Paula's Choice

Resist Intensive Repair Cream

Butylene 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.  

BG’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 water (humectant) into the skin.

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• A natural moisturizer that’s also in our skin
• A super common, safe, effective and cheap molecule used for more than 50 years
• Not 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
• Effective from as low as 3% with even more benefits at higher concentrations up to 20-40% (around 10% is a good usability-effectiveness sweet spot)
• High-glycerin moisturizers are awesome for treating severely dry skin

A super common emollient that makes your skin feel nice and smooth. It comes from coconut oil and glycerin, it’s light-textured, clear, odorless and non-greasy. It’s a nice ingredient that just feels good on the skin, is super well tolerated by every skin type and easy to formulate with. No wonder it’s popular. 

The famous Vaseline or Petroleum Jelly. Just like mineral oil, it is also a by-product of refining crude oil, aka petroleum, and it is also a mixture of hydrocarbons but with bigger (C18-90+) carbon chain length.

The unique thing about petrolatum is that it is the most effective occlusive agent known today. While the occlusivity of mineral oil is in the same league as the occlusivity of plant oils, petrolatum is in a league of its own. It sits on top of the skin and hinders so-called transepidermal water loss (TEWL) like nothing else.

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An extremely common multitasker ingredient that gives your skin a nice soft feel (emollient) and gives body to creams and lotions. It also helps to stabilize oil-water mixes (emulsions), though it does not function as an emulsifier in itself. Its typical use level in most cream type formulas is 2-3%.  

It’s a so-called fatty alcohol, a mix of cetyl and stearyl alcohol, other two emollient fatty alcohols.  Though chemically speaking, it is alcohol (as in, it has an -OH group in its molecule), its properties are totally different from the properties of low molecular weight or drying alcohols such as denat. alcohol. Fatty alcohols have a long oil-soluble (and thus emollient) tail part that makes them absolutely non-drying and non-irritating and are totally ok for the skin.

Probably the most common silicone of all. It is a polymer (created from repeating subunits) molecule and has different molecular weight and thus different viscosity versions from water-light to thick liquid.

As for skincare, it makes the skin silky smooth, creates a subtle gloss and forms a protective barrier (aka occlusive). Also, works well to fill in fine lines and wrinkles and give skin a plump look (of course that is only temporary, but still, it's nice). There are also scar treatment gels out there using dimethicone as their base ingredient. It helps to soften scars and increase their elasticity. 

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A medium viscosity, odorless oily liquid that leaves an excellent afterfeel, with the skin feeling soft and conditioned. The feel is described by the manufacturer as slightly oily but not tacky or sticky.

Dipentaerythrityl Hexacaprylate/Hexacaprate often comes to the formula mixed with two other emollients, Tridecyl Stearate, and Tridecyl Trimellitate, as the trio can match the aesthetic and textural properties of ruined-by-natural-marketers mineral oil.

A super common, waxy, white, solid stuff that helps water and oil to mix together, gives body to creams and leaves the skin feeling soft and smooth.

Chemically speaking, it is the attachment of a glycerin molecule to the fatty acid called stearic acid. It can be produced from most vegetable oils (in oils three fatty acid molecules are attached to glycerin instead of just one like here) in a pretty simple, "green" process that is similar to soap making. It's readily biodegradable.

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A viscous, thick liquid emollient that gives lubricity and cushion at low use levels. It's great for night creams, eye area products, and skin treatment products due to the substantive film forming ability. 

A very common water-loving surfactant and emulsifier that helps to keep water and oil mixed nicely together. 

It's often paired with glyceryl stearate - the two together form a super effective emulsifier duo that's salt and acid tolerant and works over a wide pH range. It also gives a "pleasing product aesthetics", so no wonder it's popular.

A silicone fluid that gives a nonoily, easy to spread emolliency to the formulas. It is also used as a water repellent additive and to reduce the tackiness and stickiness of other ingredients. It also imparts gloss, softness and better manageability to hair.

• Retinol (pure Vitamin A) is probably the most proven anti-aging ingredient available OTC
• It has to be converted in the skin to retinoic acid to work its magic
• Once converted, it has the same effect as all-trans-retinoic acid, aka tretinoin
• A generally accepted ballpark number is that retinol is 10-to-20 times less potent than retinoic acid
• It makes skin less wrinkled, smoother, firmer and tighter
• It might also be helpful for acne prone skin as it normalizes keratinization and makes the pores produce less sebum
• Possible side effects and irritation are also much less than with retinoic acid
• Do not use whilst pregnant

Adenosine is an important little compound in our body that has a vital cell-signalling role. Research on smearing it on our face is also promising and shows so far a couple of things:

• It can help with wound healing
• It’s a good anti-inflammatory agent
• It might even help with skin’s own collagen production and improve skin firmness and elasticity
• It helps with barrier repair and protection
• It might be even useful for the hair helping with hair thickness and hair growth

A four amino acid peptide with the amino sequence of glycine-glutamine-proline-arginine. It is attached to palmitic acid (a fatty acid)  to increase oil solubility and skin penetration. 

It works by reducing the production of the signal molecule, inteleukin-6 (IL-6) which promotes inflammation in the skin and less inflammation means slower degradation of important things (like collagen) that results in younger looking skin for a longer time. 

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A six amino acid peptide that is claimed to improve firmness and skin tone. Its amino acid sequence is Val-Gly-Val-Ala-Pro-Gly that is also called the "spring fragment" and is repeated six times in the important skin protein, elastin molecule.

The manufacturer made a double-blind, one-month long clinical study on 10 women and found that twice a day application of 4%  Biopeptide El improved skin firmness by 33% and skin tone by 20%. 

A really famous peptide that is part of Matrixyl 3000, the most sold peptide complex in the word. Before we go and find out what the big deal with Matrixyl 3000 is, let's just focus on Palmitoyl Tripeptide-1 itself for a bit.

It's a small three amino acid (they are the building blocks of all proteins) peptide with the amino sequence of glycine-histidine-lysine, or GHK. GHK is attached to palmitic acid (a fatty acid) to increase oil solubility and skin penetration. 

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One of the 9 types of ceramides that can be found naturally in the upper layer of the skin. Ceramides make up a big part (about 50%) of the goopy stuff that's between our skin cells (called extracellular matrix) and play a super important role in having a healthy skin barrier and keeping the skin hydrated. 

We wrote way more about ceramides at ceramide 1, so click here to know more.

It’s the - sodium form - cousin of the famous NMF, hyaluronic acid (HA). If HA does not tell you anything we have a super detailed, geeky explanation about it here.  The TL; DR version of HA is that it's a huge polymer (big molecule from repeated subunits) found in the skin that acts as a sponge helping the skin to hold onto water, being plump and elastic. HA is famous for its crazy water holding capacity as it can bind up to 1000 times its own weight in water.

As far as skincare goes, sodium hyaluronate and hyaluronic acid are pretty much the same and the two names are used interchangeably. As cosmetic chemist kindofstephen writes on reddit  "sodium hyaluronate disassociates into hyaluronic acid molecule and a sodium atom in solution". 

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A form of skincare superstar, Vitamin C. If you do not know, what the big deal about Vitamin C is, click here and read all about it, we will wait here for you. 

So now you know that pure vitamin C (aka ascorbic acid, AA) is really unstable and hard to formulate so the cosmetics industry is coming up with a bunch of derivatives to solve the problem and Magnesium Ascorbyl Phosphate (or MAP) is one of them.  

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• A multi-functional skincare superstar with several proven benefits for the skin
• Great anti-aging, wrinkle smoothing ingredient used at 4-5% concentration
• Fades brown spots alone or in combination with amino sugar, acetyl glucosamine
• Increases ceramide synthesis that results in a stronger, healthier skin barrier and better skin hydration
• Can help to improve several skin conditions including acne, rosacea, and atopic dermatitis

• Primary fat-soluble antioxidant in our skin
• Significant photoprotection against UVB rays
• Vit C + Vit E work in synergy and provide great photoprotection
• Has emollient properties
• Easy to formulate, stable and relatively inexpensive

A very common ingredient that can be found in all cell membranes. In cosmetics it's quite the multi-tasker: it's an emollient and water-binding ingredient but it's also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes. 

The famous omega-6 fatty acid, the mother of all ω-6 fatty acids in our body. It is a so-called polyunsaturated fatty acid meaning it has more than one (in this case two) double bonds and a somewhat kinky structure that makes LA and LA-rich oils a thin liquid.

It is also an essential fatty acid meaning our body cannot synthesize it and has to take it from food. This is not hard at all as plenty of nuts (such as flax, poppy or sesame seeds) and vegetable oils (such as sunflower or safflower) are rich in LA. The hard thing seems to be eating enough omega-3-s, more specifically eating a healthy ratio of omega-6 to omega-3, but that is a topic for a what-is-good-to-eat-site and not for us. 

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The famous omega-3 fatty acid, the mother of all ω-3 fatty acids in our body. Next to linoleic acid, it is the other essential fatty acid that our body cannot synthesize and we have to ingest it from our food. It is also a PUFA, aka polyunsaturated fatty acid with three double bonds, a kinky chemical structure and thus a liquid consistency.

While linoleic acid is abundant in the skin, this is not the case with alpha-linolenic acid (ALA). It is not entirely clear if it is meant to be like that or if this is a consequence of not eating enough Omega-3 with the typical Western diet.

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It's an ester form of vitamin A (retinol + palmitic acid) that belongs to the "retinoid family". The retinoid family is pretty much the royal family of skincare, with the queen being the FDA-approved anti-aging ingredient tretinoin. Retinol is also a very famous member of the family, but it's like Prince William, two steps away from the throne. Retinyl palmitate will be then little Prince George, quite far (3 steps) away from the throne. 

By steps, we mean metabolic steps. Tretinoin, aka retinoic acid, is the active ingredient our skin cells can understand and retinyl palmitate (RP) has to be converted by our metabolic machinery to actually do something. The conversion is a 3 step one and looks like this:

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You might know licorice as a sweet treat from your childhood, but it's actually a legume that grows around the Mediterranean Sea, the Middle East, central and southern Russia. It's sweet and yellow and not only used for licorice all sorts but it's also a skincare superstar thanks to two magic properties:

Nr. 1 magic property is that it has skin-lightening or to say it another way depigmenting properties. The most active part is called glabridin. The topical application (meaning when you put it on your face) of 0.5% glabridin was shown to inhibit UVB caused pigmentation of guinea pigs. Another study even suggested that licorice is more effective than the gold standard skin-lightening agent hydroquinone. All in all, licorice is considered to be one of the safest skin lightening agents with the fewest side effects.

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Camellia Oleifera is a type of green tea plant that's mostly known for the oil that comes from its seeds. As for the leaves, it has similar properties as the better known and more often used Camellia Sinensis leaves. You can read all the geeky details about green tea  and why it's awesome by clicking here, but in short, it has antioxidants and anti-inflammatory magic properties.

We love a cold slice of watermelon on a hot summer day and we love watermelon as a skincare ingredient. It's really full of good-for-the-skin stuff: it contains a bunch of vitamins (A, B, C and E), mineral salts (K, Mg, Ca and Fe), amino acids citrulline and arginine and antioxidant carotenoids and phenolics. 

It's especially rich in potent antioxidant, lycopene (a type of carotenoid), the cool pigment that's responsible for the red color of the watermelon. According to manufacturer info, in-vitro (made in the lab not on real people) studies show that watermelon extract gives significant DNA protection against UV damage. The in-vivo (made on real people) study also confirmed this and the watermelon formula showed 25% increase in skin protection compared to placebo.

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Lentil extract that has nice moisturizing properties on the skin. According to manufacturer info, it contains vitamin B5 and trisaccharides.

Most often lentil comes to the formula as part of a moisturizing trio together with watermelon and apple. The three of them is called AquaCell and is claimed to give 24 hours hydration and to reduce fine lines after only 2 hours. After 2 weeks 3% Aquacell increased key elements in the skin significantly: citrulline by 440%, Sodium PCA by 180%, Sodium Lactate by 60%. Moisture in the skin increased by 35%, dryness decreased by 60% and skin cohesion increased by 50%

Apple needs no introduction as one of the most common fruits on planet Earth. It's not only a healthy fruit snack, it's also a goodie if you put in all over your face. 

It's loaded with proteins, starch, sugars, acids, vitamins and salts. The sugars (mainly fructose, glucose, sucrose) give apple fruit extract nice moisturizing and smoothing properties, while the acids (mainly malic  and gallic acid) give it mild exfoliant, skin brightening and antibacterial properties. 

We don't have description for this ingredient yet.

It's the triglyceride of behenic acid that works as a thickening or gelling agent, as a compacting agent for pressed powders, and improves heat stability of emulsions. 

We don't have description for this ingredient yet.

A type of clay mineral that works as a nice helper ingredient to thicken and stabilize formulas. As a clay, it consists of platelets that have a negative charge on the surface (face) and a positive on the edge. So the face of one platelet attracts the edge of the other and this builds a so-called "house of card" structure meaning that Magnesium Aluminum Silicate (MAS) thickens up products and helps to suspend non-soluble particles such as color pigments or inorganic sunscreens (zinc oxide and titanium dioxide).

As the "house of card" structure takes some time to form but collapses quickly if the formula is stirred, products thickened with MAS can be thick in the jar but become easily spreadable upon application (called thixotropy). MAS also gives nice sensory properties, it is not tacky or sticky and gives a rich, creamy skin feel. Also a good team player and works in synergy with other thickeners such as Cellulose Gum or Xanthan Gum. 

PCA stands for Pyrrolidone Carboxylic Acid and though it might not sound like it, it is a thing that can be found naturally in our skin. The sodium salt form of PCA is an important skin-identical ingredient and great natural moisturizer that helps the skin to hold onto water and stay nicely hydrated. 

The sodium salt of lactic acid. It's a great skin moisturizer and also used to regulate the pH value of the cosmetic formula. It's a natural ingredient approved by both ECOCERT and COSMOS.

The unfancy name for it is lye. It’s a solid white stuff that’s very alkaline and used in small amounts to adjust the pH of the product and make it just right. 

For example, in case of AHA or BHA exfoliants, the right pH is super-duper important, and pH adjusters like sodium hydroxide are needed.  

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An emollient ester (basically an oil like liquid) with a light, elegant and silky feel. It gives a matte finish to the products.

It often comes together with two other esters (called Tridecyl Stearate and Tridecyl Trimellitate) as the three of them can be blended so that they mimic very closely the aesthetic and textural properties of controversial, but nice feeling mineral oil.

A sugar based emulsifier that's especially great for low viscosity lotions or even sprays. It's effective in small amounts, only 1-1.5% is needed to form an emulsion. The resulting cream or lotion has great cosmetic properties with good spreadability and an enhanced soft skin feel. 

A clear, colorless oily liquid that works as a medium feel emollient. It absorbs very quickly into the skin, leaves no shine and gives a nice, velvety after-feel.

A fatty alcohol (the non-drying type with a long oil loving chain of 22 carbon atoms) that is used to increase the viscosity of the formula and it also helps the oily and the watery parts to stay nicely mixed together (called emulsion stabilizing). 

A big sugar molecule (polysaccharide) that is used as a natural thickening and gelling agent. It is similar to more commonly used Xanthan Gum, and the two are also often combined to create gel formulas or to stabilize emulsions. 

A big molecule created from repeated subunits (a polymer of acrylic acid) that magically converts a liquid into a nice gel formula.  It usually has to be neutralized with a base (such as sodium hydroxide) for the thickening to occur and it creates viscous, clear gels that also feel nice and non-tacky on the skin. No wonder, it is a very popular and common ingredient.

An often used emollient with a light and silky feel. It's very mild to both skin and eyes and spreads nicely and easily. It's often used in sunscreens as it's also an excellent solvent for sunscreen agents. 

It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula. 

Super common little helper ingredient that helps products to remain nice and stable for a longer time. It does so by neutralizing the metal ions in the formula (that usually get into there from water) that would otherwise cause some not so nice changes.

A little helper ingredient that works as a preservative. It works against bacteria and some species of fungi and yeast. It's often combined with IT-preservative, phenoxyethanol.

It’s pretty much the current IT-preservative. It’s safe and gentle, but even more importantly, it’s not a feared-by-everyone-mostly-without-scientific-reason paraben.

It’s not something new: it was introduced around 1950 and today it can be used up to 1% worldwide. It can be found in nature - in green tea - but the version used in cosmetics is synthetic. 

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An Ecocert-approved, natural preservative that counts as gentle and non-irritating to the skin. Usually, it comes to the formula as part of a preservative blend as it's not enough on its own.

A mild, natural preservative that usually comes to the formula together with its other mild preservative friends, such as Benzoic Acid and/or Dehydroacetic Acid. Btw, it's also used as a food preservative.