Ingredients overview
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Key Ingredients
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Boots Aqua Hydrating Sleep 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.
- 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 for dry skin at higher concentrations up to 20-40%
- High-glycerin moisturizers are awesome for treating severely dry skin
A clear, colorless liquid that works as a solvent and viscosity decreasing ingredient. It also has great skin-moisturizing abilities.
A so-called fatty (the good, non-drying kind of) alcohol that does all kinds of things in a skincare product: it makes your skin feel smooth and nice (emollient), helps to thicken up products and also helps water and oil to blend (emulsifier). Can be derived from coconut or palm kernel oil.
An often used emollient with a light and silky feel. It's very mild to both skin and eyes and spreads nicely and easily. It's often used in sunscreens as it's also an excellent solvent for sunscreen agents.
Triethylhexanoin is a colorless to pale yellow liquid ester that makes the skin nice and smooth, aka emollient. It has a pleasant non-sticky, non-greasy feel to it, gives formulas smooth application properties and also helps moisture retention.
A thick, paste-like emollient ester that is touted as a vegetable-derived lanolin alternative. It has a smooth spreadability and touch, and it gives a substantive film to protect and moisturize the skin.
A super common, waxy, white, solid stuff that helps water and oil to mix together, gives body to creams and leaves the skin feeling soft and smooth.
Chemically speaking, it is the attachment of a glycerin molecule to the fatty acid called stearic acid. It can be produced from most vegetable oils (in oils three fatty acid molecules are attached to glycerin instead of just one like here) in a pretty simple, "green" process that is similar to soap making. It's readily biodegradable.
It also occurs naturally in our body and is used as a food additive. As cosmetic chemist Colins writes it, "its safety really is beyond any doubt".
A very common water-loving surfactant and emulsifier that helps to keep water and oil mixed nicely together.
It's often paired with glyceryl stearate - the two together form a super effective emulsifier duo that's salt and acid tolerant and works over a wide pH range. It also gives a "pleasing product aesthetics", so no wonder it's popular.
An oily kind of ingredient that can magically blend with water all by itself. This is called self-emulsifying and SE in its name stands for that.
The difference between "normal" Glyceryl Stearate and this guy is that the SE grade contains a small amount of water-loving soap molecules, such as sodium stearate. This increases Glyceryl Stearate's affinity for water and gives it stronger emulsifying abilities.
Other than that, it’s a nice emollient that gives a smooth and soft appearance to the skin.
You can read some more at Glyceryl Stearate >>
A common little helper ingredient that helps water and oil to mix together, aka emulsifier.
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 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.
A little helper ingredient that works as a preservative. It works against bacteria and some species of fungi and yeast. It's often combined with IT-preservative, phenoxyethanol.
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).
A skin protecting ingredient obtained by enzymatic synthesis from natural sugars (sucrose and maltose). It's claimed to be a bio-selective substrate that protects and stimulates the beneficial microbial skin flora without doing the same with pathogens and undesirable flora. It also stimulates the antimicrobial peptide release by keratinocytes (skin cells).
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.
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!).
We don't have description for this ingredient yet.
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).
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).
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.
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.
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.
A super common and cheap fragrance ingredient. It's in many plants, e.g. rosemary, eucalyptus, lavender, lemongrass, peppermint and it's the main component (about 50-90%) of the peel oil of citrus fruits.
It does smell nice but the problem is that it oxidizes on air exposure and the resulting stuff is not good for the skin. Oxidized limonene can cause allergic contact dermatitis and counts as a frequent skin sensitizer.
Limonene's nr1 function is definitely being a fragrance component, but there are several studies showing that it's also a penetration enhancer, mainly for oil-loving components.
All in all, limonene has some pros and cons, but - especially if your skin is sensitive - the cons probably outweigh the pros.
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.
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.
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.
A 2007 study showed that Phytosphingosine even works against evil acne-causing bacteria, Propionibacterium acnes and shows promise as a complementing active ingredient in treating acne-prone skin thanks to its anti-inflammatory and antimicrobial activities.
A nice one to spot in the ingredient list. :)
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.
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.
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%).
Ok, so now we know what ceramides are, let's see what they do in our skin: research shows clearly that they play a super important role in keeping the skin barrier healthy and the skin hydrated. If ceramides in the skin are decreased, more water can evaporate from the skin and there is less water remaining in the skin. So ceramides form kind of a "water-proof" protecting layer and make sure that our skin remains nice and hydrated.
Now the question is only this: If we put ceramides all over our face do they work as well as ceramides already naturally in our skin? Well, the answer is probably a no, but they do work to some extent. The BeautyBrains blog made a fantastic article about ceramides and they have listed a couple of examples about studies showing that ceramides - especially when used in certain ratios with cholesterol and fatty acids - do hydrate the skin and can help to repair the skin barrier.
So far we were writing about ceramides in plural. It's because there are lots of different ceramides, a 2014 article writes that currently 12 base classes of ceramides are known with over 340 specific species. Chemically speaking, ceramides are the connection of a fatty acid and a sphingoid base and both parts can have different variations that result in the different types of ceramides.
Our current one, Ceramide 1, or more recently called Ceramide EOP, was the first one that was identified in 1982 and it's a special snowflake. It contains the essential fatty acid, linoleic acid and has a unique structure. It's believed that ceramide 1 plays a "binding role" in the lipid layers of the extracellular matrix. Along with ceramides 4 and 7, they also play a vital role in epidermal integrity and serve as the main storage areas for linoleic acid (a fatty acid that's also very important for barrier repair).
Oh, and one more thing: alkaline pH inhibits enzymes that help ceramide synthesis in our skin. So if you use a soap and you notice your skin is becoming dry, now you know why.
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what‑it‑does | solvent |
what‑it‑does | skin-identical ingredient | moisturizer/humectant |
irritancy, com. | 0, 0 |
what‑it‑does | solvent |
what‑it‑does | emollient | viscosity controlling |
irritancy, com. | 2, 2 |
what‑it‑does | emollient | antimicrobial/antibacterial |
what‑it‑does | emollient | perfuming |
what‑it‑does | emollient |
what‑it‑does | emollient | emulsifying |
irritancy, com. | 0, 1 |
what‑it‑does | surfactant/cleansing | emulsifying |
irritancy, com. | 0, 0 |
what‑it‑does | emulsifying |
irritancy, com. | 2, 3 |
what‑it‑does | emulsifying | surfactant/cleansing |
what‑it‑does | preservative |
what‑it‑does | viscosity controlling |
irritancy, com. | 0, 1 |
what‑it‑does | preservative | antimicrobial/antibacterial |
what‑it‑does | viscosity controlling |
what‑it‑does | buffering |
what‑it‑does | perfuming |
what‑it‑does | moisturizer/humectant |
what‑it‑does | skin-identical ingredient | moisturizer/humectant |
irritancy, com. | 0, 0 |
what‑it‑does | chelating |
what‑it‑does | moisturizer/humectant |
what‑it‑does | emulsifying |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | perfuming | solvent |
what‑it‑does | skin-identical ingredient |
what‑it‑does | skin-identical ingredient |
what‑it‑does | skin-identical ingredient | cell-communicating ingredient | anti-acne | antimicrobial/antibacterial |
what‑it‑does | skin-identical ingredient | emollient |
irritancy, com. | 0, 0 |
what‑it‑does | preservative |
what‑it‑does | skin-identical ingredient |