Why do we use water in cosmetics?
You may not have noticed this before, but if you go through all of the personal care products in your bathroom right now - your moisturizer, your toothpaste, your shampoo, your shaving cream, your soap - you’ll notice they all have something in common.
No matter the texture, viscosity, color, or use, every single one of these products have a common ingredient: water! Not to mention it’s usually the ingredient with the highest concentration, sometimes over 70-80% (that’s why it’s listed first)!
So what exactly is the role of water in cosmetics?
Why do we use water in cosmetics?
Before we get into that, it’s important to point out that cosmetic brands don’t use any type of water in their formulations. You may have noticed that the first ingredient in your products is often referred to as “aqua” rather than just “water”. What’s the difference, you say? Brands don’t use aqua to sound fancy or to mislead you - it’s required by law. Cosmetics companies have to formulate their products using water that’s free of toxins, pollutants, and microbes. And thank goodness, too! While tap water is safe to be ingested (your immune system knows exactly how to deal with all those things), a lotion or a soap is a perfect breeding ground for bacteria. Purified water ensures your final formula has the least amount of toxins and it extends its shelf life at the same time. Which brings us to our first questions: why do we use water in almost every personal care formulation?
From a cost point of view, water is very affordable (even purified water). That’s how brands can get away with making lotions and soaps that cost under $10. Sometimes, it’s referred to as the “profit-margin” ingredient - meaning it’s used as a filler. But even the high-end brands use it in their formulation because of how water gets absorbed into the body. We are, in fact, made up of almost 60% water. So it’s not entirely a cost issue.
The main reason why we use water in our formulations is because of its chemical properties. Water acts as a solvent: that means it’s the vehicle where all the other active ingredients can dissolve. Remember your science classes where you needed to dissolve a certain amount of salt in a certain volume of water? This is the same idea. Water can contain dissolved amounts of several different minerals depending on what kind of environment it’s found in. Then, as our body absorbs it, it becomes the vehicle for delivering all these active ingredients to the deeper layers of our skin. To prevent this hydration from escaping, we add emollients to create a barrier on the surface of the skin. If you ever take the time to notice, look at how high-end brands talk about the type of water they use in their formulations - this is the science behind those claims.
Water can also emulsify (in other words, blend) into oils, to create lotions and foams. In these cases, it’s used to create textures and give a lotion some body (otherwise, it would merely be liquid).
Can we make water-less cosmetics?
There is a growing trend and demand for creating water-less cosmetics and personal care products (like beauty bars). Due to the overwhelming amounts of water being used to develop such formulations, consumers are starting to put pressure on the industry to go water-less. However, not all products can be made without water and still be functional and affordable. And regardless, you would still need water to activate the ingredients and have them perform the way you’d want to (think of a bar of soap - it won’t clean without water).
While we seem to be very concerned with how much water is used to create these products, there’s a darker side to this story that seems to go unnoticed: where do all the chemicals go when we wash them off our body? While some ingredients do get absorbed in our skin, the majority simply remain at the surface and are washed down the drain. What happens then?