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Curly Nikki

Thick or Thin Moisturizers: Which Is Better?

By January 27th, 2021No Comments
Thick or Thin Moisturizers: Which Is Better?

As a cosmetic chemist, I am always looking for novel ways to deliver the best results to my target consumer using techniques and delivery methods that make her regimen more convenient. I often relate this process to be very much like cooking. There are hundreds of ways to make a cake, and even the smallest of changes to the recipe or procedure can change the end result. Similarly, hair and skin products are made up of a number of different types of ingredients that have different functions and purposes, and together they deliver certain results that they couldn’t deliver alone.

It is commonly said that you can’t judge a book by its cover and this also applies to hair products. One misconception that I often hear is the consumer’s correlation between product consistency with overall effectiveness of the product providing moisture and slip to the hair. However, consistency (or viscosity which is the technical term) is only one of many factors that contribute to the effectiveness of a product. The consistency of a product is commonly used to improve the delivery of a product or to help provide weight to the hair mold it into the shape or style that the user is attempting to achieve. Although emulsifiers and thickeners used to thicken products are often great conditioning agents, they are not necessarily the primary conditioning agents in the formula.

Read On!>>>
What’s really happening with thick products?
Many ingredients lay on top of the hair fiber to help smooth the cuticles to lay flatter, which attributes to the hair feeling smoother, softer, and looking shinier. Thicker products commonly have ingredients that serve this function, but some of the best conditioning polymers that provide the ideal tactile feel of the hair do not drastically change the consistency of a product and can be found in thinner products such as conditioners and foams. We often associate a product’s effectiveness by determining if the product absorbs into the hair or “penetrates” the cuticle layer, but the truth is that the molecular size of most ingredients is too large to bypass the openings on the cuticle layer. Don’t be alarmed. This is not necessarily a bad thing because ingredients that are substantive to the outer portion of hair fiber are commonly what provide the slip and softness that consumers often associate with moisture.

Confusing Softness for Moisture
Here’s a common misconception that most consumers don’t realize…scientifically the only ingredient that can add moisture to the hair is water, whether it be in liquid or vapor form. As consumers, we often confuse moisture with softness or lubricity. Due to the fact that this is a common and universally accepted concept in the industry, brands often promote and make claims around products being more moisturizing even though what the consumer is feeling may not technically be considered moisture.

Moisture is still an important variable in maintaining healthy hair, but the trick is to infuse as much moisture in the hair and seal it in using non-penetrable ingredients that are light enough to not weigh the hair down, but substantive enough to last for long periods of time to provide the softness we crave.

Why thickness doesn’t guarantee effective detangling
The pH of a product is also an extremely important variable in product formulations because the pH of the hair can alter the permeability level of the cuticle layer. An easy way to explain pH is a measure of the level of acidity or alkalinity in an aqueous solution. The pH scale runs from 1 – 14, with 7 being the neutral point. Therefore, anything under 7 is considered acidic and anything above 7 is considered alkaline. In acidic conditions, the hair cuticle layer constricts causing the cuticle scales to close tighter, making the hair smoother, less permeability, and easier to detangle, because the strands have lesser friction with a closed cuticle. In alkaline conditions, the hair swells and permeability is increased due to the cuticles expanding or “lifting” creating more space for molecules to penetrate between the cuticle layers into the cortex. The average pH of healthy hair is approximately 4.5 – 5.5, making hair slightly acidic. Therefore, products with higher pH levels (including water which has a pH of 7) can cause the hair to swell causing this effect. Conditioners are products that often have a lower pH (an average of 4 – 5) which help the cuticle layer to close back after being exposed to higher pH conditions.

Thickness doesn’t guarantee penetration
The molecular weight (MW) of an ingredient varies and determines its size. The larger the MW, the less likely it is able to penetrate the cuticle later. The opening on the cuticle layer varies by individual, but in its resting state only allows for molecules smaller than 10 Daltons to penetrate. In a swollen state after hair has been exposed to very high pH conditions, molecules as large as approximately 500 Daltons may be able to penetrate. To provide some context, one water molecule is approximately 180 Daltons. There are very few ingredients that can penetrate the cuticle layer, which is why it is critical to formulate with materials that are highly substantive to the hair fiber to help lock moisture.

As you can see, there are a number of scientific variables happening at a microscopic level that contribute to how a product performs. As consumers, we can easily start to translate common product experiences into what we perceive to be “product laws,” but this can handicap us from being open to experiencing unconventional products that may deliver the same or better results using different methods. There are always advances in cosmetic science and the ability to combine new and novel ingredients together to perform in unique ways. Therefore, it is important to keep an open mind when trying new products because a new combination of ingredients that may look and feel different from the norm could be easily become your new favorite product!

Thin, Moisture-Rich Products
These products may not feel thick, but in our experience they are just as moisturizing as your thicker formulas.
SheaMoisture Jamaican Black Castor Oil Leave-in Conditioner
Creme of Nature Argan Oil Perfect 7 Leave-in Treatment
Karen’s Body Beautiful Sweet Ambrosia Leave-in Conditioner
Yes to Cucumber Color Protection Conditioner
ApHogee Curlific Moisture Rich Leave-in Conditioner
Curl Junkie Curl Assurance Smoothing Lotion
Koils by Nature Moisturizing Shealoe Leave-in Conditioner

Do you typically choose products based on thickness?

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