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Skin science article

La Roche-Posay 10% Pure Vitamin C Serum Versus Vichy Liftactiv Peptide-C Ampoule Serum

La Roche-Posay 10% Pure Vitamin C Serum Versus Vichy Liftactiv Peptide-C Ampoule Serum This brightening serum is formulated around Ascorbic Acid and Salicylic Acid to brighten dull-looking skin and refine skin texture. This anti-aging ampoule is formulated aro

La Roche-Posay 10% Pure Vitamin C Serum Versus Vichy Liftactiv Peptide-C Ampoule Serum

This brightening serum is formulated around Ascorbic Acid and Salicylic Acid to brighten dull-looking skin and refine skin texture.

This anti-aging ampoule is formulated around Ascorbic Acid to soften the look of wrinkles and brighten dull-looking skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Ascorbic Acid

Cyclohexasiloxane

Glycerin

Alcohol Denat.

Potassium Hydroxide

Polymethylsilsesquioxane

Polysilicone-11

Dimethicone

Propylene Glycol

Pentaerythrityl Tetraethylhexanoate

C13-14 Isoparaffin

Tocopherol

Sodium Hyaluronate

Hydrolyzed Hyaluronic Acid

Adenosine

Acetyl Dipeptide-1 Cetyl Ester

PEG-20 Methyl Glucose Sesquistearate

Poloxamer 338

Salicylic Acid

Polyacrylamide

Toluene Sulfonic Acid

Ammonium Polyacryloyldimethyl Taurate

Xanthan Gum

Caprylyl Glycol

Disodium EDTA

BHT

Laureth-7

Parfum

Water, Ascorbic Acid, Cyclohexasiloxane, Glycerin, Alcohol Denat., Potassium Hydroxide, Polymethylsilsesquioxane, Polysilicone-11, Dimethicone, Propylene Glycol, Pentaerythrityl Tetraethylhexanoate, C13-14 Isoparaffin, Tocopherol, Sodium Hyaluronate, Hydrolyzed Hyaluronic Acid, Adenosine, Acetyl Dipeptide-1 Cetyl Ester, PEG-20 Methyl Glucose Sesquistearate, Poloxamer 338, Salicylic Acid, Polyacrylamide, Toluene Sulfonic Acid, Ammonium Polyacryloyldimethyl Taurate, Xanthan Gum, Caprylyl Glycol, Disodium EDTA, BHT, Laureth-7, Parfum

Butylene Glycol

Dipropylene Glycol

Hydrolyzed Rice Protein

Hydrolyzed Lupine Protein

Ceramide AP

Water, Ascorbic Acid, Butylene Glycol, Dipropylene Glycol, Glycerin, Sodium Hyaluronate, Hydrolyzed Rice Protein, Hydrolyzed Hyaluronic Acid, Hydrolyzed Lupine Protein, Ceramide AP

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Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Ascorbic Acid is is pure Vitamin C and is the biologically active form used directly by skin.

Not only is vitamin C great for your overall health and immune system, but it also has plenty of benefits for your skin. It is best supported by academic literature for:

Topical vitamin C has been shown to help neutralize oxidative stress from UV and pollution, helping to improve photoaging and hyperpigmentation when used consistently.

One clinical study found that using 5% topical vitamin C for six months improved signs of photodamaged skin, both on the surface and in the deeper structural layers of the skin.

While vitamin C doesn’t replace sunscreen, studies show it can boost photoprotection when combined with Vitamin E and ferulic acid. These two ingredients help improve stability and protective effects.

The big downside of this ingredient is formulation difficulty. Vitamin C is prone to oxidation and doesn't penetrate the skin unless formulated correctly. Research found that vitamin C absorbs into the skin best at a low pH (< 3.5) with about 20% being the upper limit for effective absorption.

Skin levels can saturate after repeated application; this means your skin won’t keep absorbing more once it’s full of vitamin C. This is why more isn’t always better with vitamin C and why very high concentrations don’t necessarily give extra benefits.

Ascorbic acid generally works well with many skincare ingredients but can be irritating when combined with other active ingredients. Strong oxidizing acne treatments like benzoyl peroxide can reduce the effectiveness of vitamin C if they are used at the same time; they are often recommended for use at different times of day.

Read more about other types of Vitamin C:

Foods rich with vitamin C include oranges, strawberries, broccoli, bell peppers, and more. When consuming Vitamin C, your skin receives a portion of the nutrients.

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.

Hydrolyzed Hyaluronic Acid is hyaluronic acid (HA) that is broken down into lower molecular weight fragments.

It's a humectant that pulls and holds water in the skin to help with hydration, plumpness, and reduce transepidermal water loss.

Because hydrolyzed hyaluronic acid is smaller in size, it can slip past your outermost layer of skin more easily than full-sized HA.

Most formulations will combine all sizes to get the best of both worlds.

Typical usage levels range from 0.01-1%. Any percentage higher than 2% might become goopy and tacky.

Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.

In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.

Interestingly, the size of the molecule affects its behavior:

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.

You'll typically see concentrations between 0.1-2% for this ingredient.

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. Remember to stay hydrated!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

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Formula cabinet

Ingredients & structured notes

Ingredient index

Ingredients Explained

  1. 01These ingredients are found in both products.
  2. 02Ingredients higher up in an ingredient list are typically present in a larger amount.
  3. 03Water. 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.
  4. 04So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
  5. 05You'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!
Source · skinsort.com
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Comparison edit

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