Dyes, pigments and how NOT to formulate makeup products

[Versione italiana]

In this article, we will briefly explore the colourful world of dyes and pigments that we can use in our cosmetic products. We’ll try to understand what is colour, what is the difference between dyes and pigments and I will give you some hints on what NOT to do when you try to formulate makeup products.

Continue reading “Dyes, pigments and how NOT to formulate makeup products”

Formulation philosophy and how to make substitutions

[Versione italiana]

If you have read all the articles of the chemistry course for DIY formulators, at this point you probably already started to make your first cosmetics or you are preparing to do so. 

I think this is the right moment to think about what is your formulation philosophy: if you have a clear idea of how your formulations should be like, in terms of type of ingredients and reasons behind them, it will be much easier for you to understand how to replace ingredients of someone else’s formula without breaking the formula apart. 

Continue reading “Formulation philosophy and how to make substitutions”

Surfactants: Cleansers and Emulsifiers

[Versione italiana]

For chemists, cleansers and emulsifiers belong to the same big family: the surfactants. Indeed, from the chemical point of view they are molecules that share similar structural characteristics and mechanism of action in solution. All surfactants are amphiphilic molecules, meaning that they get along with both water and oil. This is the key feature that allow them to act as cleansers and as emulsifiers: they are able to interact with both water and oil, therefore they can help washing away greasy dirt when used as cleansers, and stabilise oil phase and water phase when used as emulsifiers. 

In this article, I will call “cleansers” the surfactants that we typically use in cleanser products (shampoos and body cleansers), and “emulsifiers” the surfactants that we typically use in lotions and creams. 

Continue reading “Surfactants: Cleansers and Emulsifiers”

Anhydrous Products: Whipped Butters, Balms, Lotion Bars, and Sticks

[Versione italiana]

[Before reading this article, I recommend the “Fat side of the cream” series about emollients]

Continue reading “Anhydrous Products: Whipped Butters, Balms, Lotion Bars, and Sticks”

The Fat Side of the Cream III: Approaches to Emollient Blending

[Versione italiana]
[Back to the previous article: Physical properties and impact on the final product]

In this final article about emollients, we will talk about how to design the fat side of our products.

  • How much fat should we add to the formula?
  • How do we combine emollients in the formula?
  • Final table with emollient characteristics
Continue reading “The Fat Side of the Cream III: Approaches to Emollient Blending”

The Fat Side of the Cream II: Physical Properties and Impact on the Final Product

[Versione italiana]
[Back to the previous article: Emollients]

In the 2nd part of “The Fat Side of the Cream” we will see the following aspects of emollients:

  • Quick definitions
  • Melting point
  • Viscosity
  • Oxidation
  • Comedogenicity
Continue reading “The Fat Side of the Cream II: Physical Properties and Impact on the Final Product”

The Fat Side of the Cream I: Emollients

[Versione italiana]

In this article series we will explore some of the oils and butters used as emollients in DIY cosmetic products. We will learn something about their chemical structure and physical properties, and we will try to understand the formulators’ approaches to the choice and combination of such emollients in creams. 

Continue reading “The Fat Side of the Cream I: Emollients”

Some analytical chemistry concepts: units of measurement, concentration, pH

[Qui trovate la versione italiana di questo articolo]

There are some concepts and definitions that I mention in my articles and formulas that I tend to consider obvious, because they are kind of obvious to me after years of working in a chemistry lab. But they might be not so obvious to you. Specifically, I use units of measurement, a certain kind of formality in writing them, concentrations and, of course, the term pH. 

I figured that for some people it might be not-so-obvious what does concentration mean and how is it expressed, or how does one switch from a unit of measurement to another one, and for sure not everyone knows what pH means. 

It’s time to find out! In the following list you can find all the pages related to these topics.

If you are a chemistry student or chemist, please don’t laugh at how I’m going to explain these concepts. These information pages are for cosmetic formulation hobbyists, not for chemists!

  • Units of measurement
    • SI units
    • Prefixes
    • How to convert units
  • Concentration
    • Molar concentration
    • Percentage concentration
    • Water calculation in formulas
  • Acids and bases
    • Definition
    • Strong and weak acids
    • Strong and weak bases
    • Amphiprotic species
    • Water: acid or base?
  • pH
    • Definition
    • pH range of DIY cosmetic products
    • How to measure pH in cosmetic products
    • How to adjust pH