What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Reviews
Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Azelaic acid is a multitasker ingredient that helps treat acne, pigmentation, and irritation. It is a great option for sensitive skin.
What makes it special?
OTC Azelaic acid is usually available in concentrations from 10-15% and anything over requires a prescription.
Here's what each tier does best:
Unlike other acids, azelaic acid will not make your skin more photosensitive/sun sensitive.
Though this ingredient is naturally occurring in grains like wheat, rye, and barley, it is usually synthetically created for cosmetics to ensure stability and effectiveness.
Learn more about Azelaic AcidBenzoic Acid is used to preserve and adjust the pH of products.
The antimicrobial property of Benzoic Acid helps elongate a product's shelf life. Its main role is to reduce fungi growth and is not found to be effective at fighting bacteria. Therefore Benzoic Acid is always added along with other preservatives.
In its pure form, Benzoic Acid looks like a white crystalline solid. It has slight solubility in water.
The name of Benzoic Acid comes from gum benzoin, which used to be the sole source of deriving this ingredient. Benzoic Acid is the most simple aromatic carboxylic acid.
Benzoic Acid is naturally occuring in strawberries, mustard, cinnamon, and cloves. It has a slight scent but is not considered to be a fragrance.
Learn more about Benzoic AcidCetearyl alcohol is a waxy mixture of two fatty alcohols: cetyl alcohol and stearyl alcohol. It is an emollient and emulsifier.
Despite having "alcohol" in its name, it has nothing to do with drying solvent alcohols; the FDA also allows "alcohol-free" products to contain fatty alcohols like this ingredient.
It plays several roles in a formula:
Typical use levels for this ingredient sit around 1-10% and the Cosmetic Ingredient Review Expert Panel has affirmed safety at concentrations up to 25% in leave-on products.
Multiple assessments have found it to be non-irritating and non-sensitizing to most people.
However, there have been some cases of allergic contact dermatitis in patients with chronically compromised skin barriers.
Cetearyl alcohol has a comedogenic rating of 2 and irritancy rating of 1. Both of these numbers come from the 1989 study that used rabbit ears; a "2" means mildly comedogenic and a "1" means low irritancy.
Here's the catch: rabbit skin is more sensitive than human skin and throws a lot of false positives. A 1996 reappraisal found that ingredients rated 1-2 in the rabbit ear tests are generally safe for humans.
Remember comedogenic ratings are unable to assess the entire formula of a product or how it will react on your skin. Just be sure to patch test if you are unsure about certain ingredients.
This ingredient is not fungal acne safe. Cetearyl alcohol is a fatty alcohol with chain lengths that fall within the range that Malassezia can metabolize.
Learn more about Cetearyl AlcoholCetearyl Ethylhexanoate is derived from cetearyl alcohol and sorbic acid.
It is an emollient and helps hydrate the skin. Emollients form a barrier on the skin to prevent water from escaping.
Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Topically, glycerin does several things at once:
Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.
Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.
This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.
Just know very high concentrations (>40%) can feel tacky in low humidity.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Learn more about GlycerinGlyceryl Stearate is made by reacting glycerin with stearic acid (typically sourced from plant oils like palm or coconut). It's an emulsifier, emollient, and mild occlusive.
Emulsifiers help ingredients like oil and water stay mixed so your formula stays nicely blended and uniform in texture.
This ingredient is typically used in concentrations between 1-10%. Studies have found it to be non-sensitizing, non-phototoxic, and non-photoallergenic.
A close cousin of this ingredient is Glyceryl Stearate SE ("self-emulsifying"). This just has a small amount of sodium or potassium stearate added so it can emulsify without a co-emulsifier.
Since this ingredient is an ester of a C18 fatty acid, it may not be fungal acne safe. The Malassezia yeast can potentially metabolize within the C11-C24 range.
Fun fact: The human body also creates Glyceryl Stearate naturally.
Learn more about Glyceryl StearateIsopropyl Myristate is an emollient, thickening agent, and texture enhancer. It is created from isopropyl alcohol and myristic acid.
It is used to help other ingredients be better absorbed. It is also an emollient and may help soften and hydrate the skin.
The comedogenic rating of this ingredient depends on the concentration. Lower amounts results in a lower rating.
Isopropyl Myristate may not be fungal acne safe. It can potentially worsen acne prone skin.
Learn more about Isopropyl MyristatePropylene Glycol is a synthetic, colorless, odorless liquid that has been a staple in cosmetics for decades. It is a skin conditioning agent, humectant, and solvent.
As a humectant, it draw water to the skin to reduce flaking and restore suppleness. It's also a solvent that helps dissolve other actives and keeps formulas stable across temperature changes.
The CIR Expert Panel has confirmed this ingredient to be nontoxic and clinical studies show no sensitization at cosmetic use concentrations.
True allergic reactions are quite rare: a 15-year retrospective study of 6,751 patients found only 0.31% had a positive reaction (and less than half were considered clinically relevant).
It seemed that when sensitization does occur, it's most commonly linked to topical medication (like corticosteroids) and not cosmetics. Allergic contact dermatitis also appears largely limited to individuals with underlying skin conditions.
Overall, propylene glycol is a well-studied ingredient that most people can tolerate without issue.
Learn more about Propylene GlycolWater. 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. Remember to stay hydrated!
Learn more about Water
