Face serum is a set of concentrated skincare ingredients that help to address specific skincare concerns. The ingredients are made up of small molecules and hence can penetrate deep into the skin and nourish the skin layers that lie beneath the surface. This feature makes serums very effective in treating specific skin issues like dark spots and wrinkles.

Though a serum is similar to a moisturizer in many aspects, there are many distinguishing aspects. A moisturizer has various ingredients to make it feel soft on the skin's surface like vitamin E, mineral oils, etc. These ingredients act as a sealant that rests on the skin's surface, prevents moisture evaporation and makes it softer. A serum, on the other hand, has less of such surface sealing ingredients as its purpose is to penetrate deeply at a cellular level and deliver targeted results.

Traditional serums are water-based. They nourish the inner layer of the skin as the molecules are relatively small and can penetrate deeper. Hence, these are predominantly applied before a face cream. Oil-based serums have a slightly bigger molecule, and therefore they are applied over the moisturizer. With the increasing popularity of face oils, many oils are also being marketed as serums.

Serums are concentrated. Hence, if one has sensitive skin or is prone to allergies or any skin reactions, it is better to consult a dermatologist prior to using it. It is always advisable to do a patch test before using serums all over the face. Choose the serum accordingly to your skin needs. Also, people who are prone to severe skin issues like eczema must use serums with caution.

Serums can be layered, but there are several factors to take into account when doing so. Some of these include ingredient compatibility, time of day, and the order in which the products are applied.

You can use multiple serums to customize your skincare routine to your specific needs. For example, if you find your skin is looking dull and dry, you can use a hyaluronic acid serum to hydrate the skin, and a vitamin C serum to brighten the skin.

The maximum number of serums that can be used at once largely depends on the ingredients in the products. Serums are only effective when they’re applied close to the skin, as this allows the ingredients to penetrate into the epidermis.

Once you go beyond two or three serums, the product you’re applying is less likely to be able to actually sink into your skin—therefore, it’s less effective. Rather than applying five different serums at once, consider alternating between them on different days. Combining serums like this will give your skin a chance to absorb each ingredient and is also less likely to cause

Serums can be used both during the day as well as night. It is best to apply it soon after cleansing and toning. When applying serum in the morning, follow it up with a sunscreen. If you use serum at night, then top it up with a moisturizer.

Serums (especially those containing vitamin C) tend to break down on being exposed to sunlight. Hence, it is best to store them in a cool dark place and use them within expiry date on the label. The cap should be replaced tightly after each use as certain potent ingredients in the serum tend to turn unstable when they come into contact with air.