22 June 2022
Hyaluronic acid (HA)- as far as skin care ingredients go, no active ingredient has stood the test of time like this hydration powerhouse. Beauty savvy readers will know that HA is a water loving ingredient in skincare because of its powerful ability to attract and bind to water molecules and moisturise the skin. It also has anti-aging benefits and is suitable for most skin types including acne and oily skin. This broad and versatile appeal of HA makes it a popular choice in moisturisers and hydrating serums.
HA is a fixture in the skincare routine of many; and you can easily find this humectant in hydrating serums and moisturisers. More recently, HA has also made its way into the world of injectable moisturisers (e.g. Profhilo and Skinboosters) due to its moisture boosting benefits to the dermis.
In the first of this 3 part blog post on how to keep skin moisturised, I’ll be reviewing everything that you need to know about hyaluronic acid in skincare. The first part of this blogpost will focus on:
• What is hyaluronic acid?
• Why is replacing hyaluronic acid in your skin essential>
• The benefits of using hyaluronic acid
• High vs low molecular weight hyaluronic acid: differences and benefits
• Tips for choosing hyaluronic acid skincare products
• How to incorporate hyaluronic acid into your daily routine
In my next blogposts, I’ll be reviewing some hyaluronic acid skincare products and the different types of injectable moisturisers and the differences i.e. Rejuran Healer vs Profhilo vs Skinboosters. Stay tuned for these upcoming reviews.
Update: Part 2 and 3 of this series on hyaluronic acid in skincare are up
First up, hyaluronic acid isn’t really an acid, in the technical sense that alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs) are acids. HA moisturises the skin; it does not exfoliate the skin or cause dryness the way AHAs and BHAs do.
Hyaluronic acid is in fact, a sugar. HA is a large sugar molecule that is made up of smaller sugar units. These sugar units are repeated many times- thousands in fact- to create a large molecule that binds to even more water molecules in the skin, thereby giving skin its firmness and turgor. It is estimated that HA molecules can bind up to 1000x their volume in water1!
The molecular structure of HA allows it to attract water molecules. This gives it its hydrating effect in skincare and injectable moisturisers
Hyaluronic acid is naturally present in the epidermis and dermis of the skin2. Majority of the HA in our skin lies in the dermis1.
Hyaluronic acid has several essential functions in the skin besides keeping the skin moist and firm3-5:
• Water balance and skin hydration
• Skin regeneration
• Skin repair and prevention of scar formation
• Skin immunity
As we age, the levels of HA in the epidermis and dermis of the skin decrease5. The decrease in HA in both the epidermis and dermis causes some of the signs of aging: dryness, roughness, thinner skin, loss of firmness and elasticity, fine lines and wrinkles4. Replenishing hyaluronic acid in the skin -either with skincare applied on the skin or injectable skincare- reverses these signs5-10.
You can replenish HA in the skin by:
• Applying skincare containing hyaluronic acid
• Injecting hyaluronic acid directly into the dermis i.e. Injectable moisturisers/ skincare
Let’s first look at the science of and details of hyaluronic acid in skincare and the differences between applying vs injecting HA into the skin.
Due to its ability to attract water molecules many times its weight, HA is commonly found in moisturisers, hydrating serums and masks. Depending on the sizes of the HA molecules in the skincare product, the molecules ‘sit’ at various depths of the epidermis to moisturise the skin.
Hyaluronic acid in skincare products- even at a concentration of 0.1%- moisturises the skin and has anti-aging benefits5-7. As a skincare ingredient, HA is also suitable for most skin types including people who have oily skin and acne.
It is also a safe ingredient- hyaluronic acid is biocompatible, non-immunogenic and biodegradable10. These safety features and its remarkable ability to hold on to water molecules are reasons why HA is commonly used in skincare, injectable moisturisers and dermal fillers.
However, one of the limitations of applying HA onto the skin is that the HA molecules (including low molecular weight HA) are too big to pass through the basement membrane of the skin that separates the epidermis from the dermis. This means that HA in skin care remains on the epidermis of the skin; it does not get absorbed into the dermis of the skin11,12. To replenish HA the dermis, injecting hyaluronic acid directly into the dermis (i.e. injectable moisturisers) is necessary.
Profhilo and Skinboosters are two very popular injectable moisturisers in Singapore and have been reviewed in Is Profhilo the Injectable Skincare of the Future? and Skinboosters-All You Need to Know About It. You can also see how I inject these injectable skincare in their respective blogposts.
The effects and effectiveness of hyaluronic acid in skincare products are dependent on several factors including the size (or molecular weight) of the HA molecules and concentration of actives.
Since regular HA molecules are made up of thousands of repeating units and are too big to pass through the skin; why don’t we use smaller ones i.e. low molecular weight HA?
Low molecular weight HA can penetrate significantly deeper into the skin than high molecular weight HA to provide better skin hydration and anti-wrinkle effects1,13. However, this does not mean that high molecular weight HA is redundant; their benefits to the skin are somewhat different1,13,14:
• High molecular weight hyaluronic acid acts like a film to hydrate the top layer of the skin
• High molecular weight hyaluronic acid also has anti-inflammatory benefits
• Low molecular weight hyaluronic acid penetrates the stratum corneum to protect and support the epidermal hydration.
The jury’s still out there for the ‘best’ or ‘most effective’ concentration of HA. Studies have shown that 0.1% of HA is effective in hydrating the skin and improving wrinkles and elasticity1.
Most over the counter serums and creams contain a wide range of concentrations.There isn’t enough data to show whether there is a maximum concentration beyond which the effects of HA plateau or decline. The maximum concentration I’ve come across is 2% HA. I’ve been formulating skincare products for a while now and I can find that as the concentration of HA increases, the viscosity (i.e. thickness) of the liquid increases and it becomes harder to spread on the skin. 2% HA is a sweet spot; it gives adequate hydration and it spreads easily on the skin.
As I’ve shared in a previous blogpost, Sunscreen Reviews: The Best, Worst and Unsafe Ones I’ve Tried, consumer choice can be swayed by the cosmetic elegance of a skincare product.
Tip #1: Look for products that contain a combination of high and low molecular weight hyaluronic acid for better uptake in the epidermis.
The ingredient list may or may not specify the types of HA used. However, beauty brands usually indicate if the product includes low molecular weight HA molecules because these smaller molecules are considered more premium. Other keywords you can look for are ‘multimolecular’, ‘hydrolysed HA’ and ‘nano’.
Tip #2: Look for a minimum concentration of 0.1% hyaluronic acid
Tip #3: Use your hyaluronic acid product together with an emollient.
HA functions as a humectant in moisturisers i.e. they bind to water to retain moisture in the skin. If you feel that this is insufficient to combat dryness, consider using an emollient on top of HA.
Emollients are another class of moisturisers that soften the skin and seal in moisture to prevent transepidermal water loss. My personal recommendation for an emollient that’s safe and suitable for most skin types (including sensitive and acne skin) is ceramides. Fatty acids and urea are also good emollients and you can easily find them in over the counter products too.
Personally, I use a HA serum and ceramide cream; this combination keeps my skin sufficiently moisturised without increasing oiliness or comedones.
Tip #4: Look for multitasking products to maximise benefits!
I like to recommend multitasking skincare products that contain additional active ingredients that add value to their application. Two common ingredients you might also find in HA serums is vitamin B5 (or pantothenic acid) and copper peptides. You might also encounter vitamin B5 as panthenol in the ingredient list).
Vitamin B5 or panthenol is another active ingredient that fortifies the skin barrier and facilitates wound healing. It also has anti-inflammatory benefits. These properties make vitamin B5 useful for patients with sensitive skin and acne.
Copper peptide is another antioxidant that also strengthens the skin barrier, anti-inflammatory and anti-aging benefits. I’ve discussed the roles and benefits of copper peptides in details in The Ordinary Skincare Review and Ingredients Decoded.
HA is suitable for most skin types- including sensitive skin, oily skin and acne. It is also safe for pregnant mothers. It can also be safely used together with most skincare ingredients and medications, including acne medications.
You can use HA in the day and night. If you want to use ceramides or other emollients, apply them on top of your HA product. Emollients tend to be lipids so they form a seal over HA which is water soluble. Don’t forget your sunscreen right on top of course!
If you’re looking for an ingredient to boost your skin’s moisture levels,HA is an effective and affordable active ingredient. HA functions mostly as a humectant in moisturisers, although it can also reduce fine wrinkles and improve skin health.HA is safe and is suitable for most skin types, including acne and sensitive skin types. If you are pregnant or nursing, HA is also safe to use.
The penetration of HA is dependent on its molecular size- higher molecular weight HA molecules stay on the top layers of the skin; and low molecular weight HA molecules can penetrate deeper into the stratum corneum to hydrate the deeper levels of the epidermis.
My top tips for choosing hyaluronic acid skincare product:
• Look for a combination of high and low molecular weight HA for hydration across the stratum corneum
• Minimum concentration of 0.1% HA for results
• Use an emollient on top of your HA product
• Look for additional active ingredients for multitasking benefits
I hope that you have found this review on hyaluronic acid skin care products useful. Applying HA to the skin moisturises the epidermis. However, applying HA to the skin alone does not hydrate the dermis of the skin. The molecules (including low molecular weight HA) are too large to pass through the membrane that separates the epidermis from the dermis.
To replenish HA in the dermis, hyaluronic acid has to be directly injected into the skin i.e. injectable moisturisers. Injectable moisturisers such as Profhilo and Skinboosters are one way to hydrate the skin, tighten pores and lift the skin.
In this series of blogposts on HA, I’ll be reviewing a couple of HA skincare products that I’ve tried and the different types of injectable moisturisers in Singapore. Stay tuned,stay home and be safe!
Read about the different types of injectable moisturisers in this blogpost, Injectable Moisturisers Explained: Profhilo vs Rejuran vs Skinboosters.
Please feel free to share this post and leave a comment if you have a question about this topic. If you enjoyed this post, you might enjoy the following reviews on skincare ingredients:Cica in Skincare: Centella Asiatica Explained
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