The Chemists' Comprehensive Guide to Cleanser PT. 2

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First Posted on July 13, 2021 in:cleansershop like a proskincare fundamentals

So you’re ready to dive deeper into the world of cleansers. Well this blog post is for you! In this post, we’ll be taking a closer look at the science of cleansing ingredients, go through some popular surfactants, and answer all your questions about exfoliating cleanser ingredients. So let's put some strategy around finding the holy grail cleanser for your skintype.

If you haven't already, check out Pt I for the cleanser routine 101 guidelines.

The Gentle Cleanser Surfactant Guide

Surfactants are the key ingredients doing all the cleansing work. They are basically bi-polar little guys since they have polar/hydrophilic heads that like water and a non-polar/hydrophobic tail that doesn't like water. This characteristic allows the surfactant to pick up excess oil and dirt and then slip right off with a splash of water.  There are a ton of surfactants to choose from and cleansers are often surfactant blends. 

For those of you trying to troubleshoot your cleanser, one method is to decode the IL and choose a particular "surfactant-forward" cleanser. These would be relatively simple cleansers with just one or two main surfactants sitting in the top 5 of the ingredient list so you can roughly gauge which surfactants seem to to best for your skin. As an example, we've listed out some coco betaine, isethionates, and glucoside forward cleansers (perhaps 3 of the most common 'gentle' surfactants you'll find). As you can see, many cleansers cross pollinate these gentle surfactants.

*This chart is really just a tiny snapshot of the surfactant world. There is a vast library of surfactants out there to try. Glutamates, sulfonates, taurates, sulfates, we could go on! For a closer look at the listed cleansers in this diagram, head to our shop my shelf page, where we've added a couple more cleansers.

Familiarizing yourself with the top 2-3 surfactants will help you get a sense of what works or maybe what surfactants to stay away from for your next shopping purchase. However, typical cleansers are a blend of several surfactants and it can get a bit confusing. For example, it’s common to find the gentle sodium cocoyl isethionate with bad-rep, SLS (sodium lauryl sulfate). But not to fear! Remember that the dose makes the poison so finding SLS in your cleanser isn’t a deal-breaker. At the end of the day, you should listen to your skin when it comes to cleanser formulas.

Despite surfactants being the headliner of your cleanser formula, the supporting cast can be just as important!

The Other Ingredients in Cleansers

Surfactants are definitely the heart and soul of any cleanser formula. What about other ingredients? Are cleansers mostly just diluted products with surfactants + water and fillers? Well, sort of. Here are some common ingredients you’ll find in your cleansers and why they’re in there:

  • Water (or oils & waxes if we’re talking about oil cleansers): it is there to dilute the product, for good reason. Anything in skincare needs to be at the right concentration. Using surfactants neat is a straight shot to irritation town. This is why Dr. Bronner’s 18-1 Castile Soap gives us hives.
  • Moisturizing ingredients: ingredients such as glycerin, light oils, panthenol, certain extracts actually could help the overall skin hydration post cleansing. It just wouldn't be effective enough for you to skip your moisturizer!
  • Preservatives: Given that most cleansers contain a good amount of water, it’s very important to properly preserve them. Fun (?) fact! It’s also a notoriously difficult category of products to preserve. It’s almost a rite of passage for a chemist to have a cleanser formula fail a preservative test and grow a small colony of mysterious living creatures… 
  • Texturizers and boosters: These are ingredients that will help thicken the formula, adjust the foaming experience, and make sure that everything goes well with the packaging.
  • Fragrance: Here’s a little secret, we both like fragrance in our cleansers (though our very own Blank Slate is fragrance free). It’s nice feeling clean and pretty. We really only see this being a deal breaker for sensitive skin types trying to troubleshoot irritation.

Active ingredients in Cleansers? What about AHAs and BHAs?

A very common question that we get is, “do active ingredients matter in a cleanser?” Generally speaking, cleansers are really lousy at delivering benefits for any sort of anti-aging, antioxidant, or skin brightening activity. We’ve definitely stumbled on some wild claims from a few pricey cleansers! Expecting fancy face washes to deliver claims of brighter, tighter skin is sadly flushing dollar bills down the toilet with the expectation of it spitting back out a 3x return -- Odds aren’t great but should you know of such a toilet do let us know.

Take AHAs glycolic and lactic acid for example. These are ingredients that are tested in leave-on cream or serum formats at 8% and up. AHA cleansers most likely have lower than that and you’re washing  it off. So AHA cleansers will absolutely not replace your glycolic serum or mask.

One notable exception is acne washes that contain BHA salicylic acid. These are OTC ingredients so you’re guaranteed at least a certain percentage. BHA washes are not going to be as effective as your topical treatments, but can enhance your overall skincare routine. They also give your routine one more step of actives since tackling acne usually requires a cocktail of treatments.

We did get quite a few questions about how to use cleansers with AHAs and BHA. So let’s tackle these rapid fire style:

    • Can you use a cleanser with AHA & BHA every day? Yes! It is unlikely that the amount of AHA BHA contained is too much for daily use
    • Can you use a BHA cleanser along with other acid toners/serums? Yes! We would just caution against BHA salicylic acid over-layering. Make sure you’re not using a salicylic acid cleanser, treatment, and cream all in the same routine. It could be irritating and ultimately not a very effective strategy.
  • I have oily skin and sal acid doesn't work for me but it’s in everything, advice? Don’t feel like you have to use a specific “oily skin cleanser" to cater to your oily skin needs. There are many more general cleansers that work just fine for cleansers and you’ll avoid the salicylic acid issue.
  • The Great pH Debate of Cleansers

    In addition to taking a closer look at cleanser ingredients, pH is a hotly discussed topic. Your skin pH is slightly acidic ~5. Traditional soap-based cleansers have high pH of 8, 9, and even 10. This leads to many studies and theories that high pH environments are disruptive to your skin’s natural acid mantle. There’s scientific basis to these concerns, especially if you have compromised skin barrier or conditions such as eczema. In fact, there’s a lot of work being done to understand how pH impacts the skin microbiome and its effect on skin conditions such as acne. However, if you have normal skin, your skin pH will self-calibrate and using higher pH cleansers in the long run wouldn’t really hurt your skin. So the key takeaway here is this: if you feel like you’re chronically dry and slightly irritated, consider trying a low pH cleanser. However, if you have been enjoying soap-based or more neutral pH cleansers with no problem, don’t let the interwebs scare you into giving up your holy grail!

    In Conclusion:

    You’ve most likely come to this article because you want to know what makes the “best” cleanser. Sadly there just isn't an objective "best" cleanser per skintype or we would be cashing out on this somehow. But there are cleansers that are a much better fit for your skin than others. While the path isn’t very straightforward, a good starting point is to simply familiarize yourself with your surfactant system and then experiment from there. 


    • Cleansers only need to do one thing. Clean well!...but gently
    • The other ingredients in cleansers aren’t fluff! They can help prevent dryness and create a better cleansing experience. We appreciate hydrators like glycerin, panthenol, niacinamide, ceramides, etc.
    • Most anti-aging, antioxidant, pigmentation fighters, and plant extracts are pretty useless in this format.
    • One caveat is salicylic acid which in some small studies have been helpful in an acne routine.
    • There’s no “best” cleanser, but there are cleansers that “best fit” your skin needs. A good first step is to get a sense of what sort of surfactant system your skin likes or doesn’t like.


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