Hyaluronic Acid: Everything You Need to Know

Hyaluronic acid (HA) is in almost every moisturiser, serum, and toner on the market today – and for good reason. It is one of the most effective humectants (moisture-binding ingredients) known to dermatology. But there is one common mistake most people make that dramatically reduces its effectiveness.

What is Hyaluronic Acid?

Hyaluronic acid is a naturally occurring polysaccharide (a type of sugar) found in the body – particularly in the skin, joints, and eyes. Its superpower is its ability to bind and retain up to 1,000 times its molecular weight in water. A single gram can hold up to six litres of water.

As we age, our natural HA levels decline, which is a major contributor to the loss of plumpness and elasticity that comes with time.

The Common Mistake

Here is the critical detail: hyaluronic acid is a humectant. This means it draws moisture from its surroundings. When applied to completely dry skin in a dry environment, it can actually pull water out of the deeper layers of the dermis, temporarily worsening dryness.

The fix: always apply HA to damp skin – ideally within 60 seconds of washing your face or spraying a hydrating mist. Then seal it immediately with a moisturiser to lock that moisture in.

Molecular Weight Matters

Not all hyaluronic acid is the same. Low-molecular-weight HA penetrates deeper into the skin; high-molecular-weight HA forms a protective film on the surface. The best serums combine both for deep hydration and surface plumping.

How to Use It

1. Cleanse and leave skin slightly damp.
2. Apply 3–4 drops of HA serum and press gently into the skin.
3. Follow immediately with a moisturiser while HA is still wet.
4. Apply SPF in the morning routine (HA is suitable for AM and PM use).

Hyaluronic acid plays well with almost every other skincare ingredient – retinol, vitamin C, niacinamide. It is the one ingredient worth keeping in your routine at all times, year-round.