Hyaluronic Acid Skincare: Best Moisturising Ingredient
Hyaluronic acid (HA), also known as sodium hyaluronate is a key ingredient in topical skincare products for cosmetic improvement of the skin. HA is abundant in the extracellular matrix of the skin, forming a key component of connective tissue in our bodies.
The amount of HA in the skin is equivalent to 50% or more of the total amount of HA in the body. Besides existing in our skin, HA also interacts with cells in many biological processes. For example, tissue homeostasis, cell proliferation, angiogenesis and anti-apoptosis. HA’s benefits in your skincare include increased skin elasticity, treatment for eczema, facial rosacea, and reduction of facial wrinkles. It is a common constituent of facial fillers, and also frequently a topical on skin as a humectant retaining moisture.
What many may not know is that the benefits and properties of HA are dependent on HA’s molecular weight in formulas. The molecular weight refers to its mass, or how big the HA molecule is. This is measured in unified atomic mass units — daltons, or kDa for short.
Why hyaluronic acid molecular weights matter in skincare
HA’s native form is at high molecular weight (HMW-HA) in our tissue. However, it can be decomposed into small fragments when wounding or damage (e.g. sunburn) occurs. Then, it can be found as a low molecular weight HA (LMWHA).
The different molecular weight of HA has varying levels of penetration into the skin. This in turn causes the different molecular weights to have unique properties and functions for our skin. For example, it has been proven that HMWHA (>1000 kDA) displays anti-inflammatory and immunosuppressive properties. Whereas, LMWHA is a potent proinflammatory molecule.
High vs low molecular weight
HMWHA is unable to permeate through the skin because it is a water-soluble macromolecule. Being a very large molecule it does not penetrate the skin. Instead, it remains on the skin surface and functions as moisturizing of the skin surface. Fortunately, molecules with lower molecular weight are smaller. Therefore, they are able to reach the deeper layers of skin, enabling them to sustain skin’s moisture content unlike HMWHA. Nevertheless, too low a molecular weight ( ≤ 25 kDA) causes inflammation. If the molecule size is too small, it can cause bacteria, dirt, and other unwanted molecules to penetrate deeply into the skin and cause inflammation.
As seen, too high a molecular size will only have a short term effect on our skin. On the other hand, too low a molecular size promotes inflammation of our skin. According to the most recent human studies, HA between 50 to 1,000 kDa is the most beneficial for skin. In fact, about 130 kDa is the sweet spot. Application of low-molecular-weight (LMW) HA at 130 kDA allows for significant reduction of wrinkle depth, increasing skin elasticity by 20 percent. Overall, LMW-HA at 130 kDA is proven to be the most beneficial molecular weight for our skin.
The multi-weighted type of hyaluronic acid formulation is actually the most beneficial type of moisturizer for dry sensitive skin. This is because it can penetrate both the top and deeper layers for its ideal cell communication enhancing benefits.
Concentration of HA
Secondly, concentration of hyaluronic acid needs to be taken into consideration as well when applied topically. Studies have shown that higher concentrations of hyaluronic acid do not guarantee utmost effectiveness. In fact, HA’s benefits to skin deteriorate after 2% in volume thus, keeping HA concentration to below 2% is ideal.
What does hyaluronic acid do in the skin?
Hyaluronic acid is a natural component that the human body naturally produces. Cells lose their ability to produce HA with aging. The skin becomes drier, thinner, and looser, leading to wrinkling and loss of firmness. Skin aging is also associated with a decrease in skin moisture. Since hyaluronic acid renewal tends to slow with age and external aggressors, it is wise to start incorporating hyaluronic acid skincare products into your regimen early.
HA has the unique capacity to link and retain water molecules. It has the ability to bind water up to 1000 times its volume. Moreover, it contributes to cellular growth, adhesion and various other functions in the skin. Research has also found that HA has an impact on the growth of keratinocytes, cells in the skin that protect the skin from aging. In the intercellular matrix of the skin, it reinforces intercellular structures, holds moisture, provides firmness and radiance to the skin, and supports hydration.
What does hyaluronic acid skincare do for your skin?
Because of its hydrophilic (water loving) nature, HA is used in skincare formulations as a moisturizing component. Using cosmetic products such as creams, lotions or serums that contain HA helps to moisturize the skin, improve elasticity, which in turn improves the appearance of wrinkles. When applied onto the skin, HA solutions form an occlusive layer that absorbs moisture, hydrating the skin and decreasing wrinkle depth.
In previous studies, some cosmetic HA products have proven efficient in protecting the skin from harmful UV radiation. Furthermore, due to its antioxidant properties, sunscreen products containing HA can help to maintain firmer skin, protecting it from the negative effects of UV radiation.
How does hyaluronic acid improve your skincare formulations?
In cosmetic formulations, HA acts as a skin conditioning agent and is a frequent component of anti-aging products. Low molecular weight hyaluronic acid (LMW-HA) has the ability to enhance the level of moisture in the skin and promote regeneration. The main function of high molecular weight hyaluronic acid (HMW-HA) is that it is film forming and reduces evaporation of water from the skin, possessing an occlusive effect.
Hyaluronic acid is also an important delivery system of active ingredients. HA in formulations has been proven to increase penetration of active ingredients into the stratum corneum. The occlusive properties of HA possibly makes it easier for the other active ingredients in the formulation to penetrate the epidermis and persist in the skin layers.