What Is a Humectant?

The Key Ingredient That Keeps Your Skin Hydrated

Woman moisturizing
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Humectants are ingredients found in lotions and cleansers that hydrate the skin by attracting water molecules like a magnet. Chemically speaking, humectants are hygroscopic substances that form hydrogen bonds with water molecules. This bonding helps moisturize the skin by drawing water from the lower cell layers.

How Humectants Work

Humectants work by pulling water from the dermis (the second layer of skin) to the epidermis (the top layer of skin). This process increases the level of moisture in the stratum corneum, the layer of dead cells that comprise the outermost crust of the epidermis. By doing so, the skin will look less flaky and be less prone to cracking and chafing.

Humectants also encourage the shedding of dead cells (called desquamation) by breaking down the proteins that hold the cells together. If the humidity is over 70 percent, humectants can even draw water vapor from the air to help moisturize the skin.

Types of Humectants

Humectants are used in many cosmetic and personal care products including hair conditioners, body cleansers, facial creams, eye lotions, after-sun lotions, frizz serums, lip balms, and some soaps.

Humectants can either be man-made or derived from nature. Each works differently and may have properties that make them suitable for certain applications. One such example is a type of humectant called a nanolipid gel which is used in many foot and heel balms because of its antifungal properties.

Synthetic Humectants

Synthetic humectants are widely used in personal care products because they are inexpensive to produce and have an inherently long shelf life.

While synthetic humectants are able to lock in moisture to a certain degree, they don't provide any nutrients or noteworthy benefits to the skin. In some cases, they can interfere with the body's own moisturizing mechanism and end up drying the skin over the long term.

Some of the more popular synthetic humectants include:

  • Butylene glycol
  • Urea
  • Glycerin
  • Tremella extract
  • Sorbitol
  • Dicyanamide
  • Sodium PCA
  • Sodium lactate

Natural Humectants

Natural humectants serve a dual purpose: drawing moisture to the surface of the skin while enhancing the skin's own hydrating ability. They do so with substances that stimulate moisture production in the dermis while encouraging the growth of new cells in the epidermis.

Some of the more popular natural humectants include:

  • Hyaluronic acid, a chemical produced by the body that promotes skin repair and the growth of basal keratinocytes
  • Aloe vera, a plant derivative which has anti-inflammatory and anti-acne properties
  • Alpha hydroxy acid, a natural compound found in fruit, milk, and sugar cane that encourages exfoliation and desquamation
  • Honey, a non-oily additive that also contains alpha hydroxy acid
  • Seaweed, a marine plant extract which contains hydrocolloids that aid in healing

Occlusives

If the weather is especially dry (particularly during the winter months), humectants can actually draw too much water from the dermis and cause premature drying. This is especially true with synthetic humectants like glycerin.

To counteract this, some moisturizers will add an occlusive agent that prevents moisture loss by creating an oil or lipid barrier on the skin. Occlusives are generally rich and oily and include such ingredients as:

  • Mineral oil
  • Petrolatum
  • Lanolin
  • Dimethicone
  • Shea butter

While there are a number of two-in-one products that contain both a humectant and an occlusive agent, some people prefer to mix-and-match moisturizers as part of their daily skincare routine. Read the product label carefully when choosing, and always apply the occlusive moisturizer after the humectant moisturizer for the best results.

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  • Sethi, A.; Taur, K.; and Gambhir, M. "Moisturizers: The Slippery Road." Ind J Dermatol. 2016; 61(3):279-87. DOI: 10.4103/0019-5154.182427.