When it comes to sunscreen, you just can't win. While it's commonly known that sunscreen is one of the best defenses against skin cancer, some controversial studies over the last few years have suggested that some of the ingredients in sunscreen itself may be linked to cancer.
And if that's not contradictory enough, this month researchers at the University of Copenhagen have discovered that many UV-filtering chemicals found in sunblock contribute to male infertility. According to the study, these chemicals have a similar effect as female progesterone and interact with calcium ions to interfere with the function of sperm cells.
Niels Skakkebaek, the study's senior investigator, and his fellow researchers tested 29 of 31 UV filters commonly used in sunscreens in the United States and Europe on live sperm, using a buffer solution that mimicked the real-life scenario of sperm traveling through the female reproductive system. 45% of the filters experienced an increase of calcium ions — key regulators of sperm function — which affected sperm mobility, for one.
As other virtually unavoidable factors — like using a WiFi-connected laptop — continue to threaten sperm health, scientists are looking for solutions to keep sperm viable. Just last month, a group of researchers in Spain found that exposing boar ejaculate — yes, boar ejaculate — to LED lights could help boar sperm perform better. If the same process can be applied to humans, their findings prove promising for preserving sperm for artificial insemination.
But in the meantime, Skakkebaek said he hopes researchers conduct more clinical studies on sunscreen to look into removing harmful chemicals and that regulatory agencies take their findings into serious consideration.
Also see sunscreens that top dermatologist wear every day:
The Sunscreens That Dermatologists Wear Every Day
Using sunscreen may weaken sperm because everything good is also bad, science says
"I wear EltaMD facial sunscreen daily. I love it because it's broad spectrum, fragrance-free, lightweight, clear (no white residue!) and it can be applied under or over moisturizer."—Dr. Anne Chapas, New York City-based dermatologist.
"CeraVe’s sunscreen for the face contains invisible zinc, ceramides for hydration and niacinamide, which is good for patients with any baseline redness. This sunscreen is lightweight and is also water resistant for up to 80 minutes.
"I always also apply (and recommend that my patients do, too) an antioxidant prior to sunscreen application. UV rays create free radicals that cause photoaging of the skin, damaging DNA, proteins and lipids. The antioxidant helps counteract the rays that get through the sunscreen, acting as a double barrier." —Dr. Tina West, a Chevy Chase, Maryland-based dermatologist
CERAVE SUNSCREEN FACE LOTION WITH SPF 50 via target.com
"I wear Elta MD UV Clear on my face and neck daily. Over it, I apply Colorescience Sunforgettable Primer, a tinted, moisturizing product that I use instead of foundation. I always keep Colorescience Sunforgettable Mineral Sunscreen in my bag so I can reapply SPF over makeup during the day.
If I'm playing sports, swimming, walking around outdoors or even sitting in a stadium in a sunny climate, I instead use Blue Lizard Sport for both my face and my body–it contains physical and chemical sunscreens in a very water-resistant base. Then I apply Headhunter Warpaint, a surfer preferred sunscreen, on the areas that get the most sun, like my forehead, nose, jawline and hands."—Dr. Heidi Waldorf, director of laser and cosmetic dermatology at Mount Sinai Medical Center in New York City
"I use MDSolarSciences Mineral Creme SPF 50 on the body and the brand’s tinted lotion on the face. Both feel smooth on the skin, are non-irritating and provide great, broad spectrum coverage. The tinted version gives the skin a nice, even tone." —Dr. Diane Berson, associate professor of dermatology, Weill Medical College of Cornell University
"I wear Biopelle's Stop The Clock on my face every day. I like it because it has a physical block (zinc) but doesn't leave a white film. It contains DNA repair enzymes—quite unique for a sunscreen—and antioxidants. Plus, it’s fragrance-free." —Dr. Joel Cohen, associate clinical professor of dermatology at the University of Colorado
BIOPELLE STOP THE CLOCK BROAD SPECTRUM SPF 50 SUNSCREEN WITH DNA REPAIR via biopelle.net
"I always use EltaMD UV Shield SPF 45 on my face, but when I'm going to be out in the sun, I'll also use Aveeno's lotion sunscreen. It’s relatively cheap, so I can apply it liberally on skin when hats and sun-protective clothing aren't enough." —Dr. Jason Reichenberg, director and associate professor of dermatology, University of Texas at Austin and Seton Healthcare Family
AVEENO PROTECT + HYDRATE LOTION SUNSCREEN WITH BROAD SPECTRUM SPF 30 via target.com
"My daily facial sunscreen varies between two products: NYDG Physician's UV Defense SPF 30 and Elta MD UV Clear SPF 46. NYDG's has a light milky consistency and spreads easily over large surface areas. It's fragrance-free, gentle on even sensitive skin types and has the added benefit of green tea extract—a potent antioxidant that can reverse skin damage, stimulate microcirculation to the skin and slow the aging process. It's also a physical barrier sunscreen (micronized titanium dioxide) and provides excellent UVA and UVB protection.
"Elta MD's contains the anti-inflammatory niacinamide to help prevent unnecessary breakouts. I love that the silky consistency allows for a smooth, sheer application." —Dr. Jessica Weiser, New York City-based dermatologist