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Kerastase Masque Densité Hair MaskIngredients 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.
We don't have description for this ingredient yet.
A handy multi-tasker, white to light yellowish oil-loving wax that works very well in oil-in-water emulsions. It makes your skin feel nice and smooth (emollient), stabilizes oil-water mixes and gives body to them.
Oh, and one more thing: it's a so-called fatty alcohol - the good, emollient type of alcohol that is non-drying and non-irritating. It is often mixed with fellow fatty alcohol, Cetyl Alcohol, and the mixture is called Cetearyl Alcohol in the ingredient list.
We don't have description for this ingredient yet.
- 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)
An emollient ester with a rich and creamy but non-greasy skin feel. It makes skin supple and protects dry skin.
It’s a handy multi-tasking ingredient that gives the skin a nice, soft feel. At the same time, it also boosts the effectiveness of other preservatives, such as the nowadays super commonly used phenoxyethanol.
The blend of these two (caprylyl glycol + phenoxyethanol) is called Optiphen, which not only helps to keep your cosmetics free from nasty things for a long time but also gives a good feel to the finished product. It's a popular duo.
A vegetable wax coming from the leaves of the North Mexican candelilla shrubs (Euphorbia cerifera and Euphorbia antisyphilitica). Similar to other waxes, it is used to stabilize products and give body to them, or to keep stick type formulas solid. It has a melting point around 70C and has high gloss making it a good choice for lip products.
We don't have description for this ingredient yet.
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.
We don't have description for this ingredient yet.
A semi-essential (infants cannot synthesize it, but adults can) amino acid that is one of the primary building blocks of hair keratin and skin collagen. It's a natural moisturizing factor, a skin hydrator and might also help to speed up wound healing.
Arginine usually has a positive charge (cationic) that makes it substantive to skin and hair (those are more negatively charged surfaces) and an excellent film former. Thanks to the positive charge, it also creates a complex with AHAs (AHAs like to lose a hydrogen ion and be negatively charged, so the positive and the negative ions attract each other) that causes a "time-release AHA effect" and reduces the irritation associated with AHAs.
Glutamic acid is a little molecule and non-essential (our body can synthesize it) amino acid with the important job of being a neurotransmitter in the human body meaning that it helps your nervous system work correctly.
As for what it's doing in cosmetics, Glutamic acids' main thing (similar to other amino acids) is being a humectant moisturizer and skin-conditioning agent (sidenote: if you attach lots of glutamic acid molecules, you get polyglutamic acid that is claimed to be a better than hyaluronic acid humectant). It also seems to affect skin barrier repair, however, it is not clear-cut in which direction.
The complication is that glutamic acid has two distinct forms, L-glutamic acid and D-glutamic acid, that are the mirror images of each other (think of it like your left and right hand). Studies show that a topical application of L-glutamic acid on damaged skin delayed skin repair, while D-glutamic acid application sped up skin repair. As both forms are used by the industry, it is a bit uncertain what you are getting with just glutamic acid on the ingredient list (but if it is a Shiseido group product, it is probably the goodie D-form :)).
Other than that, Glutamic acid can also be used as a pH adjuster and can be processed via biological pathways into pyrrolidone carboxylic acid, the sodium salt of which is a goodie and one of your skin’s natural moisturizing factors.
A common fragrance ingredient that smells like jasmine. It is one of the “EU 26 fragrances” that has to be labelled separately because of allergen potential. Best to avoid if your skin is sensitive.
Serine is an amino acid that most often comes to the formula as part of a moisturizing complex. It's a non-essential amino acid (meaning that our body can synthesize it) and serves as a water-binding ingredient.
In general, amino acids are great skincare ingredients that play an important role in proper skin hydration but there is not much info out there about what specifically serine can do for the skin.
We don't have description for this ingredient yet.
Linalool is a super common fragrance ingredient. It’s kind of everywhere - both in plants and in cosmetic products. It’s part of 200 natural oils including lavender, ylang-ylang, bergamot, jasmine, geranium and it can be found in 90-95% of prestige perfumes on the market.
The problem with linalool is, that just like limonene it oxidises on air exposure and becomes allergenic. That’s why a product containing linalool that has been opened for several months is more likely to be allergenic than a fresh one.
A study made in the UK with 483 people tested the allergic reaction to 3% oxidised linalool and 2.3% had positive test results.
Citronellol is a very common fragrance ingredient with a nice rose-like odor. In the UK, it’s actually the third most often listed perfume on the ingredient lists.
It can be naturally found in geranium oil (about 30%) or rose oil (about 25%).
As with all fragrance ingredients, citronellol can also cause allergic contact dermatitis and should be avoided if you have perfume allergy. In a 2001 worldwide study with 178 people with known sensitization to fragrances citronellol tested positive in 5.6% of the cases.
There is no known anti-aging or positive skin benefits of the ingredient. It’s in our products to make it smell nice.
It’s a common fragrance ingredient that is one of the “EU 26 fragrances” that has to be labelled separately (and cannot be simply included in the term “fragrance/perfume” on the label) because of allergen potential. Best to avoid if your skin is sensitive.
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.
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).
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
Ci 19140 or Tartrazine is a super common colorant in skincare, makeup, medicine & food. It’s a synthetic lemon yellow that's used alone or mixed with other colors for special shades.
FDA says it's possible, but rare, to have an allergic-type reaction to a color additive. As an example, it mentions that Ci 19140 may cause itching and hives in some people but the colorant is always labeled so that you can avoid it if you are sensitive.
A super common synthetic colorant that adds a purple-red color - similar to red beet - to a product.
- 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
It's the acronym for Butylated Hydroxy Toluene. It's a common synthetic antioxidant that's used as a preservative.
There is some controversy around BHT. It's not a new ingredient, it has been used both as a food and cosmetics additive since the 1970s. Plenty of studies tried to examine if it's a carcinogen or not. This Truth in Aging article details the situation and also writes that all these studies examine BHT when taken orally.
As for cosmetics, the CIR (Cosmetic Ingredient Review) concluded that the amount of BHT used in cosmetic products is low (usually around 0.01-0.1%), it does not penetrate skin far enough to be absorbed into the bloodstream and it is safe to use in cosmetics.
A little helper ingredient that is used to adjust the pH of the product. It also helps to keep products stay nice longer by neutralizing the metal ions in the formula (they usually come from water).
Exactly what it sounds: nice smelling stuff put into cosmetic products so that the end product also smells nice. Fragrance in the US and parfum in the EU is a generic term on the ingredient list that is made up of 30 to 50 chemicals on average (but it can have as much as 200 components!).
If you are someone who likes to know what you put on your face then fragrance is not your best friend - there's no way to know what’s really in it.
Also, if your skin is sensitive, fragrance is again not your best friend. It’s the number one cause of contact allergy to cosmetics. It’s definitely a smart thing to avoid with sensitive skin (and fragrance of any type - natural is just as allergic as synthetic, if not worse!).
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what‑it‑does | solvent |
what‑it‑does | viscosity controlling |
what‑it‑does | surfactant/cleansing |
what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
irritancy, com. | 2, 2 |
what‑it‑does | preservative |
what‑it‑does | moisturizer/humectant | solvent |
irritancy, com. | 0, 0 |
what‑it‑does | emollient |
what‑it‑does | emollient |
what‑it‑does | moisturizer/humectant | emollient |
what‑it‑does | emollient |
irritancy, com. | 0, 1 |
what‑it‑does | solvent | viscosity controlling | perfuming |
irritancy, com. | 0, 0 |
what‑it‑does | preservative |
what‑it‑does | skin-identical ingredient |
what‑it‑does | moisturizer/humectant |
what‑it‑does | perfuming |
what‑it‑does | skin-identical ingredient |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | buffering |
what‑it‑does | skin-identical ingredient | moisturizer/humectant |
irritancy, com. | 0, 0 |
what‑it‑does | colorant |
what‑it‑does | colorant |
irritancy, com. | 2, 1 |
what‑it‑does | antioxidant |
irritancy, com. | 0-3, 0-3 |
what‑it‑does | antioxidant | preservative |
what‑it‑does | chelating | buffering |
what‑it‑does | perfuming |