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A serum is a lightweight formula built around a specific ingredient or goal, such as hydration, a more even-looking tone or smoother-looking skin. It is an optional extra, not a requirement. If you already have a cleanser, moisturizer and sunscreen you like, a serum is simply a way to add a little more focus.
What a serum does
Serums are usually thinner than creams and absorb quickly. Because they are light, they are often built around one key ingredient, which is why they suit targeted goals.
A serum does not replace moisturizer. Most people follow it with a cream, which helps skin feel comfortable and keeps the lightweight layer in place.
Serums come as watery liquids, light gels and silky fluids, usually in a dropper or pump bottle. Texture is a matter of preference, so choose the one that feels pleasant enough to use every day.
Where serums fit in your routine
The general rule is thinnest to thickest. After cleansing, a serum goes on before moisturizer. Our guide to what order to apply skin care covers the full sequence.
- Cleanse
- Serum, a few drops pressed gently into the face and neck
- Moisturizer
- Sunscreen in the morning
Common serum ingredients
You will see the same handful of ingredients again and again. Here is what each is commonly used for.
| Ingredient | Commonly used for | Good to know |
|---|---|---|
| Hyaluronic acid | Hydration and a plumper-looking feel | An easy first serum; apply to damp skin |
| Vitamin C | A brighter, more even-looking tone | Often used in the morning; store away from heat and light |
| Niacinamide | Skin that looks balanced and smooth | Often suits oily or combination skin |
| Peptides | The look of firmness and fine lines | Usually fits easily into most routines |
| Retinol | The look of fine lines and uneven texture | Best used in the evening, with sunscreen the next day |
Our ingredient guides on vitamin C and retinol go into more detail. If you are pregnant or nursing, ask a healthcare professional before using retinol products. The same goes if you use prescription skin care or take medication that affects your skin.
How to add your first serum
- Pick one goal. Choose the ingredient that matches the change you would most like to see. If you are undecided, hyaluronic acid is the easiest place to start.
- Patch test. Follow our steps for patch testing a new product before your first full application.
- Start small. A few drops cover the face and neck. More does not mean better results.
- Go slowly with stronger ingredients. Retinol and exfoliating acids are best introduced two or three nights a week at first.
- Add one product at a time. Wait a couple of weeks before adding another, so you can tell what is working.
- Wear sunscreen. Some active serums can leave skin feeling more sensitive to the sun.
Keeping your serum fresh
Store serums away from heat and direct sunlight, and close the cap firmly after each use. If a formula changes noticeably in color or smell, it may have aged, so check the label for a recommended use-by window.
Where to go next
Browse the full range of serums and treatments to compare formulas. If hydration is your goal, Hyaluronic Hydration Serum is a simple first step. Give any new serum a few weeks of steady use before you judge it. Hydration can feel different quickly, while changes in tone or texture take longer.
Frequently asked questions
Do I need a serum?
No. A cleanser, moisturizer and sunscreen cover the basics. A serum is an add-on for a specific goal, such as extra hydration or a more even-looking tone.
Can I use more than one serum?
Yes, with care. Apply the thinnest formula first and introduce them one at a time. Some people use vitamin C in the morning and retinol in the evening rather than layering several together.
Does serum go on before or after moisturizer?
Before. Serum goes on clean skin, and moisturizer follows to help skin feel comfortable and to sit over the top.
How long until I notice a difference?
A hydrating serum can make skin feel different within days. Changes in the look of tone or texture usually need several weeks of consistent use, and results vary from person to person.
What if my serum stings?
Mild tingling can happen with some active ingredients, but burning, lasting redness or itching is a signal to stop and rinse. If the reaction persists or gets worse, talk with a healthcare professional.
This content is for general cosmetic and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease or skin condition. If you have a skin condition, are pregnant or nursing, or have concerns about a product, talk with a qualified healthcare professional.
