Hyaluronic acid is in almost every hydrating product sold, and it is also the ingredient people most often report making their skin feel worse. Both things are true, and the explanation is simple.
What it does
Hyaluronic acid is a humectant: it binds water and holds it in the upper layers of the skin. Applied correctly, that is exactly what dehydrated skin needs.
Why it sometimes backfires
A humectant pulls water from wherever it can find it. In a humid room, it pulls from the air. In dry air, central heating, an aeroplane cabin, an air-conditioned office, there is no water in the air to take, so it pulls from the deeper layers of your own skin instead, and then that water evaporates off the surface. You end up drier than before.
The two rules
- Apply it to damp skin. Straight after cleansing, while your face is still slightly wet. You are giving the humectant water to work with rather than making it find its own.
- Always seal it. A moisturizer, a balm or an overnight mask on top traps the water. Hyaluronic acid applied on its own and left bare is the single most common mistake.
That is the entire technique. Everything else about hyaluronic acid is detail.
Molecular weight, briefly
You will see products advertising several molecular weights. Larger molecules sit on the surface and hold water there; smaller ones penetrate slightly further. A formula using a mix covers both, and this matters far less than the two rules above.
How much is enough
One hydrating layer in the morning and one at night. Stacking a hyaluronic acid toner, then a serum, then a cream all containing it does not multiply the effect. It just costs more.
Signs you are dehydrated rather than dry
- Skin feels tight but still produces oil during the day.
- Fine lines look more pronounced in the morning and soften after moisturizer.
- Makeup clings to flaky patches on an otherwise oily face.
Dehydration is a water problem and responds to humectants. Dryness is an oil problem and needs lipids, ceramides and richer textures. Most people treating dry skin are actually dehydrated.
The easiest way to apply both rules at once
An overnight mask does the sealing for you: the hydrating ingredients go on and a film holds them against the skin for the whole night. Our hydrating overnight mask combines hyaluronic acid with ceramide NP and collagen for exactly this, and the full night masks collection covers the other variants.
For where hydration fits in the sequence, see how to layer skincare products.