What to Know · July 15, 2026 · 5 min · By Leticia Arrington
1550 nm or 1927 nm: How to Read the Two Numbers Behind Non-Ablative Fractional Resurfacing
Beverly Hills consult rooms quote both wavelengths for the same face, often in the same sentence. Here is what each one actually does to skin, why depth and water absorption decide the answer, and which concerns favor which number.
Walk into almost any laser consultation in Beverly Hills and ask about non-ablative fractional resurfacing, and you will hear two numbers: 1550 and 1927. Both describe wavelengths of infrared light, measured in nanometers, and both are delivered as microscopic columns of heat rather than as a continuous sheet. Patients often assume one is simply a stronger version of the other. That is not how it works. The two wavelengths interact with water in the skin differently, reach different depths, and are suited to different problems. Understanding the distinction is the difference between a well-matched treatment plan and a series of sessions aimed at the wrong layer of skin.
The mechanism both share. Non-ablative fractional lasers create thousands of tiny zones of thermal injury, called microthermal treatment zones, while leaving the surface of the skin intact. Because the stratum corneum stays largely unbroken, healing is faster and infection risk is lower than with ablative resurfacing, which vaporizes tissue outright. The surrounding untreated skin acts as a reservoir of healthy cells that migrate in and repair each column. The controlled injury triggers a wound-healing cascade: fibroblasts activate, new collagen is deposited over weeks to months, and damaged pigment and old sun-related debris are pushed upward and shed. For an independent overview, see Laser resurfacing: what to know.
Why the number matters: water absorption. Skin is mostly water, and infrared wavelengths are absorbed by water at different rates. The 1927 nm wavelength, typically produced by a thulium fiber laser, is absorbed by water roughly ten times more strongly than 1550 nm, which comes from an erbium-doped fiber source. Strong absorption means the energy is spent quickly, so 1927 nm penetrates shallowly, generally around 150 to 300 microns, staying in the epidermis and the very top of the dermis. Weaker absorption means 1550 nm keeps traveling, reaching roughly 800 to 1400 microns into the mid dermis depending on settings.
What 1927 nm is actually for. Because it concentrates energy where pigment lives, 1927 nm excels at superficial problems: diffuse sun damage, mottled discoloration, actinic changes on chronically sun-exposed skin, rough surface texture, and dull tone. Clinicians often describe it as a resurfacing of the pigment layer. Downtime is usually a few days of redness, a bronzed or sandpapery feel, and fine flaking as the treated epidermis turns over. It does comparatively little for deep acne scars or established wrinkles, because the energy never reaches the collagen that needs remodeling.
What 1550 nm is actually for. The deeper wavelength targets the dermis, where collagen and elastin sit. That makes it the workhorse for atrophic acne scars, fine to moderate wrinkles, surgical scars, and skin laxity that stems from thinned dermal collagen. Results build slowly, since collagen remodeling continues for three months or more after each session, and most protocols call for a series of three to five treatments spaced about a month apart. It will soften pigment somewhat, but it is not the efficient tool for it.
Why many devices now offer both. Several platforms house both wavelengths in one system, and some allow them in the same visit: 1927 nm passes for the surface, 1550 nm passes for depth. For a patient with both sun spots and acne scarring, a common Beverly Hills scenario given the local sun exposure, combining them can address two layers in one appointment. The tradeoff is a longer recovery and more total heat delivered, which matters for anyone prone to post-inflammatory hyperpigmentation.
A note on skin tone. Neither wavelength targets melanin directly, which is why non-ablative fractional lasers are generally considered safer across a wider range of skin tones than pigment-seeking devices. But bulk heating can still provoke reactive pigmentation in medium to deep skin tones. Conservative densities, lower energies, more sessions, and strict sun protection are the standard adjustments. Any practice that quotes a single setting for every patient is skipping the most important variable.
Questions worth asking at a consult. First, which wavelength is being proposed and why, in terms of your specific concern rather than a package name. Second, what density and energy will be used, since aggressive settings raise both results and risk. Third, how many sessions the plan assumes, because a single non-ablative treatment rarely delivers the outcome shown in marketing photos. Fourth, what the pre-treatment and post-treatment pigment precautions are for your skin tone.
The honest summary: 1927 nm is a surface tool for color and texture, 1550 nm is a depth tool for scars and wrinkles, and the right choice depends on which layer of your skin holds the problem. A clinician who can explain that in plain language, before quoting a price, is usually the one worth trusting with the settings.