Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Paula's Choice C5 Super Boost Moisturizer Versus Olehenriksen C-Rush Brightening Gel Crème

Paula's Choice C5 Super Boost Moisturizer Versus Olehenriksen C-Rush Brightening Gel Crème This brightening moisturizer is formulated around 3-O-Ethyl Ascorbic Acid and Ascorbyl Glucoside to brighten dull-looking skin. This brightening moisturizer is formulate

Paula's Choice C5 Super Boost Moisturizer Versus Olehenriksen C-Rush Brightening Gel Crème

This brightening moisturizer is formulated around 3-O-Ethyl Ascorbic Acid and Ascorbyl Glucoside to brighten dull-looking skin.

This brightening moisturizer is formulated around 3-O-Ethyl Ascorbic Acid and Tetrahexyldecyl Ascorbate to brighten dull-looking skin and fade the look of dark spots.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Dicaprylyl Carbonate

3-O-Ethyl Ascorbic Acid

Dimethicone

Butylene Glycol

Polyglyceryl-6 Distearate

Ascorbyl Glucoside

Squalane

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Acetyl Sh-Hexapeptide-5 Amide Acetate

Citrullus Lanatus Seed Oil

Hydrogenated Lecithin

Theobroma Cacao Seed Butter

Hydrogenated Phosphatidylcholine

Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate

Sodium Hyaluronate

Oryza Sativa Bran Extract

Propanediol

Jojoba Esters

Tocopherol

Acetyl Zingerone

Cetyl Palmitate

Caprylyl Glycol

Cetyl Alcohol

Polyglyceryl-3 Beeswax

Sodium Hydroxide

Sorbitan Olivate

Sorbitan Palmitate

Helianthus Annuus Extract

Ethylhexylglycerin

Hexylene Glycol

Sodium Phytate

Polysorbate 60

Sorbitan Isostearate

Lecithin

Rosmarinus Officinalis Leaf Extract

Glycine Soja Oil

Lysolecithin

Bacillus Ferment

Citric Acid

Polyglutamic Acid

Beta-Sitosterol

Phytic Acid

Squalene

Phenoxyethanol

Sodium Benzoate

Potassium Sorbate

Water, Dicaprylyl Carbonate, 3-O-Ethyl Ascorbic Acid, Dimethicone, Butylene Glycol, Polyglyceryl-6 Distearate, Ascorbyl Glucoside, Squalane, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Acetyl Sh-Hexapeptide-5 Amide Acetate, Citrullus Lanatus Seed Oil, Hydrogenated Lecithin, Theobroma Cacao Seed Butter, Hydrogenated Phosphatidylcholine, Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate, Sodium Hyaluronate, Oryza Sativa Bran Extract, Propanediol, Jojoba Esters, Tocopherol, Acetyl Zingerone, Cetyl Palmitate, Caprylyl Glycol, Cetyl Alcohol, Polyglyceryl-3 Beeswax, Sodium Hydroxide, Sorbitan Olivate, Sorbitan Palmitate, Helianthus Annuus Extract, Ethylhexylglycerin, Hexylene Glycol, Sodium Phytate, Polysorbate 60, Sorbitan Isostearate, Lecithin, Rosmarinus Officinalis Leaf Extract, Glycine Soja Oil, Lysolecithin, Bacillus Ferment, Citric Acid, Polyglutamic Acid, Beta-Sitosterol, Phytic Acid, Squalene, Phenoxyethanol, Sodium Benzoate, Potassium Sorbate

Glycerin

Caprylic/Capric Triglyceride

Glycereth-26

Ammonium Acryloyldimethyltaurate/Beheneth-25 Methacrylate Crosspolymer

Hydrolyzed Jojoba Esters

Cetearyl Alcohol

Polyacrylate Crosspolymer-6

Hydroxyacetophenone

Panthenol

Polyglyceryl-3 Methylglucose Distearate

Tetrahexyldecyl Ascorbate

Linoleic Acid

Parfum

Xanthan Gum

Cetearyl Glucoside

Linolenic Acid

Citrus Aurantium Dulcis Fruit Extract

Citrus Limon Fruit Extract

Hippophae Rhamnoides Extract

Lycium Barbarum Fruit Extract

Rosa Canina Fruit Extract

Leuconostoc/Radish Root Ferment Filtrate

Sodium Citrate

Camellia Japonica Flower Extract

Aroma

Sodium Polyacrylate

Hyaluronic Acid

Triacetin

Hydrolyzed Vegetable Protein

Ascorbic Acid

Limonene

Linalool

Benzyl Alcohol

CI 15985

CI 19140

Water, Glycerin, Dicaprylyl Carbonate, Propanediol, Caprylic/Capric Triglyceride, 3-O-Ethyl Ascorbic Acid, Glycereth-26, Ammonium Acryloyldimethyltaurate/Beheneth-25 Methacrylate Crosspolymer, Hydrolyzed Jojoba Esters, Cetearyl Alcohol, Polyacrylate Crosspolymer-6, Hydroxyacetophenone, Panthenol, Polyglyceryl-3 Methylglucose Distearate, Tetrahexyldecyl Ascorbate, Linoleic Acid, Citric Acid, Phenoxyethanol, Parfum, Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate, Xanthan Gum, Cetearyl Glucoside, Linolenic Acid, Citrus Aurantium Dulcis Fruit Extract, Citrus Limon Fruit Extract, Hippophae Rhamnoides Extract, Lycium Barbarum Fruit Extract, Rosa Canina Fruit Extract, Ethylhexylglycerin, Leuconostoc/Radish Root Ferment Filtrate, Sodium Citrate, Camellia Japonica Flower Extract, Aroma, Sodium Hyaluronate, Sodium Polyacrylate, Sodium Phytate, Hyaluronic Acid, Triacetin, Hydrolyzed Vegetable Protein, Ascorbic Acid, Tocopherol, Limonene, Linalool, Benzyl Alcohol, CI 15985, CI 19140

Reviews

Be the first to review

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

3-O-Ethyl Ascorbic Acid is one of the most popular "stable" vitamin C derivatives in skincare.

Plain ascorbic acid is fantastic but notoriously fragile; it browns, oxidizes, and loses potency fast. So attaching an ethyl group to the third carbon of the molecule gives it some cool perks:

In a formula, it does the 3 classic vitamin C jobs: it acts as an antioxidant, helps brighten skin tone by inhibiting tyrosinase, and supports collagen.

The evidence is reasonably solid for a cosmetic ingredient; Liao and colleagues (2018) showed it's significantly more stable than ascorbic acid while still being effective.

A 2021 study by Zerbinati and colleagues tested a serum with 30% 3-O-ethyl-l-ascorbic acid and 1% lactic acid significantly increased collagen production, reduced UVB-induced DNA damage, and decreased melanin on a reconstructed pigmented skin model.

Typical real world usage sits around 0.5-5% (and 1-2% is common for daily serums).

Amounts up to 30% have been shown to be non-irritating on human skin samples, but two isolated cases reported allergic contact dermatitis so a patch test is sensible if you have reactive skin.

Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.

Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.

However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.

Dicaprylyl Carbonate comes from carbonic acid and caprylyl alcohol, a fatty alcohol. It is an emollient and gives skin a velvet feel. The sources of Dicaprylyl Carbonate may be synthetic or from animals.

As an emollient, Dicaprylyl Carbonate creates a film on the skin. This film traps moisture in, keeping your skin soft and hydrated.

Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:

The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate (long name, huh?) is a synthetic antioxidant.

It is used to help stabilize other antioxidants or prevent the color from changing in a product.

As an antioxidant, it helps fight free-radical molecules. Free-radical molecules are capable of damaging our cells and other genetic material. Thus, antioxidants may reduce the signs of aging.

This ingredient is oil-soluble.

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

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.

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.

Sodium Phytate is the synthetic salt form of phytic acid. Phytic acid is an antioxidant and can be found in plant seeds.

Sodium Phytate is a chelating agent. Chelating agents help prevent metals from binding to water. This helps stabilize the ingredients and the product.

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

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.

01

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. 03Glycolic Acid is arguably the most famous alpha hydroxy acid (AHA) with tons of research backing its benefits.
  4. 04It is found naturally in sugar cane but the form used in skincare is usually synthetic for purity and stability.
  5. 05Glycolic acid removes the top layer of dead skin cells to allow newer and fresher ones to emerge.
  6. 06AHAs work by breaking down the structural “glue” that holds old skin cells in place. When that buildup is gone, your skin can renew itself more efficiently.
  7. 07Research also shows glycolic acid stimulates collagen production, helping to firm and thicken the skin over time. This is one of its biggest advantages over other AHAs.
  8. 08Overall, glycolic acid helps with:
  9. 09Fun fact: Glycolic acid boosts skin hydration by helping it produce molecules that increase hyaluronic acid naturally.
  10. 10To work best, glycolic acid products should have a pH between 3-4 (that’s where exfoliation is most effective but still gentle on skin).
  11. 11The pH and concentration of a product are key to its effectiveness:
  12. 12It is normal to feel a slight stinging sensation when using glycolic acid. This usually fades as your skin adjusts.
  13. 13Because glycolic acid has the smallest molecular size in the AHA family, it can penetrate deeper, which enhances its effectiveness but also makes it more likely to irritate sensitive skin.
  14. 14If your skin is very sensitive or prone to rosacea, glycolic acid may be too strong; in that case, try milder options like lactic acid or a PHA instead.
  15. 15Recent studies suggest glycolic acid might even help protect against UV damage. But don’t skip sunscreen! Freshly exfoliated skin is more sensitive to the sun.
  16. 16Glycolic acid is a skincare superstar. It smooths, brightens, hydrates, and firms the skin. Unless you’re highly sensitive, it’s well worth adding to your routine.
  17. 17Read more about some other popular AHA's here:
  18. 18Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).
  19. 19It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.
  20. 20On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.
Source · skinsort.com
02

Product index

Related product references

03

Comparison edit

Read side by side