Bat Guano (Fertilizer) In Mascara?

That’s right ladies (and some dudes). The next time you “bat your eyes,” it might be literal.

Have you ever noticed the pearlescent quality in fertilizer? Bird poo? Eye shadow?

While I was researching bat guano recently for my gardening adventures, and I came across something strange. There seems to be a buzz on the internet about bat guano as an ingredient in mascara.

I’m not kidding. Google it. People are even talking about it on yahoo answers.

UPDATE: I did some more digging and here’s what I found:

Yes. It’s true.


Ok. It’s not completely true. Bat Guano does not exist in mascara. How many obvious sanitary reasons would you need?

However, a derivative of guano does exist in mascara. It’s called guanine. It helps provide a certain pearly shine to nail polish, shampoo, eye shadow, and mascara. So while they don’t actually use guano, they do derive guanine from it. They also, produce it synthetically.

* It should also be noted that guanine can be found in seabird guano as well as bat guano.

Long story short, there is some truth to the urban legend that mascara, eye shadow, shampoo and other everyday items contain guano.


  • Fertilizer Purple
  • Guano Green
  • Flying Rat Poo Red

Ok. I’ll stop. This is getting ridiculous.

Back to my bat guano research. (It really does make a great garden fertilizer: Guano know more?)

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9 thoughts on “Bat Guano (Fertilizer) In Mascara?

  1. There is no bat guano in mascara. I looked up mascara in the Wikipedia it said that it contained guanine, but it didn’t come from bat guano it came from fish scales. They even have a full article in the mascara one about the urban legend, which clearly states that one of the ingredients is fish scale guanine.

  2. @John Lloyd Scharf – They covered that. Did you even read the Snopes article?

  3. Guanine comes from the Spanish word guano which comes from a Peruvian word for bat and bird dung. That is the entymology of the word guanine, regardless of what Snopes claims. They did not go far enough in their research. There may or may not be guanine used in mascara, but the source is more likely to be dung rather than fish scales.

  4. There are much more stable and safer sources for Guanine than just Guano, such as fish scales. All the sources I found said that fish scales are used as the source, not bat guano.

  5. Bat Guano is already used in Cosmetic Sector since 1850’s.. It’s interesting, but true..

    We sell Bat Guano worldwide from Turkey.

    High quality Bat Guano available from Turkey to any destination in World. 10, 000 to 50, 000 ton’s shipping capacity in a month. Excellent quotations given depending the order size and the durability of the orders.

    We are Bat & Bat Ltd. Company and have more than 45 caves all arround Turkey issued by Republic of Turkey.

    Please contact with us via and [email protected].

  6. guanine is also one of the four nucleotides that makes up our (and every other living thing’s) DNA.

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