Sun protection (SPF) is the essential foundation of any skincare routine; using other cosmetics without sun protection is useless. It is recommended to apply sunscreen as soon as the UV index reaches or exceeds 3 to prevent premature aging and preserve skin health.

noli's read

This advice is based on particularly solid scientific foundations. A landmark randomized controlled trial (RCT), published by Hughes et al. (2013) in the Annals of Internal Medicine, demonstrated that regular sunscreen application significantly reduces visible skin aging over several years. Furthermore, an observational study published by Flament et al. (2013) in Clinical, Cosmetic and Investigational Dermatology estimates that UV rays are responsible for nearly 80% of facial signs of aging, validating the idea that SPF is the priority step for skin longevity. The recommendation to apply protection as soon as the UV index reaches 3 is also perfectly aligned with World Health Organization (WHO) guidelines. The claim that other skincare products would be totally "useless" without SPF is a slight stylistic turn of phrase intended to make an impression, as hydrating or antioxidant active ingredients retain their own value. However, the spirit of the message remains scientifically accurate: UV rays degrade collagen and create oxidative stress that neutralizes a large portion of the benefits of your other products.

the sources

1. 1Green AC, Williams GM, Logan V, Strutton GM 2011
2. 2Hughes MCB, Williams GM, Baker P, Green AC 2013