Hydrating Serum
Ingredients overview
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Key Ingredients
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e.l.f. Hydrating SerumIngredients 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.
Butylene glycol, or let’s just call it BG, is a multi-tasking colorless, syrupy liquid. It’s a great pick for creating a nice feeling product.
BG’s main job is usually to be a solvent for the other ingredients. Other tasks include helping the product to absorb faster and deeper into the skin (penetration enhancer), making the product spread nicely over the skin (slip agent), and attracting water (humectant) into the skin.
It’s an ingredient whose safety hasn’t been questioned so far by anyone (at least not that we know about). BG is approved by Ecocert and is also used enthusiastically in natural products. BTW, it’s also a food additive.
- 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 synthetic liquid oil that can replace mineral oil or silicone oils in the cosmetic formulas. There are different grades depending on the molecular weight ranging from very light, volatile, non-residue leaving ones to more substantial, slight residue leaving ones.
Apart from leaving the skin soft and smooth (emollient), it's also used as a waterproofing agent in sunscreens or makeup products and as a shine enhancer in lip gloss formulas.
An odorless and colorless emollient ester (cetyl alcohol + ethylhexanoic acid) that gives a velvety and silky feel to the skin. It has great spreadability and a non-oily feel. It's a popular ingredient in makeup removers.
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).
A waxy solid material that helps oil and water to mix together, aka emulsifier. It is super similar to Steareth-20 with just a little more ethoxylation and thus a little more water solubility. It works very well when combined with mostly oil-soluble emulsifiers such as Steareth-2 and the two together can form exceptionally stable emulsions.
A waxy solid material that helps oil and water to mix together, aka emulsifier. It is derived from the fatty alcohol, stearyl alcohol by ethoxylating it and thus making the molecule a little water-soluble. This version has only a small amount of ethoxylation and thus the molecule is still largely oil soluble. It is often mixed with more water-soluble emulsifiers (such as Steareth-20) to create stable emulsion systems.
Jojoba is a drought resistant evergreen shrub native to South-western North America. It's known and grown for jojoba oil, the golden yellow liquid coming from the seeds (about 50% of the weight of the seeds will be oil).
At first glance, it seems like your average emollient plant oil: it looks like an oil and it's nourishing and moisturizing to the skin but if we dig a bit deeper, it turns out that jojoba oil is really special and unique: technically - or rather chemically - it's not an oil but a wax ester (and calling it an oil is kind of sloppy).
So what the heck is a wax ester and why is that important anyway? Well, to understand what a wax ester is, you first have to know that oils are chemically triglycerides: one glycerin + three fatty acids attached to it. The fatty acids attached to the glycerin vary and thus we have many kinds of oils, but they are all triglycerides. Mother Nature created triglycerides to be easily hydrolyzed (be broken down to a glycerin + 3 fatty acid molecules) and oxidized (the fatty acid is broken down into small parts) - this happens basically when we eat fats or oils and our body generates energy from it.
Mother Nature also created wax esters but for a totally different purpose. Chemically, a wax ester is a fatty acid + a fatty alcohol, one long molecule. Wax esters are on the outer surface of several plant leaves to give them environmental protection. 25-30% of human sebum is also wax esters to give us people environmental protection.
So being a wax ester results in a couple of unique properties: First, jojoba oil is extremely stable. Like crazy stable. Even if you heat it to 370 C (698 F) for 96 hours, it does not budge. (Many plant oils tend to go off pretty quickly). If you have some pure jojoba oil at home, you should be fine using it for years.
Second, jojoba oil is the most similar to human sebum (both being wax esters), and the two are completely miscible. Acne.org has this not fully proven theory that thanks to this, jojoba might be able to "trick" the skin into thinking it has already produced enough sebum, so it might have "skin balancing" properties for oily skin.
Third, jojoba oil moisturizes the skin through a unique dual action: on the one hand, it mixes with sebum and forms a thin, non-greasy, semi-occlusive layer; on the other hand, it absorbs into the skin through pores and hair follicles then diffuses into the intercellular spaces of the outer layer of the skin to make it soft and supple.
On balance, the point is this: in contrast to real plant oils, wax esters were designed by Mother Nature to stay on the surface and form a protective, moisturizing barrier and jojoba oil being a wax ester is uniquely excellent at doing that.
Unless you live under a rock you must have heard about shea butter. It's probably the most hyped up natural butter in skincare today. It comes from the seeds of African Shea or Karite Trees and used as a magic moisturizer and emollient.
But it's not only a simple emollient, it regenerates and soothes the skin, protects it from external factors (such as UV rays or wind) and is also rich in antioxidants (among others vitamin A, E, F, quercetin and epigallocatechin gallate). If you are looking for rich emollient benefits + more, shea is hard to beat.
A goodie plant oil coming from the polyphenol-rich seeds of the grape. It's a light emollient oil that makes your skin feel smooth and nice and also contains a bunch of good-for-the-skin stuff. It's a great source of antioxidant polyphenols, barrier repair fatty acid linoleic acid (about 55-77%, while oleic acid is about 12-27%) and antioxidant, skin-protectant vitamin E.
The extract coming from the juice containing leaves of the Aloe vera plant. It's usually a hydroglycolic extract (though oil extract for the lipid parts also exists) that has similar moisturizing, emollient and anti-inflammatory properties as the juice itself. We have written some more about aloe here.
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.
It’s a little helper ingredient that helps to set the pH of a cosmetic formulation to be just right. It’s very alkaline (you know the opposite of being very acidic): a 1% solution has a pH of around 10.
It does not have the very best safety reputation but in general, you do not have to worry about it.
What is true is that if a product contains so-called N-nitrogenating agents (e.g.: preservatives like 2-Bromo-2-Nitropropane-1,3-Diol, 5-Bromo-5-Nitro- 1,3-Dioxane or sodium nitrate - so look out for things with nitro, nitra in the name) that together with TEA can form some not nice carcinogenic stuff (that is called nitrosamines). But with proper formulation that does not happen, TEA in itself is not a bad guy.
But let’s assume a bad combination of ingredients were used and the nitrosamines formed. :( Even in that case you are probably fine because as far as we know it cannot penetrate the skin.
But to be on the safe side, if you see Triethanolamine in an INCI and also something with nitra, nitro in the name of it just skip the product, that cannot hurt.
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.
We don't have description for this ingredient yet.
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 - 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).
- 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
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.
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.
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| what‑it‑does | solvent |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | emollient | viscosity controlling |
| irritancy, com. | 2, 1 |
| what‑it‑does | emollient |
| what‑it‑does | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | emulsifying | surfactant/cleansing |
| irritancy, com. | 2, 2 |
| what‑it‑does | emollient |
| irritancy, com. | 0, 0-2 |
| what‑it‑does | emollient |
| what‑it‑does | antioxidant | emollient |
| what‑it‑does | soothing | emollient | moisturizer/humectant |
| what‑it‑does | viscosity controlling |
| irritancy, com. | 0, 1 |
| what‑it‑does | buffering |
| irritancy, com. | 0, 2 |
| what‑it‑does | antioxidant |
| irritancy, com. | 0, 0 |
| what‑it‑does | chelating |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | preservative |
| what‑it‑does | moisturizer/humectant | emollient |