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Paula's Choice Resist C15 Super Booster

Paula's Choice
Resist C15 Super Booster

This concentrated vitamin C booster with 15% pure vitamin C dramatically brightens uneven skin while improving the appearance of wrinkles and fine lines.
Uploaded by: btbitbt on 24/04/2017

Paula's Choice Resist C15 Super Booster
Ingredients explained

Also-called: Aqua | What-it-does: solvent

Good 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. 

It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water. 

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Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying. 

One 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. 

Ascorbic Acid - superstar
Also-called: Vitamin C, L-ascorbic acid | What-it-does: antioxidant, skin brightening
  • Works best between a concentration of 5-20%
  • Boosts the skin’s own collagen production
  • Fades pigmentation and brown spots
  • If used under sunscreen it boosts its UV protection
  • Extremely unstable and oxidizes very easily in presence of light or air
  • Stable in solutions with water only if pH is less than 3.5 or in waterless formulations
  • Vit E + C work in synergy and provide superb photoprotection
  • Ferulic acid doubles the photoprotection effect of Vit C+E and helps to stabilize Vit C
  • Potent Vit. C serums might cause a slight tingling on sensitive skin
Read all the geeky details about Ascorbic Acid here >>

What-it-does: moisturizer/humectant, solvent | Irritancy: 0 | Comedogenicity: 1

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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It’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. 

What-it-does: solvent | Irritancy: 0 | Comedogenicity: 0

A nice odorless liquid used mainly as a superior solubilizer and efficacy booster for cosmetic active ingredients such as skincare bigshot vitamin C, self-tanning active DHA or the anti-acne gold standard, benzoyl peroxide

Other than that it can also be used in hair care products where it gives a longer-lasting and more uniform coloring. According to a manufacturer, it might even prevent the formation of split ends.

Glycerin - superstar
Also-called: Glycerol | What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0
  • 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
Read all the geeky details about Glycerin here >>

A helper ingredient that usually comes to the formula coupled with PEG-40 Hydrogenated Castor Oil. The two together work as surfactants and oil solubilizers. It's a non-sticky duo that works at low concentration and is often used to solubilize fragrance components into water-based formulas.

A mildly viscous, amber-colored liquid with fatty odor, made from Castor Oil and polyethylene glycol (PEG).

If it were a person, we’d say, it’s agile, diligent & multifunctional. It’s mostly used as an emulsifier and surfactant but most often it is used to solubilize fragrances into water-based formulas.

A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent and a broad spectrum antimicrobial. According to manufacturer info, it's also a moisturizer and helps to make the product feel great on the skin. It works synergistically with preservatives and helps to improve water-resistance of sunscreens. 

Tocopherol - superstar
Also-called: Vitamin E | What-it-does: antioxidant | Irritancy: 0-3 | Comedogenicity: 0-3
  • 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
Read all the geeky details about Tocopherol here >>

What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0

It’s the - sodium form - cousin of the famous NMFhyaluronic 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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In spite of this, if you search for "hyaluronic acid vs sodium hyaluronate" you will find on multiple places that sodium hyaluronate is smaller and can penetrate the skin better. Chemically, this is definitely not true, as the two forms are almost the same, both are polymers and the subunits can be repeated in both forms as much as you like. (We also checked Prospector for sodium hyaluronate versions actually used in cosmetic products and found that the most common molecular weight was 1.5-1.8 million Da that absolutely counts as high molecular weight).

What seems to be a true difference, though, is that the salt form is more stable, easier to formulate and cheaper so it pops up more often on the ingredient lists. 

If you wanna become a real HA-and-the-skin expert you can read way more about the topic at hyaluronic acid (including penetration-questions, differences between high and low molecular weight versions and a bunch of references to scientific literature).

A new tripeptide (meaning that it contains three building blocks called amino acids) that can do all kinds of good things for the skin, at least according to the ingredient's manufacturer. Its modest trade name is simply "PerfectionPeptide P3" :) and it can supposedly reactivate the natural desquamation process of the skin. Better desquamation means better skin quality with fewer irregularities and imperfections and in general fewer signs of aging. 

It also speeds up cell renewal that results in fresh, glowing skin, it intensely hydrates, refines skin texture and reduces wrinkle depth. Hence the name Perfection Peptide. (Don't forget, these are all claims coming from the manufacturer, so maybe take it with a little grain of salt. :))

Lecithin - goodie
What-it-does: emollient, emulsifying

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

Ferulic Acid - goodie

Ferulic Acid (FA) is a goodie that can be found naturally in plant cell walls. There is a lot of it especially in the bran of grasses such as rice, wheat and oats. 

FA - whose main job is to be an antioxidant - owes its fame to a 2005 research that discovered that adding in 0.5% FA to a 15% Vitamin C + 1% Vitamin E solution not only stabilizes the highly unstable, divaish Vit C, but it also doubles the photoprotection abilities of the formula. 

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Couple of other studies show that FA just by itself is also a nice addition to cosmetic formulations: it can penetrate the skin (which is kind of important to do the job) and it has protecting properties against UV caused skin damage.

So if you spot it on the ingredient list be happy about it. :)

Panthenol - goodie
Also-called: Pro-Vitamin B5 | What-it-does: soothing, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0

An easy-to-formulate, commonly used, nice to have ingredient that’s also called pro-vitamin B5. As you might guess from the “pro” part, it’s a precursor to vitamin B5 (whose fancy name is pantothenic acid). 

Its main job in skincare products is to moisturise the skin. It’s a humectant meaning that it can help the skin to attract water and then hold onto it. There is also research showing that panthenol can help our skin to produce more lovely lipids that are important for a strong and healthy skin barrier. 

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Another great thing about panthenol is that it has anti-inflammatory and skin protecting abilities. A study shows that it can reduce the irritation caused by less-nice other ingredients (e.g. fragrance, preservatives or chemical sunscreens) in the product.

Research also shows that it might be useful for wound healing as it promotes fibroblast (nice type of cells in our skin that produce skin-firming collagen) proliferation. 

If that wasn’t enough panthenol is also useful in nail and hair care products. A study shows that a nail treatment liquide with 2% panthenol could effectively get into the nail and significantly increase the hydration of it.

As for the hair the hydration effect is also true there. Panthenol might make your hair softer, more elastic and helps to comb your hair more easily. 

Bisabolol - goodie
Also-called: Alpha-Bisabolol | What-it-does: soothing

It's one of the active parts of Chamomile that contains about 30% of bisabolol. It's a clear oily fluid that is used in skincare as a nice anti-inflammatory and soothing ingredient. 

We don't have description for this ingredient yet.

What-it-does: emollient

We don't have description for this ingredient yet.

What-it-does: antioxidant, perfuming

We don't have description for this ingredient yet.

The neutralized form of gluconic acid. It's a great ingredient to neutralize metal (especially iron and copper) ions in a cosmetic product. This helps to prevent discoloration of the formula over time or rancidity of cosmetic oils. It can also be a pH regulator and a humectant (helps skin to cling onto water).

It's also used in oral care products where it reduces the bitterness of other ingredients. And it's natural, both Ecocert and Cosmos approved. (source: manufacturer info)

Also-called: lye | What-it-does: buffering

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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BTW, lye is not something new. It was already used by ancient Egyptians to help oil and fat magically turn into something else. Can you guess what? Yes, it’s soap. It still often shows up in the ingredient list of soaps and other cleansers.

Sodium hydroxide in itself is a potent skin irritant, but once it's reacted (as it is usually in skin care products, like exfoliants) it is totally harmless.

What-it-does: preservative

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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Other than having a good safety profile and being quite gentle to the skin it has some other advantages too. It can be used in many types of formulations as it has great thermal stability (can be heated up to 85°C) and works on a wide range of pH levels (ph 3-10). 

It’s often used together with ethylhexylglycerin as it nicely improves the preservative activity of phenoxyethanol.

What-it-does: preservative

If you have spotted ethylhexylglycerin on the ingredient list, most probably you will see there also the current IT-preservative, phenoxyethanol. They are good friends because ethylhexylglycerin can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too.

Also, it's an effective deodorant and a medium spreading emollient

You may also want to take a look at...

what‑it‑does solvent
Normal (well kind of - it's purified and deionized) water. Usually the main solvent in cosmetic products. [more]
what‑it‑does antioxidant | skin brightening
Pure Vitamin C. A skincare superstar that is clinically proven to boost collagen production (in 5-20% concentration), fade hyperpigmentation and boost UV protection under sunscreen. Also, it's extremely unstable and hard to formulate. [more]
what‑it‑does moisturizer/humectant | solvent
irritancy, com. 0, 1
An often used glycol that works as a solvent, humectant, penetration enhancer and also gives a good slip to the products. [more]
what‑it‑does solvent
irritancy, com. 0, 0
A nice odorless liquid used mainly as a superior solubilizer and efficacy booster for cosmetic active ingredients such as vitamin C or benzoyl peroxide. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
A real oldie but a goodie. Great natural moisturizer and skin-identical ingredient that plays an important role in skin hydration and general skin health. [more]
A helper ingredient that usually comes to the formula coupled with PEG-40 Hydrogenated Castor Oil. The two together work as surfactants and oil solubilizers. [more]
what‑it‑does emulsifying | surfactant/cleansing
A mildly viscous, amber-colored liquid that works as an emulsifier and surfactant. [more]
what‑it‑does solvent | moisturizer/humectant
A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent, and a broad spectrum antimicrobial. [more]
what‑it‑does antioxidant
irritancy, com. 0-3, 0-3
Pure Vitamin E. Great antioxidant that gives significant photoprotection against UVB rays. Works in synergy with Vitamin C. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
It's the salt form of famous humectant and natural moisturizing factor, hyaluronic acid. It can bind huge amounts of water and it's pretty much the current IT-moisturizer. [more]
what‑it‑does cell-communicating ingredient
A tripeptide that - according to the manufacturer - can reactivate the natural desquamation process of the skin that results in fresh, glowy skin. [more]
what‑it‑does emollient | emulsifying
It's quite the multi-tasker: an emollient and water-binding ingredient but also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes.  [more]
what‑it‑does antioxidant | antimicrobial/antibacterial
A great antioxidant that is most famous for stabilizing the highly unstable Vitamin C. It also doubles the photoprotection abilities of Vit C+E formulas. [more]
what‑it‑does soothing | moisturizer/humectant
irritancy, com. 0, 0
Pro-Vitamin B5 is a goodie that moisturises the skin, has anti-inflammatory, skin protecting and wound healing properties. [more]
what‑it‑does soothing
One of the active parts of Chamomile that is used in skincare as a nice anti-inflammatory and soothing ingredient. [more]
what‑it‑does emollient
what‑it‑does antioxidant | perfuming
what‑it‑does chelating | moisturizer/humectant
The neutralized form of gluconic acid. It's a great ingredient to neutralize metal (especially iron and copper) ions in a cosmetic product. This helps to prevent discoloration of the formula over time or rancidity of cosmetic oils. [more]
what‑it‑does buffering
Lye - A solid white stuff that’s very alkaline and used in small amount to adjust the pH of the product.  [more]
what‑it‑does preservative
Pretty much the current IT-preservative. It’s safe and gentle, and can be used up to 1% worldwide. [more]
what‑it‑does preservative
It can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too. [more]