The established methods for measurement of epidermal water content and TEWL have been supplemented with important new technologies including methods that allow imaging of epidermal water distribution and water depth profiles. A much more complete and sophisticated characterization of the various aspects of the dermal water barrier has been accomplished by means of today's noninvasive techniques; however, instrument standardization and validation remain a challenge.

Morphological, structural and biophysical differences were found when assessing the skin of the Brazilian and French participants, who were exposed to different environmental factors.

The blood supply to the skin is provided by a network of arterioles, capillaries and venules organized into a superficial and a deep plexus. The assessment of skin microcirculation is of valuable interest in cosmetology in the quantification of the sun protection factor, skin irritation and efficacy of antiredness treatments. Skin microcirculation can be measured by means of different techniques, based mainly on the quantification of optical and thermal properties of the skin which are modified by the amount of blood perfusion. Relevant and reproducible data can be obtained only through the understanding of the biophysical background of the technique(s) utilized. Standardization of measuring conditions and procedures is particularly required for blood flow assessment. In this paper, the advantages and disadvantages of the main techniques in use are discussed, and optimization of measurements for laser Doppler techniques is described.

Overproduction of sweat, sweaty skin and body odours are unpleasant for many social groups. Body cleansing products are designed to combat these undesirable features of skin. In addition, antiperspirant and deodorant products are more specifically used in the underarm site by a large part of the adult population. Antiperspirants are offered to control emotionally triggered sweating in the armpit. Deodorants are designed to combat malodour generated from bacteria-modified sweat. This review summarizes the physiology of eccrine, apocrine and apoeccrine sweat glands. The mechanisms of action of antiperspirants and deodorants are described as well as the factors influencing their efficacies. A series of tests using various measurement methods can be used to demonstrate the efficacy of antiperspirants. These include the gravimetric method, water evaporation quantification, electrodermal measurements, staining procedures, dye injections and cyanoacrylate skin surface strippings and casting replicas. Deodorant efficacy can be evaluated by sensory assessments performed by an expert panel. Indirect support is provided by visualization of apocrine gland excretion and collection of sweat and volatile compounds. Microbiological assessments and chromatographic analysis also provide indirect information.

The use of sunscreens is an important and essential component of photoprotection. Since their introduction during the first half of the last century, sunscreens have benefited enormously from major technological advances such as the development of novel UV filters; as a result, their efficacy in preventing UV‐induced erythema is unequivocal. More recently, however, new challenges have appeared, which have prompted a robust discussion about the safety of sunscreens. These include topics directly related to photoprotection of human skin such as improved/alternative methods for standardization of assessment of the efficacy of sunscreens, but also many others such as photoprotection beyond UV, concerns about human toxicity and ecological safety, the potential of oral photoprotective measures, consequences of innovative galenic formulations. On a first glance, some of these might raise questions and doubts among dermatologists, physicians and the general public about the use sunscreens as a means of photoprotection. This situation has prompted us to critically review such challenges, but also opportunities, based on existing scientific evidence. We conclude by providing our vision about how such challenges can be met best in the future in an attempt to create the ideal sunscreen, which should provide adequate and balanced protection and be easy and safe to use.