Hyaluronic acid is a complex sugar customarily found between the collagen bundles in the skin. It is a humectant which means it absorbs water from the environment and water from the deeper layers of the skin. Thus it plumps and hydrates the skin. Therefore, hyaluronic acid is less likely to produce side effects or allergic reactions if applied topically to the skin. It can be combined with products that include retinol, vitamin C or AHAs/BHAs and niacinamide.
However, Hyaluronic Acid Is Not A Stand-Alone Moisturiser
Firstly, applying Hyaluronic acid on a dry skin surface only takes moisture from the deeper layers, dehydrating the skin.
Also, you must top the Hyaluronic acid serum with a moisturiser to lock the Hyaluronic acid within, so if you don't do that again, it dries up your skin.
Secondly, if the air around you is dry and your skin is dehydrated, HA can suck water from deeper layers of the skin.
So, the best way to use hyaluronic acid is first to cleanse your face with a cleanser, then apply the hyaluronic acid serum on your damp face to retain the moisture.
Do not apply it on dry skin. Topi t with a moisturiser to lock in the moisture and help the HA to maintain water and keep the skin hydrated.
Thirdly, even though HA can absorb moisture, serums, creams, or lotions containing huge hyaluronic acid molecules may not penetrate the skin.
Hence there may be no effect some HA serums with moderate-size HA when applied to the skin.
So the outcome may be temporary and short-lived, eventually leading to dryness.
For maximum surface hydration, look for a product including HA molecules in different sizes.
Usually, highly reputed brands which have been researched enough do include different molecular sizes of hyaluronic acid in the same product. These would be better than low-quality products.