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A-Derma Epitheliale A.H Duo

Epitheliale A.H Duo

A-Derma epitheliale Ah duo ultra-repairing cream soothes and helps with the epidermal repair of fragile, irritated skin. Its formula, rich in cicahyalumidea helps reduce residual marks linked to epidermal damages or superficial dermatological procedures.
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Highlights

A-Derma Epitheliale A.H Duo
Ingredients explained

A thick, high molecular weight silicone that is usually diluted in another, lighter silicone fluid (like dimethicone or cyclopentasiloxane). The dimethiconol containing silicone blends leave a silky smooth, non-greasy film on the skin.

A helper ingredient that functions as a film-forming polymer (big molecule from repeated subunits).

It usually comes to the formula as part of a thickener-emulsifier trio paired with Polyisobutene and Polysorbate 20. The three togeather have excellent thickening properties with remarkable emulsifying-stabilising abilities. They also have a nice silicone feel with glide-on spreading. 

What-it-does: viscosity controlling

A polymer (big molecule from repeated subunits) that's used as a gloss improver for lipsticks and lipglosses. Its stickiness also helps lip products to stay on longer. 

Combined with polyacrylate-13 and polysorbate 20, it forms a very effective tickener-emulsifier trio.

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: 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". 

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).

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.  

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: emulsifying | Irritancy: 0 | Comedogenicity: 1-2

A handy helper ingredient that helps water and oil to mix nicely together, aka emulsifier. It is especially recommended for protective, baby care and general purpose emollient creams. 

It also helps to disperse insoluble particles (think color pigments or zinc/titanium dioxide sunscreen) nice and even in cosmetic formulas. 

Also-called: Vitamin E Acetate | What-it-does: antioxidant | Irritancy: 0 | Comedogenicity: 0

It’s the most commonly used version of pure vitamin E in cosmetics. You can read all about the pure form here. This one is the so-called esterified version. 

According to famous dermatologist, Leslie Baumann while tocopheryl acetate is more stable and has a longer shelf life, it’s also more poorly absorbed by the skin and may not have the same awesome photoprotective effects as pure Vit E. 

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). 

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what‑it‑does emollient | moisturizer/humectant
A thick, high molecular weight silicone that is usually diluted in a lighter silicone fluid. The dimethiconol containing silicone blends leave a silky smooth, non-greasy film on the skin. [more]
A film forming polymer that usually comes to the formula as part of a thickener-emulsifier trio paired with Polyisobutene and Polysorbate 20. [more]
what‑it‑does viscosity controlling
A polymer (big molecule from repeated subunits) that's used as a gloss improver for lipsticks and lipglosses. Combined with polyacrylate-13 and polysorbate 20, it forms a very effective tickener-emulsifier trio. [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 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 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 emulsifying
irritancy, com. 0, 1-2
A handy helper ingredient that helps water and oil to mix nicely together. [more]
what‑it‑does antioxidant
irritancy, com. 0, 0
A form of vitamin E that works as an antioxidant. Compared to the pure form it's more stable, has longer shelf life, but it's also more poorly absorbed by the skin. [more]
what‑it‑does viscosity controlling
A super commonly used thickener and emulsion stabilizer. [more]