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iS Clinical Hydra-Cool Serum

Hydra-Cool Serum

Hydra-Cool Serum contains the powerful, healing antioxidant centella asiatica with vitamin B5, hyaluronic acid, kojic acid and soothing menthol. It works to hydrate and nourish the skin while providing intense protection through antioxidants. Ideal for all ages and all skin types, including sensitive, just-sunburned skin.
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iS Clinical Hydra-Cool Serum
Ingredients explained

Also-called: Aqua;Water | 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. 

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).

What-it-does: moisturizer/humectant, solvent, viscosity controlling | Irritancy: 0 | Comedogenicity: 0
  • It's a helper ingredient that improves the freeze-thaw stability of products
  • It's also a solvent, humectant and to some extent a penetration enhancer
  • It has a bad reputation among natural cosmetics advocates but cosmetic scientists and toxicology experts do not agree (read more in the geeky details section)
Read all the geeky details about Propylene Glycol here >>

We don't have description for this ingredient yet.

Asiaticoside - goodie
What-it-does: antioxidant, perfuming

One of the main biologically active components of the famous medicinal plant, Centella Asiatica, aka Gotu Kola. It has well established wound healing and antioxidant activities.  

In-vitro (made in the lab) studies also show that Asiaticoside stimulates GAGs (glycosaminoglycans - polysaccharides that are part of the liquidy stuff between our skin cells) production as well as collagen I synthesis.  Read more at Gotu Kola >>

Asiatic Acid - goodie

One of the biologically active components of Gotu Kola. It's a bit less prominent than its sister component, Asiaticoside, but in-vitro (made in the lab) studies show that Asiatic Acid also stimulates GAGs (glycosaminoglycans - polysaccharides that are part of the liquidy stuff between our skin cells) production as well as collagen I synthesis.

English translation equals that it probably contributes to the well-established moisturizing and wound healing abilities of Gotu Kola

One of the biologically active components of Gotu Kola that is thought to contribute to the plant extract's well-documented skin regenerating, wound healing, and moisturizing properties

If you are into Gotu Kola we have some more info at Centella Asiatica Extract and its other biologically active components MadecassosideAsiaticoside and Asiatic Acid.

We don't have description for this ingredient yet.

Menthol - icky
What-it-does: soothing

Menthol needs no introduction: it's the thing that causes the cooling sensation so well-known both from cosmetic products as well as a bunch of other things like chocolate, chewing gum, toothpaste or cigarette. It's a natural compound that comes from the essential oil of Mentha species (peppermint oil contains 40-50% menthol) and it gives them their typical minty smell and flavor.

As for skincare, menthol seems to be a mixed bag. Apart from the cool cooling sensation (that might last up to 70 mins!), it also has painkilling, itch reducing, antibacterial, antifungal and even penetration enhancing properties. On the other hand, it also seems to act as a skin irritant that increases trans-epidermal water loss (the water that evaporates from the outer layer of the skin) and thus contributes to drying out the skin.

Also-called: Ci 42090 | What-it-does: colorant

CI 42090 or Blue 1 is a super common synthetic colorant in beauty & food. Used alone, it adds a brilliant smurf-like blue color, combined with Tartrazine, it gives the fifty shades of green.

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.

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
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 moisturizer/humectant | solvent | viscosity controlling
irritancy, com. 0, 0
A common glycol that improves the freeze-thaw stability of products. It's also a solvent, humectant and to some extent a penetration enhancer. [more]
what‑it‑does antioxidant | perfuming
One of the main biologically active components of the famous medicinal plant, Centella Asiatica, aka Gotu Kola. It has well established wound healing and antioxidant activities.  In-vitro (made in the lab) studies also show that Asiaticoside stimulates GAGs (glycosaminoglycans - polysaccharides that are part of the liquidy stuff between our skin cells) production as well as coll [more]
One of the biologically active components of Gotu Kola. It's a bit less prominent than its sister component, Asiaticoside, but in-vitro (made in the lab) studies show that Asiatic Acid also stimulates GAGs (glycosaminoglycans - polysaccharides that are part of the liquidy stuff between our skin cells) production as well as collagen I synthesis. [more]
One of the biologically active components of Gotu Kola that is thought to contribute to the plant extract's well-documented skin regenerating, wound healing, and moisturizing properties. If you are into Gotu Kola we have some more info at Centella Asiatica Extract and its other biologically active components  [more]
what‑it‑does soothing
Menthol needs no introduction: it's the thing that causes the cooling sensation so well-known both from cosmetic products as well as a bunch of other things like chocolate, chewing gum, toothpaste or cigarette. It's a natural compound that comes from the essential oil of Mentha species (peppermint oil contains 40-50% menthol) and it gives them their typical minty smell a [more]
what‑it‑does colorant
Synthetic colorant with smurf-like blue color. [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]