Hyaluronic acid is probably one of the best-known ingredients when it comes to moisturizing your skin. I’ve been in the skin care game for about six years, and I’ve always seen it referenced as a sort of “gold standard” ingredient that was great for anybody.
So, when one of my friends sent me a TikTok video about why hyaluronic acid might be bad for your skin, I did a triple take. Surely not! I thought hyaluronic acid was about as vanilla and safe as you could get! But it is just TikTok, so I went digging through the rest of the internet for actual scientific opinions on the topic.
IS hyaluronic acid bad for your skin? Turns out, the answer isn’t quite as simple as I thought.
I thought hyaluronic acid was about as vanilla and safe as you could get! Turns out, the answer isn’t quite as simple as I thought.
But First: What is Hyaluronic Acid?
Many of you are probably familiar with hyaluronic acid (HA for short), but in case you aren’t, let me give you a quick rundown.
Unlike most skin care acids, HA is a super hydrating molecule. It doesn’t exfoliate, so it’s not technically an active like other acids.
Its claim to fame is its ability to hold up to 1,000 times its weight in water. This is obviously important for keeping your skin plump and hydrated. It’s also a molecule that is found naturally in our bodies, but production declines as we age. This is part of the reason why aging skin starts to look duller and less bouncy, and it’s why wounds take longer to heal for older people.
While topical HA doesn’t penetrate down into the deepest layers of our skin to reverse signs of aging, it DOES add noticeable hydration to the upper layers of our skin, which is why it’s so appealing in skin care formulations.
Molecular Weight Matters
So then, if HA is a safe and effective moisturizer, how can it possibly be controversial?
The issue is that there are people who have started noticing red, irritated, and inflamed patches on their skin, and hyaluronic acid has been the culprit. I was just as surprised as you are!
After I did some digging, though, I understood that the problem isn’t all HA molecules. (Thank goodness! I can’t handle anymore life-altering revelations, 2020.)
Remember when I mentioned earlier how HA doesn’t penetrate into the skin? This is because most HA molecules are way too big to do so. Since HA can’t get past the surface of our skin on its own, scientists have come up with a few ways to get around this so that we can get that sweet, sweet deep hydration.
High Molecular Weight HA
When HA is in its natural state, it’s pretty huge (as far as molecules go). This is called “high molecular weight hyaluronic acid” (HMWHA for short).
We like this guy. He’s anti-inflammatory, great at surface-level hydration, and pretty universally safe. The ultimate Boy Next Door of moisturizing.
We like HMWHA. He’s anti-inflammatory, great at surface-level hydration, and pretty universally safe. The ultimate Boy Next Door of moisturizing.
This type of HA creates a kind of “hydration film” on the surface of your skin that draws in moisture and helps to plump up any fine lines, wrinkles or dull spots.
You’ve almost certainly seen this ingredient in your serums and moisturizers. This is a salt form of HA, but for our purposes, this really just means that this form of HA is a little smaller than its cousin.
In a lot of cases, when you see “hyaluronic acid” on a product label, the actual ingredient in the formula will be sodium hyaluronate. This is because this type of HA is cheaper and able to penetrate more deeply into your skin, which usually means you get better results.
The molecules are just small enough to be able to squeeze past the surface layer of your skin, but they’re still large enough that they don’t go very far down. Because sodium hyaluronate can pull moisture into your skin more deeply, it helps to provide longer-lasting hydration.
Sodium hyaluronate is also generally considered by dermatologists to be safe and non-irritating.
Low Molecular Weight HA (LMWHA)
And now we’ve come to the molecule that’s the source of all of the controversy!
The other solution that scientists came up with to help HA penetrate more deeply into the skin was to basically chop the huge molecules up into much smaller ones. This is how we get low molecular weight HA.
These molecules are so much smaller than the other forms of HA that they’re able to get all the way into the lower epidermis. This provides lasting hydration and typically improves skin function when used long-term.
Unfortunately, this type of HA can also set off an inflammatory response for some people. While there are studies that show how effective low molecular weight HA can be, especially for people with certain skin conditions, it also has the most potential for irritation.
Remember when I said that HA is found naturally in our bodies? This includes HMW and LMW hyaluronic acid. So what gives?
Hyaluronic acid is an important part of the wound healing process, and LMWHA is responsible for signaling to the body that an injury needs to be mended. This signal comes in the form of—you guessed it—inflammation.
So, while LMW hyaluronic acid has the potential to help, it can also cause a negative reaction for some people. These reactions typically show up as redness, itching, and sensitivity. If you’re curious, this article does a great job of explaining how this type of irritation can happen, and a few experts weigh in, too!
While low molecular weight hyaluronic acid has the potential to help, it can also cause redness, itching, and sensitivity for some people.
Is It Safe to Use Hyaluronic Acid Products?
The short answer? Yes, absolutely!
Before you panic and toss anything with HA in it, remember that “your mileage may vary” is the number one rule of skin care! Plenty of people are able to use all kinds of HA products with no issues at all.
Additionally, not all HA products are created equally. If one type of product is irritating your skin, it might take a bit of trial-and-error to determine if it’s the HA, the formula, or another ingredient that’s causing the issue. For example, I love the CosRx hyaluronic acid essence, but The Ordinary’s HA formula doesn’t agree with my skin.
If you’d prefer to avoid LMWHA, know that most brands will highlight its inclusion in their formulas. This makes it easier for you to spot while shopping!
It’s also important to remember that how you use HA matters too. It works best on damp skin, and it should be used alongside other hydrating and occlusive products so that it can really retain that moisture you’re working so hard to give your skin!
I know I threw a lot of info at you all at once, so let me hit the highlights one more time:
- Hyaluronic acid is an amazing hydrator that’s found naturally in your body. It helps your skin stay plump, moist, and healthy.
- Natural HA molecules can only sit on the surface of your skin, so scientists have found alternative ways to help HA permeate the skin a little deeper for more effective hydration.
- All forms of HA are safe and effective for most people, but low molecular weight HA has the potential to cause irritation for some people because it penetrates more deeply than other forms.
- Product formulation is just as important as how you use the products. Remember to provide plenty of extra moisture to your skin when using HA products for the best results.
What’s your experience with hyaluronic acid? Did you know that there was even a debate? Tell me about it in the comments!