The Inkey List
Beta Hydroxy Acid
|Ingredient name||what-it-does||irr., com.||ID-Rating|
|Salicylic Acid||exfoliant, anti-acne, soothing, preservative||superstar|
|Sodium Hyaluronate||skin-identical ingredient, moisturizer/humectant||0, 0||goodie|
|Zinc Pca||anti-acne, moisturizer/humectant||goodie|
|Biosaccharide Gum-1||soothing, moisturizer/humectant||goodie|
|Trisodium Ethylenediamine Disuccinate||chelating|
The Inkey List Beta Hydroxy AcidIngredients explained
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.
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.
Propanediol 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.
It's quite a multi-tasker: can be used to improve skin moisturization, as a solvent, to boost preservative efficacy or to influence the sensory properties of the end formula.
A sugar beet derived amino acid derivative with nice skin protection and moisturization properties. Betain's special thing is being an osmolyte, a molecule that helps to control cell-water balance. It is also a natural osmoprotectant, meaning that it attracts water away from the protein surface and thus protects them from denaturation and increases their thermodynamic stability.
It also gives sensorial benefits to the formula and when used in cleansers, it helps to make them milder and gentler.
- It's one of the gold standard ingredients for treating problem skin
- It can exfoliate skin both on the surface and in the pores
- It's a potent anti-inflammatory agent
- It's more effective for treating blackheads than acne
- For acne combine it with antibacterial agents like benzoyl peroxide or azelaic acid
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".
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).
If you have oily, acne-prone skin, Zinc PCA is one of the actives to put on your "TO TRY" list.
It's a synergistic association of two great things: Zinc and L-PCA. The Zinc part is there to help normalize sebum production and limit the proliferation of evil acne-causing bacteria. L-PCA stands for pyrrolidone carboxylic acid and it's a key molecule in the skin that helps with processes of hydration and energy (it's actually an NMF, a natural moisturizing factor).
L-PCA is not only there to hydrate the skin, but it also helps to increase the efficacy and bioavailability of zinc. An in-vivo (done on real people) test done by the manufacturer shows that Zinc PCA reduces sebum production statistically significantly after 28 days of application (1% was used in the test), and in-vitro (made in the lab) measurements show that Zinc PCA has strong anti-microbial activity against P. acnes (between 0.1-0.25%) and other bacterial strains.
If that would not be enough there is also a 2011 research paper saying that based on in-vitro (made in the lab, not on real people) findings Zinc PCA might be a promising anti-aging active that helps with the production of type I collagen (and we all know more collagen = firmer skin).
All in all, definitely a goodie for oily, acne-prone skin.
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.
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.
A nice little helper ingredient that can thicken up cosmetic products and create beautiful gel formulas. It's derived from cellulose, the major component of the cell wall of green plants. It is compatible with most co-ingredients and gives a very good slip to the formulas.
It's a little helper ingredient coming from corn, rice or potato starch that can help to keep skin mat (absorbent), to stabilise emulsions, and to keep the product together (binding).
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.
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.
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.
Biosaccharide Gum-1 is a pretty interesting kind of sugar ingredient that is created from sorbitol via bacterial fermentation.
According to the manufacturer it’s a “S.M.A.R.T.” sugar: it has Soothing, Moisturizing, Anti-aging, Restructuring and Touch properties. Let’s look at them quickly one by one.
Soothing: the manufacturer tested out the soothing effect in vivo (meaning on humans that is always a good thing!) by measuring how 3% Biosaccharide Gum-1 decreased the tingling sensation caused by 10% lactic acid. The result was good: the tingling was decreased by 47%.
Moisturizing: Compared to famous hyaluronic acid, it turns out that the two are great together. HA has a quicker effect and provides more instant hydration (much more hydration was measured after 1h of application), while our nice sugar has a somewhat delayed effect demonstrating stronger hydration after 3h of application. After 8 hours both had similar moisturizing effect.
Anti-aging: According to ex-vivo tests (meaning not on humans, so do not trust it too much) Biosaccharide Gum-1 can stimulate a protein in our skin called sirtuin-1. This is supposed to help our skin cells to live longer, and function better.
Resurfacing: The sirtuin-1 stimulation also results in quicker cell renewal - something that happens anyway but slows down as we age. And the quicker cell renewal is good because it helps the regeneration of the barrier function. That is especially nice for fragile, sensitive skin.
Touch: our fermented sugar is not only good to the skin, but it also feels great on the skin. It gives a nice “soft touch” feeling and makes the products pleasant to use.
The bottom line is that the above info is from the manufacturer (and we could not find any relevant independent research) so obviously take it with a grain of salt. But Biosaccharide Gum-1 does look as an interesting and promising ingredient that’s why it earned our goodie rating.
A helper ingredient that helps to neutralize the metal ions in the formula (they usually come from water) so it stays nice longer. The special property of this particular ingredient is that it's more effective against more problematic ions, like Cu (copper) and Fe (iron) compared to less problematic ones like Ca (calcium) and Mg (magnesium).
Copy and paste into your blog
|what‑it‑does||solvent | moisturizer/humectant|
|what‑it‑does||exfoliant | anti-acne | soothing | preservative|
|what‑it‑does||skin-identical ingredient | moisturizer/humectant|
|irritancy, com.||0, 0|
|what‑it‑does||anti-acne | moisturizer/humectant|
|what‑it‑does||soothing | moisturizer/humectant|