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Laser Resurfacing

Also known as: laser, fractional laser, CO2 laser, erbium laser

A controlled thermal injury delivered by a laser whose wavelength is absorbed by tissue water, either vaporising the epidermis and upper dermis (ablative) or heating the dermis while leaving the epidermis intact (non-ablative), applied confluently across the surface or as microscopic treatment zones.

Evidence status

Moderate

For atrophic acne scars, evidence is comparatively strong: a 2025 network meta-analysis pooled 68 RCTs and NICE names CO2 laser within a consultant dermatologist-led pathway for severe persistent scarring. Evidence beyond acne scarring is thinner and heterogeneous, with no clear winner for pigmentary adverse outcomes and very little Fitzpatrick V–VI or UK-population data. A favourable recent review of 1550/1927 nm systems included a device-company employee and Solta consultants, so its conclusion is commercially conflicted.

What laser resurfacing is, and the types available#

Laser resurfacing uses a wavelength absorbed principally by tissue water to create a controlled thermal injury at a selected depth. Ablative systems vaporise epidermis and part of the dermis; non-ablative systems heat dermis while leaving the epidermis intact.[2]i

A second, independent axis describes coverage. Confluent treatment covers the surface continuously; fractional treatment creates microscopic treatment zones separated by untreated skin. These axes produce four broad combinations—fractional ablative, confluent ablative, fractional non-ablative and confluent non-ablative—rather than one simple scale from gentle to strong. That four-part map is a synthesis of the two source definitions.[2, 11]i

Common ablative wavelengths include CO₂ and Er:YAG; commonly studied non-ablative fractional systems include 1550 and 1927 nm. “Fractional” describes spatial delivery, not whether the device is thermal, superficial or low risk.

In the originating 1.5 μm fractional-photothermolysis study, a typical microscopic zone was 100 μm wide and 300 μm deep, with re-epithelialisation within one day. Patterns spaced at least 250 μm apart were the well-tolerated ones. Those dimensions are historical study conditions, not a transferable protocol.[11][11]

Use of laser resurfacing in aesthetic practice#

Rules differ across Great Britain. In England, purely cosmetic laser or IPL work is not itself a CQC-regulated activity. CQC excludes interventions carried out purely for cosmetic purposes from treatment of disease, disorder or injury and notes that very few laser or IPL procedures inherently require healthcare-professional skills.[4, 3]

England's 2023 consultation proposed laser photorejuvenation for wrinkles, acne scarring and sun damage as green; other non-ablative lasers as amber; and lasers targeting deeper dermis, including extensive fully ablative CO₂ resurfacing, as red. These placements are proposals. The August 2025 response said more work was required before procedures could be assigned, and no national scheme is in force. Fractional ablative CO₂ was not assigned explicitly.[2][3]

Scotland now specifies ablative laser treatment—removing one or more skin layers—under Schedule 1 of its 2026 Act, with age and premises offences, although not all provisions are in force. Non-ablative laser and light treatment is separately licensable under the 2026 Scottish order effective 13 February 2026.[5][6]

In Wales, HIW says settings providing treatment with Class 3B/4 laser or IPL usually must register as independent healthcare providers. This is distinct from Wales' four special procedures. In London boroughs, premises used for light or electric special treatment require a licence under the 1991 Act, subject to exemptions.[8, 4][7]

The cited sources do not establish the position in Northern Ireland, which requires a separate local check.

The GB device regime depends on the manufacturer's intended purpose under the Medical Devices Regulations 2002. A US FDA clearance has no UK legal effect. JCCP offers a voluntary lasers, IPL and LED register, but that is not statutory authorisation.

Contraindications and cautions#

The current IFU and governance documents for the exact wavelength, platform, handpiece and indication control contraindications. Active infection, an undiagnosed or suspicious lesion, impaired healing, a history of abnormal scarring, unstable inflammatory disease and inability to follow the device-specific recovery plan require deferral or clinical assessment.

Phototype materially changes pigment risk. In nine Chinese patients with Fitzpatrick III–IV skin, a single full-face fractional ablative CO₂ treatment produced PIH in five (55.5%) at one month and one (11.1%) at six months.[15] A narrative review of 1550/1927 nm fractional systems in Fitzpatrick III–VI found lower PIH with lower energy and/or density in direct setting comparisons and called for more data in type VI.[16] It concluded positively on safety and efficacy, but included a device-company employee and several manufacturer consultants or advisers.

Systemic isotretinoin requires modality-specific reading. A 2017 review of 32 publications and 1,485 procedures found insufficient evidence to delay fractional ablative and non-ablative laser after recent isotretinoin, but did not recommend mechanical dermabrasion or fully ablative laser during treatment. The ASDS consensus went only as far as non-ablative devices; it did not clear any ablative resurfacing. The prescriber, device instructions and treating clinician govern rather than a universal six-month rule.[9][10]

Clinical uses and the evidence behind them#

Atrophic acne scarring

This is the strongest indication. A 2025 network meta-analysis included 68 randomised trials and 4,480 participants. No treatment showed strong evidence of reducing erythema or PIH relative to alternatives. Laser plus platelet-rich plasma ranked highest for scar-severity reduction (SUCRA 98.4%), while laser plus chemical peel ranked highest for satisfaction (SUCRA 89.6%); these are rankings, not effect sizes.[14][14]

A 2024 meta-analysis of eight studies and 418 patients found fractional CO₂ had a higher effective rate than fractional Er:YAG (OR 1.81, 95% CI 1.08–3.01) and higher pain scores, with no significant difference in PIH incidence.[13]

NICE NG198 sets a narrower UK boundary. For severe acne scarring persisting one year after acne has cleared, it recommends referral to a consultant dermatologist-led scarring team and consideration there of CO₂ laser, alone or after punch elevation, or glycolic-acid peel. Severity, time since acne clearance and specialist setting are all part of the recommendation; it is not a general aesthetic-practice endorsement.[1][1]

Photoageing and texture

The founding non-ablative fractional study reported 2.1% linear tissue shrinkage and an 18% wrinkle-score improvement three months after four periorbital treatments in 30 participants. The result was measurable and modest, with short follow-up.[11]

Melasma and pigmentary indications

A recent narrative review of 1550/1927 nm non-ablative systems in skin of colour concluded that treatment was safe and effective and reported consistent melasma improvement.[16] The review was not systematic and carried manufacturer ties, so its positive conclusion is retained with a lower evidential weight. Laser may also trigger PIH or recurrence; melasma diagnosis and management belong to the melasma pathway.

Selecting laser resurfacing#

Selection begins with the correct two-axis classification: ablative versus non-ablative, fractional versus confluent. Wavelength alone does not determine residual heat or downtime. Coverage density is a dose variable in its own right, as the founding fractional study showed.[11]

Er:YAG is not inherently “gentle”. In one minipig flank study, lengthening pulse duration produced residual thermal damage up to 80 μm, while multi-pass CO₂ created a uniformly coagulated surface. The 80 μm figure is an animal maximum with no clinical endpoint, not a typical human facial result. Human pooled data found CO₂ more effective and more painful than Er:YAG but no significant PIH difference.[13][12]i

Phototype, indication, scar type, active acne status, past PIH, isotretinoin, anatomic site, device output and operator scope all bear on selection. No generic wavelength, fluence, density, pass count, interval or aftercare plan transfers safely across platforms. The exact manufacturer's instructions and verified training govern.

Adverse effects and their management#

Expected and transient effects

Pain, erythema, oedema, crusting, exudation and temporary pigment change vary substantially with ablation, coverage and depth. Fractional treatment generally leaves intervening skin but remains a thermal wound.

Post-inflammatory hyperpigmentation

PIH is a dominant concern. The 55.5% one-month rate in the nine-person Fitzpatrick III–IV CO₂ series fell to 11.1% by six months, illustrating both high early frequency in that specific study and partial resolution over time.[15] Across the 68-trial acne-scar network, no modality had strong evidence of lower PIH risk than others.[14]

Burns, scarring and infection

Excess thermal injury can cause delayed healing, infection, persistent erythema, textural change, hypertrophic scarring or dyspigmentation. Herpes reactivation and bacterial infection require medical management. Unexpected severe pain, blistering outside the anticipated wound pattern, spreading erythema, purulence, visual symptoms or delayed epithelial recovery requires prompt assessment.

Isotretinoin-related healing concerns

Evidence no longer supports one blanket rule for every laser, but fully ablative treatment remains excluded in the 2017 review during systemic isotretinoin, and the ASDS statement is narrower still.[9, 10] Exposure decisions belong to the prescribing and treating clinical team.

Referral and scope boundaries#

Severe persistent acne scarring within the NICE indication belongs to a consultant dermatologist-led team.[1] Active inflammatory acne is treated before scarring procedures; an uncertain lesion, suspected infection, abnormal scarring, severe PIH or prolonged wound healing requires medical assessment.

Fully ablative resurfacing, deep CO₂ treatment and procedures needing prescription anaesthesia or medical management must match jurisdiction, premises, operator qualification and device governance. Scotland and Wales have specific statutory routes; England's proposed tiers are not law.[2, 3, 4, 5, 6, 7, 8]

Ocular injury, suspected deep burn, disseminated herpes, spreading bacterial infection, necrosis, neurological change or systemic illness warrants urgent review. Device incidents follow the manufacturer and MHRA vigilance pathways where applicable.

Mechanism of action#

Water absorbs the laser energy and converts it to heat. At ablative exposures, water vaporisation removes tissue; at non-ablative exposures, controlled thermal injury is created while the surface remains intact.[2]

Fractional delivery distributes microscopic thermal zones among untreated tissue, supporting rapid re-epithelialisation in the founding model.[11] At three months, that study reported enhanced undulating rete ridges and increased superficial dermal mucin, consistent with remodelling. The magnitude and depth depend on wavelength, pulse shape, energy and density rather than the word “fractional” alone.

Commonly misstated claims#

“Fractional laser is safe for darker skin.”

Fractional spacing may aid recovery, but PIH occurred in 55.5% at one month in a small Fitzpatrick III–IV fractional ablative CO₂ series; evidence for V–VI is thinner.[15, 16]

Supported statement: fractional delivery can be used in skin of colour with device- and phototype-specific assessment, while pigment risk remains substantial and incompletely quantified.

“NICE recommends CO₂ laser for acne scars.”

NICE limits consideration to severe scarring persisting a year after acne clears and treatment within a consultant dermatologist-led team.[1]

Supported statement: CO₂ laser is a NICE option for a narrowly defined severe persistent-scarring pathway, not a general endorsement.

“Every laser requires six months off isotretinoin.”

The 2017 review found insufficient evidence to delay fractional ablative or non-ablative procedures but continued to exclude fully ablative laser during systemic treatment. ASDS covered non-ablative devices only.[9, 10]

Supported statement: isotretinoin decisions are modality-specific and prescriber-led; fully ablative treatment remains outside the permissive evidence.

“Er:YAG is always gentler than CO₂.”

Thermal damage changes with pulse delivery, and the often-quoted 80 μm Er:YAG result is a maximum from minipig skin. Pooled human comparison found higher CO₂ efficacy and pain but no significant PIH difference.[12, 13]

Supported statement: wavelength, pulse structure, energy and coverage jointly determine injury; neither name supplies a universal risk ranking.

Areas of remaining uncertainty#

  • Where fractional ablative CO₂ would sit in England's proposed tiers; until legislation assigns it, no clinic should represent a tier as settled.[2, 3]
  • The CO₂-versus-Er:YAG meta-analysis reports both shorter downtime and longer erythema for CO₂ without reconciling them; counselling should not collapse those endpoints into one recovery claim.[13]
  • Whether settings associated with lower PIH in Fitzpatrick III–IV transfer to V–VI; without comparative type-VI data, risk remains poorly quantified.[16]
  • Durability beyond the short follow-up of most trials; without multi-year controlled data, maintenance intervals cannot be evidence-based.
  • Whether combination SUCRA rankings reflect true superiority or sparse indirect comparisons; rankings should not be presented as effect sizes.[14]

Frequently asked questions#

Is fractional laser non-ablative?

Not necessarily. Fractional describes the spatial pattern; either ablative or non-ablative energy can be delivered fractionally.[2, 11]

Does NICE support cosmetic-clinic CO₂ resurfacing for acne scars?

NICE specifies severe scarring after a one-year wait and a consultant dermatologist-led team.[1]

Must isotretinoin always be stopped for six months?

No universal evidence-based delay applies to every modality. Fully ablative laser remains excluded during systemic treatment, and the decision belongs to the prescriber and treating laser clinician.[9, 10]

Is laser resurfacing regulated the same way across Great Britain?

No. England, Scotland and Wales have materially different positions, and local London premises licensing adds another layer. Northern Ireland requires a separate check.[2, 3, 4, 5, 6, 7, 8]

Which settings and aftercare apply?

The exact device IFU, operator training and responsible clinical plan govern. Skinipedia does not publish a generic laser protocol.

References#

Each source is graded by evidence tier. Tier 4 material (manufacturer documents, expert consensus, practitioner experience) is useful for protocol and context, and is never presented as equivalent to independent clinical evidence.

  1. National Institute for Health and Care Excellence. Acne vulgaris: management. NICE guideline NG198. Published 25 June 2021, last updated 30 April 2026. Section 1.8, Management of acne-related scarring.Tier 1Supports: Recommendation 1.8.2 verbatim: 'If a person's acne-related scarring is severe and persists a year after their acne has cleared: refer the person to a consultant dermatologist-led team with expertise in scarring management; in a consultant dermatologist-led team setting, consider CO2 laser treatment (alone or after a session of punch elevation) or glycolic acid peel.' Recommendation 1.4.3 separately lists 'acne that is leading to scarring' as a trigger for considering referral to a consultant dermatologist-led team or nationally accredited GPwER. Scope limits: this is an acne guideline, not a resurfacing guideline. It addresses acne-related scarring only, gives no laser parameters, no wavelength other than CO2, no fractional/confluent distinction, and no guidance on skin type. The underlying evidence is NICE evidence review M, which was not fetched for this package.
  2. Department of Health and Social Care. The licensing of non-surgical cosmetic procedures in England: consultation document. Consultation closed 28 October 2023.Tier 1Supports: Proposes a green/amber/red tier model. Verbatim placements for lasers and light: GREEN (all practitioners eligible where they meet agreed standards) includes 'IPL and light emitting diode (LED) therapies', 'non-ablative laser hair removal' and 'photo rejuvenation (the use of a laser to treat skin conditions including wrinkles, acne scarring, sun damage)'; AMBER (non-healthcare professionals licensed with oversight by a named regulated healthcare professional) includes 'non-ablative lasers (excluding photo rejuvenation and laser hair removal)'; RED (qualified and regulated healthcare professionals only, in CQC-registered premises, outside the licensing scheme) includes 'lasers which target the deeper layers of the dermis. For example, CO2 lasers, where used for extensive fully ablative resurfacing'. Annex A defines the modality verbatim: 'The laser beam heats up water in skin cells, at a specific depth, causing them either to vaporise or injure them in a controlled way' and 'Non-ablative lasers cause controlled tissue injury in the dermis but leave the epidermis intact. Fully ablative lasers completely remove the epidermis and some of the dermis by vaporising skin cells.' Scope limits: England only; a consultation proposal, not law; the document itself states that 'the procedures listed are indicative of the types of procedures that will be included in the licensing scheme - they are not a final or complete list and may change'. Fractional ablative CO2 is not named in any tier. The Annex A physics description is a lay policy description written for a consultation audience, not a measurement, and nothing in it distinguishes water from other chromophores. VERIFICATION NOTE: all quotes above re-fetched and confirmed verbatim on 1 August 2026; the closing date is confirmed in the document, the 2 September 2023 opening date previously stated in this citation was not re-verified and has been removed.
  3. Department of Health and Social Care. The licensing of non-surgical cosmetic procedures in England: consultation response. Updated 7 August 2025.Tier 1Supports: 11,848 responses to the online consultation ('Over 11,800' in the high-level summary); of 11,588 answering the tiering question, 'A majority (61%) of respondents support the 3-tier classification system based on the risk that different cosmetic procedures present to the public. Support was slightly higher among members of the public (63%) than among professionals (58%)' - with only 38% of aesthetic practitioners supporting it. Critically, the response does NOT assign procedures to final tiers. Verbatim: 'further work is required to determine where specific procedures will sit in the proposed tiering system and to determine which practitioners should be permitted to carry out certain procedures' and 'initial work in this area will prioritise the introduction of regulations for the highest-risk procedures, and we will develop proposals which will be consulted on early next year.' On lasers specifically the response records that 'several responses advocated for laser and IPL treatments to be moved to the amber category', that 'some felt that laser procedures in general or ablative or CO2 lasers specifically could be moved to a lower category' while others wanted periorbital and gynaecological laser moved up to red, and that 'A few responses highlighted that, prior to 2010, laser and intense pulsed light (IPL) treatments were regulated by CQC, and stated that this requirement had added significantly to CQC's workload and had not been enforced adequately.' Scope limits: England only; sets out intent, not law; secondary legislation not yet made. The 2010 CQC history is reported as respondent commentary, not as a government finding. VERIFICATION NOTE: all figures and quotes re-fetched and confirmed verbatim on 1 August 2026; the previous wording 'many respondents' and 'a few wanted CO2 laser moved out of red' overstated and understated the source's own quantifiers respectively and has been corrected to 'several' and 'some'.
  4. Care Quality Commission. Scope of registration: regulated activities - Treatment of disease, disorder or injury. Guidance updated 26 March 2026.Tier 1Supports: Under 'What this regulated activity does NOT include', verbatim: 'Interventions carried out purely for cosmetic purposes.' Under 'Registering for specific services - Lasers and intense pulsed light (IPL)', verbatim: 'even in a clinical service such as dermatology or plastic surgery, very few laser or IPL procedures require the skills of a healthcare professional. Use of lasers and IPLs is not part of professional training in healthcare professions.' Registration is required only where the specific skills of a listed healthcare professional are used (e.g. laser as part of plastic surgery, where the Surgical procedures activity applies), where the service is combined with procedures requiring a healthcare qualification such as prescribing, or where the service is described as being carried out by someone acting in their capacity as a registered healthcare professional. Scope limits: England only; describes registration scope, not clinical safety or competence.
  5. Non-surgical Procedures and Functions of Medical Reviewers (Scotland) Act 2026 (2026 asp 13), section 1 and schedule 1. Royal Assent 12 May 2026.Tier 1Supports: Section 1(1)(a)(i) defines a non-surgical procedure as one that 'pierces or penetrates the person's skin, including by means of a needle, chemical, medicine, heat, cold, light, laser, sound or electricity' and is of a kind in schedule 1. Schedule 1 paragraph 1, verbatim: 'Ablative laser treatment - A procedure in which a laser is used to remove one or more layers of skin.' Sections 2 and 3 create offences of providing a specified non-surgical procedure to a person under 18, and of providing one outwith permitted premises. Excluded from the definition are procedures provided by or on behalf of the health service, or by a health care provider (registered independent health care service, regulated health care professional, or a person acting on such a professional's directions) for preventing, diagnosing or treating an illness. Scope limits: Scotland only. Not all provisions are in force - legislation.gov.uk lists sections 1, 2(3), 4(3), 5, 14, 15, 17, 19, 20, 23 and schedules 1 and 2 as coming into force by S.S.I. 2026/206, changes not yet applied to the text.
  6. The Civic Government (Scotland) Act 1982 (Licensing of Non-surgical Procedures) Order 2026 (S.S.I. 2026/87), schedule 1. Made 12 February 2026, in force 13 February 2026.Tier 1Supports: Schedule 1 lists the specified non-surgical procedures requiring a local authority licence in Scotland. Paragraph 7, verbatim: 'Non-ablative laser and light treatment - A procedure in which light treatment or laser treatment is used to destroy or stimulate skin tissue or fat cells in a specific area of the body but which does not remove any of the epidermis.' Also licensable: superficial chemical peels not penetrating deeper than the epidermis (para 1), cryolipolysis, cryotherapy, electrocautery, HIFU, microneedling below 1.5 mm without radiofrequency, and radiofrequency treatments. Scope limits: Scotland only; this Order covers non-ablative work, while ablative laser sits under the 2026 Act instead.
  7. London Local Authorities Act 1991, section 4 (interpretation of Part II - special treatment premises).Tier 1Supports: Defines an 'establishment for special treatment' as 'any premises in the borough used, intended to be used or represented as being used for the reception or treatment of persons requiring massage, manicure, acupuncture, tattooing, cosmetic piercing, chiropody, light, electric or other special treatment of a like kind or vapour, sauna or other baths'. 'Light' and 'electric' treatment are expressly within scope, so laser and IPL premises in London boroughs need a special treatment licence. The section carries exclusions for premises operated by registered medical practitioners, certain other health professionals and registered nursing homes. Scope limits: London boroughs only. This is premises licensing, not practitioner competence, and there is no equivalent national scheme for the rest of England.
  8. Healthcare Inspectorate Wales. Registration - Frequently Asked Questions.Tier 1Supports: Verbatim: 'Usually all settings in Wales who wish to provide any treatments using a class 3B/4 laser or an IPL device must first register with HIW.' The page notes exceptions exist and directs applicants to submit a registration enquiry form. HIW's separate page on independent services using Class 3B/4 laser and IPL equipment states that inspections check compliance with the National Minimum Standards for Independent Health Care Services in Wales, the Care Standards Act 2000 and the Independent Health Care (Wales) Regulations 2011, but that page does not itself state which services are legally required to register. Scope limits: Wales only; a regulator's guidance page rather than the primary legislation.
  9. Spring LK, Krakowski AC, Alam M, et al. Isotretinoin and Timing of Procedural Interventions: A Systematic Review With Consensus Recommendations. JAMA Dermatol. 2017;153(8):802-809. PMID 28658462.Tier 1Supports: Systematic PubMed review of English-language articles 1982-2017 plus expert consensus. Thirty-two relevant publications reporting 1,485 procedures. Verbatim finding: 'There was insufficient evidence to support delaying manual dermabrasion, superficial chemical peels, cutaneous surgery, laser hair removal, and fractional ablative and nonablative laser procedures for patients currently receiving or having recently completed isotretinoin therapy. Based on the available literature, mechanical dermabrasion and fully ablative laser are not recommended in the setting of systemic isotretinoin treatment.' The paper states the six-to-twelve-month delay convention 'is based on 3 small case series from the mid-1980s'. Scope limits: 1,485 procedures across all procedure types combined, not 1,485 laser resurfacing cases; absence of evidence of harm is not evidence of safety at this sample size; US panel; a 2022 published comment in Clin Exp Dermatol exists and was not retrieved. Author affiliations include multiple private laser and skin surgery centres; no funding statement was retrievable from the PubMed record.
  10. Waldman A, Bolotin D, Arndt KA, et al. ASDS Guidelines Task Force: Consensus Recommendations Regarding the Safety of Lasers, Dermabrasion, Chemical Peels, Energy Devices, and Skin Surgery During and After Isotretinoin Use. Dermatol Surg. 2017;43(10):1249-1262. PMID 28498204.Tier 4Supports: American Society for Dermatologic Surgery task force; literature extraction, clinical question review, Delphi consensus, peer-review validation. Verbatim result: 'there is insufficient evidence to justify delaying treatment with superficial chemical peels and nonablative lasers, including hair removal lasers and lights, vascular lasers, and nonablative fractional devices for patients currently or recently exposed to isotretinoin. Superficial and focal dermabrasion may also be safe when performed by a well-trained clinician.' Ablative laser resurfacing - fractional or fully ablative - is absent from the cleared list. Scope limits: expert consensus, not a graded evidence synthesis, hence tier 4 despite the 'Guidelines Task Force' title. US society; no UK legal or professional standing. Author affiliations are predominantly private laser and skin surgery centres; no funding statement was retrievable from the PubMed record.
  11. Manstein D, Herron GS, Sink RK, Tanner H, Anderson RR. Fractional photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury. Lasers Surg Med. 2004;34(5):426-438. PMID 15216537.Tier 3Supports: The originating human study of fractional photothermolysis. Two prototype 1.5 micrometre devices; MTZ density effects tested on the forearms of 15 subjects, plus 30 further subjects given four periorbital treatments over 2-3 weeks. Results: 'Pattern densities with spacing of 250 microm or more were well tolerated. Typical MTZ had a diameter of 100 microm and penetrated 300 microm into the skin. Reepithelialization was complete within 1 day.' Histology at 3 months showed enhanced undulating rete ridges and increased mucin deposition in the superficial dermis. Linear tissue shrinkage 2.1% and wrinkle score improvement 18% (P<0.001) three months after the last periorbital treatment. Scope limits: n=15 and n=30, prototype devices, forearm and periorbital sites only, 3-month follow-up, no control arm, no skin-type breakdown reported in the abstract, photoaging not scarring. Conflict-of-interest and funding statements are not present in the PubMed record for this 2004 paper; the concept was subsequently commercialised, so a commercial interest cannot be excluded either way.
  12. Ross EV, McKinlay JR, Sajben FP, et al. Use of a novel erbium laser in a Yucatan minipig: a study of residual thermal damage, ablation, and wound healing as a function of pulse duration. Lasers Surg Med. 2002;30(2):93-100. PMID 11870787.Animal studyTier 4Supports: ANIMAL STUDY - n=1 pig. Bilateral flanks of one Yucatan minipig; eight sites treated per group; biopsies immediately and at 1, 3, 7, 21 and 60 days. A variable-pulsewidth Er:YAG (250 microsecond ablative pulse followed by a heating pulse of variable duration) was compared with a CO2 resurfacing laser. Findings, verbatim: 'cold' (no coagulation pulse) erbium sites 'showed a reddish papillary dermis consistent with conventional erbium laser ablation'; 'Two and three pass CO2 sites showed uniform surface yellowing'; 'The longer pulsewidth ("hot") erbium groups showed only slight surface yellowing'; 'Biopsies showed immediate thermal damage that increased with erbium pulse duration; however, actual residual thermal damage (RTD) was sometimes less than that predicted by the laser control panel'; 'All wounds healed uneventfully by 14 days'. Conclusion verbatim: 'An erbium laser with a variable macropulse pulsewidth was capable of achieving RTD of up to 80 mum.' Scope limits: one pig, flank skin, not human facial skin; no clinical outcome; 80 micrometres is a stated maximum capability, not a typical result. Supports the physical relationship between Er:YAG pulse duration and residual thermal damage, and the greater coagulative signature of multi-pass CO2, but cannot be read as a human safety or efficacy finding. The paper evaluates a then-novel commercial variable-pulsewidth Er:YAG device against a named competitor class; no funding or conflict statement is retrievable from the PubMed record, and authors include US Navy (Naval Medical Center San Diego) and private dermatology affiliations, among them Zelickson, an author with a long record of device-industry work. VERIFICATION NOTE: re-tiered from 3 to 4 at verification. Tier 3 in this package holds human clinical studies (Manstein 2004, Chan 2010); a single-animal flank study must not sit level with them.
  13. Liu F, Zhou Q, Tao M, Shu L, Cao Y. Efficacy and safety of CO2 fractional laser versus Er:YAG fractional laser in the treatment of atrophic acne scar: A meta-analysis and systematic review. J Cosmet Dermatol. 2024;23(9):2768-2778. PMID 38733085.Tier 1Supports: PubMed, Embase and Cochrane searched to August 2023. Eight studies included (seven RCTs, one retrospective), sample sizes 28-106, 418 patients total (210 fractional CO2, 208 fractional Er:YAG). Pooled results: effective rate significantly higher for fractional CO2 (OR 1.81, 95% CI 1.08-3.01); downtime significantly shorter for CO2 (WMD -2.11, 95% CI -3.11 to -1.10); VAS significantly higher for CO2 (WMD 1.77, 95% CI 1.32-2.21); duration of erythema significantly longer for CO2 (WMD 1.85, 95% CI 1.63-2.07). No significant difference in duration of pain or in PIH incidence between the two. Scope limits and internal tension: the abstract reports CO2 as having BOTH shorter downtime and longer erythema duration without reconciling the two, and the stated conclusion that CO2 'may carry a higher risk of post-treatment pigmentation' is not supported by the pooled PIH result, which was non-significant. Atrophic acne scars only. Skin types not reported in the abstract; author affiliations are Chinese hospitals and one private plastic surgery clinic. No funding or conflict statement retrievable from the PubMed record.
  14. Wu B, Gao M, Zhang Y, Bai X. Optimal treatment options for acne scars in patients with historic acne: a systematic review and network meta-analysis. PeerJ. 2025;13:e19938. PMID 41081097, PMCID PMC12515001.Tier 1Supports: PubMed, Embase, Cochrane Library and Web of Science searched to 19 September 2024; PROSPERO CRD42024598780; Bayesian network meta-analysis; Cochrane RoB 2. Sixty-eight RCTs, 4,480 patients with acne scarring. Laser + platelet-rich plasma ranked best for reducing ECCA scores (SUCRA 98.4%); laser + filler injection best for reducing Goodman and Baron Scale (SUCRA 72.1%); laser + chemical peels best for patient satisfaction (SUCRA 89.6%); microneedling most tolerable for pain (SUCRA 72.6%). Key honest negative, verbatim: 'no strong evidence suggesting a treatment reduced the risk of erythema nor post-inflammatory hyperpigmentation compared to the other treatments.' Scope limits: acne scarring only; SUCRA rankings are probabilistic orderings, not effect sizes, and can rank sparse comparisons highly; 'laser' is aggregated across devices and wavelengths; skin types not reported in the abstract. Funding/conflicts: 'The authors declare there are no competing interests.'
  15. Chan NP, Ho SG, Yeung CK, Shek SY, Chan HH. Fractional ablative carbon dioxide laser resurfacing for skin rejuvenation and acne scars in Asians. Lasers Surg Med. 2010;42(9):615-623. PMID 20976801.Tier 3Supports: Nine Chinese patients, Fitzpatrick skin types III and IV, mean age 44.8, University of Hong Kong. One full-face fractional ablative CO2 treatment (Fraxel Re:pair), energies 30-70 mJ, coverage 30-45%. Follow-up to 6 months with standardised Canfield Visia CR photography scored by two independent observers. Statistically significant improvements in skin texture, laxity, wrinkles, enlarged pores and acne scars. Post-inflammatory hyperpigmentation rate 55.5% at 1 month and 11.1% at 6 months. 86% of patients satisfied to very satisfied. The authors' conclusion has TWO halves and both are load-bearing, verbatim: 'Ablative fractional CO2 laser resurfacing was overall safe and effective for skin rejuvenation and acne scars in Asians. However, in view of the high post-inflammatory rate and the statistically significant but only mild to moderate improvement after a single treatment as observed in this study, there is a need to review the current role of fractional ablative CO2 laser treatment as compared to fractional non-ablative for skin rejuvenation and acne scar treatment in Asians.' Scope limits: n=9, single treatment, no control arm, Fitzpatrick III-IV only (not V-VI), one device, 2010 parameters. Named commercial device; no funding or conflict statement retrievable from the PubMed record. VERIFICATION NOTE: the previous version of this field quoted only the sentence beginning 'in view of the high post-inflammatory rate' and labelled it the authors' conclusion, omitting the preceding sentence in which the authors call the treatment overall safe and effective. That omission made the source read more negatively than it is and has been corrected.
  16. Goldman MP, Wu DC, Khetarpal S, Jacobson A, Wang JV, Geronemus RG. Dual 1550-nm Erbium Glass Fiber and 1927-nm Thulium Fiber Non-ablative Fractional Laser System Treatment in Patients With Skin of Color: A Review of Clinical Studies and Unmet Needs. Lasers Surg Med. 2026;58(3):169-179. PMID 41668543, PMCID PMC12997386.Tier 4Supports: Narrative review of 15 clinical studies of the 1550 nm and/or 1927 nm non-ablative fractional wavelengths in Fitzpatrick III-VI. Reported verbatim: 'Despite variability across study designs, consistent improvement was reported with the 1550-nm wavelength for the treatment of scarring and melasma and the 1927-nm wavelength for the treatment of melasma and photoaging. Postinflammatory hyperpigmentation (PIH) rates varied across studies. Studies directly comparing different settings reported reduced PIH rates with lower energy and/or density. Histologic studies confirmed dermal remodeling and reduced melanin after treatment.' The review's own conclusion, verbatim and in full: 'The 1550/1927-nm dual-laser system is safe and effective. Reducing pulse energy and density may confer fewer adverse effects in patients with skin of color. Additional studies are needed, particularly for patients with FST VI and the 1927-nm wavelength treatment.' Scope limits: narrative review, not systematic; no pooled estimates, no numeric PIH rates in the abstract; one device family only; the review does not establish whether energy or density should be reduced first. VERIFICATION NOTE: the previous version quoted only the 'additional studies are needed' caveat and omitted the favourable conclusion sentence, which is the review's actual finding; both are now stated so the reader can weigh the conclusion against the disclosures below.Funding / interest: Substantial declared commercial interest, reproduced verbatim from the paper's conflict-of-interest statement: 'Mitchel P. Goldman has no disclosures to declare. Douglas C. Wu is currently serving or has served as an advisor, investigator, speaker, and/or consultant for AbbVie, Candela, Cynosure, and Solta Medical. Shilpi Khetarpal has served as a consultant, trainer, or advisor for Allergan, Crown Aesthetics, Galderma, and MTF Biologics. Abby Jacobson is an employee of Bausch Health Companies Inc. Jordan V. Wang and Roy G. Geronemus are advisors, investigators, and consultants for Solta Medical.' Solta Medical manufactures the 1550/1927 nm system under review. Note also that Goldman's 'no disclosures' sits alongside his listed affiliation to Cosmetic Laser Dermatology: A Platinum Dermatology Partners Company, a private laser practice - an institutional interest in the modality that a personal disclosure line does not capture. No separate funding statement was retrievable from the PubMed record. Treat the favourable conclusion accordingly.