Humectants are substances that attract water. In personal care products, they help hydrate the skin, hair, or nails. Hyaluronic acid and glycerin are examples of humectants.

The benefits of humectants depend on the ingredient. In general, however, the effects include relief of dry skin, reduction of thickened skin, and strengthening of the skin barrier.

Humectants are different from emollients and occlusives. These ingredients are also in many personal care products for dry skin. However, they work by forming a barrier over the skin, trapping moisture inside rather than attracting it. Oils, butters, and waxes, such as lanolin, are examples.

This article discusses humectants and the products that contain them, as well as examples and benefits. It also outlines the difference between a humectant and an emollient and an occlusive.

Humectants are ingredients that attract and bind water. In skin care, they draw water from the deeper layers of the skin to the outermost layer. If air humidity is higher than 70%, they also draw water from the surrounding environment to the skin.

In hair care, humectants perform a similar function. They attract water to the hair shaft, helping keep it hydrated.

Examples of products that can contain humectants include:

Many ingredients act as humectants, including:

All humectants have slightly different properties. Below is some of the research on common humectants.

The outermost layer of the skin, the stratum corneum, has an important function of serving as a barrier. It slows the evaporation of water from the skin and helps protect against microbes.

A 2021 review notes that urea helps enhance the stratum corneum by increasing hydration and improving the skin barriers integrity. Because of this, it has a long history as a skin care ingredient.

Urea can help with many skin conditions, such as:

An older 2013 study evaluated the effects of once and twice daily applications of a humectant-rich moisturizer containing 15% AHAs and 15% urea. The study involved 62 participants. Of them, 12 had no skin conditions, and 50 had hyperkeratosis, or thickened skin, on the feet.

Among the participants with hyperkeratosis, the results indicated that the moisturizer:

The participants with no skin conditions experienced an improvement in skin barrier function.

As people age, they have a higher risk of developing dry skin. A 2019 review analyzed databases from 19902018 that dealt with skin conditions of people over the age of 50 years. It found that leave-on products containing lipophilic humectants decreased skin dryness and itching. A lipophilic humectant is one that manufacturers have dissolved in fats or lipids.

Additionally, a 2021 research article notes that the humectant lactic acid can relieve rough, dry skin at concentrations up to 12%.

Older research from 2012 states that hyaluronic acid helps speed up wound repair and reduces scar appearance. These benefits stem from the humectants actions of promoting new blood vessel formation and increasing fibroblasts, which are cells in connective tissue that produce collagen and other fibers.

Another popular group of ingredients for moisturizing the skin and hair are emollients and occlusives. These work by creating a barrier, often consisting of a plant oil or butter, over the skin or hair. Instead of attracting moisture, they trap it beneath this barrier, preventing it from evaporating.

In comparison to humectants, emollients and occlusives tend to be thicker, heavier ingredients.

A 2017 study notes that emollients consist mostly of lipids, such as natural oils and waxes. They increase skin:

Examples of emollients include:

Occlusives are mostly oil-based. They provide a layer on the skin surface that helps protect against water evaporation. This preservation of skin hydration helps prevent dry skin and eczema, reports research from 2018.

Examples of occlusives include:

Whether a person should use humectants, emollients, or both depends on their skin type.

Emollients and occlusives tend to be heavier ingredients. Some add more oil to the skin and hair, which can be helpful for those with dry skin. However, individuals with oily skin or hair may find this unhelpful.

Some emollients and occlusives are also comedogenic, which means they have the potential to block pores and cause acne.

Humectants, on the other hand, tend to be noncomedogenic and non-oily. They can add hydration without the use of heavier ingredients. Some also have other benefits. For example, AHAs are also exfoliants.

According to the American Academy of Dermatology Association, a person with oily skin should choose skin care products that have oil-free and noncomedogenic on the label. People with hair that gets greasy quickly may prefer to look for hair products that do not contain much oil, if any.

In contrast, someone with dry skin or hair could benefit from products that contain humectants, emollients, and occlusives.

Learn about skin types and how to identify them here.

A humectant is a substance that draws water into the skin, hair, or nails. In the skin, this may come from the deeper layers, or from the air if it is humid enough. Humectants are useful for adding hydration without feeling heavy or oily.

Humectants include ingredients such as glycerin, urea, AHAs, and hyaluronic acid. People can find them in a wide range of personal care products.

Aside from humectants, personal care products often contain emollients and occlusives. While humectants provide hydration, emollients soften the skin, and occlusives help prevent water in the skin from evaporating.

People can consult a dermatologist to identify their skin type and find the best regimen for them.

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Humectant: Examples and benefits for skin, hair, and lips - Medical News Today