Sunscreen Dangers: Sunscreens may disrupt Progesterone Pathways and reduce Male Fertility.

Sunscreen Dangers: Sunscreens may disrupt Progesterone Pathways and reduce Male Fertility.

By Marc Sorenson, EdD  Sunlight Institute… Sunscreen dangers..

Sperm count in men has dropped by more than half since 1950, possibly due to powerful chemicals that are finding their way into the water supply.[1] Now, the sperm that are still viable may have another problem, according to recent research: sunscreen chemicals are absorbed into the blood and carried into the sperm, which can render the sperm infertile.[2] [3] One investigation showed that an incredible 9% or more of the applied amount is absorbed through the skin.[4] Sunscreen chemicals also have potential “gender-bending” characteristics; they increase estrogen and decrease testosterone in men,[5] [6] and are also known to cause the feminization of fish. [7]And environmental pollution by these and similarly-structured chemicals are now thought to cause feminization in alligators and the gradual extinction of Florida panthers due to failure to breed.[8] Sunscreens also increase the absorption of pesticides through the skin. [9] [10] There are many more sunscreen dangers, but time and space will not permit us to discuss them all.

How does the system work to cause infertility? Many of the chemicals that filter out UV radiation can induce calcium signals in human sperm cells and mimic the effect of progesterone. This can render the sperm infertile. The aforementioned study that showed the influence of sunscreen chemicals was a lab study or “in vitro” investigation, using collected human sperm. It is not known if the same would happen in living human subjects, but it is likely.

These chemicals are known as endocrine disruptors, and with sperm count going down and many cancers increasing, they are not something I would recommend for public consumption.

Nature intends for us to cover up or seek the shade when we have had enough sun exposure. Nature also intends that we seek the sun to reap the benefit of it marvelous healthful benefits. Soak up the sun, but be sure not to burn. And don’t’ use sunscreens. There are too many sunscreen dangers, and they stop vitamin D production on the skin they cover.



[3] Rehfeld A, Dissing S, Skakkebæk NE

[4] Hayden CG, Roberts MS, Benson HA. Systemic absorption of sunscreen after topical application. Lancet 1997:350:863-64.

[5] Environmental Working Group: Americans Carry Body Burden of Toxic Sunscreen Chemical. March 25, 2008.  (available at

[6] Ma R, Cotton B, Lichtensteiger W, Schlumpf M.  UV Filters with Antagonistic Action at Androgen Receptors in the MDA-kb2 Cell Transcriptional-Activation Assay.  Toxicological Sciences 2003;74:43-50.

[7] Kunz PY, Galicia HF, Fent K. Comparison of in vitro and in vivo estrogenic activity of UV filters in fish. Toxicol Sci 2006:90:349-61.

[8] Pickart, L.  The Chemical Sunscreen Health Disaster.  2000-2008.  (available at

[9] Brand RM, Pike J, Wilson RM, Charron AR. Sunscreens containing physical UV blockers can increase transdermal absorption of pesticides. Toxicol Ind Health. 2003;19:9-16

[10] Pont AR, Charron AR, Brand RM. Active ingredients in sunscreens act as topical penetration enhancers for the herbicide 2,4 dichlorophenoxyacetic acid. Toxicol Appl Pharmacol. 2004;195:348-54.

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