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What Is the Connection between Bat Guano and Mascara?

Bat guano was once rumored to be a component in mascara, sparking safety concerns. However, modern formulas use synthetic and safer alternatives to ensure product quality and consumer health. Intrigued by the evolution of cosmetic ingredients? Discover how the beauty industry has transformed over the years, prioritizing your well-being while enhancing beauty. Ready to uncover more beauty myths and truths?
N. Swensson
N. Swensson

In the beginning of the 21st century, a rumor was in circulation on various websites, chat rooms, and television shows about the relationship between bat guano and mascara, stating that the guano is actually an ingredient in the makeup. The rumor goes on to say that one of the ingredients found in most mascaras, guanine, which is used to give many cosmetics and other beauty products a pearly sheen, is made from bat guano. Although it may be technically possible to derive guanine from bat feces, the United States Food and Drug Administration (FDA), which regulates the cosmetic industry, prohibits the use of any ingredients that come from any type of feces. The guanine used in makeup and beauty products is actually made from fish scales. Bat guano does have some practical uses thanks to its high nitrogen content, however; it has been used as fertilizer and to make certain types of explosives.

The urban legend about bat guano and mascara is one of many rumors that have circulated over the years about cosmetics, all with varying degrees of truth. They most likely come from a general anxiety that many consumers have about beauty products, with their complicated lists of ingredients and manufacturers who are highly protective of their formulas and processes. The use of animal products as well as the practice of testing cosmetics on animals, sometimes with harsh and painful consequences for them, is also a source of controversy that contributes to rumors about the cosmetics industry. In many cases, it is difficult to find hard evidence that supports assertions like the one that mascara contains bat feces, yet the stories persist.

A woman wearing mascara.
A woman wearing mascara.

It appears that some cosmetic companies and salespeople have adapted the rumor about bat guano and mascara to suit their own purposes. Many discussion posts on the Internet can be found that describe salespeople telling stories about other competitors using guano to make mascara, but assuring potential customers that their product does not contain this ingredient. One good way to ease concerns that a person may have about the ingredients in a particular cosmetic or beauty product is to consult a dermatologist or a licensed cosmetologist. They often have knowledge of any possible health effects that may result from compounds used in these types of products.

Feces from bats has some uses, but not in mascara.
Feces from bats has some uses, but not in mascara.

Although there is no connection between guano and mascara, bat feces has been used, like other forms of excrement, as fertilizer. It is very rich in nitrogen, one of the most important components in fertile soil. Bat guano is also often used by organic gardeners. They prefer it because bats eat only fruit and insects, while other livestock animals whose manure is often used as fertilizer may be fed diets containing hormones, antibiotics, and other substances that may make their way into the excrement.

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Discussion Comments


I am allergic to all mascara, but even if I weren't, I doubt I'd wear it. Too gloppy. Petroleum jelly works just as well,

I doubt bat guano is used, but I'm still glad I don't wear the stuff -- just in case.


I swear to goodness: some people will believe *anything!* And if it's on the internet, well, it has to be true, right? Right? The whole idea is just nuts. That's the kind of thing companies get closed down and sued for.

I'm not saying the FDA is made up of altruistic angels, but any kind of poo in a cosmetic is just a death sentence. The days are long gone when Asian women used face creams with nightingale droppings in it. Believing this stuff is just silly.

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    • A woman wearing mascara.
      A woman wearing mascara.
    • Feces from bats has some uses, but not in mascara.
      By: cheri131
      Feces from bats has some uses, but not in mascara.
    • Guano is said to be used in many cosmetics products to create a pearly sheen.
      By: Gennadiy Poznyakov
      Guano is said to be used in many cosmetics products to create a pearly sheen.