Oral nicotinamide reduces transepidermal water loss: a randomised controlled trial.

Transepidermal water loss (TEWL) is a marker of cutaneous barrier function, which is impaired in age-related skin dryness as well as being a central feature of atopic eczema. There is some evidence that topical nicotinamide (vitamin B3) can reduce TEWL, possibly by modulating aquaporins and sphingolipids. We evaluated the effect of oral nicotinamide on TEWL in participants of the ONTRAC skin cancer prevention study. 292 participants (mean age 66 years, range 30-91) at a single study site were randomised to receive nicotinamide 500mg or matched placebo twice daily for 12 months. TEWL measurements were taken at baseline and 3-monthly for 12 months on the forehead, forearm and lower leg. The estimated relative reduction in TEWL on the forehead with nicotinamide was 5% at 3 months (p=0.13), 5% at 6 months (p=0.13), 6% at 9 months (p=0.03), and 6% at 12 months (p=0.039). The estimated relative reduction in TEWL on the limbs with nicotinamide was 2% at 3 months (p=0.53), 4% at 6 months (p=0.30), 1% at 9 months (p=0.72), and 8% at 12 months (p=0.04). Oral nicotinamide was well-tolerated and significantly reduced TEWL on the forehead and limbs, and is a potential new oral agent for improving skin barrier function. This article is protected by copyright. All rights reserved.