Cosmetic Science - What is known and unknown

One of my Facebook friends posted a question looking for advice about which sunscreen she could use for her child. It turns out her daughter had a skin reaction to the sunscreens she had been using. Of course, without knowing what was in the formulas that could have caused the reaction I was hesitant to give advice. But that didn’t stop her well-meaning friends from making a number of suggestions including various natural brands, popular brands and even a reference to the Environmental Working Groups sunscreen guide to 2016. And some of them were certain that their suggestion was absolutely correct. They seemed to have no doubts at all despite the fact that they weren’t dermatologists, toxicologists or even cosmetic chemists. 

Why is it that subject experts are so cautious while people with no expertise are so sure of themselves?

It turns out this phenomena is called the Dunning – Kruger effect. It’s a fascinating topic and I encourage you to read the Wikipedia entry on it for a little background.

This got me thinking about the kind of knowledge that we have about cosmetics and cosmetic science. The reality is that we know a few things with a high level of certainty but most of the information we have in cosmetic science is uncertain. For formulators it is useful to know what we know and what we don’t really know.

Solid Cosmetic Science

There are a wide variety of subjects for which we have good experimental evidence. Perhaps the most informed are high level mechanisms of action. For example, the behavior of surfactants in oil and water environments is well established. We know why they remove dirt, how they can make water and oil compatible, why bubbles are formed and all the other characteristics that make them useful. We know how preservatives work and on which microbes they are effective. We know about moisturizers, colorants, fragrances, cosmetic thickeners, polymers, sunscreens, and pretty much how all cosmetic raw materials work.

We also have a great idea about the chemical structure of the raw materials we use. Well, at least for ingredients that are primarily one material. When you start talking about plant extracts, resins, or other naturally-derived materials our knowledge about the composite molecules is less certain. There are just so many different types of chemicals that can be found in natural extracts that most suppliers don’t bother figuring out everything in there.

Raw material uncertainty

While we have solid answers to questions about the structure and function of the raw materials, we are much less certain when you turn to questions like “what material is best to use” or “will my system be stable”. This type of knowledge is not known by most of the scientists in the cosmetic industry. The reasons are varied, but it is a combination of the fact that the research hasn’t been done, or it has been done and not widely published. We are in a competitive industry and companies use technological advantages to create superior products. They don’t want other scientists to know all that they know.

Another problem with answering these types of questions is that there is a lot of misinformation published. Raw material marketers who want you to use their materials have an incentive to exaggerate results of experiments or avoid publishing results of experiments that don’t show their raw material in the best light. This leads to a knowledge base in our industry that is uncertain at best and possibly false at worst. Never forget that you are an industrial scientist and much of your knowledge will be biased.

Learning what’s true

Although you will always be biased, the way to cut through this type of uncertainty is to figure out what is most likely true and be open to the possibility that what you believe now quite likely may be wrong. Our heads are filled with mistaken information and it is our responsibility as scientists to purge our brains of this as best we can.

To figure out what is true you need to skeptically read all you can about raw materials or any kind of cosmetic science, then test it yourself. Don’t rely on supplier’s testing to make your decisions about your final raw material selection. Certainly, you can use what they tell you as a guide, but just because surfactant supplier X tells you that their sulfate-free detergent is less harsh than Sodium Lauryl Sulfate, that doesn’t mean it will be true for you.

And don’t automatically believe some aspect of cosmetic science just because you read it in a book. Our information changes over time and the details of some of the things you previously read in a book like Harry’s Cosmeticology may be wrong. For example, we have long been taught that the stratum corneum can be thought of as a brick and mortar model with corneocytes as the bricks and the skin NMF as the mortar holding it together. But this has been changed recently with the realization that desmosomes hold the cells together, not the NMF.

It gets more uncertain

Now, the things we have discussed thus far are rather easy compared to the really complicated questions in cosmetic science. And when I say ‘really complicated’ I mean seemingly simple questions like “how long does it take for hair to dry” or “what causes wrinkles” or “what sunscreen should my daughter use that won’t react with her skin?” Even a question like “what preservative should I use” is not one with a simple answer.

The reason these things are complicated is because the answers are impacted by a variety of factors. To figure out how long it takes for hair to dry you have to first define what you mean by dry. Is it all the moisture gone? Is it when consumers think their hair is dry? Is it based on hair mass or something else? Does the hair type matter? Is hair damaged? We could go on and on.

Or a question of which sunscreen to use depends highly on the genetics of whoever is using the product. You couldn’t do an experiment on a general population or on animals and provide an answer to an individual. Some questions just don’t have knowable answers unless you conduct an experiment.

Is it safe to use?

These questions are perhaps the most difficult to answer. It’s not because of the uncertainty about the safety of raw materials (most common ones have been thoroughly tested). It’s because different people have different definitions for what they think is safe. Most consumers have a terrible ability to ascertain risk versus reward. They default to simplistic conclusions such as “estrogen disrupter = bad”, “lead = bad”, “synthetic = bad.” And this is further emphasized by groups like the EWG and their ridiculous raw material safety ratings. They don’t believe that the dose makes the poison and that all materials whether they are natural or not can be dangerous at certain levels.

What’s a cosmetic chemist to do?

So, this might leave you wondering what you should do. How should you learn about what is true and how do you communicate this? Well, here are a few tips.

1. Realize that anything you know could be wrong – Be changeable
2. Require evidence to change your view – Opinions are not evidence
3. Test things yourself whenever you can. Lots of published things are wrong
4. Keep learning but be skeptical about what you read.
5. Publish things you learn to help out other cosmetic chemists

If we cosmetic chemists follow these tips we can improve the science for everyone and move more questions into a category where we’re much more certain about our answers.