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Skin science article

Paula's Choice Resist Intensive Wrinkle-Repair Retinol Serum Versus Paula's Choice Resist Intensive Repair Cream

Paula's Choice Resist Intensive Wrinkle-Repair Retinol Serum Versus Paula's Choice Resist Intensive Repair Cream This anti-aging serum is formulated around Retinol and Tetrahexyldecyl Ascorbate to soften the look of wrinkles and refine skin texture. This anti-

Paula's Choice Resist Intensive Wrinkle-Repair Retinol Serum Versus Paula's Choice Resist Intensive Repair Cream

This anti-aging serum is formulated around Retinol and Tetrahexyldecyl Ascorbate to soften the look of wrinkles and refine skin texture.

This anti-aging moisturizer is formulated around Retinol and Simmondsia Chinensis Seed Oil to soften the look of wrinkles and hydrate skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Cyclopentasiloxane

Dimethiconol

Neopentyl Glycol Diheptanoate

Dicaprylyl Carbonate

Caprylic/Capric Triglyceride

Phenyl Trimethicone

Squalane

Bisabolol

Tetrahexyldecyl Ascorbate

Retinol

Tocotrienols

Tocopherol

Lecithin

Laminaria Ochroleuca Extract

Avena Sativa Kernel Extract

Elaeis Guineensis Oil

Stearyl Glycyrrhetinate

Hexylene Glycol

Caprylyl Glycol

Ethylhexylglycerin

Phenoxyethanol

Cyclopentasiloxane, Dimethiconol, Neopentyl Glycol Diheptanoate, Dicaprylyl Carbonate, Caprylic/Capric Triglyceride, Phenyl Trimethicone, Squalane, Bisabolol, Tetrahexyldecyl Ascorbate, Retinol, Tocotrienols, Tocopherol, Lecithin, Laminaria Ochroleuca Extract, Avena Sativa Kernel Extract, Elaeis Guineensis Oil, Stearyl Glycyrrhetinate, Hexylene Glycol, Caprylyl Glycol, Ethylhexylglycerin, Phenoxyethanol

Water

Ethylhexyl Stearate

Simmondsia Chinensis Seed Oil

Butylene Glycol

Glycerin

Petrolatum

Cetearyl Alcohol

Dimethicone

Dipentaerythrityl Hexacaprylate/Hexacaprate

Glyceryl Stearate

Tridecyl Trimellitate

PEG-100 Stearate

Adenosine

Palmitoyl Tetrapeptide-7

Palmitoyl Hexapeptide-12

Palmitoyl Tripeptide-1

Ceramide Ng

Sodium Hyaluronate

Magnesium Ascorbyl Phosphate

Niacinamide

Linoleic Acid

Linolenic Acid

Retinyl Palmitate

Glycyrrhiza Glabra Root Extract

Camellia Oleifera Leaf Extract

Citrullus Lanatus Fruit Extract

Lens Esculenta Fruit Extract

Pyrus Malus Fruit Extract

Glycine Soja Sterols

Tribehenin

PEG-10 Phytosterol

Magnesium Aluminum Silicate

Sodium PCA

Sodium Lactate

Pullulan

Xanthan Gum

Sodium Hydroxide

Neopentyl Glycol Dicaprylate/Dicaprate

Cetearyl Glucoside

Tridecyl Stearate

Behenyl Alcohol

Sclerotium Gum

Carbomer

C12-15 Alkyl Benzoate

Polysorbate 20

Disodium EDTA

Sorbic Acid

Chlorphenesin

Benzoic Acid

Water, Ethylhexyl Stearate, Simmondsia Chinensis Seed Oil, Butylene Glycol, Glycerin, Caprylic/Capric Triglyceride, Petrolatum, Cetearyl Alcohol, Dimethicone, Dipentaerythrityl Hexacaprylate/Hexacaprate, Glyceryl Stearate, Tridecyl Trimellitate, PEG-100 Stearate, Phenyl Trimethicone, Retinol, Adenosine, Palmitoyl Tetrapeptide-7, Palmitoyl Hexapeptide-12, Palmitoyl Tripeptide-1, Ceramide Ng, Sodium Hyaluronate, Magnesium Ascorbyl Phosphate, Niacinamide, Tocopherol, Lecithin, Linoleic Acid, Linolenic Acid, Retinyl Palmitate, Glycyrrhiza Glabra Root Extract, Camellia Oleifera Leaf Extract, Citrullus Lanatus Fruit Extract, Lens Esculenta Fruit Extract, Pyrus Malus Fruit Extract, Glycine Soja Sterols, Tribehenin, PEG-10 Phytosterol, Magnesium Aluminum Silicate, Sodium PCA, Sodium Lactate, Pullulan, Xanthan Gum, Sodium Hydroxide, Neopentyl Glycol Dicaprylate/Dicaprate, Cetearyl Glucoside, Tridecyl Stearate, Behenyl Alcohol, Sclerotium Gum, Carbomer, C12-15 Alkyl Benzoate, Polysorbate 20, Disodium EDTA, Sorbic Acid, Phenoxyethanol, Chlorphenesin, Benzoic Acid

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Caprylic/Capric Triglyceride (aka MCT Oil) is a lightweight emollient, solvent, and texture enhancer. It is considered a skin-softener by helping to prevent moisture loss.

Though it behaves like an oil, it is not technically one due to its chemical composition. One perk of this ingredient is that it is very stable, resistant to oxidation, and unlikely to go rancid.

In practice, that translates to a long shelf life and a consistently elegant skin feel.

While there is an assumption Caprylic Triglyceride can clog pores due to it being derived from coconut oil, there is no research supporting this. Just patch test if you have concerns.

Fractionated coconut oil and MCT Oil are both listed as Caprylic/Capric Triglyceride according to INCI. This is because INCI names are based on the ingredient’s final chemical composition and not its marketing name or source.

This ingredient is treated as the gold standard fungal acne safe oil. Even though it is coconut derived, the problematic lauric acid is stripped out.

This leaves just caprylic (C8) and capric (C10) acid. These chain lengths actually trend antifungal; a 2020 study found caprylic acid was enough to disrupt Malassezia furfur cell membrane, with a caprylic acid derivative damaging membrane structures at concentrations as low as 0.2%.

Lecithin is a term for a group of substances found in the cell membranes of plants, animals, and humans. They are made up of phospholipids.

Thanks to its amphiphilic structure (water-loving head and oil-loving tail), it is a true multitasker:

It plays well with most ingredients and is typically used at 0.1-1%. However, concentrations up to 50% have been reported in moisturizers.

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.

Phenyl Trimethicone is a silicon-based polymer. It is derived from silica.

Phenyl Trimethicone is used as an emollient and prevents products from foaming.

As an emollient, it helps trap moisture in the skin. It is considered an occlusive.

Retinol is one of the most studied anti-aging ingredients in skincare (and for good reason!).

It's a form of vitamin A that your skin converts into Retinoic Acid, the active molecule that actually does the work in your cells.

That conversion happens in two steps: your skin first turns Retinol into Retinaldehyde (also called Retinal), then turns Retinaldehyde into Retinoic Acid.

Retinol is converted to biologically active retinoic acid via retinaldehyde by dehydrogenases in a two-step oxidation process.

Each step is a little "upgrade" toward the active form which is part of why Retinol is gentler than prescription Retinoic Acid; your skin does the work gradually. This also explains where Retinol sits in the retinoid family.

Here is the retinoid family ranked roughly by strength: Retinyl Esters (like Retinyl Palmitate) < Retinol < Retinaldehyde < Retinoic Acid.

Retinoid activity increases in that order, while tolerance runs in reverse; retinyl esters are the gentlest and retinoic acid the most irritating.

The more conversion steps an ingredient needs, the gentler (and slower) it tends to be, so Retinol lands in a nice middle spot. It's more effective than the esters, gentler than prescription options.

Once it becomes Retinoic Acid, it binds to receptors inside your cells' nuclei (called RARs and RXRs). These receptor pairs bind to specific DNA motifs called retinoic acid response elements and act like switches that turn certain genes on or off.

In practice, this means a few things happen in a formula. It:

That last two are worth a closer look.

A study that tested Retinol directly (not just prescription Retinoic Acid) found that four weeks of retinol thickened the epidermis and switched on the genes for Collagen I and Collagen III, with more procollagen I and III showing up in the skin. And after twelve weeks, facial wrinkles were visibly reduced.

Retinoids more broadly stimulate the skin's synthesis of hyaluronan and other glycosaminoglycans, part of what gives skin a plumper, more hydrated look over time.

So even the gentler OTC form is doing real structural work (not just sitting on the surface).

It's also worth knowing Retinol isn't only a wrinkle ingredient; it can help with uneven tone, dark spots, rough texture, and the look of pores as well because it speeds up turnover and influences pigment.

The research backs this up as well.

A pooled analysis of six clinical studies found that 0.1% stabilized retinol improved all signs of photoaging versus vehicle as early as week 4 and through 12 weeks, with only a few mild cases of irritation.

Another study comparing concentrations found that 0.3% and 1% Retinol were similarly effective at remodeling photodamaged skin, but 0.3% caused fewer adverse reactions when used daily (a useful reminder that more isn't always better).

Retinol is about tenfold less potent than Retinoic Acid. This is why it works as a gentler, non-prescription option that builds results over time.

Typical concentrations range from 0.1-1%, with 0.1% to 0.3% being a well-supported sweet spot for visible benefits with good tolerability.

One quirk worth mentioning: Retinol is famously unstable.

It's highly sensitive to light and oxygen, and UV exposure breaks it down into a range of degradation products.

Real-world testing bears this out, with retinoid content in some products dropping anywhere from 0% to 80% after six months at room temperature, and even more at higher temperatures.

This is why good formulations lean on opaque, air-tight packaging (think tubes and pumps, not clear jars) and often "encapsulate" the Retinol to shield it.

Signs of oxidation include your product turning yellow or smelling "off". Keeping it somewhere cool and dark, and using it up within a few months of opening helps it stay effective.

The most common side effects are mild and temporary: usually some dryness, redness, or light peeling as your skin adjusts. These tend to settle with consistent and lower-frequency use.

Like all retinoids, Retinol works best with nightly use, a good moisturizer, and daytime sunscreen.

The "ramp up" method works well: start with Retinol once a week to give your skin time to adjust, which keeps irritation low. Slowly add more nights until you reach your goal frequency once your skin feels comfortable.

Retinoids also make your skin more sensitive to the sun in the first few weeks, so wear sunscreen every morning and protect your skin from direct sun while you build up tolerance.

One safety note: topical Retinoids aren't recommended during pregnancy or breastfeeding. Systemic absorption from creams is low but because high oral vitamin A is a known teratogen and topical safety data are limited, most clinicians recommend stopping retinoids when pregnant or trying to conceive.

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.

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. 03Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
  4. 04Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
  5. 05Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.
  6. 06Sodium 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.
  7. 07In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.
  8. 08Your 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.
  9. 09"Alkaline" refers to a high pH level. A low pH level would be considered acidic.
  10. 10Water. 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.
  11. 11So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
  12. 12You'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
02

Product index

Related product references

03

Comparison edit

Read side by side