August Newsletter

From Defense to Offense –The Truth About Chemical Sunscreens

Health advisers touting the benefits of sunscreens with high SPF always forget to tell you that these so called protective skin products contain a high concentration of chemical UV-absorbers, which can end up inside your body. Many of those chemical compounds are endocrine disrupters and have estrogenic qualities.

In one study, researchers investigated skin absorption of three chemical UV-filters commonly used in sun protective cosmetics – benzophenone-3, octyl-methoxycinnamate and 3-(4-methylbenzylidene) camphor. Immediately after the first application, their level in blood plasma was negligible. However, in only 2 hours all three chemicals were detected in plasma. After whole body application of 2 mg/cm² of each sunscreen, the chemicals were detected in plasma even after 96 hours.

Some people believe that they can avoid the harmful effects of sunscreens by choosing natural reflective UV-protectors such as titanium dioxide. However, this is only partially true. In reality, good safety records exists only for pure reflective titanium dioxide in its natural form. The downside of using this form of titanium dioxide is that it adds a whitish hue to the skin, which is now considered undesirable.In their efforts to avoid a product that will give a "pasty" look, most modern cosmetic products contain nanoparticles of titanium dioxide, which have different chemical properties. One issue with this is that such chemicals can enter the skin cells. In fact, one study showed significant uptake of titanium dioxide nanoparticles in skin cells. At the same time, the cells’ viability and antioxidant level plummeted, while oxidative damage and cell death soared.

Another study demonstrated that titanium dioxide nanoparticles sized 4 nm, 10 nm, 21 nm, 25 nm and 60 nm induced free radical formation in cultured human skin cells, as well as decreased viability.

Thus, national obsession with sunscreens displaying high SPF ratings as well as consumers’ desire for invisible and easy to apply sun protective products (not to mention the advice to reapply those products every two hours) seem very dangerous in the light of recent data on skin penetration, oxidative damage and endocrine disruptive qualities of chemical and nano-sized UV-absorbers. Therefore, those who want to protect their skin should stick with the old fashioned mineral sunscreens, avoiding chemical UV-absorbers as well as nano-versions of the mineral ones.

Finally, don’t forget that a certain amount of sunlight is highly beneficial for your skin and can infuse your body with health and vigor. Sensible suntanning in the absence of alien chemicals is the key to beautiful skin.

References.

Janjua N.R. et al. Sunscreens in human plasma and urine after repeated whole-body topical application. J Eur Acad Dermatol Venereol. 2008;22(4):456-61.

Shukla R.K. et al. Titanium dioxide nanoparticles induce oxidative stress-mediated apoptosis in human keratinocyte cells. J. Biomed. Nanotechnol. 2011;7(1):100-1.

Xue C Nano titanium dioxide induces the generation of ROS and potential damage in HaCaT cells under UVA irradiation. J Nanosci Nanotechnol. 2010;10(12):8500-7.