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This product has been discontinued. See the current version here.
Paula's Choice Resist Hyaluronic Acid Booster

Resist Hyaluronic Acid Booster (Discontinued)

This specialized hyaluronic acid anti-aging booster plumps fine lines and helps prevent moisture loss when added to your favorite moisturizer or serum.
Uploaded by: judit on

Paula's Choice Resist Hyaluronic Acid 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. 

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 >>

Yeast Extract - goodie
What-it-does: moisturizer/humectant

You probably know yeast from the kitchen where you put it into milk with a little sugar and then after a couple of minutes brownish bubbles form. That is the fungi fermenting the sugar

As for skin care, yeast contains beta-glucan that is a great soothing ingredient and also a mild antioxidant.  The yeast extract itself is a silky clear liquid that has some great moisturizing, skin protecting and film-forming properties on the skin. 

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". 

  • It’s naturally in our skin and behaves there like a sponge
  • It can bind up to 1000 times its own weight in water
  • It is a big molecule from repeated subunits (polymer) so different molecular weight versions exist (unfortunately there is no way to determine MW from INCI list only)
  • High-molecular-weight-HA (>500 kDa) is an excellent surface hydrator, skin protectant and can act as an osmotic pump helping water-soluble actives to penetrate deeper into the skin
  • Low-molecular-weight-HA (< 500 kDa) can hydrate the skin somewhat deeper though it is still a big molecule and works mainly in the epidermis (outer layer of the skin)
  • Low-molecular-weight-HA might also help the skin to repair itself by increasing its self-defense (~ 200kDa used in the study)
  • Ultra-low-molecular-weight-HA (<50kDa) is a controversial ingredient and might work as a pro-inflammatory signal molecule
Read all the geeky details about Hyaluronic Acid here >>

Ceramide NP - goodie
Also-called: Ceramide 3 | What-it-does: skin-identical ingredient

One of the many types of ceramides that can be found naturally in the upper layer of the skin. Ceramides make up about 50% of the goopy stuff that's between our skin cells and play a super important role in having a healthy skin barrier and keeping the skin hydrated. It works even better when combined with its pal, Ceramide 1.

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

Ceramide AP - goodie
Also-called: Ceramide 6 II | What-it-does: skin-identical ingredient

A type of ceramide that can be found naturally in the upper layer of the skin. Ceramides make up 50% of the goopy stuff that's between our skin cells and play a super important role in having a healthy skin barrier and keeping the skin hydrated. 

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

Ceramide EOP - goodie
Also-called: Ceramide 1 | What-it-does: skin-identical ingredient

Ceramides get quite a lot of hype recently and good news: there is a reason for that. But before we go into the details, let's just quickly define what the heck ceramides are:

They are waxy lipids that can be found naturally in the outer layer of the skin (called stratum corneum - SC). And they are there in big amounts! The goopy stuff between our skin cells is called extracellular matrix that consists mainly of lipids. And ceramides are about 50% of those lipids (the other important ones are cholesterol with 25% and fatty acids with 15%). 

It's a type of lipid, a so-called sphingoid base that can be found naturally in the upper layer of the skin. It's found both in "free-form" and as part of famous skin lipids, ceramides.

There is emerging research about Phytosphingosine that shows that it has antimicrobial and cell-communicating properties and is considered part of the skin's natural defense system.

Adenosine - goodie

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
Cholesterol - goodie
What-it-does: skin-identical ingredient, emollient | Irritancy: 0 | Comedogenicity: 0

It's one of the important lipids that can be found naturally in the outer layer of the skin. About 25% of the goopy stuff between our skin cells consists of cholesterol. Together with ceramides and fatty acids, they play a vital role in having a healthy skin barrier and keeping the skin hydrated. 

Apart from being an important skin-identical ingredient, it's also an emollient and stabilizer

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. 

We don't have description for this ingredient yet.

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.

What-it-does: emulsifying

A helper ingredient that's used as a co-emulsifier (meaning next to other emulsifiers in the formula it helps water and oil to mix) and as a stabilization agent for foams. Also, has some antimicrobial activity so it can help to boost the effectiveness of the preservative system.

What-it-does: viscosity controlling, emulsion stabilising | Irritancy: 0 | Comedogenicity: 1

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. Typically used at 1% or less in most formulations.

It's one of the most commonly used thickeners and emulsion stabilizers. If the product is too runny, a little xanthan gum will make it more gel-like. Used alone, it can make the formula sticky and it is a good team player so it is usually combined with other thickeners and so-called rheology modifiers (helper ingredients that adjust the flow and thus the feel of the formula). The typical use level of Xantha Gum is below 1%, it is usually in the 0.1-0.5% range. 

Btw, Xanthan gum is all natural, a chain of sugar molecules (polysaccharide) produced from individual sugar molecules (glucose and sucrose) via fermentation. It’s approved by Ecocert and also used in the food industry (E415). 

What-it-does: emulsifying, surfactant/cleansing | Irritancy: 0 | Comedogenicity: 0

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. 

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. 

What-it-does: preservative, deodorant

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 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]
what‑it‑does moisturizer/humectant
A silky clear liquid that has great moisturizing, skin protecting and film-forming properties on the skin. [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 skin-identical ingredient | moisturizer/humectant
A famous natural moisturizing factor that can bind up to 1000 times its own weight in water. Works as an excellent surface hydrator in skincare. [more]
what‑it‑does skin-identical ingredient
Ceramides make up 50% of the goopy stuff that's between our skin cells and play a super important role in having a healthy skin barrier and keeping the skin hydrated.  [more]
what‑it‑does skin-identical ingredient
A type of ceramide that can be found naturally in the upper layer of the skin. Ceramides make up 50% of the goopy stuff that's between our skin cells and play a super important role in having a healthy skin barrier and keeping the skin hydrated.  We have written way more about ceramides at ceramide 1, so click here to know more. [more]
what‑it‑does skin-identical ingredient
Ceramides get quite a lot of hype recently and good news: there is a reason for that. But before we go into the details, let's just quickly define what the heck ceramides are: They are waxy lipids that can be found naturally in the outer layer of the skin (called stratum corneum - SC). [more]
what‑it‑does skin-identical ingredient | cell-communicating ingredient | anti-acne | antimicrobial/antibacterial
A type of lipid that can be found naturally in the skin. Has antimicrobial and cell-communicating properties and is considered to be part of the skin's natural defence system. [more]
what‑it‑does cell-communicating ingredient
An important compound in our body that has a vital cell-signalling role. It is wound healing, anti-inflammatory and can help with barrier repair. [more]
what‑it‑does skin-identical ingredient | emollient
irritancy, com. 0, 0
It's one of the important lipids that can be found naturally in the outer layer of the skin. About 25% of the goopy stuff between our skin cells consists of cholesterol. [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 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 emulsifying
A helper ingredient that's used as a co-emulsifier and as a stabilization agent for foams. [more]
what‑it‑does viscosity controlling
irritancy, com. 0, 1
A handy white powder that magically converts a liquid into a nice gel formula. [more]
what‑it‑does viscosity controlling
A super commonly used thickener and emulsion stabilizer. [more]
what‑it‑does emulsifying | surfactant/cleansing
irritancy, com. 0, 0
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. 
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]