Transepidermal water loss in healthy adults: a systematic review and meta-analysis update.

Reference estimates are useful for clinical study planning and interpretation of results. TEWL is highly dependent on skin area, and our results further support the symmetry between right and left measuring sites. TEWL in elderly people seems to be generally similar or decreased compared with younger individuals, but available evidence is limited. Reporting of TEWL should be improved: mean and spread parameters should always be reported in future studies.