Sunscreen Products and Sun Protection

UVB radiation: solar rays with wavelengths between 290-320 nm,

UVA radiation: solar rays with wavelengths between 320-400 nm,

UVB represents UV-induced Burning, or skin tanning, while UVA represents UV-induced Aging effects. Critical wavelength: the wavelength equivalent to 90% of the integrated region between 290-400 nm wavelengths, referring to the wavelength under the integrated optical density curve starting from 290 nm. Sun Protection Factor (SPF): the ratio of the minimal erythema dose on skin protected by a sunscreen product to the minimal erythema dose on unprotected skin. UVA Protection Factor: the ratio of the minimum UVA dose required to produce continuous tanning on skin protected by a sunscreen product to the minimum UVA dose required to produce minimum tanning effect on unprotected skin. In this context, if your skin tans in 10 minutes without sun protection, using an SPF 15 product would extend protection to 15x10=150 minutes. Therefore, you would need to reapply an SPF 15 product every 2 hours for sun protection. The following basic elements must be stated on the label of sunscreen products: • The amount that should be used (Sunscreen products are equivalent to 0.5mg/cm² or 17.5 grams on an adult.) • How frequently it should be used, • The duration of protection it can provide (SPF factor, UVA protection), • The risks of prolonged sun exposure even when using sunscreen, • Whether the sunscreen is suitable for children or infants, • Whether the sunscreen is water-resistant, • How the sunscreen should be stored for stability, • The efficacy of the sunscreen (low, medium, high or very high). Sunburns are primarily caused by UVB radiation (290-320 nm). UVA radiation (UVA II 320-340 nm, UVA I 340-400 nm) alters the skin's renewal process and causes premature skin aging. UVB and UVA radiation can cause skin cancer. UVB and UVA filters required in sunscreen products provide superior protection when used together. In the EU and Turkey, sunscreen products must ensure that at least one-third of the SPF value comes from UVA filters.

PPD (Persistent Pigment Darkening)

A measure of the degree of protection against UVA radiation. Rather than measuring extreme erythema or skin redness, the PPD method determines the amount of UVA radiation that will cause permanent skin darkening or tanning. Theoretically, a sunscreen with a PPD rating of 10 should allow a person 10 times the UVA exposure they would receive without protection. The PPD method is an in vivo test, similar to SPF. Additionally, Colipa has developed an in vitro method for which PPD claims can be made.

Star Rating System UVA+++++

A method established in the UK and Ireland by Boots using in vitro methodology to define the UVA/UVB protection ratio of a product. One star represents the lowest UVA protection, while five stars represent the highest UVA protection. This method uses a spectrophotometer to measure the absorption of UVB relative to UVA.

PA System

A system used particularly in Japan and other Asian products to indicate the degree of UVA protection. The PA system is based on the PPD reaction and is now widely adopted on sunscreen labels. PA+ represents UVA protection of 2 to 4. PA++ represents UVA protection of 4 to 8. PA+++ represents UVA protection of 8 and above, and in 2013 was revised to include PA++++ corresponding to a PPD rating of 16 or higher. In cosmetic products, when calculating product safety using raw materials and their application ratios, sunscreen products are assumed to be applied to the entire body, i.e., 17,500 cm² area, according to SCCP's 8th Revision, with daily usage of 18 grams. According to this, daily exposure to sunscreen is 300 mg/kg bw/day. When a product uses UV filters at maximum permitted levels, calculation of the product safety value shows that the MoS (Safety Margin) of Octocrylene and Benzophenone-3 is less than the required MoS > 100 for a cosmetic product, indicating unsafe levels.

When daily usage is considered as 36 grams according to the Turkish Medicines and Medical Devices Agency's Sunscreen Cosmetic Guideline, these ratios are even less safe.

For adults, the MoS must be greater than 100, and for children from birth onwards, it should be at the following values: 230: at birth, 180: up to 6 months, 160: up to 12 months, 150: up to 5 years, 130: up to 10 years. In this case, if Ethylhexyl Methoxycinnamate (OMC) is used at the permitted level (10%), an unsafe product would be produced for children under 5 years of age. When examining the MoS values of OMC at different percentages: 10% OMC: inadvisable for children under 5 years, 9% OMC: suitable for ages 12 months and above, 8% OMC: suitable from 6 months onwards, 6% OMC: shown to be suitable even for infants. When manufacturing sunscreen products, especially high protection factor products, detailed product safety assessments regarding safe use in children and pregnant women should be conducted. Otherwise, the target user group should be carefully specified in product descriptions and warnings. When examining the Product Safety range of Benzophenone-3 at different concentrations for use by children and pregnant women, the following findings are notable: In conclusion, attention should be paid to whether oils used in sunscreen products are photoallergens (phototoxic) when exposed to light, and although the scientific committee has proven that nano-form UV titanium and zinc are safe up to 25%, considering that they may still be absorbed through the scalp and phototoxic effects, formulating the product as water-resistant and with UV boosters that enhance the effects of UV filters rather than using high amounts of UV filters will make the products safer.

Sources:

1. FDA Consumer Health Information / U. S. Food and Drug Admintration May 2012.

2. SCCS 8. Revision the Sccs's Notes of Guidance for the Testing of Cosmetic Substances and Their Safety Evaluatıon.

3. Survey and health assessment of UV filters by The Danish Environmental Protection Agency, 2015.

4. Turkish Medicines and Medical Devices Agency - Guideline on Sunscreen Products.

5. SCCP/1201/08.