Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Stay hydrated!

Learn more about Water

Alcohol

Antimicrobial, Astringent, Masking

Alcohol comes in many different forms. Different types of alcohol will have different effects on skin. This ingredient is usually an astringent alcohol.

These alcohols are drying on the skin. They may strip away your skin's natural oils and even damage your skin barrier. Astringent alcohols may also irritate skin.

Other types of astringent alcohols include:

According to the National Rosacea Society based in the US, you should be mindful of products with these alcohols in the top half of ingredients.

Any type of sanitizing product will have high amounts of alcohol to help kill bacteria and viruses.

Fatty alcohols come from plant oils such as coconut oil. These can help hydrate the skin and are non-irritating. Some fatty alcohols include cetyl and stearyl alcohol.

Learn more about Alcohol

Propanediol

Solvent

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.

It’s often used to:

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

Learn more about Propanediol

1,2-Hexanediol

Skin Conditioning, Solvent

1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.

It is a:

Humectant, drawing moisture into the skin
Emollient, helping to soften skin
Solvent, dispersing and stabilizing formulas
Preservative booster, enhancing the antimicrobial activity of other preservatives

Pentylene Glycol

Skin Conditioning, Solvent

Pentylene glycol is typically used within a product to thicken it. It also adds a smooth, soft, and moisturizing feel to the product. It is naturally found in plants such as sugar beets.

The hydrophilic trait of Pentylene Glycol makes it a humectant. As a humectant, Pentylene Glycol helps draw moisture from the air to your skin. This can help keep your skin hydrated.

This property also makes Pentylene Glycol a great texture enhancer. It can also help thicken or stabilize a product.

Pentylene Glycol also acts as a mild preservative and helps to keep a product microbe-free.

Some people may experience mild eye and skin irritation from Pentylene Glycol. We always recommend speaking with a professional about using this ingredient in your routine.

Pentylene Glycol has a low molecular weight and is part of the 1,2-glycol family.

Learn more about Pentylene Glycol

Glycerin

Humectant, Skin Conditioning, Skin Protecting

Glycerin is already naturally found in your skin. It helps moisturize and protect your skin.

A study from 2016 found glycerin to be more effective as a humectant than AHAs and hyaluronic acid.

As a humectant, it helps the skin stay hydrated by pulling moisture to your skin. The low molecular weight of glycerin allows it to pull moisture into the deeper layers of your skin.

Hydrated skin improves your skin barrier; Your skin barrier helps protect against irritants and bacteria.

Glycerin has also been found to have antimicrobial and antiviral properties. Due to these properties, glycerin is often used in wound and burn treatments.

In cosmetics, glycerin is usually derived from plants such as soybean or palm. However, it can also be sourced from animals, such as tallow or animal fat.

This ingredient is organic, colorless, odorless, and non-toxic.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Learn more about Glycerin

Ingredient Ratings

Here's what our community thinks of the ingredients in these products.

A+ High-Dose Retinol Serum

When to use

Dr. Jart+ Ceramidin™ Liquid 49 ingredients

Sunday Riley A+ High-Dose Retinol Serum 55 ingredients

48 Routines

48% use in am

52% use in pm

90% use every day

When to use See routines that use it ->

159 Routines

4% use in am

96% use in pm

69% use every day

When to use See routines that use it ->

Reviews

Here's what our community thinks

Dr. Jart+ Ceramidin™ Liquid 49 ingredients

Ceramidin™ Liquid hasn't been rated yet.

Rate it now

Sunday Riley A+ High-Dose Retinol Serum 55 ingredients

5.0 /5

from 1 rating

reneelovesherskin

2 years ago

Review

Definitely high-dose retinol!
This is a powerful retinol serum that is no joke. I tried easing into it by going every other night, then moved to every night. I ended up with signs of a damaged skin barrier (redness) on my chin. I'm going to lay off this on my chin for a couple weeks, then try again, but stick to every other night. I like that I'm getting a strong dose of an excellent skincare Show more