to heal with some types of professional laser resurfacing . Smaller home lasers have no down-time but demand many more sessions than professional treatments for noticeable results.

This article explains everything you need to know about professional laser resurfacing treatments, how home versions measure up and where you can get one.

How do cosmetic lasers work?

First, let’s understand what a laser is and then what they do in our skin.

A laser generates a narrow beam of very intense light. Laser beams are monochromatic which means they’re of all one wavelength. The waves are also in the same phase (coherent) and are parallel to each other (collimated), don’t you know 🤓.

diagram of electromagnetic waves in a laser beam
A frikkin laser beam has waves of the same wavelengths and they’re in phase Source
Diagram of types of laser by wavelength
Types of lasers and the different wavelengths

A laser beam is either a continuous or pulsed source of photons. Photons are the smallest measurements of electromagnetic radiation and the basic energy units of all light.7

Roger that. So, what do they do?

They zap specific substances in our skin causing controlled damage with heat.

The substances are called chromophores. These are parts of molecule responsible for its colour. That’s because, chromophores absorb photons from light of various wavelengths, and the colour our eyes see is the colour/wavelength NOT absorbed by the chromophore. Chromophores occur naturally in our tissues (or endogenously). Examples are melanin, haemoglobin in blood, protein, nucleic acid, and water. Or they can be from an external source (or exogenous) like tattoo ink.8

As mentioned, target chromophores absorb light photons from the laser beams. And because the energy’s intense it converts to heat. If no chromophore is present, the laser beam passes straight without causing any heat or damage. It’s only when the chromophore absorbs photons that the laser causes damage and an injury.10

Photo of laser tattoo removal treatment
Tattoo ink absorbs laser photons and vaporizes, leaving surrounding normal skin untouched source

So, surrounding skin tissues without that chromophore remain unchanged. This principle is called selective photothermolysis. Therefore, when we know which wavelengths chromophores absorb, we can use intense light and lasers for various controlled effects on our skin. Effects such as laser hair removal, tattoo removal, and laser resurfacing.

Selective Photothermolysis
Cosmetic lasers use the scientific principle of selective photothermolysis

Controlled damage

Laser operatives must configure the laser beams to control the heat and damage to the surrounding skin structures.

To do this, the pulse width of the laser must be shorter than the Thermal Relaxation Time (TRT) of the target. TRT is the amount of time needed for an object to cool down to 50% of the initial temperature. It depends on the size of the target chromophore. Larger objects have a longer TRT. For example, in tattoo removal, tattoo particles need a few nanoseconds, whereas varicose leg veins require a hundred milliseconds.

Some experts now believe that the TRT is an outdated concept, because it concerns cooling time, not heating time. They think the unique properties of the skin and how well it absorbs heat should dictate the laser pulse, not how quickly it cools. However, operatives still widely use TRT to calculate laser pulse duration. 

So, what effect do lasers have on our skin?

What lasers do to your skin

The skin damage caused by lasers starts a natural healing response called neocollagenesis. This kickstarts your cells into building more collagen and elastin to repair the damage.

Collagen and elastin are the mesh of fibres that support your skin. They’re the main proteins of the extracellular matrix (ECM).

✔️ Collagen makes your skin strong and firm

✔️ Elastin keeps your skin tight and supple

Fibroblast cells found in the dermis layer of your skin, produce both collagen and elastin..

You’ve plenty when you’re young. But from around 30 you produce less and less each year. The result is fine lines, wrinkles, sagging, loss of tone, dull skin, rosy-redness and darker spots. Collagen creams can’t help because the collagen molecules are too big to sink into your skin.

Cross section diagram of young skin with a strong collagen and elastin matrix, next to another of aging skin where the matrix isbroken down and weeker, and surface skin wrinkled.
Comparison of younger and aging skin. The dermis ECM deteriorates in aging skin.

So, neocollagenesis with laser rejuvenation is awesome for aging skin. Here’s what happens.

👉 When the laser destroys or heats the skin cells, they release inflammatory mediators, such as histamine and prostaglandins. These chemical messengers trigger cell growth and collagen remodelling. Your fibroblasts become more active and boost their production of collagen which spreads throughout your dermis. The collagen and elastin fibres then tighten and rearrange in the connective tissues. These cellular-level effects lead to a reduction in wrinkles and sagging 11 and repairs and revitalises your skin. This gives you fresher, smoother and supple, younger-looking skin!

Lasers also treat acne scarring and inflammation, and the visible blood vessels you experience with rosacea. Professionals use Pulse Dye lasers (PDL) to destroy the vascular components (blood vessels) of the dermis, which then regrows without scars and redness.12

But not all laser treatments are the same. That’s because there are different types of laser.

Different types of laser

There are various types of cosmetic lasers for facial rejuvenation. The wavelength and how they deliver the laser beams determine their classification. 

First, we’ll look at ablative vs non-ablative laser, then fractional vs non-fractional.

Diagram illustrating the differencesand likely depths of ablative, non-ablative and fractional lasers
Ablative vs non-ablative and Fractional vs non-fractional lasers

Ablative lasers

Ablative lasers generate temperatures over 100 °C to vapourize the outer skin layer (epidermis).

They’re the most aggressive and produce the most dramatic results.  They create a carefully controlled pattern of skin micro-wounds in the skin surface. They do this by superheating the intracellular water in the skin’s outer layer (epidermis), which then vapourizes the skin cells. This also heats the underlying dermis. The effect extends around 1.5 mm deep into the skin.

And they leave your skin red-raw. Ouchy.

Side by side patient comparison showing red raw skin that's healing after a CO2 ablative laser treatment
Before & after with a CO2 ablative laser. Extensive skin healing needed Source

Your skin reacts by producing loads of collagen and elastin to build a fresh new epidermal layer. This ‘resurfacing’ has a dramatic effect on ageing skin by continuously producing buckets of collagen. However, it takes weeks to heal and there’s also a risk of infection.

Side by side comparison of the before and after healing photos for a CO" ablative laser patient
And dramatic results from CO2 ablative laser resurfacing Source

Types of ablative laser include the carbon dioxide (CO2) laser which emits light at a 10,600 nm wavelength, the erbium laser emitting infrared light at 2940 nm wavelength, and systems that combine these.1 These combined systems have fewer side-effects, and some studies find they’re equally as effective for facial rejuvenation and wrinkle reduction.2

Non-ablative lasers

Non-ablative lasers are gentler on the skin than ablative.

The laser beam heats up and damages the outer (epidermis) and lower (dermis) layers of skin, but it doesn’t destroy them. The epidermis remains in-tact, which means there’s no skin peeling. But also that results are more subtle and gradual.

Non-ablative lasers generate temperatures of around 65°C which makes the dermal collagen shrink and uncoil, leading to thermal remodelling of the dermis.9 Your body produces a surge of collagen and elastin to repair and renew the damaged cells, which then gradually freshens up the rest of your skin too.

Photo of a lady undergoing Fraxel re:store non-ablative fractional laser resurfacing
Non-ablative laser rejuvenation with Fraxel re:store

Non-ablative lasers emit light at wavelengths between 1320nm and 1927nm.3 There are two types of non-ablative lasers. Pulsed dye lasers (PDL) and intense pulsed light (IPL, which uses intense light energy but isn’t a laser). These devices create controlled wounds in the dermal micro-vasculature. Mid-infrared lasers target water in the dermis to create heat. 

Both ablative and non-ablative lasers can be non-fractional or fractional.

Non-fractional lasers

Non-fractional lasers have a wide area of effect. A single, larger beam of energy zaps the entire surface of the treatment zone. This leads to more side effects and an extended recovery period.

Fractional lasers

Close-up pattern of tiny fractional laser dot-zaps on the skin
Close-up pattern of fractional laser zaps on the skin

Fractional lasers are like a pixelated beam. The laser beam breaks into thousands of tiny evenly spaced beams that create columns of thermal injury in the skin, called microthermal zones (MTZs). MTZs range in size from 100 to 400 microns (μm) in width and around 300 to 700 μm in depth.5


TIP: A micron, also known as a micrometre, is a millionth of a metre. Therefore, 300 to 700 μm depth is 0.3 to 0.7 millimetres. Teeny. The symbol for microns is μm.

Because the laser only treats a fraction of the skin, there is less downtime and fewer side-effects.6

Lasers for darker skin tones

There is a common misconception that laser treatments do not suit darker skin tones. The old theory was that as lasers target chromophores, which include melanin, they could burn and scar darker skin.

Side by comparison of before and after photos for dark skinned non-ablative laser resurfacing female patient
Before & after non-ablative fractional laser rejuvenation on dark skin source

However, melanin doesn’t absorb non-ablative wavelengths. So, you can use it to reduce acne scarring and for facial rejuvenation on darker skin tones. Fractional lasers are a better choice for darker skin tones too as they affect a smaller area, minimising potential issues.13 Avoid ablative lasers on darker skin tones because they can result in permanent hyperpigmentation.

A 2013 research review found that longer wavelength lasers are safe for ethnic skin.14

What clinical evidence is there? 

Whilst a few independent clinical studies do exist, overall, there’s a lack of clinical evidence confirming the effectiveness of laser resurfacing and rejuvenation.

👉 Here’s a summary of the existing studies.

A 2017 study published in the Journal of Clinical and Aesthetic Dermatology reviewed 48 research studies on fractional, non-ablative, skin resurfacing methods. The researchers specifically looked at darker skin types. They conclude that fractional resurfacing is safe and effective for treating acne, surgical, and traumatic scars, melasma, and skin rejuvenation.15

A 55-person trial compared the effects of ablative and non-ablative fractional laser treatments on thyroidectomy scars. Researchers found that both types of lasers significantly reduced the scars’ colour, contour, and skin distortion.16

In another study, researchers combined fractional ablative and non-ablative laser resurfacing treatments on one half of the face and purely ablative on the other. Using just eight subjects, they found there were improvements in wrinkles and pigment in both groups, and results were equivalent. However, in the combination areas, there were fewer immediate side effects.17

Is laser resurfacing FDA approved?

Despite this sparse clinical evidence, several laser resurfacing manufacturers have gained FDA 501K clearance for their professional machines. So, this is some good reassurance that approved machinery is safe and effective.

The job of protecting US citizens’ health lies with the US Food and Drug Administration (FDA). All manufacturers of laser resurfacing facial devices must have FDA clearance before they can sell or market the device in the US. 

US Food & Drug Administration logo
Many professional and at-home machinery manufacturers have FDA-clearance

To apply for clearance, the manufacturer must submit evidence showing the device is substantially similar to another cleared or approved machine (called a ‘predicate’ device). This ‘substantial equivalence’ then implies the device is at least as effective and safe as the predicate device.

And there are many professional grade laser machines cleared by the FDA from brands such as Lumenis, Sciton, Candela, Cynosure, Fraxel, and Syneron. You can search the 501K database here.

Several home-use laser resurfacing devices, including the NIRA and Tria skin care lasers, are also FDA cleared as over the counter class II medical devices. This means they have a moderate risk associated with their use.18,19

At home laser devices

Compared to a doctor’s clinic, at-home lasers are considerably smaller and use much less power.

These home lasers can reach a depth of around 500 μm (remember, a micron is a millionth of a metre, so it’s 0.5 millimetres). By comparison, an example professional grade laser goes 500 to 1400 μm deep.

This means with professional treatments you need many fewer sessions to see results. Most doctors recommend 3 to 5 for non-ablative lasers. And there’s a few days recovery before your skin heals and is back to normal. With home lasers you need many more treatments, but your skin heals quickly within 24 hours.

Professional grade lasers have professional operators too. They’re medically trained specialists who configure the laser specifically to suit the patient. At home it’s just you, so it must be easy, safe and simple.

So, this is all good stuff. Home devices are designed to:

✔️ keep us safe,
✔️ work with minimal discomfort,
✔️ repair fast, and
✔️ still give visible results overtime
✔️ with clinical evidence proving safety and effect

The best at-home laser rejuvenation round-up

These are the best at-home laser rejuvenation devices tested & reviewed by

Learn all the pros & cons of the best at-home laser resurfacing & rejuvenation devices to give you firm, smooth, supple & radiant skin, with softened wrinkles, redness & scars.


TIP: Another laser is the LYMA rejuvenation laser. However, this works in a different more gentle way to energise and not damage your skin cells, using Near infrared (NIR) light.

Laura Gladman
I'm a bit obsessed with at-home beauty devices. It's a habit I've had for around 9 years now. I love the science, testing and reviewing them, and sharing my experience and feedback on my site I'm also a crazy dog lady, and I don't care.

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