Caffeine
Applied topically, caffeine has a temporary tightening effect and influences the appearance of fluid accumulation near the skin surface. It is one of…
Reference
Ingredient encyclopedia
Every active we use, what it does, and which products contain it. Entries are written in plain language, and where the evidence for an ingredient is mixed or still developing, this says so rather than rounding up.
Nothing here is medical advice. These are cosmetic ingredients, described for people choosing skincare.
C
H
Hyaluronic Acid
A humectant, meaning it attracts and binds water. Applied to damp skin and sealed with something occlusive on top, it helps skin hold moisture and loo…
- Also
- HA, hyaluronan
N
Niacinamide
Niacinamide is a form of vitamin B3 used widely in skincare as a general-purpose conditioning ingredient. It supports the skin barrier — the outer lay…
- Also
- Vitamin B3, nicotinamide
P
Peptides
Peptides are short chains of amino acids, the same building blocks that make up the proteins in skin. In cosmetics they are used to support skin feel,…
- Also
- Signal peptides, matrikines
Prebiotics
Prebiotics are intended to support the microorganisms that already live on skin, rather than adding new ones. The usual analogy is fertiliser rather t…
- Also
- Microbiome-supporting ingredients
R
Retinol
A vitamin A derivative that influences the rate at which skin cells turn over. It has the longest research history of any over-the-counter ingredient…
- Also
- Vitamin A, retinoid
S
Salicylic Acid
Salicylic acid is an oil-soluble exfoliating acid. Because it can move through sebum, it is used to help clear pores rather than only working on the s…
- Also
- BHA, beta hydroxy acid
T
Tea Tree Oil
An essential oil derived from the Australian tea tree, traditionally used on blemish-prone skin. In cosmetics it is typically included at low concentr…
- Also
- Melaleuca oil