Ingredient Library

What each cosmetic ingredient does, at what level, and what the evidence actually supports.

These pages cover the ingredients used across the Vegalab and Youlief ranges — what each one is, the level it is typically used at, and what the evidence supports at that level. Concentration matters more in cosmetics than almost any other factor, and an ingredient present at a trace is not the same claim as the same ingredient at a studied level.

Several entries are group pages rather than single ingredients, because the useful content is the comparison. The vitamin C forms differ in stability and in what has actually been tested; the humectants differ in molecular weight and in what they do without an occlusive over them. A page per molecule would repeat itself and bury the comparison that answers the question.

Where the evidence is thin, the page says so rather than filling the gap with supplier material. Some of these ingredients have decades of independent clinical work behind them; others have a single in-vitro study and a lot of marketing. Both situations are described plainly, with study type and funding labelled.

Claims stay cosmetic throughout, describing appearance rather than physiological structures, and findings are attributed to the researchers who produced them.

Each page carries the level the ingredient is actually used at in the range, where that is known, alongside the level the studies used. Those two numbers are frequently different, and a page that gives you only the second is not telling you much about the product in front of you.

Where an ingredient also appears in the crop range, it is covered in full once and linked from the other pillar rather than written twice. Rosemary oil is a pesticidal active in crop science and a fragrance and antimicrobial component in skincare — one molecule, two genuinely different use cases, and one page that states which is which.

Pages in this section

40 pages in this section.