Last Updated on April 24, 2023 by Verna Meachum

Do you know the difference between hair hydration and hair moisture? If not, you’re not alone. A lot of people get these two terms confused, but they are actually quite different.

In this informative how-to guide, we will break down the differences between hair hydration and hair moisture and teach you how to properly hydrating and moisturizing your locks.

Hair Hydration and Hair Moisture

Hair hydration and moisture are key in any hair care routine, which is why these terms are often highlighted to market hair care products. But what, exactly, do they mean?

These frequently-utilized words strongly attract consumer attention and are often used in product positioning. I mean who doesn’t want to have beautiful, hydrated and moisturized hair? However, they can be a bit confusing.

You’ve probably seen “Hydration,” “Hydrating,” or even “Moisturizing” on shampoo, conditioner, treatment mask, or styling gel before. These products claim that they will boost the water content in your hair when you use them.

As a consumer, we perceive that ‘hydrated’ and ‘moisturized’ means that hair is healthy.

But what does that actually mean? Does water matter for hair quality and health?

What is the science of hair hydration? And, how can we maintain or boost hair moisture levels?

Let’s dive a little deeper into the science of hair hydration and moisturization.

Hair – Water Science

Water is an essential component of life and just like skin, the hair also needs a continuous supply of water molecules for its health.

Hair is a protein fiber that contains approximately 30-35% of water.¹ Hair’s moisture level varies with changing humidity and temperature conditions.

Without water, hair is dry, brittle, porous, and frizzy. Dry hair is difficult to comb, manage, and style and also more susceptible to breakage.

We often measure the lack of hair moisture content by analyzing how porous the hair is, which lets us know how strong it is. ^2-3 

Hair absorbs water molecules during washing (wet stage), as well as from surrounding air under high humidity conditions. Scientific studies have revealed that hair undergoes significant swelling under wet conditions and its diameter increases.⁴

Keratin, a structural protein in our hair follicles, absorbs water via concentration gradient.

More water molecules will enter the hair fiber when there is a higher concentration of water in the surrounding environment, and fewer water molecules will enter the hair fiber when the surrounding environment is dry and has low humidity.

Hydration versus Moisturization: What’s the Difference?

The two terms stand for almost the same thing; however, there is a slight difference. 

• Hydration is the “addition of water molecules“
• Moisturization stands for “addition, as well as preservation of hair water molecules”

In hair care science, both strategies work together to add water molecules as well as preserve the already present hair water molecules.

• Humectants are known to impart water molecules to the hair fiber and boost hair moisture content.
• Emollients can also be called moisturizing agents.
• All natural oils and butter are known to preserve hair moisture content by minimizing the evaporation of water molecules from the hair shaft.

How to hydrate hair

To hydrate hair fibers, the cleansing and conditioning formulation needs to be gentle without containing any harsh chemicals.

Repeated use of certain sulfates are known to cause hair and scalp dryness by stripping off essential lipids from hair and scalp surfaces.

If you have curly hair, you should look for a cleansing formulation that contains glucosides or isethionates to get ultra-hydrating benefits.

Here are a few curly hair shampoos that contain these ingredients are:

Bounce Curl Gentle Clarifying Shampoo

Righteous Roots Clarifying Shampoo

Mielle Organics Pomegranate & Honey Moisturizing and Detangling Shampoo

SheaMoisture Coconut and Hibiscus Shampoo

Avalon Organics Lemon Clarifying Shampoo

CurlMix Shampoo

GIOVANNI Eco Chic Golden Wheat Deep Cleanse Shampoo

AG Balance Apple Cider Vinegar Sulfate Free Shampoo

L’Oreal Paris EverCreme Sulfate-Free Moisture System Intense Nourishing Shampoo

Flora & Curl Cream Shampoo

We strongly advise using a conditioner and mask treatment containing a blend of humectants and cationics.

See below for a list of our preferred hydrating ingredients, under the heading – The Most Effective Ingredients for Hydrating and Moisturizing Hair.’

How to moisturize hair

In addition to hydrating ingredients, emollients offer extra benefits for moisturizing. Natural oils and butter or their derivatives are excellent agents for minimizing water loss from the hair or scalp.

These hydrophobic materials form a water-resistant coating on the hair shaft thus preventing water loss.

Curly-haired people should use light oils on their hair to keep it from feeling heavy and making their curls limp.

An ideal hydrating and moisturizing formulation needs to have both hydrating and emollient ingredients to keep curly hair bouncy and healthy.

How To Know If Your Hair Needs Moisture

The state of your hair fibers can be determined by simply visual observation and feel.

• Do you see any frizz or dullness?
• Is your hair difficult to style and manage on a daily basis?
• Does your hair feel brittle or rough?

If so, it needs hydration and moisturizing.

More common signs that your hair needs moisture:

1. Dryness

2. Rough hair

3. Difficult to comb in wet and dry states

4. Tangles easily

5. Curl knots

6. Split ends

7. Lifeless curls

8. No gloss/Shine

9. High porosity

Hydrating and Moisturizing: Marketing Ploy or Science?

“Hydrating” and “Moisturizing” are terms copiously used for hair care products on the market. But does it mean anything, or is it just a marketing tactic, or does it involve any science?

Did you know that both of these terms are backed by scientific study? That’s right! Studies have shown that using hydrating or moisturizing agents (humectants and emollients) can not only boost hair water content, but also prevent any further water loss.⁵

Most manufacturing companies today back their claims with scientific studies and share their data with consumers through various marketing platforms.

The Most Effective Ingredients for Hydrating and Moisturizing Hair

No matter your hair type, keeping your locks hydrated and moisturized is key to maintaining a healthy head of hair.

But what are the most effective ingredients for achieving this?

Hydrating agents

• Glycerin – traditional humectant, causes tackiness, not highly recommended for curly hair, however, it depends on the formulation.

• Propylene Gylcol – another traditional humectant, no tackiness.

• Betaine – a natural hydrating agent extracted from beetroot, more effective than traditional ingredients. Strongly recommended for curly hair.

• Propanediol – a nature-derived hydrating and emollient with other multifunctional benefits, highly preferred.

Moisturizing agents

• Natural Oils – e.g. coconut oil, olive oil, sunflower oil, soybean oil, cotton seed oil, etc. Light textured oils and butter are recommended for curly hairs, e.g. sesame seed oil, refined olive oil, argan oil, crambe oil, grape seed oil, baobab oil, etc.

• Natural Butter – excellent moisturizing effect with a unique sensational aesthetic feel. Shea butter and Mango butter are preferred for curly hair due to their gentle application and non-greasy texture.

• Natural Waxes – Natural waxes are gentle compared to synthetic materials, Jojoba oil is favorite being a natural liquid wax, with amazing sensorial and moisturizing benefits for skin as well as hair.

• Aloe Vera – a natural moisturizing agent, very gentle and scalp healing benefits, and does not cause any heaviness. 

• Proteins – hydrophilic peptide fragments have a hydrating impact on hair. The key is to limit their dosage; higher concentrations may cause frizz and protein loads. 

• Petrolatum and White Oil – Though, both are excellent moisturizing agents, however, both are petroleum-derived and hence are not recommended for curly hair.

• Silicones – Hi-Tech materials with diverse applications for hair care, however, they are strongly lipophilic, cause build up, and may cause limp curls. Not always recommended.

Conclusion

Hair moisture content is important for its quality, styling, and manageability. Curly hair is more likely to be dry and frizzy, so it’s important to maintain a regular hydration and moisturization regimen.

When combined, humectants and emollients create a formulation that is effective for both hydration and moisturization. These ingredients work to either increase moisture levels in hair or prevent water loss from the fibers.

I hope that this information has helped you to better understand the science behind hydration and moisturization, as well as the most effective ingredients for curly hair.

Whether you’re looking for a hair care product or simply want to learn more about the science behind healthy hair, I encourage you to check out my other blogs.

Thanks for reading!