Effectiveness of sunscreens and factors influencing sun protection: a review

Abstract

The effectiveness of sun protection depends directly on the photo-protective product employed, the way it is used and the amount applied. Many studies report that sunscreens are often applied incorrectly, at amounts much lower than those recommended for the sun protection factor (SPF) specified on the label. When not used properly, the effectiveness of the product against sun exposure damage is reduced. Currently, sunscreens are available in a variety of different formulations and types, such as stick (bar), aerosol, cream, lotion, oil, tanning formulations and makeup. However, developing an effective stable photo-protective formula that can be correctly applied regardless of type poses a challenge, as effectiveness is dependent on several factors. Factors influencing effectiveness include sun exposure conditions (direct or indirect), level of protection (SPF), amount of product applied, maximum exposure period before reapplication, product type (spray, lotion, etc.), layer thickness required, coverage, and ability to spread and permeate into the skin. Studies comparing the effectiveness of different forms of sunscreens, the amount of product applied by consumers and SPF and UVA protection determined by validated methodologies, are lacking. Therefore, the objective of this study was to review the available literature on the topic and discuss the effectiveness of sunscreen formulations and factors influencing sun protection. This review was carried out on the scientific databases MEDLINE, PubMed and Scielo. Of the many publications retrieved, thirty-nine articles most relevant for this review were selected.

Anti-UV Microgel Based on Interfacial Polymerization to Decrease Skin Irritation of High Permeability UV Absorber Ethylhexyl Methoxycinnamate

“…The UV protection efficacy of the EHMC-pEDGMA microgel was shown to be significantly superior to that of the original UVB absorbent EHMC. The determination of the sun protection factor is influenced by various factors, such as the methodology employed during experimentation, the formulation used, and the specific apparatus utilized for measurement [ 41 , 42 ]. The primary distinction observed in both the composition and functionality of the sunscreen recipe was the variation in the anti-UV ingredient utilized.…”

Assessment of prevalence of sunscreen use and related practices among people living in Saudi Arabia: A cross‐sectional survey‐based study

“…12 The data related to sunscreen SPF in this study is consistent with the current recommendation of using an SPF of 30 or more to provide the optimal protection which reflects good practice, Table 5. 16 Similarly, majority of sunscreen users (72%) in al Al-Robaee study used an SPF >30. 17…”

A Recent Update on the Potential Use of Catechins in Cosmeceuticals

“…The higher the SPF, the more protective the sunscreen [58] to prevent sunburn as well as skin cancer in the long term. The SPF can be determined with in vivo or in vitro methods.…”

“…Another study showed that the inhibition zone of catechin is 18.45 mm for P. acnes and 15.68 mm for S. epidermidis [60]. The antibacterial mechanism The higher the SPF, the more protective the sunscreen [58] to prevent sunburn as well as skin cancer in the long term. The SPF can be determined with in vivo or in vitro methods.…”