Molecular Weight: 92.09
Skin and hair conditioning; Humectant; Solvent; Denaturing agent; Viscosity Controlling; Skin Protecting; Oral Care; Fragrance
When used on the skin, never use undiluted glycerin directly, as it will cause the opposite effect.
It is a small-molecule moisturizing ingredient. Glycerin has a significant moisturizing effect among polyols. It can keep water in the stratum corneum and prevent cosmetics from drying out. Therefore, it is widely used in various cosmetics. One gram of glycerin can absorb 0.6 grams The ratio of catching water is not high, and in a high humidity environment, the moisturizing effect of glycerin is better.
 Wikipedia, the free encyclopedia, http://en.wikipedia.org.
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
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.