Hyaluronic Acid

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Few skincare ingredients have received the same kind of love and universal approval from dermatologists and skincare enthusiasts alike as hyaluronic acid acid does—and for good reason. No self-respecting skincare routine is complete without this magic, moisturizing ingredient. Here's why.

What Is Hyaluronic Acid?

The name "hyaluronic acid" sounds kind of scary—when we think of acids, it's easy to think of a vat of bubbling green liquid that a Bond villain would threaten to dissolve someone in. However, don't be fooled: hyaluronic acid is a naturally-occuring substance, somewhere between a liquid and a gel in texture, which our own bodies produce to help with moisture retention. Half of our own, naturally-occurring hyaluronic acid is found in the skin, and the rest can be found in our joints and eyes, keeping both lubricated. Hyaluronic acid is a superhero when it comes to skin moisture because it binds to water molecules like nobody's business, resulting in super-plumped skin. A single molecule of the stuff can retain up to 1,000 times its weight in water—and is largely responsible for dewy, smooth complexions.

As with so many of the good things our bodies produce, as we age, the amount of hyaluronic acid we make begins to decline—and skin hydration needs a little help. This is where products like hyaluronic acid serums can work their magic and boost your skin’s moisture levels. But not all hyaluronic acid formulations are the same, and it’s important to understand the differences to make sure that you’re using actually getting the skin-saving effects of this ingredient that you need.

Forms Of Hyaluronic Acid

There are several forms of hyaluronic acid, each with its own properties and effects on different skin types. To better understand the difference between them, it’s a good call to take a quick dive into their makeup. The benefits of hyaluronic acid largely depends on its molecular weight. Hyaluronic acid molecules are measured in Daltons (kDa) and most can be categorized as low, medium, and high weight.

Lower-weight molecules (under 1000 kDa) will go deep down, addressing fine lines, wrinkles, and skin elasticity. These molecules are here to stay. and have long term benefits, especially for aging skin

Medium-weight molecules (1000-1800 kDa) have a slighty longterm, effect and help you retain moisture slightly below the skin’s barrier. 

Higher-weight molecules (more than 1800 kDa). These can’t penetrate the skin deeply, and will stay on the skin’s surface. However, these heavier molecules are valuable, too: here, they can help the outer skin layer hold on to the moisture it already has, though only in the short term as it will be washed away fairly quickly. Because this type of hyaluronic acid works on the surfaces, it’s great for people with sensitive skin, and has anti-inflammatory properties.

The best hyaluronic acid serum will use a formulation that includes molecules of all three weights, addressing moisture loss, wrinkles, and elasticity across all skin layers. There are also super low-weight molecules, but those formulations can cause inflammation and redness, and are best used only by a dermatologist.

Hyaluronic Acid Concentration

The recommended concentration of hyaluronic acid in skincare products is around 2%. Although it may seem counterintuitive, too-high concentrations of hyaluronic acid can lead to the acid molecules extracting moisture from your skin.

Does Hyaluronic Acid Have Any Side Effects?

Topical application of hyaluronic acid is deemed safe by the EWG Cosmetic Database

Plus, hyaluronic acid is also known for its ability to play well, and even increase skin’s absorption of other good-for-you ingredients. A great hyaluronic acid serum is one of the few skincare products that won’t destabilize Vitamin C, for instance. 

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