You might not know it, but the beauty products you use every day could be the cause of some serious harm.

Recently, we found out that triclosan, an ingredient used in many common anti-bacterial hand soaps, can cause impaired muscle function. Say what?! Intrigued, we did some research and dug up these five examples of products and treatments many women use, but don't know are potentially hazardous to their health. From nail polish to spray-tanning, click through the gallery to see the deadliest cosmetic practices on the market.

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