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Skin science article

Paula's Choice 1% Retinol Booster Versus Murad Retinol Youth Renewal Serum

Paula's Choice 1% Retinol Booster Versus Murad Retinol Youth Renewal Serum This anti-aging treatment is formulated around Retinol and Ceramide NP to soften the look of wrinkles and refine skin texture. This anti-aging serum is formulated around Retinol and Hyd

Paula's Choice 1% Retinol Booster Versus Murad Retinol Youth Renewal Serum

This anti-aging treatment is formulated around Retinol and Ceramide NP to soften the look of wrinkles and refine skin texture.

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

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

Carthamus Tinctorius Seed Oil

Polyglyceryl-10 Caprylate/Caprate

Butylene Glycol

Pyrus Malus Fruit Extract

Polysorbate 20

Retinol

Glycyrrhiza Glabra Root

Ceramide NP

Palmitoyl Tripeptide-1

Avena Sativa Kernel Extract

Epilobium Angustifolium Extract

Arctium Lappa Seed Oil

Salix Alba Extract

Allantoin

Dipotassium Glycyrrhizate

Caprylyl Glycol

Polyglyceryl-10 Laurate

Dipentaerythrityl Hexacaprylate/Hexacaprate

Ethylhexyl Olivate

Hydrogenated Lecithin

Glyceryl Ascorbate

Disodium EDTA

Sorbic Acid

Xanthan Gum

Phenoxyethanol

Water, Glycerin, Carthamus Tinctorius Seed Oil, Polyglyceryl-10 Caprylate/Caprate, Butylene Glycol, Pyrus Malus Fruit Extract, Polysorbate 20, Retinol, Glycyrrhiza Glabra Root, Ceramide NP, Palmitoyl Tripeptide-1, Avena Sativa Kernel Extract, Epilobium Angustifolium Extract, Arctium Lappa Seed Oil, Salix Alba Extract, Allantoin, Dipotassium Glycyrrhizate, Caprylyl Glycol, Polyglyceryl-10 Laurate, Dipentaerythrityl Hexacaprylate/Hexacaprate, Ethylhexyl Olivate, Hydrogenated Lecithin, Glyceryl Ascorbate, Disodium EDTA, Sorbic Acid, Xanthan Gum, Phenoxyethanol

Cyclopentasiloxane

Isopropyl Palmitate

C14-22 Alcohols

Polymethylsilsesquioxane

Dimethicone

Propanediol

Glyceryl Stearate

PEG-100 Stearate

Shea Butter Ethyl Esters

Hydroxypinacolone Retinoate

Sodium Hyaluronate

Solanum Lycopersicum Fruit Extract

Swertia Chirata Extract

Squalane

Punica Granatum Extract

Tocopheryl Acetate

Glycine Soja Extract

Urea

Yeast Amino Acids

Trehalose

Inositol

Taurine

Betaine

Caprylic/Capric Triglyceride

Dimethyl Isosorbide

Silica

Ethylhexyl Palmitate

Silica Dimethyl Silylate

Lecithin

Ammonium Acryloyldimethyltaurate/Vp Copolymer

C12-20 Alkyl Glucoside

Cetyl Palmitate

Laureth-23

Trideceth-6 Phosphate

Synthetic Fluorphlogopite

Ethylhexylglycerin

Chlorphenesin

Sodium Hydroxide

Tris(Tetramethylhydroxypiperidinol)Citrate

Sodium Benzotriazolyl Butylphenol Sulfonate

CI 77891

CI 14700

Alpha-Isomethyl Ionone

Citronellol

Parfum

Water, Cyclopentasiloxane, Isopropyl Palmitate, C14-22 Alcohols, Polymethylsilsesquioxane, Dimethicone, Propanediol, Glyceryl Stearate, PEG-100 Stearate, Shea Butter Ethyl Esters, Retinol, Hydroxypinacolone Retinoate, Ceramide NP, Sodium Hyaluronate, Solanum Lycopersicum Fruit Extract, Swertia Chirata Extract, Squalane, Punica Granatum Extract, Tocopheryl Acetate, Glycine Soja Extract, Urea, Yeast Amino Acids, Trehalose, Inositol, Taurine, Betaine, Glycerin, Caprylic/Capric Triglyceride, Dimethyl Isosorbide, Silica, Ethylhexyl Palmitate, Silica Dimethyl Silylate, Butylene Glycol, Lecithin, Ammonium Acryloyldimethyltaurate/Vp Copolymer, C12-20 Alkyl Glucoside, Cetyl Palmitate, Laureth-23, Polysorbate 20, Trideceth-6 Phosphate, Synthetic Fluorphlogopite, Phenoxyethanol, Ethylhexylglycerin, Chlorphenesin, Disodium EDTA, Sodium Hydroxide, Tris(Tetramethylhydroxypiperidinol)Citrate, Sodium Benzotriazolyl Butylphenol Sulfonate, CI 77891, CI 14700, Alpha-Isomethyl Ionone, Citronellol, Parfum

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Though 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.

Ceramide NP (formerly known as Ceramide 3) is one of the skin's naturally occurring lipids.

Since ceramides are the major lipid components of the skin, they are crucial for maintaining skin barrier and hydration. Ceramide NP most closely mirrors the dominant kind in human skin amongst ceramide subtypes.

This ceramide works by slotting into gaps within the stratum corneum's lipid matrix to limit trans-epidermal water loss (TEWL) and shield the skin against external irritants.

A study with 312 patients found that using a ceramide-containing routine for 4 weeks reduced the severity of atopic dermatitis by over 61%.

Another clinical study in subjects aged 60 and older found that a ceramide body wash and moisturizer improved skin dryness and itchy skin in 15 days.

Overall, ceramides are considered non-irritating and safety tests have found little to no observable adverse effects from using this ingredient.

Ceramide NP is usually sourced from plants (like soybean or rice bran), or produced synthetically.

Disodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.

This ingredient mainly works behind the scenes and helps with:

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

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.

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.

Polysorbate 20 is a gentle, water-soluble emulsifier and mild surfactant. It stops oil and water from separating to keep your formulas blended and stable.

It also acts as a mild penetration enhancer by helping active ingredients absorb slightly better.

The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.

Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).

True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.

Because it is derived from lauric acid, it may not be fungal acne safe.

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.

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. 03We don't have a description for Salix Nigra Bark Extract yet.
  4. 04Triethoxycaprylylsilane is a silicon-based surface modifier that makes sunscreens feel silky and makeup stay put.
  5. 05Its main job is to coat mineral particles like titanium dioxide, zinc oxide, and color pigments in a thin, oily layer so they spread smoothly, don't clump, and stick to skin better.
  6. 06This ingredient is typically used at low levels (up to 2.5% in eyeshadow and 1% in lipstick).
  7. 07Water. 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.
  8. 08So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
  9. 09You'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!
  10. 10Zinc Oxide (ZO) is a mineral broad-spectrum UV filter and the broadest-spectrum filter recognized by the FDA. It covers everything from UVB through to long-wave UVA.
  11. 11On top of sun protection, it has skin protectant and skin-soothing properties too.
  12. 12Here's a myth worth busting: mineral filters are usually described as working by "reflecting" or "bouncing" UV off your skin.
  13. 13That's mostly not true: when researchers actually measured it, ZO and Titanium Dioxide reflect only about 4-5% of UV (less than SPF 2 worth of protection).
  14. 14The vast majority of the work (~95%) is done by absorption, similar to chemical UV filters. ZO is a semiconductor that absorbs UV photos through its energy band gap.
  15. 15So the old "physical blocker vs. chemical absorber" framing is really an oversimplification.
  16. 16Zinc Oxide is one of the most effective broad-spectrum UV filters out there. It protects across UVB, UVA2, and UVA1 with a flat, even absorption curve across the whole UVA-UVB range.
  17. 17That uniform UVA coverage is its standout feature; titanium dioxide skews more toward UVB as its particle size drops so ZO gives more consistent and extended UVA protection.
  18. 18It's also very photostable. As an inorganic oxide, ZO doesn't break down in sunlight the way some organic filters can, so it holds up over a day of wear.
  19. 19This ingredient is gentle and soothing, making it go-to for sunscreens aimed at sensitive skin, rosacea, or ecezma-prone skin, babies, and children.
  20. 20It's also unlikely to cause the "eye sting" that some sunscreen ingredients are known for, and regulatory agencies broadly consider it non-toxic and safe for topical use.
Source · skinsort.com
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Comparison edit

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