Hidra Primer
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Fina Severina Hidra PrimerIngredients 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.
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.
An extremely common multitasker ingredient that gives your skin a nice soft feel (emollient) and gives body to creams and lotions. It also helps to stabilize oil-water mixes (emulsions), though it does not function as an emulsifier in itself. Its typical use level in most cream type formulas is 2-3%.
It’s a so-called fatty alcohol, a mix of cetyl and stearyl alcohol, other two emollient fatty alcohols. Though chemically speaking, it is alcohol (as in, it has an -OH group in its molecule), its properties are totally different from the properties of low molecular weight or drying alcohols such as denat. alcohol. Fatty alcohols have a long oil-soluble (and thus emollient) tail part that makes them absolutely non-drying and non-irritating and are totally ok for the skin.
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.
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.
A common functional ingredient that helps to keep the oil-loving and water-loving ingredients together (emulsifier), stabilizes and thickens the products.
Chemically speaking, it is ethoxylated Cetearyl alcohol, meaning that some ethylene oxide is added to the fatty alcohol to increase the water-soluble part in the molecule. The result is that the mainly oil soluble, emollient fatty alcohol is converted to an emulsifier molecule that keeps oil and water mixed in creams. The number in the name of Ceteareth emulsifiers refers to the average number of ethylene oxide molecules added and 20 makes a good emulsifier.
A white, waxy emollient that gives "body" to skincare formulas. Comes from coconut or palm kernel oil.
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 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
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).
Yes, it's the thing that can be found naturally in pee. And in the skin. It is an awesome natural moisturizing factor, aka NMF. NMFs are important components that help the skin to hold onto water and keep it plump, elastic and hydrated. Urea makes up about 7% of NMFs next to other things such as amino acids (40%), PCA (12%) or Lactate (12%).
What makes urea special, is that it is not only a simple moisturizer, but it is thought to be a "small-molecule regulator of epidermal structure and function" meaning that it has a bunch of extra biological activities. It acts as a mild keratolytic agent (some of its moisturizing action is thought to come from urea's ability to break down bonds in the protein called filaggrin and thus freeing up amino acids in the skin), enhances antimicrobial peptide expression and improves skin barrier function.
Being a mild keratolytic agent and strong moisturizer means that high-percentage (10-40%) urea treatments are found effective in a bunch of skin disorders connected to excessive dryness and malfunctioning skin barrier such as ichthyosis, xerosis, psoriasis, eczema and seborrheic dermatitis.
Overall, just like glycerin, urea is a real oldie but a goodie, a nice ingredient in any moisturizer.
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.
- Green tea is one of the most researched natural ingredients
- The active parts are called polyphenols, or more precisely catechins (EGCG being the most abundant and most active catechin)
- There can be huge quality differences between green tea extracts. The good ones contain 50-90% catechins (and often make the product brown and give it a distinctive smell)
- Green tea is proven to be a great antioxidant, UV protectant, anti-inflammatory, anticarcinogenic and antimicrobial
- Because of these awesome properties green tea is a great choice for anti-aging and also for skin diseases including rosacea, acne and atopic dermatitis
Probably the most common silicone of all. It is a polymer (created from repeating subunits) molecule and has different molecular weight and thus different viscosity versions from water-light to thick liquid.
As for skincare, it makes the skin silky smooth, creates a subtle gloss and forms a protective barrier (aka occlusive). Also, works well to fill in fine lines and wrinkles and give skin a plump look (of course that is only temporary, but still, it's nice). There are also scar treatment gels out there using dimethicone as their base ingredient. It helps to soften scars and increase their elasticity.
As for hair care, it is a non-volatile silicone meaning that it stays on the hair rather than evaporates from it and smoothes the hair like no other thing. Depending on your hair type, it can be a bit difficult to wash out and might cause some build-up (btw, this is not true to all silicones, only the non-volatile types).
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.
Super common little helper ingredient that helps products to remain nice and stable for a longer time. It does so by neutralizing the metal ions in the formula (that usually get into there from water) that would otherwise cause some not so nice changes.
It is typically used in tiny amounts, around 0.1% or less.
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.
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!).
A common fragrance ingredient that has a nice floral scent and also goes by the name Lilial. It is a known fragrance allergen and as of 1st of March 2022, it has been banned in the EU due to animal studies showing a possible link to infertility (in rats - so no need to panic even if you used a product before with Butylphenyl Methylpropional).
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.
Geraniol is a common fragrance ingredient. It smells like rose and can be found in rose oil or in small quantities in geranium, lemon and many other essential oils.
Just like other similar fragrance ingredients (like linalool and limonene) geraniol also oxidises on air exposure and becomes allergenic. Best to avoid if you have sensitive skin.
A common fragrance ingredient that has a sweet scent somewhere between lily and fruity melon. Can be found in essential oils, such as lavender oil, orange flower oil or ylang-ylang.
In cosmetics, it can be used up to 1%. It’s 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.
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 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.
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.
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| what‑it‑does | solvent |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 1, 2 |
| what‑it‑does | emollient | viscosity controlling |
| irritancy, com. | 2, 2 |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 2, 2 |
| what‑it‑does | emulsifying | surfactant/cleansing |
| irritancy, com. | 3, 2 |
| what‑it‑does | emollient |
| irritancy, com. | 0, 0 |
| what‑it‑does | emollient | emulsifying |
| irritancy, com. | 0, 1 |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | viscosity controlling |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| what‑it‑does | antioxidant |
| irritancy, com. | 0, 0 |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | preservative |
| what‑it‑does | chelating |
| what‑it‑does | antioxidant | preservative |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming | solvent |