What is the 1% line in skincare?Updated a year ago
As explained by cosmetic chemist Perry Romanowski, “1% line refers to the place in the list of ingredients which indicates where the concentration of ingredients is less than 1%.”
Product labels list ingredients based on the concentration, from highest to lowest. But, after that 1% line, ingredients no longer have to be listed in order.
Cosmetic chemists use the 1% exercise to re-create cosmetic formulas. But for us consumers, this is a useful tool of analysis. Any ingredient that shows up below the 1% line is therefore being used at a concentration that’s less than 1%.
With some ingredients, like retinaldehyde, 1% would be excessive, but in most other cases, including vitamin C, niacinamide, hyaluronic acid, and glycolic acid, we need a higher percentage to see real benefits.
So how do we identify the 1% line? It’s simple. Some ingredients (especially preservatives) will never be used at more than 1%, so learning to identify them will direct you.
- Parabens have become less popular in recent years, but they’re also always used below 1%.
- Sodium benzoate, potassium sorbate, and sodium dehydroacetate are also preservatives never used at more than 1%.
- Xantham gum is a thickener. Unless the product you’re considering is very viscous, this ingredient won’t be used at more than 1%.
- Fragrances and essential oils are rarely used at a concentration higher than 1%, and ideally far below it. We try to avoid them altogether because they can be sensitizing.