Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Cocokind Advanced Retinol Gel 0.5% Versus Paula's Choice Pro Retinaldehyde Dual-Retinoid Treatment

Cocokind Advanced Retinol Gel 0.5% Versus Paula's Choice Pro Retinaldehyde Dual-Retinoid Treatment This anti-aging treatment is formulated around Retinol and Hydroxypinacolone Retinoate to soften the look of wrinkles and refine skin texture. This anti-aging tr

Cocokind Advanced Retinol Gel 0.5% Versus Paula's Choice Pro Retinaldehyde Dual-Retinoid Treatment

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

This anti-aging treatment is formulated around Retinal and Oleyl Adapalenate to soften the look of wrinkles and refine skin texture.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Aloe Barbadensis Leaf Juice

Glycerin

Glycine Soja Oil

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Caprylic/Capric Triglyceride

Coco-Caprylate/Caprate

C14-22 Alcohols

Fructooligosaccharides

Dimethyl Isosorbide

Glyceryl Caprylate

Pentylene Glycol

Squalane

Retinol

Hydroxypinacolone Retinoate

Retinal

Tocopherol

Centella Asiatica Extract

Allantoin

Beta Vulgaris Root Extract

Sodium Hyaluronate

Tamarindus Indica Seed Polysaccharide

Potassium Lactate

Cellulose

Sorbitan Isostearate

Propanediol

Tetrasodium Glutamate Diacetate

C12-20 Alkyl Glucoside

Caprylhydroxamic Acid

Lactic Acid

Potassium Sorbate

Sodium Benzoate

Citric Acid

Sodium Hydroxide

Water, Aloe Barbadensis Leaf Juice, Glycerin, Glycine Soja Oil, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Caprylic/Capric Triglyceride, Coco-Caprylate/Caprate, C14-22 Alcohols, Fructooligosaccharides, Dimethyl Isosorbide, Glyceryl Caprylate, Pentylene Glycol, Squalane, Retinol, Hydroxypinacolone Retinoate, Retinal, Tocopherol, Centella Asiatica Extract, Allantoin, Beta Vulgaris Root Extract, Sodium Hyaluronate, Tamarindus Indica Seed Polysaccharide, Potassium Lactate, Cellulose, Sorbitan Isostearate, Propanediol, Tetrasodium Glutamate Diacetate, C12-20 Alkyl Glucoside, Caprylhydroxamic Acid, Lactic Acid, Potassium Sorbate, Sodium Benzoate, Citric Acid, Sodium Hydroxide

Simmondsia Chinensis Seed Oil

Dimethicone

Polyglyceryl-2 Stearate

Polyglyceryl-3 Diisostearate

Sodium Stearoyl Glutamate

Oleyl Adapalenate

Tocopheryl Acetate

Saccharomyces Ferment Filtrate

Albatrellus Confluens Extract

Punica Granatum Pericarp Extract

Glyceryl Stearate

Stearyl Alcohol

Hydroxyapatite

Butylene Glycol

Cetyl Glyceryl Ether

Ricinus Communis Seed Oil

Sodium Polyacrylate

Isopropyl Myristate

Hydroxyacetophenone

Sodium Phytate

Xanthan Gum

Hydroxystearic Acid

Ceramide AP

1,2-Hexanediol

Sorbitan Oleate

Naringin

Titanium Dioxide

Water, Caprylic/Capric Triglyceride, Simmondsia Chinensis Seed Oil, Dimethicone, Polyglyceryl-2 Stearate, Propanediol, Polyglyceryl-3 Diisostearate, Sodium Stearoyl Glutamate, Retinal, Oleyl Adapalenate, Tocopherol, Tocopheryl Acetate, Saccharomyces Ferment Filtrate, Albatrellus Confluens Extract, Punica Granatum Pericarp Extract, Glyceryl Stearate, Stearyl Alcohol, Hydroxyapatite, Butylene Glycol, Cetyl Glyceryl Ether, Ricinus Communis Seed Oil, Sodium Polyacrylate, Isopropyl Myristate, Hydroxyacetophenone, Caprylhydroxamic Acid, Sodium Phytate, Xanthan Gum, Glycerin, Hydroxystearic Acid, Ceramide AP, 1,2-Hexanediol, Sorbitan Oleate, Naringin, Citric Acid, Titanium Dioxide

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.

Caprylhydroxamic Acid is a chelating agent that helps cosmetics stay fresh, stable, and consistent over time.

Chelating agents help prevent metal ions from binding to other ingredients. This helps prevent unwanted reactions and effects from using the product. It also helps prevent the growth of unwanted microbes in products that contain water.

Caprylhydroxamic Acid is often used with natural antimicrobial products as an alternative to preservatives.

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%.

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.

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.

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.

Retinal (aka retinaldehyde) is a form of retinoid that formulators use mainly as an antiaging and skin-renewing active.

What makes it special is its position in the retinoid family; skin converts it to retinoic acid (the prescription gold standard) in just one step.

Because retinal only requires 1 conversion step to become retinoic acid, it's the strongest over-the-counter retinoid. It also works at lower concentrations than retinol, since retinal is about 10x more bioavailable.

Studies back up its efficacy in skin:

A foundational trial showed that applying 0.05-0.5% retinal for 1-3 months produced a dose-dependent and significant increase in epidermal thickness + cell turnover markers.

And a head-to-head comparison of 0.05% retinal against a 0.05% retinoid acid found both formulations were effective for the basis of wrinkle/skin roughness features, but retinoic acid caused more local irritation.

More recent controlled trials confirm it improves wrinkles, dermal density, and firmness over 12-24 weeks, with significant improvements in skin texture and firmness (particularly with the higher 0.1% concentration).

Retinal also has one trick the other retinoids do not: it directly fights against acne bacteria since a clinical study showed retinaldehyde-treated areas displayed a significant decrease in counts of viable P. acnes.

This makes it a great pick for people who want to treat aging and breakouts.

Typical cosmetic use sits in the 0.05-0.1% range with 0.05% being the gentle starting point and 0.1% giving stronger results.

Like all retinoids, retinal works best with nightly use, a good moisturizer, and daytime sunscreen. It can cause some irritation so ease into it slowly rather than going all in.

The "ramp up" method works well: start with Retinal 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.

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

Paula's Choice Defense Triple Algae Pollution ShieldIngredients explained

  1. 01Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product.
  2. 02It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water.
  3. 03Expand to read more
  4. 04Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying.
  5. 05One more thing: the water used in cosmetics is purified and deionized (it means that almost all of the mineral ions inside it is removed). Like this, the products can stay more stable over time.
  6. 06A natural moisturizer that’s also in our skin
  7. 07A super common, safe, effective and cheap molecule used for more than 50 years
  8. 08Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
  9. 09Effective from as low as 3% with even more benefits for dry skin at higher concentrations up to 20-40%
  10. 10High-glycerin moisturizers are awesome for treating severely dry skin
  11. 11Butylene glycol, or let’s just call it BG, is a multi-tasking colorless, syrupy liquid. It’s a great pick for creating a nice feeling product.
  12. 12BG’s main job is usually to be a solvent for the other ingredients. Other tasks include helping the product to absorb faster and deeper into the skin (penetration enhancer), making the product spread nicely over the skin (slip agent), and attracting…
  13. 13It’s an ingredient whose safety hasn’t been questioned so far by anyone (at least not that we know about). BG is approved by Ecocert and is also used enthusiastically in natural products. BTW, it’s also a food additive.
  14. 14A light emollient ester (C8-10 fatty acids connected to C12-18 fatty alcohols) that absorbs quickly and leaves a dry but silky finish on the skin. In terms of skin feel, it is similar to Dicaprylyl Carbonate, another commonly used light emollient.
  15. 15We don't have description for this ingredient yet.
  16. 16Cucumber is a nice, non-irritating plant extract that’s known for it’s soothing and emollient properties. It’s not something new to put it on our face: even Cleopatra used it to “preserve her skin”.
  17. 17It’s commonly believed that cucumber is the answer to puffy eyes, but there is no research confirming this. What research does confirm is that it contains amino acids and organic acids that’s helpful for the skin’s acid mantle. There is also an enzy…
  18. 18Arctostaphylos Uva-Ursi is a little plant with nice red berries that lives in the North and is also called bearberry or kinnikinnick. According to Wikipedia the uva-ursi part means “grape of the bear”.
  19. 19As for skincare bearberry is interesting because it contains the well-known skin lightening agent arbutin. The leaves contain 5-15% percent of it and might be able to help fading brown spots on the skin. Also, kinnikinnick (such a cool name :)) is a…
  20. 20Propanediol is a natural alternative for the often used and often bad-mouthed propylene glycol. It's produced sustainably from corn sugar and it's Ecocert approved.
Source · incidecoder.com
02

Product index

Related product references

03

Comparison edit

Read side by side