Er:YAG Laser

In short: The Er:YAG (erbium:yttrium-aluminium-garnet) laser is an ablative laser working at 2940 nm. This wavelength lies very close to water’s absorption peak, so energy is absorbed in a very superficial layer of skin: tissue is vaporised in a controlled way, with less heat spreading to surrounding tissue than with a CO2 laser. It is used for wrinkles, atrophic acne scars and some superficial benign lesions. Darker skin carries a risk of pigment change, and any skin can develop infection or scarring; recovery time and suitability are assessed individually by the physician.

Definition

The Er:YAG laser uses an erbium-doped yttrium-aluminium-garnet crystal to produce mid-infrared light at 2940 nm. Its target chromophore is water. 2940 nm is far closer to water’s absorption peak at about 3000 nm than the CO2 laser’s 10,600 nm, so intracellular water absorbs the energy rapidly, tissue vaporises in thin layers (ablation) and less heat damage is left in the tissue below (Riggs et al., 2007).

In a side-by-side study of facial wrinkles, biopsies showed residual thermal damage of up to about 50 micrometres on the Er:YAG side and up to about 200 micrometres on the CO2 side (Khatri et al., 1999). Less thermal damage is associated with faster healing, but it also means less collagen tightening and less coagulation of small vessels (bleeding control).

Er:YAG is used in two main ways:

• Full-surface (fully ablative) treatment: the whole surface of the treated area is removed to a chosen depth. The effect is marked and recovery takes longer.
• Fractional ablative treatment: the beam is split into many microscopic columns, and the intact skin between them speeds healing. Several sessions are usually needed.

How It Is Performed

The skin is cleaned and a topical anaesthetic cream is usually applied; fully ablative or deeper treatments may need additional pain control. The patient wears eye protection rated for the wavelength, and internal metal eye shields are used when working close to the eyelids. For people with a history of herpes simplex, the physician decides whether antiviral prophylaxis is needed. Energy density, pulse duration, spot size and cooling are not values for patients to choose; the physician sets them for the specific device (following the manufacturer’s instructions), the skin type and the treatment area. Ablation depth, number of passes and fractional density are part of that decision.

In the first days after treatment there is redness, oozing, crusting or flaking; how long this lasts depends on treatment depth. Wound care, sun protection and follow-up visits during healing are part of the plan.

Indications and Level of Evidence

• Fine to moderate facial wrinkles: in a side-by-side study of 21 people with Fitzpatrick I–III skin, the CO2 side showed relatively better wrinkle improvement across all participants, but with more than five Er:YAG passes the difference was not significant. The Er:YAG side had significantly less redness at weeks 2 and 8, and hypopigmentation was less frequent (5% versus 43%) (Khatri et al., 1999).
• Atrophic acne scars: in a randomised split-face study in Asian patients, fractional Er:YAG and fractional CO2 gave similar improvement at 6 months after two sessions, with more discomfort on the CO2 side (Manuskiatti et al., 2013). A meta-analysis of five studies found broadly similar efficacy, with a slight advantage for CO2 on physician assessment (Husein-ElAhmed and Steinhoff, 2021). A newer meta-analysis of eight studies found a higher effective-response rate with fractional CO2, along with higher pain scores and longer-lasting redness (Liu et al., 2024).
• Some superficial benign lesions: selected superficial lesions with a clinical diagnosis (confirmed by biopsy if needed) can be treated. A lesion with an uncertain diagnosis is not vaporised, because that removes the chance of pathological examination.

The comparative meta-analyses do not reach exactly the same conclusion, because the studies are small and use different devices and protocols. There is therefore no single answer to “Er:YAG or CO2?”; the choice depends on the goal, skin type and the recovery time the patient can accept.

Skin Type (Fitzpatrick) Suitability and Risks

Because Er:YAG targets water, melanin is not its direct target; even so, the inflammation that follows any ablative treatment can cause post-inflammatory hyperpigmentation (PIH) in darker skin. A recent review states that ablative modalities carry higher complication rates in skin of colour and require conservative settings and strict sun protection (Dreifus et al., 2026). For Fitzpatrick IV–VI skin, the physician weighs a fractional approach, lower density and a pre- and post-treatment pigment plan.

• Expected effects: redness, swelling, oozing and crusting, lasting longer after fully ablative treatment.
• PIH: more common in darker skin; it often fades over months.
• Hypopigmentation: can appear late, especially after deep or fully ablative treatment, and can be long-lasting.
• Infection: bacterial, fungal or herpes infection can develop while the skin is open.
• Scarring and ectropion: in a review of eye-area complications of dermatologic lasers, 59 cases were ectropion (outward turning of the eyelid) after eyelid resurfacing (Flegel et al., 2022).
• Eye injury: 2940 nm light is absorbed by water in the cornea. Eye protection is an integral part of treatment.

Device and Model Verification

“Erbium laser” can mean different products: 2940 nm Er:YAG, 2790 nm Er:YSGG and 1550 nm erbium-glass (non-ablative) devices are not the same. A general link to a regulator’s homepage or a device class does not show that a specific model is authorised for a specific indication. Ask for the exact brand and model, the wavelength, whether it is ablative or non-ablative, registration in Türkiye’s TİTCK Product Tracking System (ÜTS), the intended use covered by the CE marking, and which model and indication any FDA 510(k) clearance covers. Check these against the device label, the instructions for use and official databases.

Pre-Procedure Assessment and Test Spots

The consultation covers skin type, scar or keloid tendency, vitiligo, herpes history, active acne or infection, previous laser or peel procedures, any radiotherapy, immune status and pregnancy. Tell your physician about all medicines and supplements, including photosensitising medicines and blood thinners. Never stop a prescribed medicine without asking the doctor who prescribed it.

Decisions about isotretinoin rest with the physician. A 2017 systematic review with expert consensus found insufficient evidence to support delaying fractional ablative lasers during or immediately after isotretinoin, but stated that fully ablative laser is not recommended during isotretinoin treatment (Spring et al., 2017). The distinction between fully ablative and fractional treatment therefore matters.

In darker skin or with a history of PIH, the physician may consider a laser test spot in an inconspicuous area. Because PIH can appear over weeks, assessing the test area takes time, and a test spot does not guarantee how the whole face will respond.

Realistic Expectations and Number of Sessions

Fully ablative Er:YAG is usually planned as a single resurfacing session, whereas fractional treatment needs a series. In the acne scar study, for example, two sessions were given two months apart, and improvement kept increasing from month 1 to month 6 (Manuskiatti et al., 2013). Complete clearance of acne scars is not expected; the goal is a measurable reduction in how visible they are. Results depend on scar type and depth, skin type and treatment depth. Because new collagen forms over months, the final assessment is usually made several months later.

When It Is Not Appropriate

• Active infection, active herpes or an open wound in the area
• An undiagnosed pigmented or suspicious lesion
• Fully ablative treatment during isotretinoin
• A marked tendency to keloid or hypertrophic scars, or active vitiligo (without physician assessment)
• Conditions that impair wound healing, or recent radiotherapy to the area (physician assessment needed)
• Pregnancy (elective procedures are usually postponed)
• Being unable to avoid sun or carry out wound care during healing

Comparison

The differences between Er:YAG, CO2 and non-ablative fractional lasers can be summarised by target chromophore, depth of thermal injury, recovery time and risk profile. The summary table is on this page.

Alternatives and Combination Treatments

For wrinkles and acne scars, alternatives include fractional CO2, non-ablative fractional lasers, microneedling, radiofrequency microneedling and chemical peels. For deep, sharp-edged scars, surgical techniques (subcision, punch techniques) can be planned alongside laser. Combinations need sequencing that gives tissue time to heal.

Our Clinical Approach

With Er:YAG we first clarify the goal, the skin type and the recovery time the patient can accept. Before treatment we share the device brand and model, whether treatment will be fully ablative or fractional, and the possible risks. We discuss the number of sessions as an evidence-based range, not a fixed figure.

Sources and References

This article is based on PubMed-indexed meta-analyses, randomised and comparative studies, expert consensus and safety reviews. It is not a personal diagnosis or treatment instruction.

Last medical review: 23 September 2026 · Medical editor: Dr. Hamza Gemici