Should you use hyaluronic acid serum in the morning or at night?

What are you using the serum for?

Hyaluronic acid helps hold water in the skin. Better hydration can help skin look smoother, which makes moisture the practical reason to add it rather than a particular application time. Hyaluronic acid also appears in moisturizers, so a separate serum is optional if your moisturizer already provides the hydration you need, despite the industry's enthusiasm for giving every step its own bottle.234

How to fit it into your routine

Use these as general moisturizing steps, not a substitute for your serum's application instructions. Damp skin advice applies to moisturizing generally; it is not a special rule that every hyaluronic acid serum label requires.4

1. 1Cleanse gently. Choose a cleanser without strong fragrance or alcohol that can dry out skin, and use comfortably warm rather than hot water.
2. 2Apply your serum as directed on the bottle. If the directions leave the choice open, applying during moisturizing while skin is still damp is a reasonable way to use general moisture retaining guidance.
3. 3Apply a facial moisturizer suited to your skin type. Moisturizing after washing helps seal moisture into the skin.
4. 4In the morning, finish with broad spectrum sunscreen with SPF 30 or higher. Apply sunscreen after moisturizer.

Keep cleanser, moisturizer and sun protection in the routine, even if the serum has the most impressive name on the shelf.3

Do you need to use it twice a day?

Twice daily application is one tested approach, not a requirement for every serum. For a specific hyaluronic acid serum paired with a peptide cream, 17 women with mild to moderate sun damage completed a twice daily routine lasting 12 weeks. Their facial and neck texture, tone and lines improved over that period. A universal timetable for results from a hyaluronic acid serum alone is not settled.1

What if your skin is sensitive?

Hyaluronic acid is used as a moisturizing ingredient for dry or sensitive skin, but choose the whole formula carefully. Fragrance can irritate skin or cause an allergic rash. For dry, sensitive skin, a thicker cream or ointment can be more soothing and less irritating than lighter moisturizing options.23

As a general skincare precaution, test a new product on a small area before using it more widely. If application causes itching, burning or stinging, wash the product off and stop using it. See a dermatologist if your skin feels worse after using the product.3