Hyaluronic Acid

Activities:

 Humectant, antiaging  

Important Chemical Components:

 Hyaluronic acid (HA) is formed by repeating units of the  disaccharides D-glucuronic acid and D-N-  acetylglucosamine, which are linked to each other by  alternating β-1,4 and β-1,3 glycosidic bonds. HA is com-  posed of carbon, hydrogen, nitrogen, and oxygen  (molecular formula: C  14  H  21  NO  11  ). See Figure 26-1.  

Origin Classification: 

HA is isolated from bacterial or yeast cultures, so it is  considered natural but laboratory made. It is not consid-  ered organic.  

Personal Care Category: 

Humectant, moisturizer

Formulation Considerations

Hyaluronic Acid (HA) is a key component of healthy skin, but its large molecular size makes it difficult to penetrate deep into the skin. However, when the right molecular weight is used, HA can reach the upper layers of the skin (epidermis), providing quick but temporary hydration that helps reduce the appearance of fine lines. It’s important to note that not all HA is the same—how it is extracted and processed affects its effectiveness.

Usage Considerations

HA is known to enhance the absorption of other skincare ingredients, which is something to keep in mind when layering products. For example, applying retinol after HA may increase retinol absorption.

One of HA’s standout features is its ability to hold up to 1,000 times its weight in water, making it a powerful hydrator. However, its effectiveness depends on the environment. In humid conditions, HA attracts moisture from the air, leaving skin plump and hydrated. But in dry conditions, it can pull moisture from the skin instead, leading to dehydration.

To prevent this, HA should be paired with an occlusive ingredient (like an oil or heavier moisturizer) in dry climates to seal in hydration. People with oily skin naturally have enough sebum to lock in moisture, so they can use HA in any environment. But those with dry skin should avoid using HA alone in dry conditions unless combined with an occlusive agent.

Conclusion

HA is a vital part of the skin’s structure, helping to maintain hydration, volume, and a youthful look. However, HA levels decrease with age, leading to dryness and fine lines. While injectable HA fillers can restore lost volume in the deeper layers of the skin (dermis), topical HA mainly hydrates the surface (epidermis).

Since most HA molecules are too large to penetrate deeply, they remain on the skin’s surface, acting as a moisture reservoir. This makes HA great for boosting hydration but less effective for long-term anti-aging benefits. Any anti-aging effects you see from topical HA come from improved hydration, and the results are temporary. Because of this, some skincare marketing claims about HA can be misleading.

To get the best results from HA, use it in a humid environment or pair it with an occlusive ingredient in drier climates. Think of it as a hydration booster rather than a deep skin-plumping agent.

Best Ingredients to Pair with HA in Formulations

Occlusives (To Seal in Hydration)

Since HA draws moisture, it’s essential to pair it with occlusives in dry environments to prevent water loss.

• Squalane – A lightweight, non-comedogenic oil that locks in moisture without feeling greasy.

• Shea Butter – Nourishing and rich in fatty acids, great for drier skin types.

• Jojoba Oil – Mimics the skin’s natural sebum, preventing moisture evaporation.

• Dimethicone – A silicone-based occlusive that smooths skin and prevents water loss.

📌 Best for: Moisturizers, serums, and creams for dry or mature skin.

Humectants (To Enhance Hydration)

HA is a humectant, but combining it with other humectants can boost hydration.

• Glycerin – One of the most effective humectants, improves water retention.

• Panthenol (Pro-Vitamin B5) – Hydrates and soothes, ideal for sensitive skin.

• Beta-Glucan – Offers deeper hydration and has soothing, anti-inflammatory properties.

• Sodium PCA – A natural component of the skin that helps maintain hydration.

📌 Best for: Hydrating serums, essences, and toners.

Barrier-Strengthening Ingredients (To Support Skin Health)

Since hydration alone isn’t enough for healthy skin, HA pairs well with ingredients that strengthen the skin barrier and prevent moisture loss.

• Ceramides – Essential for repairing and reinforcing the skin’s natural moisture barrier.

• Niacinamide (Vitamin B3) – Helps improve skin barrier function, reduces inflammation, and enhances hydration.

• Cholesterol & Fatty Acids – Key components of the skin barrier that work well with HA.

📌 Best for: Anti-aging creams, serums, and barrier-repairing treatments.

Exfoliants (To Improve Absorption)

Since HA struggles to penetrate deeply, pairing it with gentle exfoliants can help.

• Lactic Acid (AHA) – Exfoliates while also acting as a humectant.

• PHA (Polyhydroxy Acids) – Mild exfoliation with added hydration benefits.

• Enzymes (Papain, Bromelain) – Provide gentle exfoliation, making HA more effective.

📌 Best for: Hydrating exfoliating toners, overnight masks, and brightening serums.

Other Active Ingredients That Work Well With HA

• Peptides – Boosts skin elasticity and works well in anti-aging formulations.

• Caffeine – Helps with de-puffing and tightening, great in eye serums.

• Aloe Vera – Soothes and hydrates, a great natural complement to HA.

Ingredients to Avoid Pairing with HA

🚫 Very Drying Actives Without Occlusion – HA alone can worsen dryness when paired with:

• High concentrations of alcohol (can counteract hydration).

• Benzoyl Peroxide (can cause excessive dryness).

🚫 Low-pH Actives (Vitamin C, Strong AHAs/BHAs)

• HA isn’t unstable, but at very low pH, it can break down and become less effective.

• If formulating with Vitamin C (L-Ascorbic Acid), apply HA afterward or in a separate product.

Best Practices for Formulating with HA

✔ Use multiple molecular weights of HA for deeper hydration (high MW for surface, low MW for penetration).
✔ Pair HA with occlusives in dry climates to prevent moisture loss.
✔ Combine HA with other humectants for enhanced water retention.
✔ Consider enzyme or mild acid exfoliation to improve absorption.