Understanding Oily vs Combination Skin: Sebum Profiles

Ever wondered why the centre of the face shines while the cheeks feel tight? This attached guide maps what is really happening on the skin and shows how to read sebum behaviour in a clear, cosmetic way. It is written for formulators, educators and small brands who want practical methods they can run in a classroom or studio without a full lab.

Inside you will find plain language explanations of sebum composition, step by step sebumetry with CSL and SER, simple ratios to classify patterns, and how to turn numbers into better textures and usage directions. It also covers optics, so you can separate true oil load from the look of shine.

Use it to design products and routines that feel balanced across the whole face, to build appearance-focused claims with confidence, and to teach students how to collect repeatable data.

What you will learn:

• How to measure CSL and SER at T0, T30 and T60
• How to classify oily versus combination using regional ratios
• How to translate results into formula and routine choices