Ingredients I Avoid: Papain, Sodium Lauryl Sulfate, Polyethylene

I’m obviously ok with putting a lot of stuff on my face that may make others cringe, but there are a handful of ingredients I actively avoid. This is my current, very short list of those items.

This is not an attempt to fear-monger or talk others into not using certain things, but an attempt to make everyone a little more aware of the things they are putting on their faces.

Papain and Papaya Extract

Bromelain and Papain, found respectively in pineapple and papaya, are enzymes that aid in the digestion of proteins. They are also used not uncommonly in skincare products as chemical and enzyme exfoliants. Papaya extract contains both papain and chymopapain. I (regrettably) do not know much about bromelain, but I started noticing that products containing papain and papaya extract seemed to irritate my skin and trigger breakouts. These weren’t regular breakouts either where I can just remove the product from my routine and the acne would retreat. These were stubborn breakouts that would keep coming back and take weeks to get under control. I made a mental note of it, started avoiding products with papain and papaya extract, but never really bothered to understand why papain was such a problem for me.

Some time later, papain was mentioned in a Chemists Corner podcast for its potential to compromise the skin’s barrier and cause allergic reactions in skin. I hung on for every word, dug up the study they referenced! The article CC cites summarizes an in vivo study done by The Medical University of Vienna. It reads:

After just a short period of time, papain increased vascular permeability and inflammatory cells infiltrated the skin,” Jensen-Jarolim explains. Around two weeks after being exposed to papain, the researchers found antibodies to papain in the mice… “Exposed mice not only experienced a loss of the barrier function of the skin, but also had a specific allergic sensitization toward papain. The animals developed an allergy,” says allergy expert Jensen-Jarolim…

But the permeation of the skin barrier does not appear to be a prerequisite for sensitization toward papain. “The enzyme remains allergenic even when its enzymatic function has been blocked,” explains Jensen-Jarolim. The disruption to the skin barrier, she says, is essential for the infiltration of other allergens and bacteria. In humans and in animals, diseases of the skin such as atopic dermatitis, commonly referred to as eczema, involve an increased permeability of the skin with a heightened risk for bacterial, fungal, or viral colonisation. Besides genetic factors, allergenic enzymes from external sources may also contribute to the symptoms. It is striking that papain has an enormous structural similarity with one of the most important house dust mite allergens. The authors conclude that sensitization toward these house dust mite allergens follows the same principle.

I also found this tidbit from The Beauty Brains about a hair growth inhibitor but mentions other risks involving papain:

There’s also the question of safety – although shave minimizing products are not recognized as a drug category, the FDA has taken action against other topical drug products that are based on papain. For topical wound healing products with papain there have been reports of not only allergic reactions but anaphactic shock, low blood pressure, and rapid heart rate which prompted the FDA to proclaim that all topical drug products containing papain require FDA approval. Of course since these hair growth products aren’t making the same kind of would healing claims, they aren’t technically affected by this action. Still, it does raise the question of whether or not these products are safe.

I felt vindicated to know there is an understood method by which papain was disturbing my skin and also a bit surprised that such a potentially harmful ingredient is wildly used without any sort of warning. I’ve seen coconut oil, fragrance, and essential oils being called out as skin sensitizing ingredients before but never papain. Obviously, skin sensitivities vary from person to person but had I known papain was an ingredient to watch, I feel like I may have caught on to my skin’s sensitivity to it earlier and maybe could have minimized some damage. Consider yourself warned!

Sodium Lauryl Sulfate


The best product I’ve found for my hair is Shiseido’s red bottle Tsubaki shampoo and conditioner. It not only makes my thick hair, which has a tendency to look coarse and straw like with the wrong product, look silky soft, but I have also struggled with dandruff for as long as I can remember, and interestingly this magical shampoo/conditioner duo seemed to reduce the severity of my dandruff! A bit of googling revealed Shiseido’s Tsubaki shampoo uses sodium laureth sulfate instead of sodium laurel sulfate.

These two ingredients sound awfully similar but are actually quite different. Sodium laureth sulfate is created through a process called ethoxylation, which means ethylene oxide is added to the chemical compound. The result? This makes sodium laureth sulfate less irritating to skin.

Sounds good, right? Well, yes and no. Sodium laureth sulfate can be irritating as well, but for right now, it suffices to say its gentler and safer than sodium lauryl sulfate.

What makes Sodium Lauryl Sulfate so bad? It’s a consistent skin irritant:

According to Dr. Leslie Baumann’s Cosmetic Dermatology text, “[Sodium lauryl sulfate] is such a consistent irritator for skin with an impaired barrier that it is actually used in ‘challenge patch tests’ to evaluate the barrier function of skin…it strips the natural lipids from the skin, disrupting the barrier and rendering it more susceptible to external irritants.”


This one has less to do with individual health and more to do with the health of the world!

Everyone already knows microbeads are terrible, right? Polyethylene is the stuff used to make microbeads.

Like microbeads, polyethylene is not readily biodegradable without special treatment. Unlike microbeads, its not so obvious what products contain it and what products don’t. It’s also not entirely clear the impact of polyethylene in skincare products, as most of the pollution-awareness is around microbeads and plastic bags. In Fanserviced’s amazing comparative review of oil cleansers she noticed all the balm cleansers she tested (and none of the non-balm cleansers) contained polyethylene. I prefer oil cleansers to balm already, but avoiding polyethylene is enough of a reason for me to completely break from balm cleansers (unless, of course, I can verify they’re polyethylene free).

4 thoughts on “Ingredients I Avoid: Papain, Sodium Lauryl Sulfate, Polyethylene

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