We all know that what’s in our products plays a critical role in helping us achieve our skincare goals. Among the laundry list of ingredients, three terms often come up: humectants, emollients, and occlusives. Though these words are often used on BeautyTok, remembering what each one is—and what makes them unique—can be tricky. To help unravel the mystery, we asked three skin experts for a complete breakdown of humectants, emollients, and occlusives.

What Is a Humectant?

Humectants are ingredients used in topical skin care products. Their primary function is to boost hydration by drawing moisture into the skin. “Like little hydration magnets, they attract water to the skin’s surface, drawing it deep beneath it,” Temple says.

But humectants don’t just attract water—they hold onto it tightly. In fact, that’s what makes them so unique. “They pull moisture from the environment, bind water to the skin, increase hydration levels, and plump the skin, helping skin look and feel more supple,” Dr. Boakye says.

That said, they are ideal for everyone, but especially for those with dry, mature, or acne-prone skin. Another important point to note about humectants is that they include a variety of ingredients you’re likely already familiar with. “Glycerin is the gold standard hydrator, as well as hyaluronic acid, algae and seaweed extracts, and propylene glycol,” says Temple. 

What Is an Emollient?

Unlike humectants, emollients soften the skin from the outside by lubricating the skin’s surface and protecting its barrier. “They mostly work on replenishing the lipid supply of the outermost surface skin layer,” Susca says.

She explains that, although they are the opposite of humectants, they still depend on them to work optimally. “Emollients don’t hydrate the skin on their own and need humectants to attract moisture,” she adds.

Temple further explains that most moisturizing products combine emollients and humectants. “There are thousands of combinations that determine the differences between rich moisturizers like creams and lotions and lightweight formulas such as fluid serums,” says Temple.

What Is an Occlusive?

Occlusives also sit on top of the skin and, like emollients, their primary function is to prevent water loss. According to Dr. Naana Boakye, they play a critical role in repairing and protecting the skin barrier. They’re basically a sealant, trapping moisture beneath the skin’s surface. In that vein, they neither hydrate nor moisturize it.

“With the use of an occlusive, hydration is kept locked within the skin while also acting as a protective barrier to the outside world, preventing microbes from entering,” Susca says,

So what makes an occlusive different from an emollient? Consistency. As Dr. Naana Boakye explains, occlusive ingredients are composed of non-polar hydrocarbons, which do not interact with water. “Think mineral oils and squalene. Other common ingredients include vegetable oils, natural waxes, silicones like dimethicone, and sterols such as cholesterol and ceramides,” she says.

Should I Add Them All to My Routine?

Given the unique properties of these ingredients, it’s easy to see why your routine would benefit from using them all. However, according to the experts, a combined approach is better than applying multiple layers of product. “You probably don’t need to use them all as separate products, but your skin will benefit from all three functions,” Dr. Boakye says. “You want hydration, barrier repair, and protection working together. Fortunately, you don’t have to work too hard to reap the rewards, since many skincare products contain some blend of these ingredients. 

The Final Takeaway

If you are working with separate products, it’s important to consider their consistency. Humectants are necessary for all skin because they draw water into the skin. They are typically lightweight and should therefore be applied first. Emollients come next. They work in tandem with humectants and prevent water loss. Occuslive products are the thickest of the three and should be used last, allowing them to act as a seal to lock in moisture. “While all three steps aren’t always necessary, they can work synergistically depending on the skin’s needs and environment,” Susca adds.