Last updated October 29, 2026
A surgical incision usually leaves some degree of scarring. Good wound care and an appropriate scar-management plan can help, but no treatment can promise an invisible scar.
Red and near-infrared photobiomodulation are being studied as additions to postoperative care. Some small trials have reported better scar scores or patient satisfaction; others have not found a significant difference in their main outcome. The evidence supports further investigation, rather than a general promise that a home panel will prevent a raised scar. [1,2]
For anyone considering red light therapy after surgery, the practical questions are whether it suits the procedure, when the surgeon considers it appropriate, and which device and exposure protocol to use.
What the research shows about red light therapy and post-surgical scars
Healed surgical incision under red light therapy panel at clinical distance
A thyroidectomy trial reported improvements in several scar measures
A 2022 randomized, double-blind, sham-controlled trial studied an 830 nm LED device after thyroid surgery. Treatment began one week after surgery and continued for four weeks; 43 patients completed the trial. At six months, the treatment group had better satisfaction, global assessment, pain, and Vancouver Scar Scale scores. Differences in the three-dimensional measures of color, height, pigmentation, and vascularity were not statistically significant. [1]
This is encouraging evidence for a particular protocol. Its small sample and single surgical setting limit how broadly the findings can be applied. The result does not establish equivalence with a 660/850 nm consumer panel.
A visible-red-light trial did not meet its main efficacy endpoint
The CURES trial tested postoperative red LED treatment using a randomized, mock-controlled, split-face design. Treatment started one week after surgery and continued three times weekly for three weeks. There was no significant difference between treated and control scars in the primary outcome of scar pliability. Some secondary findings were more favorable, but they do not change the main result. Mild treatment-site events included two cases of blistering and one of swelling, all of which resolved. [2]
Including this result gives a more balanced view of the evidence. A plausible biological mechanism does not guarantee a meaningful clinical benefit.
Knee-replacement recovery is a separate question
A 2025 randomized trial enrolled 30 knee-replacement patients and added photobiomodulation on postoperative days one through five. The researchers reported improvements in swelling-related measures and early walking performance, without significant between-group differences in pain or active range of motion. [3]
This study concerned early rehabilitation. It did not establish prevention of hypertrophic scars or keloids, so it should not be used as direct evidence for a scar-prevention claim.
How red light therapy may interact with healing tissue
Photobiomodulation pathway diagram from light absorption to collagen remodeling
Photobiomodulation uses selected wavelengths to influence cellular activity. Proposed pathways include changes in mitochondrial function, energy metabolism, redox signaling, and inflammatory responses. These effects depend on the tissue and exposure conditions. [4]
Scar formation involves inflammation, fibroblast activity, collagen deposition, and later remodeling. Researchers are interested in whether light can influence these processes enough to improve a scar's appearance or symptoms. However, laboratory findings about fibroblasts cannot by themselves establish an effective clinical treatment.
It is also too simple to say that red light always stimulates collagen while simultaneously suppressing excess collagen. The response can vary with dose, timing, and the state of the tissue. Wound repair and limiting fibrosis are related but distinct goals.
What wavelength can—and cannot—tell you
Red and near-infrared wavelengths interact differently with tissue, but they do not stop at fixed anatomical boundaries. Penetration depends on absorption, scattering, skin characteristics, and device geometry. [4]
The 830 nm thyroidectomy trial and the visible-red CURES trial used different protocols. Their results do not prove that one wavelength is universally superior, or that combining wavelengths improves postoperative scar outcomes. [1,2]
For device selection, the important question is whether evidence applies to the device, exposure, and intended use being considered. A wavelength label alone cannot answer that question.
How to use red light therapy for scars after surgery: timing, distance, and duration
Patient positioning red light therapy panel near healing abdominal incision at home
Timing depends on the procedure and wound assessment
There is no universal postoperative start date. The 2022 thyroidectomy trial began at one week, while an earlier controlled thyroidectomy study began on postoperative day one with a different LED protocol. These were study-specific arrangements, not instructions for self-treatment. [1,5]
Before using a device at home, ask the surgeon to assess the incision and confirm whether light exposure is appropriate. Dressings, surgical adhesive, sutures, grafts, infection risk, and the reason for surgery may affect that decision. Do not remove a prescribed dressing simply to expose the site.
Wound closure is relevant to assessment, but it is not the only consideration and should not be treated as automatic permission to begin.
Distance and duration must match the device
A general instruction to use every panel at 15 cm for 10–20 minutes is not supported by the trials cited here. Different devices produce different irradiance and coverage at the skin.
Radiant exposure can be estimated as:
Radiant exposure (J/cm²) = average irradiance (mW/cm²) × exposure time (seconds) ÷ 1,000.
That calculation describes incident light energy per unit area. It does not tell you how much energy a particular tissue absorbs or whether the exposure is safe and effective for a healing incision. With pulsed light, average irradiance rather than peak output is needed for this calculation.
A higher output figure is not, by itself, a reason to select a device or shorten a session without guidance.
Frequency and follow-up need separate decisions
A treatment course and a scar-assessment period are different things. A study may deliver treatment for several weeks and assess scar outcomes months later. There is no established daily or alternate-day schedule that applies to all surgeries and devices.
If a clinician recommends photobiomodulation, agree on the schedule, how to monitor the site, and when to review progress. Track comfort and wound changes as well as appearance. Photograph the area under similar lighting if the clinician finds that useful.
Missing an early treatment window does not mean that an established scar is beyond treatment. A raised, painful, itchy, or restrictive scar can still be assessed for other interventions. [6]
When to pause or stop: safety signals and precautions
Nurse inspecting post-surgical wound before applying red light therapy device
Red light therapy should never delay assessment of a possible wound complication. The CDC advises contacting a healthcare provider immediately for signs of a surgical-site infection, including redness and pain around the site, cloudy drainage, or fever. [7]
Pause light treatment and contact the surgical team if the incision opens, drainage develops, or symptoms worsen. Burning, blistering, or marked irritation also warrants stopping exposure and seeking advice. The CURES trial's treatment-site reactions show why "non-invasive" should not be taken to mean risk-free. [2]
Before treatment, review the following with the clinician:
- Current medicines and topical products, including anything associated with light sensitivity. A warning about UV exposure does not automatically establish the same risk at red or near-infrared wavelengths; the medication and proposed light exposure need individual review.
- Any condition that causes light sensitivity, or a history of reactions to light devices.
- The location and reason for surgery, especially recent eye procedures or cancer treatment.
- Reduced sensation or difficulty noticing uncomfortable heat at the treatment site.
- The device's instructions and the eye protection recommended for it.
The American Academy of Dermatology advises checking medical suitability, following device directions, and using the specified eye protection when required. [8]
Why might a doctor advise against it?
The answer depends on the patient and procedure. Possible reasons include an unsuitable wound, uncertain benefit, limited evidence for a particular device, or a better-supported treatment option.
Small trials with different devices, exposure schedules, and outcome measures do not yet provide a broadly accepted postoperative scar protocol. That uncertainty is a reasonable basis for caution. Device availability without a prescription does not establish effectiveness for scar prevention.
What else helps manage scarring after surgery?
Comparison of scar prevention approaches: silicone sheeting, compression garment, red light therapy panel, and topical treatments
Follow the wound-care plan first
Cleaning, dressings, stitch removal, and activity restrictions should follow the surgical team's instructions. General advice for minor cuts should not override directions for an incision closed with adhesive, a graft, or a more complex wound. The American Academy of Dermatology also emphasizes following the treating doctor's instructions when stitches are involved. [9]
Avoid adding creams, tape, or other products to a fresh incision without checking first.
Ask about silicone once the wound has closed
Silicone gel and sheets are commonly used for raised-scar prevention and management after skin closure. They require regular use and may cause irritation or skin breakdown in some people. [6]
Their evidence should also be described honestly. A Cochrane review found possible preventive benefit in people prone to abnormal scarring, but the underlying studies were highly susceptible to bias. Silicone is an established option in clinical practice, not a guarantee of a flat or invisible scar. [10]
Protect healed skin from the sun
Sun protection can help reduce persistent red or brown discoloration. Once the wound has healed, dermatologists recommend broad-spectrum SPF 30 or higher, along with appropriate coverage. Do not put sunscreen into an open incision. [9]
Use pressure or specialist treatments when indicated
Pressure therapy may be recommended in selected cases, particularly burns or keloid management. It is not something every surgical patient needs. A dermatologist may also consider injections, lasers, or other treatments for a raised or symptomatic scar. These approaches should be selected for the scar type and the patient's circumstances. [6]
Check the evidence behind a device claim
Ask for the exact model, intended use, instructions, and relevant clinical evidence. If optical measurements are supplied, check the measurement distance, operating mode, and whether the reading is a central peak or an average across the treatment area.
Quality-system documents and safety testing serve different purposes from clinical scar-outcome studies. They cannot substitute for evidence that a particular treatment improves scars. FDA establishment registration and device listing likewise do not mean that FDA has cleared or approved a device for scar prevention. [11]
Key takeaways
Red and near-infrared photobiomodulation may have a role in selected postoperative scar-management plans, but the clinical findings are mixed. It should be discussed as a possible adjunct with a defined protocol, rather than a reliable way to prevent all surgical scarring.
The most useful next step is a discussion with the surgical team about the incision, scar risk, and available treatments. Keep prescribed wound care in place, and do not copy another device's distance or exposure schedule.
FAQ
Is red light good for post-surgery scars?
Some small studies report benefits, while others have not demonstrated a significant difference in their primary outcome. Whether treatment is worthwhile depends on the procedure, scar concern, device, and clinical plan. Current evidence does not justify promising scar prevention to everyone. [1,2]
Why don't all doctors recommend red light therapy?
There is no universal postoperative protocol, and evidence from one device or procedure may not apply to another. A clinician may recommend an established scar treatment first, or decide that the potential benefit does not justify adding light treatment in a particular case.
What helps prevent noticeable scarring after surgery?
Follow the surgeon's wound-care and activity instructions. Ask about silicone after closure, protect healed skin from the sun, and have an emerging raised or symptomatic scar reviewed. No approach guarantees that a scar will be invisible. [6,9]
How soon after surgery can you use red light therapy?
Only on the timetable agreed with the treating clinician. Studies have started treatment at different points, including postoperative day one and one week, but those examples are not general permission for home use. [1,5]
Can red light therapy treat an old scar or a keloid?
Early postoperative scar studies do not establish efficacy for mature scars or keloids. An established scar needs assessment of its type, symptoms, and treatment options. Do not assume that a home panel will flatten a keloid. [6]
References
Kim YH, Kim HK, Choi JW, Kim YC. Photobiomodulation therapy with an 830-nm light-emitting diode for the prevention of thyroidectomy scars: a randomized, double-blind, sham device-controlled clinical trial. Lasers in Medical Science. 2022;37(9):3583–3590. DOI: 10.1007/s10103-022-03637-6. PubMed. Direct evidence for one postoperative LED protocol, with both positive and nonsignificant outcomes.
Kurtti A, Nguyen JK, Weedon J, et al. Light emitting diode-red light for reduction of post-surgical scarring: Results from a dose-ranging, split-face, randomized controlled trial. Journal of Biophotonics. 2021;14(7):e202100073. DOI: 10.1002/jbio.202100073. PubMed. The CURES trial; no significant difference in the primary scar-pliability outcome.
Chia WT, Wong TH, Jaw FS, Hsieh HC. The Impact of Photobiomodulation Therapy on Swelling Reduction and Recovery Enhancement in Total Knee Arthroplasty: A Randomized Clinical Trial. Photobiomodulation, Photomedicine, and Laser Surgery. 2025;43(2):65–72. DOI: 10.1089/photob.2024.0120. PubMed. Early swelling and mobility outcomes; not a scar-prevention study.
Avci P, Gupta A, Sadasivam M, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Seminars in Cutaneous Medicine and Surgery. 2013;32(1):41–52. PubMed. Mechanistic and dermatologic background; not a universal postoperative dosing guideline.
Park YJ, Kim SJ, Song HS, et al. Prevention of Thyroidectomy Scars in Asian Adults With Low-Level Light Therapy. Dermatologic Surgery. 2016;42(4):526–534. DOI: 10.1097/DSS.0000000000000680. PubMed. An earlier controlled study using an 830/590 nm LED protocol with an early postoperative start.
American Academy of Dermatology Association. Scars: Diagnosis and treatment. Read the guidance. Clinical options including silicone, pressure therapy, injections, and laser treatment; laser evidence should not be assumed to apply to LED panels.
Centers for Disease Control and Prevention. Surgical Site Infection Basics. April 11, 2024. Read the guidance. Infection signs and when to contact a healthcare provider.
American Academy of Dermatology Association. Is red light therapy right for your skin? Updated September 13, 2024. Read the guidance. General precautions for home devices, medical suitability, and eye protection.
American Academy of Dermatology Association. Minimize a scar: Proper wound care tips from dermatologists. Updated July 2, 2025. Read the guidance. General wound care and sun protection after healing; surgical instructions take priority.
O'Brien L, Jones DJ. Silicone gel sheeting for preventing and treating hypertrophic and keloid scars. Cochrane Database of Systematic Reviews. 2013;(9):CD003826. DOI: 10.1002/14651858.CD003826.pub3. Read the review summary. Describes possible benefit alongside substantial uncertainty and risk of bias.
U.S. Food and Drug Administration. Important Reminders about Registration and Listing. Read the FDA guidance. Explains why establishment registration and device listing do not denote approval, clearance, or authorization.