The Science of Luca

LUCA™ is the best UVA/UVB sunscreen available in the United States, because our formulations contain Polycrylene®, a novel Avobenzone stabilizer and strengthener. Avobenzone provides great UVA protection, but without the addition of Polycrylene®, it begins to breakdown after 10 minutes in intense sunlight. In addition to excellent UVB coverage rated by familiar SPF ratings, LUCA™ is the only product in the United States to voluntarily place a critical wavelength value (see critical wavelength below) on our label showing our level of UVA protection.

Good daily UVA protection is very important. As a pathologist, I have seen an increase in the numbers of skin carcinomas and melanomas which are diagnosed each year in an ever younger patient population. UVA rays are strongly linked not only to melanoma, but to the aging associated with sun exposure (wrinkles, sun spots, loss of elasticity, skin thinning, etc). Daily UVA/UVB protection is necessary on chronically sun exposed skin surfaces (face, arms, ect.).

The graph below shows the protection with LUCA™ versus a “good” broad spectrum formulation. Notice that both give good UVB protection and both can state UVA/UVB on the label; however LUCA™ gives substantially more UVA protection. The orange area shows the increased protection possible with LUCA™ because it uses Avobenzone which has been stabilized and strengthened by Polycrylene®. This increased UVA protection is reflected in our critical wavelength, which is the highest in the U.S. market. Critical wavelength is an internationally recognized rating system for UVA protection which will likely be adopted by the FDA at some point in the future.

Photostability: LUCA vs. Other SPF 30 Sunscreens

*Critical Wavelength: Critical wavelength is an international rating system for UVA protection. It is a measurement performed on a machine in which sunscreen is applied to a slide. The slide is then irradiated from an artificial light source to simulate sun exposure. Exposure begins at 290nm, with subsequent exposure to progressively higher wavelengths of light. The point at which the sunscreen allows 10% of the rays to penetrate through the slide is defined as the critical wavelength. Another way of looking at this, would be this is the point where the level of protection provided by the sunscreen has dropped, to the point where only 90% of the rays are blocked (absorbed). The advantage of the critical wavelength is that it is an in vitro, very reproducible laboratory test. A sunscreen with a critical wavelength over 370nm is considered by the FDA to provide excellent UVA protection.

Providing a UVA rating system such as critical wavelength is essential in allowing consumers to select products that provide appropriate levels of UVA protection. However when measuring critical wavelength, it is important that this measurement be performed on a sample that has been irradiated. This provides proof that the formulation is stable when exposed to intense sunlight. The following graph shows an absorption curve for LUCA both before and after irradiation. As shown in this graph, there is no significant difference between the pre and post irradiation curves, proving that LUCA is photostable. The level of radiation used equivalent to 4-6 hours of intense sun.

Photostability: Of LUCA SPF 30 Sunscreen

LUCA Sunscreen FAQ

WHAT IS UVB AND UVA?
UVB rays produce the familiar sunburn. They also cause skin cancer. SPF (sun protection factor) ratings effectively rate the level of UVB protection provided by sun protection products. The UVB rays have a shorter wavelength meaning that they do not penetrate into the deep layers of the skin.

By contrast, UVA rays have a longer wavelength, penetrating deeper into the skin, and produce the aging associated with chronic sun exposure such as: skin sagging, loss of elasticity, pigment changes, deep wrinkles, and dry skin. Recent studies have shown a strong link between UVA rays and the development of melanoma. Critical wavelength (CW) is the international standard to rate the level of protection against UVA rays.

WHAT DOES SPF MEAN?
SPF (sun protection factor) measures how long it takes sunscreen protected skin to begin to sunburn (turn red) as compared to unprotected skin. For instance, if it takes unprotected skin takes 10 minutes to burn, then sunscreen protected skin with a SPF value of 15 will take 150 minutes to burn. SPF values only rates the level of UVB protection.

WHAT IS CRITICAL WAVELENGTH?
Critical wavelength (CW) is the most effective way to rate UVA protection. Solar radiation travels in waves. The wavelength corresponds to the solar energy of the wave. Solar radiation of 290nm to 400nm (the UVB-UVA range) is reproduced in a laboratory device designed to measure the amount of radiation absorbed by a sunscreen. Starting at the beginning of the UVB range (290nm), progressively higher wavelengths of light are aimed at the sunscreen. The point at which the sunscreen lets 10% of the radiation through is defined as the critical wavelength. The higher the number, the better. A sunscreen with a critical wavelength over 370nm is considered by the FDA to provided good UVA protection. LUCA, with a critical wavelength of 383nm, provides the best UVA protection available.

WHAT IS AVOBENZONE AND WHY IS IT IMPORTANT?
Avobenzone is the best UVA filter available. It, along with zinc and titanium dioxide, are the only compounds which are FDA approved for protection against UVA rays. Consumers often say that zinc and titanium dioxide formulations feel “heavy.” Avobenzone formulations by comparison are light and cosmetically elegant. The highest critical wavelengths(CW) are also achieved in formulations using stabilized avobenzone. LUCA with a CW of 383nm, has the highest critical wavelength of any product on the market.

WHAT DOES “STABILIZED” AVOBENZONE MEAN?
Although Avobenzone is a superior UVA absorber, it is a photounstable compound, meaning that it breaks down quickly in sunlight. It is necessary for formulations using avobenzone to be stabilized. LUCA uses Polycrylene® (CPH Innovations) to stabilize avobenzone. Manufactures not only need to provide a critical wavelength to rate UVA protection, but this measurement should be performed on specimens which have been irradiated to simulate 4-6 hours in intense sunlight, proving that the formulations have been effectively stabilized.

WHEN SHOULD YOU USE A SPF15 AS OPPOSED TO A SPF30?
A SPF of 15 will absorb approximately 94% of the UVB rays with a SPF of 30 absorbing approximately 97% of the UVB rays. This means that by wearing a SPF of 15, one can remains in direct sunlight for 2 hours before beginning to sunburn. Wearing a SPF of 30 will increase this time in the sun to 4 hours before a sunburn begins. This extra protection is achieved with a significant increase in the levels of active ingredients, which some individuals find to be irritating to the skin. It is best to use a moisturizing SPF 15 formulations everyday, with the use of a SPF30 for times of intentional sun exposure.

WHY NOT USE A SPF 45 OR HIGHER IF SUN PROTECTION IS SO IMPORTANT?
After reaching a SPF level of 30-33, there is a plateau in the effectiveness of UVB filters. SPF values above 30 are relatively meaningless and do not provide any significant increase in UVB protection. For example, a SPF of 30 will block approximately 97% of the UVB rays with a SPF of 50 blocking approximately 98% of the UVB rays. This 1% increase in protection will allow for an extra 10 minutes or so of sun exposure (4 hours versus 4 hours and 10 minutes). However, this extra 10 minutes of sun exposure is achieved with a marked increase in levels of often irritating active ingredients.

Luca Products:

LUCA SPF 15 Sunscreen
LUCA SPF 30 Sunscreen

© 2007 Island Air, LLC. All rights reserved. Content and charts provided by LUCA SUNSCREEN. Learn more about Luca.