透明無色，具有甜味及黏稠性的液體，吸濕性非常強，易和水、乙醇充分混合。能使皮膚的細胞膨潤、柔軟，防止角質的落屑，具有幫助皮膚吸收力之作用。弱適度稀釋的甘油塗布於皮膚時，可將空氣中的水分抓住在皮膚上。若是濃度高的甘油則會奪取皮膚組織的水分

Glycerin is a skin-replenishing and restoring ingredient, meaning it is a substance found naturally in skin. In that respect it is one of the many substances in skin that helps maintain a healthy look and feel, defending against dryness.

WHAT-IT-DOES: skin-identical ingredient, moisturizer/humectant
IRRITANCY: 0
COMEDOGENICITY: 0
Quick Facts
A natural moisturizer that’s also in our skin
A super common, safe, effective and cheap molecule used for more than 50 years
Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
Effective from as low as 3% with even more benefits at higher concentrations up to 20-40% (around 10% is a good usability-effectiveness sweet spot)
High-glycerin moisturizers are awesome for treating severely dry skin

- it’s a totally natural ingredient that’s also in the outermost layer of our skin (called stratum corneum - SC).
- It’s a so-called humectant - it helps our skin to cling onto water
- more glycerin means better hydrated skin
- It helps to maintain the healthy state of the cell membranes and intracellular lipids (keeping the lipids in a nice liquid crystal state that is optimal for barrier function)
- It protects against skin irritation (such as washing your face too much and/or too aggressively)
=> What this all means is that glycerin is a real superstar and helps to maintain the healthy state of our skin in several ways.

So the thing to know about the optimal amount of glycerin is this: it is an effective molecule already from 3% (even from 1%, at least when combined with skin lipids), and the benefits tend to increase up until 20-40%. Around 10%, glycerin seems to have a reals sweet spot in terms of effects and usability.