Did you know that tons of your favorite beauty products are loaded with algae? But don't run shrieking to your bathroom to throw it all out. The green, slimy gunk–which ranges in size from single cell organisms to giant sea kelp–has tons of potential benefits for your skin.

"There are a few studies that indicate algae (and seaweed) have cosmetic benefits. One says that algae can stabilize minerals that aid in skin moisturization," Randy Schueller, a cosmetic chemist and editor-in-chief of The Beauty Brains told me. "Another claims that seaweed provides anti-acne properties without the irritation of over the counter drugs. And yet another type of seaweed may help with skin lightening." (Go here for the scientific explanation of algae's benefits. It's fascinating. No, truly.)

Algae, often interchangeably called seaweed, has been a hot topic lately in the cosmetics ingredient world. One company, Heliae Development (which has used algae to make jet fuel, among other things), got some attention in May when it announced it would be using its cutting-edge algae harvesting technology towards branding its own health and beauty products. Former marketing execs from Elizabeth Arden, Esteé Lauder, and Unilever are on board.

Algae comes with some caveats, as do all beauty product ingredient claims. "There's enough science here to say that algae, seaweed and kelp may provide some benefits but of course it depends on the specific type of extract, how it's processed, and how much is used," Schueller cautioned.

Dr. Marcene Alexiades-Armenakas (who coincidentally was profiled this week in this rather unbelievable New York Times article about women who get plastic surgery to look middle-aged), uses it in her signature 37 Extreme Actives cream. "These creatures have spent millions of years on the sea surface and evolved mechanisms to protect their DNA from UV damage. These mechanisms are conserved cross species, meaning [they] work in human skin, too! That is why I included blue algae extract for DNA defense in 37," she said.

So in the spirit of beach season–you've been interacting with algae unknowingly for the last two months at your favorite shoreline hangout!–we've rounded up all the best algae-laden summer beauty products. Every single one contains a type of algae, and we'll break down what it does in each product. Click through–you're going to be surprised which products contain these green/blue/brown/red wonders.

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Photo Credit: Frederic Pacorel/Stock Image