A Phase 2 interventional study of topical Timolol maleate 0.5% eye drops and topical Vitamin C 15% in Post-acne Erythema, sponsored by Cairo University. Completed at 1 site in Egypt. Open to participants aged 15 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Cairo University · Phase 2, Interventional, and Treatment
Acne is very common, especially among young adults. After acne heals, some people are left with persistent red or pink marks, called post-acne erythema (PAE). These marks can last for several months and, in some people, may be associated with a higher risk of developing acne scars.
PAE is more common in people with lighter skin. It is thought to happen because healing after acne can cause changes in the small blood vessels in the skin, making them wider and more visible. Skin irritation from some acne treatments may also contribute to the redness.
There is currently no single treatment that is considered the best treatment for post-acne redness. Several treatments have shown benefits, including different types of lasers and light treatments, as well as topical creams or serums such as vitamin C, tranexamic acid, oxymetazoline, and brimonidine. Timolol, a medication that can narrow small blood vessels, has also recently shown promising results.
Fractional CO₂ laser may help improve post-acne redness by stimulating skin healing and affecting the small blood vessels responsible for the redness. Other fractional lasers have also been shown to improve PAE.
Vitamin C is a powerful antioxidant that can help protect and repair the skin. When applied directly to the skin, it may reduce inflammation, support collagen production, and promote healing. Studies have shown improvement in post-acne redness with topical vitamin C.
Timolol is a medication that can cause narrowing of small blood vessels and may reduce the formation of new blood vessels. Because of these effects, it has recently been studied as a treatment for post-acne redness.
Because there is still no established standard treatment for PAE, this study was designed to compare three approaches: fractional CO₂ laser alone, fractional CO₂ laser combined with vitamin C, and fractional CO₂ laser combined with timolol. The goal is to determine which approach provides the best improvement in post-acne redness.
Background:
Acne vulgaris is one of the most prevalent causes of the clinic visit among young adults. Post-acne erythema (PAE) is one of the major sequelae of acne vulgaris and it commonly persists for long times as several months. It can be a predictor of developing atrophic scars in predisposed people. It almost develops in individuals with light skin phototypes. Although the exact mechanism of PAE is unknown, it is thought to occur secondary to epidermal thinning with resultant telengectasia and dermal vascular dilatation changes in response to the healing process. Other explanation is that PAE results from external agents as topical therapy which may cause irritation. Searching the literature, different results were found yet no gold standard treatment for PAE could be found till now. A very novel review categorized treatment of PAE into light and laser therapies which included; alexanderite (Alex) laser, pro-yellow laser, erbium glass fractional laser, Q-switched Neodymium:yttrium aluminum-garnet (Nd:YAG) laser pulsed dye laser, high power optically pumped semiconductor laser (HOPSL), broad band treatment, intense pulsed light (IPL) therapy, and radiofrequency (both fractional microneedling, and invasive short pulsed-type bipolar radiofrequency device (IPBRF)), they were all found to be effective modalities. The other modalities mentioned with also favorable outcome and more affordability were topical therapies including; 1.5% Oxymetazoline (OXZ), 5% tranexamic acid, vitamin C gel, brimonidine tartarate 0.2%, and a topical complex containing Glyceryl-octyl-ascorbic acid (GOVC), ascorbyl 2-phosphate 6-palmitate (APP), and DL-a- tocopherol phosphate (TP). Moreover topical timolol was found recently to be an effective option for PAE treatment. Fractional Co2 laser role in post acne erythema scars wasn't found in the literature; yet a study by Park et al, illustrated the role of fractional potothermolysis of 1550 nm, erbium-doped laser in PAE by many theories including; targeting tissue water which is a major component of blood vessels, it also results in photothermal damage of dermal vasculature leading to improved erythema. In addition, it produces multitudes of dermal microthermal zones of injury that may lead to multiple, random targeting of the dermal blood vessels. Although pulsed dye laser (PDL) targets hemoglobin, the fact that fractional laser penetrates deeper adds a more benefit for the more deeply located vessels in the dermis. Vitamin C (Vit. C) is a known potent antioxidant. A limited amount of vit. C is absorbed regardless the oral dose, due to its active transport. Moreover, vit. C bioavailability in the skin is insufficient with its oral intake, so its topical preparations are preferred in dermatological uses. It is used in numerous dermatological purposes including; photodamage, hyperpigmentation, and rejuvenation. A Japanese study was done using Isostearyl-L-ascorbic acid (ISAA) for treatment of post acne erythema, and post inflammatory hyperpigmentation and found significant improvement. They attributed this role to wound healing promoting effects of vitamin C through proliferation of collagen synthesis and inhibition of matrix metalloproteinase (MMP), and inhibition of tyrosinase. Besides, Vitamin C has anti-inflammatory effects by inhibiting pro-inflammatory cytokines including; IL1β, and TNF-α. Another study was done combining Vit.C with tranexemic acid and microneedling has found significant decrease in post acne erythema scars in comparison with microneedling alone.
Timolol, is a well tolerated nonselective β-adrenergic receptor blocker, its use becomes obviously increasing nowadays in a lot of dermatological purposes such as; infantile hemangioma, wound healing, Kaposi sarcoma, pyogenic granuloma. Moreover, it was reported recently to be effective in PAE treatment by inducing vasoconstriction, and inhibiting neoangiogenesis, this is deduced from its known role in treatment of infantile hemangioma. Taken together, and to the best of our knowledge, the literature lacks gold standard treatment for post acne erythema management, and no studies were found to compare effects of combined fractional CO2 laser with timolol Vs, fractional Co2 laser combined with Vit. C, Vs, fractional Co2 alone in patients of post acne erythema, which necessitates to be evaluated, to reach a better consensus while dealing with such common sequel.
Objectives:
Study design:
Randomized controlled trial
Study Methods
Statistical analysis • The collected data will be coded, entered, presented, and analyzed by computer using a database software program, Statistical Package for Social Science (SPSS) version.
funding: Vichy will fund us with topical Vitamin C 15%
Cairo University is the lead sponsor of 4,907 studies on the registry; 1,445 are open to participants now.
Of its 37 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
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Exclusion Criteria:
40 patients enrolled in the study have a left-sided split-face application of fractional CO2 monotherapy
Device: Fractional CO2 laser
Twenty (20) patients have right-sided application of topical vitamin C after and between sessions of fractional CO2 laser
Drug: topical Vitamin C 15% · Device: Fractional CO2 laser
Twenty (20) patients have right-sided application of topical timolol after and between sessions of fractional CO2 laser
Drug: topical Timolol maleate 0.5% eye drops · Device: Fractional CO2 laser
Group B received fractional CO₂ laser plus topical Timolol(after and between laser sessions) on the right side of the face
Group A received fractional CO₂ laser plus topical Vitamin C (after and between laser sessions) on the right side of the face
Group C received left-sided application of fractional CO2 laser alone
The percentage of improvement in post-acne erythema from baseline using erythema assessment scores.
Assessment made using erythema scores as the clinician erythema assessment scale, and dermoscopy. Also, patient satisfaction assessment, and Investigator global assessment were used.
Time frame: 4 months
Reaching a common consensus with post-acne erythema management in future.
Time frame: 12 months
Plan to share: Yes
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: July 2025
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Timolol · Ascorbic Acid