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Product Comparison

Here's our complete breakdown comparing the ingredients, attributes, and more of Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum versus SkinCeuticals Blemish + Age Defense .

Last updated on February 16, 2024. Published on March 22, 2023

Overview

What they are

These products are both reef safe . They have a total of 4 ingredients in common

Cool Features

They both contain AHA

Suited For

They're both likely to be good for anti aging, brightening skin, oily skin, reducing pores, scar healing, dark spots and better texture

Free From

They both do not contain any common allergens, fragrances, oils, parabens, silicones or sulfates

What's Inside

They both contain harsh alcohols

We independently verify ingredients, and our claims are backed by peer-reviewed research. Spot a product that need an update? Let us know.

Exfoliator American Brand United States
Serum American Brand United States

Exfoliator

Exfoliators are used to exfoliate the skin, or remove dead skin cells from the skin. Exfoliators may be chemical or physical.

Serum

Serums are highly concentrated with ingredients to provide skin with benefits. They should be used after cleansing and before moisturizing.

Price

Shop

Buy Ultra Pure High-Potency 9.8% Glycolic Acid Serum

Starts at $35.00
Shop

Buy Blemish + Age Defense

Starts at $88.00

Ingredient Info

Click any item below to learn more and view relevant ingredients.
alcohol-free
silicon-free
fragrance-free
sulfate-free
paraben-free
oil-free
fungal-acne safe
reef-safe
eu-allergen-free
vegan
cruelty-free
alcohol-free
silicon-free
fragrance-free
sulfate-free
paraben-free
oil-free
fungal-acne safe
reef-safe
eu-allergen-free
vegan
cruelty-free

At a glance

Click on any of the items below to learn more

Notable Ingredients

AHA
Hyaluronic Acid

Benefits

Hydrating
Good For Oily Skin
Skin Texture
Reduces Large Pores
Anti-Aging
Dark Spots
Scar Healing
Brightening (2)

Concerns

Drying
May Worsen Oily Skin
Irritating (2)
Rosacea (2)
Eczema

Notable Ingredients

AHA

Benefits

Good For Oily Skin
Skin Texture
Reduces Large Pores
Anti-Aging
Dark Spots
Scar Healing
Brightening

Concerns

Drying
May Worsen Oily Skin
Irritating (2)
Rosacea (2)
Eczema
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Ingredients Side-by-side

Ingredients that are highlighted in purple are present in both products.

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Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

1
What it does: Skin Conditioning, Solvent
Community Rating: Loved

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. Talk about multi-purpose! If you see this, drink a glass of water. Stay hydrated!

Learn more about Water

Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum contains this as ingredient number 1.

SkinCeuticals Blemish + Age Defense contains this as ingredient number 2.

2
What it does: Buffering
Community Rating: Loved

Glycolic Acid is arguably the most famous AHA with research to back up its benefits. Its main role is to peel the top layer of skin cells from the newer layer of skin underneath. This helps skin to remove dark spots and look more even.

Glycolic Acid has shown to boost collage production, a protein that helps skin stay firm. Overall, Glycolic Acid helps with improving uneven tone, rough patches of skin, fine lines, wrinkles, and sun damage. It also increases skin hydration by playing a role in creating molecules that create hyaluronic acid naturally.

When applying Glycolic Acid, it is normal to feel slight stinging. The pH value and concentration of glycolic acid play a role in the effectiveness of the product.

Recent studies have shown Glycolic Acid may protect the skin against UV damage. However, you should always wear SPF, especially when using exfoliants.

Read more about some other popular AHA's here:

Learn more about Glycolic Acid

Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum contains this as ingredient number 2.

SkinCeuticals Blemish + Age Defense contains this as ingredient number 4.

3
What it does: Antimicrobial, Astringent, Masking, Solvent
Community Rating: Very Disliked

Alcohol Denat. is an alcohol with a denaturant property. It is created by mixing ethanol and other additives. It has a low molecular weight and will evaporate quickly. This helps other ingredients become better absorbed and dry once applied.

Alcohol Denat. is volatile and may cause irritation. It helps draw out natural oils in skin and dry out your skin.

One study from 2005 found adding emollients to propanol-based sanitizer decreased irritation.

Alcohol is antibacterial by nature. This can help preserve products and increase their shelf life.

Other types of astringent alcohols include:

Learn more about Alcohol Denat.

Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum contains this as ingredient number 4.

SkinCeuticals Blemish + Age Defense contains this as ingredient number 1.

4
What it does: Buffering
Community Rating: Mixed

Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.

In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

Learn more about Sodium Hydroxide

Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum contains this as ingredient number 5.

SkinCeuticals Blemish + Age Defense contains this as ingredient number 10.

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

57% are loved or liked
29% have mixed ratings
14% are disliked or very disliked
0% have no rating yet
36% are loved or liked
18% have mixed ratings
27% are disliked or very disliked
18% have no rating yet

Usage

Here's some more info on how this product is used by our community.

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Alternatives

Our Dupe Finder has found 50 potential alternatives that have similar ingredients to Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum.

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Our Dupe Finder has found 17 potential alternatives that have similar ingredients to SkinCeuticals Blemish + Age Defense.

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