Understanding Serums
Understanding Serums — lightweight, concentrated formulas designed to deliver a high dose of active ingredients — such as antioxidants, hydrators or exfoliants — deeper and faster than a moisturiser. They are applied after cleansing and before moisturiser.
Key points
- Serums target specific concerns: brightening, hydration, firming, texture or blemishes.
- They are concentrated, so a few drops are usually enough.
- Water-based serums go under heavier, oil-based products; layer thin to thick.
- A serum treats; a moisturiser seals and protects — most routines benefit from both.
Frequently asked
Do I still need moisturiser if I use a serum?
Usually yes — serums deliver actives but most don't fully seal in moisture, so a moisturiser on top helps lock in hydration and protect the barrier.
How many serums can I use at once?
One to three is plenty; layering too many concentrated actives raises the risk of irritation and makes it hard to tell what is working.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
