Humectants for hair can be beneficial or cause unwanted effects, depending on when they are used. Once you know how humectants work, you can use the knowledge to help your hair attract and retain the right moisture levels.
Humectants for hair attract and absorb moisture from the surrounding environment. These hair hydrators help moisturize dry, thirsty hair. However, humectants can cause frizz if the humidity is too high or cause dryness if the humidity is too low. Common humectants for hair include hyaluronic acid, glycerin, and alpha hydroxy acid.
What Are Humectants?
Humectants are water magnets.
They pull water from your local environment into your hair. Humectants for hair are important because healthy hair needs moisture to retain strength.
Although your scalp’s sebaceous glands produce sebum, this natural oil isn’t always able to travel completely down the hair shaft, especially if the hair is curly.
That means the entire hair shaft doesn’t have the protective coating it needs to lock in moisture. This makes hair prone to dryness, brittleness, and breakage.
Fortunately, humectants can attract moisture to your hair. They bind water molecules along the hair shaft and hold them there.
Humectants are not the same as emollients or occlusives, which are other types of moisturizing agents.
Occlusive ingredients like petroleum jelly and waxes create a physical barrier that prevents moisture from escaping.
Emollients like butters and oils also help lock in moisture while softening and nourishing hair.
Types Of Synthetic Humectants
Synthetic humectants are man-made. They tend to be more stable, cheaper, and have a longer shelf-life.
- Butylene glycol
- Synthetic propylene glycol
- Sodium lactate
Types Of Natural Humectants
Natural humectants are derived from nature. Besides hydrating hair, they tend to have additional benefits.
For instance, aloe Vera is a good humectant for hair because it has anti-inflammatory properties that boost the health of your scalp.
- Hyaluronic acid
- Seaweed extracts
- Aloe vera
- Alpha hydroxy acid
- Elastin and collagen
How Do Humectants Work For Hair Care?
Humectants Are Hygroscopic Substances
Chemically speaking, hygroscopic substances can attract water molecules by absorption or adsorption.
This happens because water molecules (formula H2O) contain oxygen atoms with a slightly negative charge and hydrogen atoms with a slightly positive charge.
Because opposites attract, the negatively charged oxygen atom of one water molecule will attract the positively charged hydrogen atom of another water molecule, forming what is known as hydrogen bonds.
Water can also form hydrogen bonds with other polar molecules. For instance, the molecules in humectants contain polar OH/hydroxyl groups.
The polar hydroxyl groups (also known as water-loving sites) can form hydrogen bonds with water molecules.
Humectants Bind Water Via Adsorption
Humectants bind water to the hair shaft through a process known as adsorption.
Adsorption is when atoms adhere to the surface of a material. It’s different from absorption, which involves a substance dissolving in another material.
So humectants essentially adsorb water through the process of hydrogen bonding. The formed hydrogen bonds are strong enough to improve water retention, making humectants ideal for dry and thirsty hair.
A humectant’s effectiveness depends on the number of polar groups or water-loving sites it contains.
Some humectants have many water-loving sites. For instance, hyaluronic acid is a powerful humectant for hair. It’s capable of binding up to 1000 times its weight in water.
Benefits Of Using Hair Products With Humectants
Humectant-containing products offer the following benefits for your hair:
Hydrates the Hair And Scalp
Humectants hydrate your hair, making it soft, supple, and more manageable. In addition, they attract and bind moisture to the scalp, keeping it hydrated and healthy.
Improve Water Retention
Humectants are used in many water-based hair products to ensure that moisture is not delivered temporarily. This helps maintain your hair and scalp’s critical moisture content.
Moisturizes High Porosity Hair
Humectants help to moisturize high porosity hair by filling in the gaps. Sometimes, high porosity hair has trouble retaining moisture, making it dry and brittle.
Plumps Up Hair
The water-binding properties of humectants can help to plump up lifeless hair.
For instance, hyaluronic acid is a powerful hydrator that plumps the hair shaft, so hair appears fuller and softer.
When Not To Use Humectants
The best way to know when to avoid humectants is to monitor the dew point.
This is the temperature at which atmospheric water vapor condenses. If the dew point is about 35 °F and below, humidity is low, so avoid humectants.
That’s because the air is colder and drier, and the humectants will pull water from the inner part of the hair shaft, causing dryness, split ends, or breakage.
Instead, apply a sealant like shea butter to lock in moisture in low humidity conditions.
If the dew point is 60 °F or above, the humidity level is high, so humectants are likely to absorb too much water.
The cuticle lifts as the hair shaft swells, causing the hair to lose shape and become frizzy. Curly hair is more prone to “flyaways” because of its high porosity.
When you’re in a high-humidity environment, it’s better to use an anti-humectant.
Anti-humectants prevent hair from absorbing moisture from the environment, helping it retain its definition. The best time to use humectants is when the dew point is between 35 °F and 50 °F.
How Do I Know If A Product Contains Humectants?
Most quality, humectant-containing products contain the following natural humectants:
- Hyaluronic acid/Sodium hyaluronate/Glycosaminoglycan
- Aloe vera
- Natural glycerin
- Alpha hydroxy acid
It’s best to avoid products that contain preservatives and chemical additives as these can irritate the scalp and damage hair.
You can also find the following humectants in hair products:
- Hydrolyzed proteins. Elastin, Collagen, Silk Keratin.
- Ethers. Teareth-x, PEG-x (polyethylene glycol), Laneth-x, Isolaureth-x, Laureth-x, Isoceteth-x, Silicone Copolyols.
- Sugars. Sorbitol, Polyglyceryl sorbitol, Glucose, Fructose, Xylitol.
- Biological Humectants. Panthenol, Sodium PCA, Inositol, Glycogen.
- Diols and triols. Triethylene glycol, Dipropylene glycol, Propylene glycol, 1,2,6 hexane triol, Butylene glycol, Glycerin, Erythritol, Capryl glycol, Phytantriol, Hexylene Glycol, Hexanediol or -triol beeswax.
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