Scars

Marks left behind by acne and by surgery.

Start here

What it is: Skin that heals with a different texture than it had. Depressed, raised and colour-only marks are different things.
Why it happens: If too little collagen fills in during healing the result is depressed; too much and it is raised. A mark that is only colour is a pigment or vessel issue rather than a scar.
Where to start: Start by separating which kind you have. Among depressed scars, rolling, boxcar and icepick are handled differently, and a red mark may not be a scar yet.

There are no numbers and no citations in this box. What has been established, and how far, is below.

On scars, the first thing this site wants to record is what not to do.

Tocopherol (vitamin E) is widely believed to help scars. But in a 1999 trial on surgical scars, it had no effect or actually made things worse in 90% of cases, and 33% developed contact dermatitis. The authors concluded that its use on surgical wounds should be discouraged.

There is far more material on the procedure side — microneedling, fractional CO2, microneedle radiofrequency. But read those pages together and something odd appears: fractional CO2 is almost always the control arm, and no trial has compared it against doing nothing.

Evidence level

Moderate evidenceSoothing

Centella asiatica

Centella Asiatica Extract

In a split-face trial of 30 people after laser resurfacing, the side treated with Centella extract gel showed a lower erythema index (coefficient −0.03, P = .046) and better crusting and wound appearance in the first days. Skin biophysics, though, did not differ between the two sides.

Early researchOther

Onion extract

Allium Cepa Bulb Extract

In the head-to-head against silicone sheeting collated by Cochrane, onion extract was the side that lost (MD −1.30, 95% CI −2.58 to −0.02, low certainty). And there is one split-scar trial in which both sides were silicone gel, so onion's share cannot be separated. In that trial the scar scales (POSAS, VSS) and melanin values did not differ; only erythema came out significantly better on the onion side.

Early researchBarrier lipid

Silicone scar products (gel and sheeting)

An ingredient class — not a single line on an ingredient list

A 2021 Cochrane review gathered 13 randomised trials. Sample sizes ran 10 to 60, and Cochrane rated all the evidence as low or very low certainty. Against no treatment, it is uncertain whether scar severity differs — the interval crosses zero — while pain may be slightly lower. And not one included study reported scar severity as rated by the participants themselves.

Ingredient dataAntioxidant

Tocopherol (vitamin E)

Tocopherol

In a 1999 double-blind trial that split each surgical scar in half, vitamin E had no effect or actually made things worse in 90% of cases, and 33% developed contact dermatitis. The authors concluded that its use on surgical wounds should be discouraged. In a six-month trial it absorbed into skin readily but left the lesions unchanged.

Medicines used for this concern

Medicines are not listed alongside cosmetic ingredients. Dosage and whether a prescription is needed are settled in consultation.

Moderate evidenceIsotretinoinPrescription only

Clinical procedures related to this concern

Procedures are not listed alongside topical ingredients. They are not something you use at home.

Moderate evidenceBotulinum toxinInjection
Moderate evidenceMicroneedle radiofrequencyDevice-based
Moderate evidenceFractional laser (Fraxel, fractional CO2)Device-based
Moderate evidenceIntralesional bleomycinInjection
Moderate evidenceIntralesional 5-fluorouracilInjection
Moderate evidenceMicroneedling (dermapen, dermaroller)Device-based
Moderate evidenceCryotherapyDevice-based
Moderate evidenceLaser-assisted drug deliveryDevice-based
Moderate evidenceVascular laser (pulsed dye laser)Device-based
Moderate evidenceChemical peelDevice-based
Moderate evidenceSubcisionDevice-based
Early researchNon-ablative fractional laserDevice-based
Early researchPicosecond laserDevice-based
Early researchIntralesional corticosteroidInjection

Surgery related to this concern

Surgery is not the same as a procedure. Most of it cannot be undone, and this site does not yet grade evidence for this layer — these are not measured with the same ruler as the lists above. Reversibility is shown in place of a grade.

Scar revisionCannot be undone