Hyaluronic Acid has been an additive in skin care for a long time, but it’s having a moment now. And there's more to it than you might think.
What is it?
The name hyaluronic acid (HA) is derived from hyalos, which is Greek for ‘glassy’,and uronic acid because it was first isolated from the vitreous humour (liquid part of the eye) and possesses a high uronic acid content. It’s a clear, natural gel-like substance found in skin, joints and eyes. Actually though – and this is key – that gel is really hyaluronic acid dissolved in water. In its pure form, HA is a crystalline powder.
Hyaluronic acid exists naturally and plentifully in young skin. It lives in the matrix, or fleshy deep layers. As with all things skin related, it begins to degrade with age and sun exposure. The only way to get more hyaluronic acid into the deep layers of the skin is to inject it. That’s worth repeating – to plump skin for an extended period of time, hyaluronic acid would have to be injected*. It is a very large molecule and is too large to penetrate the skin. You may read about large and small molecular weight HA, and claims that the smaller forms can penetrate deeper into the skin. If this is so (and we are still looking for research to prove it), it will only go a few layers deeper in the epidermis, but still cannot enter the dermis where it occurs naturally.
But fear not - HA does have a benefit in topical skin care when used properly!
If you want the short version, feel free to watch this video by dermatologist Dr. Sam Bunting. For more information, read on.
Why is it so popular in skin care?
HA has been an additive in skin care for a long time, but it’s having a moment now. In particular, sodium hyaluronate (the salt of hyaluronic acid) is an ingredient that you will often see on skin care labels. This chemical form is smaller than the large HA molecules we discussed earlier. Its great strength is that it is a powerful humectant – which means it attracts water. It then can bind, or hold onto, up to 1,000 times its weight in water! So it acts like a sponge. A super sponge.
This hydrating property makes sodium hyaluronate an excellent skin care ingredient because it helps to reduce water loss. The result is a slight temporary swelling of the skin that will help to minimize the appearance of wrinkles and fine lines. Well-hydrated skin also handles exposure to the sun and other environmental assaults better. You’ll find many claims attributed to sodium hyaluronate and HA, but there are no published studies regarding its ability to rejuvenate skin or help boost collagen levels – so watch out for unsubstantiated claims.
This binding of water is what yields the dewy, plumped effect from products with HA in them (it’s temporary, but real.} But there’s a catch! As water evaporates and the film of HA becomes dry, it will draw moisture from one of two places: either the air (if humid enough) or the deeper layers of your skin. Therefore, using hyaluronic acid products without an emollient to lock in water is only really productive for plumping if you are in a humid environment.
HA does not add hydration to the skin—a common misconception - unless it remains more wet than the inner layers of the skin. This means, 1) it’s best used on damp skin to bind water, 2) an emollient moisturizer/oil is needed on top to keep that water from evaporating, and/or 3) it will work best if rehydrated periodically with misted water like an Evian Brumitaseur or the like.
Now, the fact that HA can help keep your skin dewy and moist without a lot of oil is a good thing for oily and blemish prone skin. Sometimes oily skin becomes dehydrated because of drying anti-acne cleansers and medications. HA can be a great solution, therefore, for people struggling with oily skin.
What can and can’t it do?
HA doesn’t behave like other acids we use in skin care like glycolic or salicylic acid. It doesn’t dissolve anything. It’s actually a rather benign and mild ingredient. Its main use is as a humectant to boost the dewiness of skin --- as long as there is sufficient water around. It is very much like glycerin in this respect. Glycerin is less expensive, super effective, and can be easily made from plant sources. HA isn’t always from plant sources – something to keep in mind. The main source of HA for a long time has, in fact, been rooster combs. Yes, those wobbly things on top of their heads. Fortunately there are non-rooster sources of hyaluronic acid too.
How is HA used?
We see HA being used in three ways – as injectable fillers (Restylane, Juvederm), as an ingredient in moisturizing products, and as a standalone serum. These each have their uses depending on your skin’s condition and the environment in which you live.
For deep wrinkles and loss of volume, of course, injectable HA is a great solution. It is bio-compatible and for most people, slowly degrades over time without unpleasant side effects.
In topical products, HA can be a solo ingredient or mixed with other ingredients. Fortunately, it plays well with other ingredients and therefore can be added to other active or basic products without interfering with their function. It is very easy to add to moisturizing products… whether you DIY or buy a good hydrating moisturizer.
We are seeing a lot of standalone HA serums coming on the market…. Which leads us to ask:
Should I use a standalone HA serum or a combination product?
Here’s another key takeaway: since HA binds so much water, it can only be used in very low percentages – as in 1-2%. So if that serum label says ‘100% HA’, it’s misleading. 100% HA is a solid heap of dry powder. Even at 20% it will make a hard gel block. You have to get down to 2% or under to have a gel or serum texture. So back to that bottle of HA serum ….. it’s really more like 99% water and 1% HA.
Here’s a short video showing a 1% solution of HA and water being made so you can see how thick it becomes even at low concentration.
(Video courtesy of Chemsources:Thailand )
Since the water that HA pulls into your skin needs to be kept in, you’ll almost always want to use a moisturizer or oil over it. So we would ask if one only needs 1% HA in a formula to be effective, why not look for a moisturizing product with HA in it? That way you have one step, not two, and will likely save money as well. We recommend reading labels and looking for HA as an ingredient in an otherwise moisturizing product rather than necessarily investing in a separate HA product.
We have several key takeaways from studying HA, how it performs and in what conditions it works best.
- High humidity helps HA to do its plumping/hydrating job without added fuss
- Use of HA in a dry environment will work best when sealing it and water in with an emollient
- Beware of products labeled 100% Hyaluronic Acid – keeping in mind that they really mean ‘just hyaluronic acid dissolved in water.’
- Unless you suffer from very oily skin, an HA serum on its own will probably not give you the super smooth, hydrated look you may be after. It therefore makes sense to look for either a moisturizer to go over it or a combination product that includes HA in a reasonable concentration (0.5-2%).