A blog that gets nerdy for beauty

Moisturizer or Serum: Which one works best for you?


What really is the difference? Should you just choose one or both? Moisturizers and Serums have common purpose of keeping moisture in your skin.  A healthy skin should be able to hold enough water to keep its protective function.


Do you remember the days when your mom swears by any of these “holy grail” beauty products?

old beauty products

Major skincare #throwback

What’s common between these products is the presence of petrolatum or mineral oil. Mineral oil has been used in the cosmetic industry for decades and was present in almost every moisturizer in the past. As years passed, many types of ingredients are used in moisturizers but they are generally are classified as either oil or wax.

Moisturizers keep the skin hydrated by keeping the moisture within the skin, by forming a layer of oil on the surface to keep water from escaping. Moisturizers are often in cream-type formulation.


Serums on the other hand, contains more water-soluble ingredients and does not contain (or contains little) oil. Oils in serum are usually in an oil-in-water emulsion where oil particles are suspended in water.

 The difference between moisturizers and serums is the presence of ingredients like petrolatum and mineral oil. 
serums and moisturizers emulsion

Difference between Water-in-Oil and Oil-in-Water Emulsions

Serums are designed to penetrate deeply in to your skin instead of just building up a film on the surface. However, since serums are usually water based (contains more water than oil), it cannot effectively penetrate in to oily layer of the skin. It is important therefore to apply serums right after washing and toning face where sebum is temporarily stripped off to improve the penetration of serums.


Examples of facial serums

When do I need Moisturizers?

1. In a dry environment

In the Philippines where weather is most of the time humid, the air rarely gets cold and dry. However, exposure of skin in cold and dry environment like a whole day in the office or in a mall can leave the skin dry over time. If you notice your skin get tight or flaky in the office, consider a heavier moisturizer.

2. For “Sealing-in” active products

You can improve the efficacy of active ingredients found in thinner product formulations like toners and serums by sealing them in by layering a heavy moisturizer. Multiple layers of products may be too heavy when applied at day time, especially when you apply another layer of sunscreen. Hence, layering several products is usually recommended at night time.

When do I need Serums?

1. Hydration for all Skin-types

All skin type can benefit from serums. For oilier skin, make sure to apply serums in a thoroughly cleansed face. Apply products that help strip off excess sebum like Salicylic acid containing toners and cleansers. This help serum penetrate the skin better.

2. When you need to target specific skin issues.

May it be exfoliating, anti-acne, treatment for hyper pigmentation or anti-aging, the active ingredients for these specific skin concerns are usually best delivered by serums as they generally penetrate better in the skin and compared to heavier formulations of moisturizers.

3. Hydration in a Humid environment

Expecting to be out under the sun for a long time? If you don’t want heavy moisturizers melting on your face, hydrating serum is definitely the way to go. Don’t stress about your skin drying out because of too much heat. The “wet air” in a hot sunny day in tropical countries keeps water from escaping your skin.

What about Emulsions? Ampoules? Essence?

The skin care industry has introduced a wide range of new products that our Moms never knew of back then. If the difference between emulsions, ampoules and essence confuse you, relax: you are not alone. Any skincare guru may look at me like I just stepped on their new shoes if I say, there isn’t really much difference. They are basically just products thicker than toner, but thinner than creams – I’d like to collectively call them serums.

The truth is, there is no strict regulation or standards on how skin care brands name their formulations. How brands name their product is a matter of marketing placement. With the fast evolving skin care market, brands always find ways to make their products stand out by naming them in a way that it sounds special. (Start a cosmetic business and name a product unicorn piss for heaven’s sake, no one will sue you)

Take Away

Moisturizer or Serum, both has the same function of hydrating the skin (besides other functions, depending on other active ingredients). The former keeps water from escaping, while the latter delivers water in to the skin. Personally, I use both serum and cream-type moisturizer. I use heavier creams at night, after I apply my serum. In the morning, I just use serum-type product, before my sunscreen. However, I always keep a tub of cream-type moisturizer in the office just incase my skin gets too dry from the weather or A/C.



Here’s a massive tub of St. Ives Moisturizer I always keep with me in the office for times when my face gets extremely dry.

How about you? Do you use both or just one? Do you like layering your serums and moisturizers? I’d be glad to know.


Article written by:

Anne Porter

Hi! I’m Anne. I am a chemical engineer from Cebu, Philippines. I created Zarins Beautylab because of my love for cosmetics, skin care products and all other stuff that makes me (and you) look and feel beautiful. My semesters of chemistry courses come in handy as I explain the science behind different beauty products: which works and how it works. Well, Sometimes its science and sometimes its just good ol’ common sense.

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