Let's get one thing straight: You should be wearing sunscreen everyday, rain or shine. Protecting your skin from the sun is essential — no matter your skin tone, location, or the forecast. Wearing sunscreen is our number one defense against skin cancer and comes with a variety of skin benefits, too. Want to protect the skin barrier? Sunscreen can do that, no problem. How about limit acne scarring? Yup, sunscreen can aid with that, too. And as for reducing fine lines, sunscreen has you covered there as well. Trust us, there's really no reason to ever skip it. Full-body sunscreen was tested on the volar region of the right forearm, and facial sunscreens were used on the left cheek two centimeters from the external canthus of the eye. The volar forearm was divided into two areas (a region without sunscreen—the control area—and an area where the sunscreen was applied). The cheek was divided into 4 areas (an area without sunscreen—the control area—and areas 1, 2, and 3, where each facial sunscreen was applied). The sunscreen was applied to each area and measures were taken after 20 min of application. All variables were also measured on the control area before (basal measure) and 20 min after (control measure). The orange tinted sunscreen, which is geared towards eliminating a white cast for those with olive undertones, can sometimes leave a gray-colored cast on other skin tones. The skin is the largest organ of the human body, and fulfills numerous defensive and regulatory functions [ 1]. Its general structure has three main layers, called the epidermis, dermis and hypodermis. The skin-barrier function resides mainly in the epidermis, especially in the stratum corneum [ 2]. The epidermal barrier maintains skin homeostasis and protects the body against numerous external factors, such as chemical, environmental and physical stress, including ultraviolet (UV) radiation. It is important to highlight the individual characteristics and behavior of the epidermal barrier, as homeostasis differs according to individual phototypes and skin-exposure behaviors [ 3].

Elasticity is another important characteristic related to the biomechanical properties of the skin. A decrease in elasticity has been related to a higher SCORAD index in patients with atopic dermatitis, and has been observed to be affected at older ages, decreasing as age increases [ 16]. In our case, facial elasticity increased after the application of sunscreens, especially with facial sunscreen 3, which could be explained by the presence of antioxidants and especially by the presence of pure hyaluronic acid in its formula, an active ingredient known for its viscoelastic properties and one of the main components of the extracellular matrix [ 29, 30]. Formula type: GH Beauty Lab scientists tend to prefer lotions and creams over sprays since "they last on skin longer and are more likely to form a uniform protective coating over skin than sprays," Wizemann says. In addition, "If your skin is prone to dryness, a cream may be better for you," Dr. Chen says. As for kids, "Sprays are easy to use, but they might require a second coating, so spray generously," she notes. TEWL is one of the most important characteristics of the skin barrier, and numerous studies have shown that high TEWL values are often associated with skin-barrier deficiencies, and lower TEWL with healthy skin [ 16, 17, 18, 19, 20]. There is also evidence that TEWL decreases with age, which could be misinterpreted as an improvement in the skin barrier [ 17, 21]. TEWL is influenced by many environmental and individual factors, such as age, sex, race, anatomical location, skin temperature and other environmental conditions such as season, smoking habits, type of measurement-technique used, and many other factors [ 22, 23, 24]. The normal range of TEWL is 1 to 25 g/m²/h, and, as we have previously stated, values above this limit indicate dysfunction of the epidermal barrier [ 20, 25] They also follow a different distribution in terms of location, so that it appears to be greater in the facial area compared to other parts of the body such as the forearm [ 17]. In our case, we obtained different results depending on the area, with an improvement of the parameter in the forearm but a slight increase in the facial area. Despite this, they results remain in the normal range. Active ingredients: Most often, you'll have to choose between chemical and mineral sunscreens (or a mix of both) as your main SPF agents:Skin pH is another essential parameter for the evaluation of epidermal functions, as the acidic nature of pH influences skin-barrier function, lipid synthesis and aggregation, epidermal differentiation, desquamation, skin-barrier regeneration and skin antimicrobial-response [ 14, 15]. Elevated pH values are related to the loss of antimicrobial activity, and it has also been shown that, in patients with atopic dermatitis, higher values of the SCORAD index are associated with skin-barrier dysfunction, which is reflected in higher pH and temperature and lower SCH and elasticity [ 15]. In our study we observed that despite the increase in pH after the application of the sunscreen, the values remain within normal ranges, and therefore the epidermal barrier is not affected by it. While sunscreen is often the first thing people reach for in terms of protection, remember that covering your skin is even more effective. Protective clothing, like sun hats or UPF clothing, are another tool to keep in your sun safety arsenal. Sunscreen should be reapplied every two hours, but be extra careful during peak sun times — 10 A.M. to 4 P.M. — depending on the season of the year. If you’re going to be spending a lot of time in direct sunlight, then it’s always best to go for SPF 50, even if you want a tan, and especially if you’re having a beach or pool day. Trust us, you’ll still get a tan, but your skin will be much better protected from those harmful rays. You’ll need to reapply your body sunscreen every two hours or every time you get wet. SPF 50 only offers slightly higher UV protection (around 2%), but over a lifetime, this does make a very big difference.

But of course, if you live in a warmer climate when more of your skin is exposed year round, you should apply body sunscreen every day too. How much sunscreen should you use on your body? There is scarce literature on the use of sunscreens and their effect on skin homeostasis. In fact, no previous research study has been performed comparing skin-homeostasis parameters before and after the application of a sunscreen. Although there have been studies on TEWL and temperature after the use of sunscreens, these were oriented to the use of sunscreens during physical exercise [ 8, 9]. SCH is another important parameter for skin integrity, and lower-than-normal values are also frequently associated with skin-barrier dysfunction. In some publications it has been observed that the face has higher hydration-indices than other anatomical regions [ 26, 27, 28]; however, there is also literature in which the measurements are reversed, and the skin of the forearm is more hydrated than that of the face [ 27]. In our case, our findings were consistent with increased facial-hydration.

3 major benefits of applying a double layer of sunscreen

There are several parameters indicative of the integrity of the skin barrier, and among them transepidermal water-loss (TEWL) is considered one of the most important. It is defined as the flux density of water diffusing from the dermis and epidermis through the stratum corneum to the skin surface. Increased TEWL levels are associated with alterations of the skin barrier [ 7]. Stratum-corneum hydration (SCH) is another important parameter for assessing the barrier function of the skin. It shows the water content of the stratum corneum, and low SCH values are often associated with dermatological conditions and increased disease severity. Other skin characteristics related to skin-barrier function are pH, elasticity, temperature, melanin and the erythema index [ 8, 9, 10, 11]. Erythema and melanin index: in AU, using the Mexameter ® MX 18 by means of the MPA multiple probe adapter: it allows measurement of the two components mainly responsible for skin color: melanin and hemoglobin (erythema). The process is based on a light absorption/reflection principle, using a sensor that emits light at three specific wavelengths, and the receiver measures the light reflected by the skin. By defining the amount of light that is emitted, it is possible to calculate the amount of light that has been absorbed by the skin. Both melanin and erythema experience a decrease after the application of sunscreen, and although melanin is not one of the most important parameters for indicating the integrity of the epidermal barrier, erythema is a good indicator of the action of irritants on it, as it is a cardinal sign of inflammation [ 11, 12, 13]. In our study, erythema decreased considerably with respect to skin without sunscreens, so we can determine that, in addition to not irritating the skin, they improve this parameter. In addition, since erythema is a cardinal sign of inflammation and its reduction occurs with all sunscreens, there is a possibility that these have an anti-inflammatory effect, so the study of sunscreens could be expanded in future research projects, since there is no literature on this subject. Nevertheless, it is also possible that sunscreen use alters the colorimeter measurements. HELPS PREVENT PREMATURE SKIN AGEING with HIGH-LEVEL PROTECTION (SPF50 and PA++++): Protects skin at its surface and from within against damage caused by UVA, UVB, visible light and infrared-A PLUS defends against free radical and DNA damage

Concerning the impact of sex and age, we did not observe great differences between men and women or participants of different age-groups. This fact is important so that recommendations about sunscreen regarding skin-barrier function could be spread to both sexes and different age-groups. It is important to mention that we only include adults, so further research is needed to evaluate the impact of sunscreen on children. ORIGINAL SPF 30 SUNSCREEN LOTION. This is the stuff we use every day. It’s the formula that started it all. People say it smells like summer. We like that. Whether we’re spending a lazy day at the beach or just hangin’ out, our Original formula is definitely our fav. As for temperature, our study shows a rise in temperature after the use of sunscreens, with an average increase of 0.76 °C on the face and 0.68 °C on the forearm. These results are contrary to those obtained by Ou-Yang et al. in their study regarding the impact of sunscreens on the skin during exercise, as they did not observe any change [ 8]. However, it is important to highlight the fact that the method used to obtain the measurements was different for the two studies. Ou-Yang took the first temperature immediately after applying the sunscreen to people doing physical exercise [ 8], and we evaluated changes after 20 min in resting conditions, without including physical exercise. Despite discrepancies, the increase in temperature experienced in our study is not significant, and remains within the normal parameters of skin temperature established by Benedict et al. In their work, they determine a normal range between 31 and 35 °C of temperature, depending on the body zone, with a higher temperature in the facial zone and lower in more distal zones such as the forearm [ 9, 10]. This distribution is also present in our data, in which we observe that the facial temperature is higher than the one obtained on the forearm and that both are within the normal range.

How to apply a double layer of sunscreen this summer?

Looking to pare down your skincare routine and spend less time getting ready in the morning? The Live Tinted Huegard helps you do that: It's a three-in-one daily mineral SPF 30, moisturizer, and primer that protects skin from the sun while imparting a natural glow that looks beautiful both on its own or as a prep step for makeup. It comes out of the bottle with a subtle orange tint (which helps offset the look of a white cast on darker skin tones), and requires a bit of blending, but, according to our tester, feels lightweight nonetheless. "I liked how the orange tint allowed me to see where I was applying the sunscreen, ensuring that I applied it evenly," she explains. "It applied nicely on my olive skin, but it may not be the best for all undertones and skin tones." Water-resistance to stand up against sweaty days or time spent swimming. Heads up: There’s no such thing as water proof or sweat proof sunscreen. Under current FDA guidelines, there are only “water-resistant for 40 minutes” or “water-resistant for 80 minutes” options. "Sweat- and water-resistant" labeling means the formula maintained its SPF level on testers’ skin in a water bath for the indicated time, says Steven Q. Wang, M.D., a board-certified dermatologist at Memorial Sloan Kettering Cancer Center in Basking Ridge, New Jersey. Beyond that timeframe, it should be reapplied.