There are, however, long-term effects of UV radiation, which are irreversible and often malignant.

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1 Sun Care Products

2 Skin exposure affects the skin in many ways. In the short term, it can lead to reddening, irritation, and eventually tanning, which is the main reason for most people sunbathing. There are, however, long-term effects of UV radiation, which are irreversible and often malignant. Sun exposure is now increasingly recognized as the possible cause of

3 For these reasons, sun protection has become a very important issue today. UV filters, ingredients that can effectively protect the skin from UV radiation, are now incorporated not only into sunscreens but also in daily-use cosmetics, such as moisturizing creams, foundations, and lipsticks.

4 the UV radiation reaching the Earth s surface is largely composed of UVA (approximately 95%) with a small UVB component (approximately 5%)

5 UVB: UVB rays mainly penetrate the superficial skin layers, i.e., epidermis. UVB radiation is the major cause of sunburn, which is acute skin damage perceived as redness. Additionally, it has been identified as a leading factor in the development of skin cancer. The immediate result of UVB radiation is

6 The redness and potential pain subside in a relatively short amount of time; however, the underlying damage accumulates over time. This leads to the formation of various types of skin cancer. Additionally, UVB contributes to photoaging and tanning and also has immunosuppressive effects. An advantageous effect of the UVB

7 The intensity of UVB varies by season, location, and time of day. The most significant amount of UVB is experienced in the US between 10 am and 4 pm during late spring and early summer. However, UVB rays can burn and damage the skin all year, especially at high altitudes and on reflective surfaces such as snow or ice.

8 UVA: UVA rays penetrate deeper into the skin, down to the dermis. On the short term, UVA radiation leads to skin tanning (i.e., browning), which is often considered a sign of health. It is unfortunate since tanning, whether outdoor or indoor tanning, causes cumulative damage over time, leading to photoaging.

9 UVA has long been identified as a leading factor in photoaging Until recently, it was not believed to cause any cancer. Studies, however, showed that UVA damages keratinocytes in the basal cell layer where the most of the skin cancers occur. Therefore, on the long term, it can also contribute to and may even initiate the formation of skin cancer.

10 Photosensitivity reactions are also primarily mediated by UVA. Tanning beds primarily emit UVA radiation. The lamps used in tanning salons can emit doses of UVA up to 12 times that of the sun. Therefore, indoor tanning is associated with a significantly increased risk of skin cancer, and the risk is higher with use in early life (<25 years).

11 UVA radiation retains the same energy level all day long, every day of the year. Therefore, it has the same damaging effect in the morning as in the late afternoon and during winter as during summer. Additionally, it can penetrate window glass. These facts underline the importance of protection against UVA light.

12 SPF is a measure that indicates how long it takes for UV rays to redden protected skin (i.e., skin with a sunscreen) compared to unprotected skin (i.e., skin without a sunscreen). As the SPF value increases, sunburn protection increases. The effectiveness of a given SPF is measured in terms of redness (medically

13 The amount of UV energy required to produce the first visible redness on the skin is referred to as the minimal erythema dose (MED). As SPF values are determined from the test that measures protection against sunburn caused by UVB radiation, SPF values only indicate a sunscreen s UVB protection.

14 SPF is calculated as: UV radiation required to produce 1 MED on protected skin after application of 2 mg/cm2 of product divided by the UV radiation to produce 1 MED on unprotected skin.

15 The number you see associated with SPF represents the length of time (in minutes) you can theoretically stay out in the sun without burning, multiplied by the corresponding number. For example, a person who would normally start to burn in 10min could theoretically have 150 min of sun protection with a sunscreen that has an SPF of 15. This is only true in theory, though since SPF is not directly related to the time of solar

16 Although the amount of solar energy is related to the exposure time, there are other factors that can impact the dose of solar energy: Geography: UV rays are the strongest in areas close to the equator. Altitude: Higher altitudes have greater UV exposure since there is a thinner layer of atmosphere to absorb UV rays. Time of the Year: UV radiation is greater during the summer months.

17 Time of the Day: The peak sun hours are considered from 10 am to 4 pm Weather Conditions: Clouds can absorb UV rays; however, one can get sunburn even on a cloudy day. Reflection: Some surfaces, such as snow, sand, and water, can reflect UV radiation; therefore, UV exposure is higher under such conditions.

18 Skin Type: Fair-skinned consumers are likely to absorb more solar energy than dark-skinned consumers under the same conditions. The amount of sunscreen applied: more sunscreen results in less solar energy absorption. The amount of 2mg/cm2 is used for SPF effectiveness testing; however, studies show that in reality, users usually use only 20 50% of

19 Sunscreens wear off over time; therefore, reapplication frequency is also critical for optimal effectiveness. Physical activities, sweating, and running may rub off the products, while swimming may wash off the product; these conditions shorten the reapplication time.

20 Historically, SPF values have ranged from 2 to greater than 100. This led to the assumption that higher SPF provides significantly better sun protection (i.e., SPF 30 being twice as protective as SPF 15). This is not true. It has been shown in in vitro tests that SPF 15 sunscreens filter out 93% of UVB rays, while SPF 30 protects against 97% and SPF 50, 98% in terms of UVB protection.

21 The highest rating would be 50+. The reason for this is that the FDA does not have adequate data demonstrating that products with SPF values higher than 50 provide additional protection compared to products with SPF values of 50. Keep it in mind that the SPF value refers to the amount of solar exposure against which the sunscreen provides protection and not the length of solar exposure you

22 Broad-Spectrum Protection The term broad-spectrum protection refers to protection against both UVA and UVB rays. Sunscreens that meet the FDA standard for both UVA and UVB protection can be labeled as broad spectrum.

23 Water Resistance Sweating, swimming, and other water exposure can reduce the efficacy of sunscreens According to the FDA monograph on sunscreens, products can be labeled as water resistant or very water resistant depending on how long they can retain the stated SPF after immersion in water.

24 Terms such as sunblock, waterproof, and sunproof are not allowed to be used on product labels since these may be misleading. No sunscreens today are 100% waterproof and none of them can filter out sunlight at 100%. Additionally, sunscreens cannot claim to provide sun protection for more than 2 h without reapplication or to provide protection immediately after application

25 Types and Definition of Sun Care Products Sunscreens provide chemical and/or physical protection. Sunscreens can be classified into two main categories : Primary sunscreens: their main purpose is to provide photoprotection for the skin Secondary sunscreens: have a primary use other than skin protection, such as daily moisturizing creams, antiaging creams, and color cosmetics, such as facial foundations.

26 After-sun products are designed to be used after exposure to the sun or other UV radiation. After sunbathing, even without any signs of redness, appropriate skin care is recommended. After-sun preparations help smooth and moisturize the skin as well as provide a cooling effect and relieve pain resulting from sunburn. Product forms include lotions, creams, and gels.

27 Required Qualities and Characteristics and Consumer Needs Sunscreens are needed provide protection against both UVB and UVA radiation and to be waterresistant Sun damage preparations are needed to alleviate pain, sooth and moisturize the skin and provide cooling effect. Non-odorous and non-sticky Non-staining for skin or clothing Pleasant feeling during and after application

28 Required Qualities and Characteristics and Consumer Needs User-friendly to encourage frequent application and provide reliable protection Non-toxic, non-irritant, and non-sensitizing Proven efficacy and/or performance Long-term stability Appropriate texture Appropriate rheological properties Stability to heat and UV radiation (photostability) Dermatological safety

29 Sunscreens UV Filters UV filters are classified into two groups based on their mechanism of action: physical and chemical sunscreens. A single product usually contains more than one active ingredient, both physical and chemical filters, to achieve the desired SPF value and broad-

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31 Physical sunscreens, otherwise known as inorganic UV filters, reflect and scatter UV radiation. There are two approved physical filters in the US, namely titanium dioxide (TiO2) and zinc oxide (ZnO). Both of these ingredients are insoluble in the sunscreen product base. Therefore, they are suspended in such products. Inorganic sunscreens can only penetrate the

32 Inorganic filters are photostable, independent of the sunscreen base and other ingredients. They provide a broad-spectrum protection The main disadvantage of inorganic filters with regular particle size is that they reflect and scatter UV radiation into the visible spectrum, which provide a white appearance on the skin after application.

33 The reflection spectrum can be modified by decreasing their particle size. The smaller the particle size, the less reflection occurs in the visible spectrum. TiO2 and ZnO are commonly used in micronized (i.e., with a particle size of μm) and nanonized (i.e., with a particle size of nm). Another advantage of smaller particles is that they feel lighter on the skin. Inorganic filters are more often used in combination with organic filters to provide

34 Chemical sunscreens, organic UV filters, are generally aromatic compounds. Their molecular structure is responsible for absorbing UV energy. Organic filters convert the absorbed energy into heat Organic UVB filters include octinoxate, octisalate, and padimate O. Organic UVA filters include avobenzone, oxybenzone, and meradimate. Organic filters are often combined with one

35 Organic sunscreens can penetrate the skin due to their lipophilic nature, which may cause safety concerns. Organic sunscreens are photo-instable. Upon exposure to UV radiation, the structure of UV filters may be destructed. As a result, they lose their absorption capacity. Therefore, most formulations contain photostabilizers Inorganic UV filters may produce free radicals after UV exposure, which can degrade organic filters. Therefore, when organic and inorganic

36 Additional Ingredients of Sunscreens Waterproofing agents: increase waterresistance properties. Important in O/W emulsion Examples include silicone oils, such as dimethicone 350, cyclomethicone, and dimethicone/ trimethylsiloxysilicate. Other examples are polymeric film-formers and alkylated polyvinylpyrrolidones (PVPs) Silicone oils are very resistant to water

37 Photostabilizers: prevent the degradation of organic UV filters Examples include UV filters, such as octocrylene (for avobenzone specifically) and TiO2, as well as other ingredients, such as polyester-8. Emollients: help increase water resistance since they are not washed off easily. They can also serve as solvents for lipophilic organic sunscreens.

38 Water is an essential ingredient in O/W and W/O emulsions as well as in gels. It also serves as a solvent for water-soluble ingredients. For aerosol products, usually alcohol is used as a solvent. Emulsifiers: usually, a combination of emulsifiers is used to provide the appropriate stability for the products.

39 Thickeners: carbomers; cellulose derivatives, such as hydroxyl propylcellulose; gums, such as xanthan gum; and other polymers Lipophilic thickeners, such as waxes, are also often used in sunscreens. Film-forming ingredients help form an even and uniform film on the skin after application and drying. They are sometimes referred to as SPF boosters for this reason.

40 Antioxidants: vitamins E and C. Preservatives: parabens, benzyl alcohol, methylisothiazolinone, and phenoxyethanol. Humectants: sorbitol, glycerin, and propylene glycol. Chelating agents: EDTA and its derivatives. Propellants: isobutane and dimethyl ether.

41 ph modifiers (neutralizers), such as citric acid and triethanolamine Fragrances; and colorants, TiO2 could act as an opacifier in certain cases; however, this effect is reduced with size reduction. Natural ingredients, such as allantoin, aloe vera, panthenol, and vitamins, can also be added to formulations.

42 Product Forms of Sunscreens: Sunscreens are available in a variety of dosage forms, including: O/W or W/O emulsions Anhydrous systems, such as ointments, sticks, oils, and silicone-based aerosols Wipes Gels

43 Emulsions are the most popular form since they offer a variety of textures (such as sprayable lotions, thicker lotions, and creams). Another advantage of emulsions is that both oil- and water-soluble ingredients can be incorporated into them. O/W emulsions are generally more popular W/O emulsions are greasier and stickier; however, they have been shown to have a higher efficacy. Additionally, due to the oily

44 Sticks are available as lipsticks and lip balms as well as sticks for babies. They are suitable for smaller surfaces areas only Due to their anhydrous nature, they provide water resistance and higher efficacy The choice of waxes determines the melting point of the stick. Melting point can be reduced by the level and type of the emollients used, although firmness must be

45 Aerosol sprays allow for quick and easy application by covering a relatively larger area on the body, so even hard-to-reach areas can be covered more easily. Usually, the amount of product applied is far less than what is recommended by the FDA. Aerosol spray sunscreens should be evenly spread on the skin and rubbed (not just sprayed on). Severe burning cases were reported from

46 Aerosol sprays are generally alcohol-based products containing alcohol-soluble organic UV filters. As physical sunscreens are not alcohol soluble, they are usually not formulated into aerosol sprays or would otherwise clog the valve. They usually contain film-forming agents to ensure the formation of an even film on the skin.

47 Ointments and oils were quite popular years ago when many people used low-spf products and wanted a deep-colored tan. Today, they are not as popular as other forms. Ointments and oils are greasier than W/O emulsions, which are not desired by consumers.

48 Gels provide a nice skin feel and absorb quickly; however, providing waterresistance properties for such formulations is quite difficult. Additionally, active ingredients that can be used for this dosage form are very limited. Another disadvantage may be irritation, if alcohol is used in the formulation.

49 Wipes These are pre-moistened by the manufacturer. The formulators can place emollients and other moisturizers onto the cloth wipes, which may, therefore, provide additional benefits.

50 These are usually perfume-free Products formulated specifically for babies Baby skin is much more sensitive than adult skin and penetration of ingredients into baby skin can be much higher and faster. Ideally, babies under 6 months should avoid sun exposure and no sunscreens should be used on their skin. For babies older than 6 months, sunscreens can be used to protect their skin

51 Products formulated specifically for babies Irritation and sensitization potential can be minimized using physical sunscreens, which do not penetrate the viable skin layers. Baby skin is more susceptible to moisture loss; therefore, formulations should have additional moisturizing benefits

52 After-Sun Preparations After-sun preparations, known as sunburn preparations, are used to hydrate the skin and sooth irritated, red, burnt skin. Even if no sunburn occurs, after exposure to UV radiation, the skin needs care Sunburn is an acute inflammatory skin reaction for excessive exposure to UV radiation, which can come from a variety of sources, including sun, tanning beds, and

53 burns at an early age increase the risk for Sunburn is generally classified as a superficial or a first-degree burn. It can cause various signs and symptoms, such as tenderness, mild pain upon touch, itching, and redness, which may be followed by scaling. More severe cases may proceed to edema or blistering. Studies have shown that repeated severe

54 Most after-sun formulations are O/W emulsions (such as lotions, creams, and sprays) and gels Gels have the advantage of an immediate cooling effect due to the high water content. The main functional ingredients in sunburn preparations: Antioxidants help replenish the depleted antioxidant pool and/or boost the antioxidant defenses of the horny layer. Examples include

55 sun exposure and prevent, or at least postpones, Soothing and anti-inflammatory alleviate pain, redness, and burning. Examples include azulene and bisabolol (from chamomile), allantoin, aloe extract, and panthenol. Witch hazel is an astringent and anti-inflammatory agent Cooling agents such as menthol, eucalyptus, and alcohol provide an immediate short cold sensation. Moisturizers help replace the water lost during