Abstract

Over the past decade, non-prescription skincare has gained significant attention. However, evidence supporting many skincare trends often lacks the rigorous testing seen in Randomised Controlled Trials (RCTs) for prescribed medications. Vehicle arms in RCTs, which test non-medicated treatments, provide insights that support the advocacy of basic skincare practices.This narrative literature review explores the lessons drawn from vehicle arms of RCTs in the management of conditions like acne vulgaris, actinic keratoses, melasma, post-inflammatory hyperpigmentation, and rosacea. A literature search was performed on MEDLINE and Embase to identify RCTs involving vehicle arms for the dermatological conditions. Data on outcomes, study design, and sample size were extracted and analysed. Basic skincare practices such as cleansing, moisturising, and sun protection have consistently demonstrated meaningful improvements in dermatological outcomes, even without active treatments. Vehicle arms often achieve a substantial proportion of the efficacy seen in active treatments, frequently exceeding half of the efficacy seen in active treatments, emphasising the potential of simple skincare regimens. For acne vulgaris, two identical international phase III RCTs (involving 2817 participants) demonstrated up to 25.7% improvement in facial acne severity and 51.2% reduction in inflammatory lesions with vehicle treatment. In actinic keratoses, an RCT (n = 468) showed up to 24% reduction in lesion count and 17% complete clearance in the vehicle arm. In melasma, an RCT (n = 48) demonstrated up to 66.6% improvement in severity with vehicle treatment. In post-inflammatory hyperpigmentation, a phase IV trial (n = 123) showed up to 44.9% improvement in overall disease severity with vehicle treatment. For rosacea, a multicentre RCT (n = 120) showed up to 27% reduction in erythema in the vehicle arm. Basic skincare is an essential component of dermatological treatment. Evidence from placebo-controlled trials reinforces the value of skincare routines, which should be incorporated into treatment plans alongside active therapies to enhance efficacy and optimise patient outcomes.