Serum vs Face Oil: What's the difference?

Heartwood’s first serum took us three years to perfect, and for good reason: It needed to pair perfectly with our Heartwood Face Oils for optimal skin health.

To honour the launch of The Royal Revival Indian Sandalwood Hydration Serum, we investigate the differences between serums and face oils and how to use them in tandem for the best skin results.

The difference between face oils and serums

While facial oils promote long-term skin barrier health and resilience, targeting the outer layers of the skin; serums are designed to penetrate to the deeper layers of the dermis with smaller molecules, to address deep-seated inflammation, discolouration and hydration. 

For optimal skin health, your skincare routine should embrace both oil and water-soluble serum products. 

How to use serums and face oils for optimal skin health 

Skincare products should always be applied in order of occlusivity (thinnest to thickest), to allow them to penetrate the skin one after the other, targeting the deepest layers of the skin first. 

Nikki O’Dwyer, Heartwood Director of Spa & Wellness said, “Your serum is arguably the most important product within your skincare routine as its actives are designed to penetrate to the deeper layers of the skin, treating sub-conditions like inflammation, dehydration, dullness and pigmentation.

“After applying your serum to clean slightly damp skin, and really working it in so that it has fully absorbed, massage your face oil into the skin, followed by your moisturiser to lock in the hydration,” she said. 

The order of your face oil and moisturiser depends on the occlusivity of your face oil. A lightweight face oil such as Heartwood’s face oils should be applied before your moisturiser. Heavy face oils that have a larger molecular weight should be applied after your moisturiser because of the slow rate at which they will be absorbed by the skin.

What’s the difference between a light-weight face oil and a heavy face oil?

The heaviness of a face oil depends on the molecular weight of its constituents. 

Heavy face oils tend to contain high volumes of saturated fatty acids which have high molecular weights, as evidenced when they solidify at room temperature e.g. coconut or shea. They are slower to absorb and have a rich consistency. 

Lightweight face oils such as jojoba and argan oils contain unsaturated fatty acids which allow them to absorb more rapidly into the skin because of their smaller molecular weight. 

“Heartwood’s face oils are embedded in a carrier of organic jojoba, which most closely resembles the skin’s own sebum, meaning that it is rapidly absorbed and actives penetrate deeply,” says Nikki. 

Lightweight Skin Oils e.g. Heartwood Face Oils:

  • Jojoba oil
  • Squalene oil
  • Rosehip oil
  • Argan oil
  • Grape seed oil
  • Apricot kernel oil

Heavy Skin Oils eg. Heartwood Royal Oil for Body + Hair:

  • Olive oil
  • Coconut oil
  • Avocado oil
  • Shea Butter
  • Sweet Almond Oil


Serums and face oils are purposefully designed to compliment eachother. Your skincare routine will benefit from the use of both but will look different depending on the products you choose. See the infographics below to guide the order of your skincare regime. 

Cleanse - exfoliate - mist - serum - lightweight oil (jojoba, squalene or rosehip) - moisturiser 

Cleanse - exfoliate - mist - serum - moisturiser - heavy oil (shea, sweet almond, coconut)