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e.l.f. Hydrating Booster Drops

Hydrating Booster Drops

This lightweight booster supercharges your routine for instant hydration to help create plump looking skin. These e.l.f. Cosmetics concentrated Hydrating Booster Drops can be used alone or added into any foundation, liquid, or cream. Infused with Vitamin E.
Uploaded by: 3mimis on

Skim through

Ingredient name what-it-does irr., com. ID-Rating
Water (Aqua) solvent
Butylene Glycol moisturizer/​humectant, solvent, viscosity controlling 0, 1
Glycerin skin-identical ingredient, moisturizer/​humectant 0, 0 superstar
Pentylene Glycol solvent, moisturizer/​humectant
Propylene Glycol moisturizer/​humectant, solvent, viscosity controlling 0, 0
Hydrolyzed Sodium Hyaluronate moisturizer/​humectant
Chondrus Crispus (Carrageenan) Extract moisturizer/​humectant, viscosity controlling goodie
Tremella Fuciformis Sporocarp Extract antioxidant, moisturizer/​humectant goodie
Sodium Hyaluronate Crosspolymer skin-identical ingredient, antioxidant, moisturizer/​humectant goodie
Tocopheryl Acetate (Ve) antioxidant 0, 0
Phenoxyethanol preservative
Hexylene Glycol solvent, emulsifying, perfuming, surfactant/​cleansing 0-1, 0-2
Tromethamine buffering
Carbomer viscosity controlling 0, 1
Xanthan Gum viscosity controlling, emulsifying, surfactant/​cleansing
PPG-26-Buteth-26
Caprylyl Glycol moisturizer/​humectant, emollient
Ethylhexylglycerin preservative
PEG-40 Hydrogenated Castor Oil emulsifying, surfactant/​cleansing
Fructose moisturizer/​humectant goodie
Disodium EDTA chelating, viscosity controlling
Glucose moisturizer/​humectant goodie
Dextrin viscosity controlling, moisturizer/​humectant
Urea skin-identical ingredient, moisturizer/​humectant goodie
Sucrose moisturizer/​humectant, soothing goodie
Glutamic Acid moisturizer/​humectant
Aspartic Acid skin-identical ingredient goodie
Hexyl Nicotinate emollient
Alanine skin-identical ingredient goodie

e.l.f. Hydrating Booster Drops
Ingredients explained

Also-called: Aqua | 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: moisturizer/humectant, solvent, viscosity controlling | Irritancy: 0 | Comedogenicity: 1

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.

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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. 

Glycerin - superstar
Also-called: Glycerol | What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0
  • 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 at higher concentrations up to 20-40% (around 10% is a good usability-effectiveness sweet spot)
  • High-glycerin moisturizers are awesome for treating severely dry skin
Read all the geeky details about Glycerin here >>

A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent and a broad spectrum antimicrobial. According to manufacturer info, it's also a moisturizer and helps to make the product feel great on the skin. It works synergistically with preservatives and helps to improve water-resistance of sunscreens. 

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 >>

Also-called: miniHA | What-it-does: moisturizer/humectant

It's a super small, chemically chopped up version of sodium hyaluronate. Its trade name is miniHA, and its molecular weight is 10 kDa. This counts as really tiny given that "normal" HA has a molecular weight of 0.5-2 million Da.

To be honest, low molecular weight (LMW), and especially this ultra-low molecular weight HA is a controversial ingredient. On the upside, it can penetrate the skin better (though 10kDa still counts as big!) and might be able to moisturize the deeper layers of the skin where normal HA cannot get. Also, according to the manufacturer of miniHA, it has better antioxidant activity than a 1.6MDa version HA and it also has better sun protection and after-sun repair abilities than the higher MW versions. It also works in synergy with higher molecular weight versions, and the combination of 0.1% 1.45MDa-HA + 0.1% 380 kDa-HA + 0.1% miniHA hydrated the skin significantly better than 0.3% 1.45MDa-HA alone.

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On the downside, the biological role of LMW-HA in the skin is being a pro-inflammatory signaling agent and there is a study by another manufacturer called Evonik showing that HA versions with smaller than 50kDa molecular weight might be pro-inflammatory when put on the skin. Granted, the study was only done on reconstituted human epidermis, so it might or might not be like this on real human skin. 

If you wanna get confused and read much more about hyaluronic acid and what the different molecular weight versions might or might not do, click here and read our excruciatingly long description

Also-called: Carrageenan Extract, Seaweed Extract | What-it-does: moisturizer/humectant, viscosity controlling

The extract of red seaweed that has nice film-forming, skin smoothing and moisturizing properties.​

The manufacturer claims that thanks to biomimetic properties between skin proteins and carrageenans it has a very long-lasting action and can form a "second skin". It also gives a "slow-release" effect to oil-loving active ingredients and measurably reduces trans-epidermal water loss (that's pretty much a synonym of saying that it moisturizes the skin). 

Also-called: Silver Ear Fungus Extract | What-it-does: antioxidant, moisturizer/humectant

polysaccharide (a big sugar molecule) coming from the edible fruit bodies of the Silver Ear mushroom in China. Legend has it, imperial Concubine Yang Kuei-fei - the most beautiful woman in Chinese history - used it for her facial care.

So Tremella Extract is a big molecule (more than 1M Da molecular weight) with sugar constituents of Mannose, Xylose, and Glucuronic acid (20%). The last one is the most important one, as Glucuronic acid is also a major component in hyaluronic acid (HA). Thanks to this, Tremella is claimed to be an awesome moisturizer with slightly greater water-holding capacities than HA itself. This is quite a big deal as HA is known for its crazy water-holding capacity (up to 1000 times its own weight).

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Not only that but Tremella also seems to have some antioxidant effect, it's not sticky (humectants do tend to be sticky) and it leaves skin moist and smooth. No wonder, Concubine Yang Kuei-fei liked this mushroom.

It's a special "cross-linked" from of IT-moisturizer, hyaluronic acid (HA). Cross-linked means that "normal" HA pieces (1-2 million Da molecular weight) are chemically bound togeather to create a big, "infinite" mesh.

The special HA mesh has a remarkable water-binding capacity, 5 times more than the already crazy water-binding capacity of "normal" HA. This water filled crosslinked HA gel forms a smooth film on the skin and continuously delivers the bound water, so it gives long-term moisturizing benefits.

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Btw, crosslinking HA was developed for dermal fillers (as crosslinking helps their longevity), and this guy is the topical version of FDA approved dermal filler called Hylan B gel. Smearing crosslinked version all over ourselves is a newish thing, and incoming evidence so far suggests that it's a great idea, even better than normal HA. 

A very recent, 2016 research article compared the topical moisturizing effect of crosslinked HA (not Hylan B gel specifically, but something called Resilient HA or RHA), HMW-HA and LMW-HA and found that "TEWL (that is trans-epidermal water loss, the water that evaporates from the skin) was reduced by 27.8% with RHA, and by 15.6% with HMW HA, but increased by 55.5% with LMW HA." (You can read much more about HMW and LMW HA here in the geeky details section.)

All in all, we think Sodium Hyaluronate Crosspolymer is an awesome version of HA, probably superior to traditional versions, so be happy to spot it on the ingredient list. 

Also-called: Vitamin E Acetate | What-it-does: antioxidant | Irritancy: 0 | Comedogenicity: 0

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. 

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.

What-it-does: solvent, emulsifying, perfuming, surfactant/cleansing | Irritancy: 0-1 | Comedogenicity: 0-2

Similar to other glycols, it's a helper ingredient used as a solvent, or to thin out thick formulas and make them more nicely spreadable. 

Hexylene Glycol is also part a preservative blend named Lexgard® HPO, where it helps the effectiveness of current IT-preservative, phenoxyethanol

What-it-does: buffering

It's a little helper ingredient that helps to set the pH of the products to be right. It has an alkaline pH and can neutralize acidic ingredients.

What-it-does: viscosity controlling, emulsion stabilising | Irritancy: 0 | Comedogenicity: 1

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.

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 helper ingredient that usually comes to the formula coupled with PEG-40 Hydrogenated Castor Oil. The two together work as surfactants and oil solubilizers. It's a non-sticky duo that works at low concentration and is often used to solubilize fragrance components into water-based formulas.

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.

What-it-does: preservative, deodorant

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

A mildly viscous, amber-colored liquid with fatty odor, made from Castor Oil and polyethylene glycol (PEG).

If it were a person, we’d say, it’s agile, diligent & multifunctional. It’s mostly used as an emulsifier and surfactant but most often it is used to solubilize fragrances into water-based formulas.

Fructose - goodie
What-it-does: moisturizer/humectant

Fancy name for fruit sugar. It has nice water-binding properties and helps to keep skin hydrated

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.

Glucose - goodie
What-it-does: moisturizer/humectant

A fancy name for sugar. Luckily when you put it on your skin it's good for you not like when you eat it. :) It has water-binding properties, which means that it helps to keep your skin nice and hydrated

A little helper ingredient that can be a thickener, a humectant, a foam booster, an adhesion promoter and a filler. It's a blend of polysaccharides that helps to moisturize and soften the skin. 

Urea - goodie
Also-called: Carbamide | What-it-does: skin-identical ingredient, moisturizer/humectant

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

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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.

Sucrose - goodie

A type fo sugar, usually refined from cane or beet sugar. On the skin, it has water-binding properties and helps to keep your skin hydrated

What-it-does: moisturizer/humectant

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.

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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.

Aspartic Acid - goodie

A non-essential amino acid  (important building block of collagen and elastin) that hydrates the skin. It is also used to set the pH of the cosmetic product (buffering).

What-it-does: emollient

There is not too much info out there about Hexyl Nicotinate. It's an emollient, moisturizer ingredient. Also according to this study it increases blood flow.

Alanine - goodie

A non-essential amino acid (a building block of skin proteins like collagen or elastin) that hydrates the skin.

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 moisturizer/humectant | solvent | viscosity controlling
irritancy, com. 0, 1
An often used glycol that works as a solvent, humectant, penetration enhancer and also gives a good slip to the products. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
A real oldie but a goodie. Great natural moisturizer and skin-identical ingredient that plays an important role in skin hydration and general skin health. [more]
what‑it‑does solvent | moisturizer/humectant
A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent, and a broad spectrum antimicrobial. [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 moisturizer/humectant
A super small, chemically chopped up version of sodium hyaluronate. Small molecular weight (SMW) HA is a controversial ingredient: it can penetrate deep into the skin and moisturize deeper layers but might act as a pro-inflammatory agent. [more]
what‑it‑does moisturizer/humectant | viscosity controlling
The extract of red seaweed that has nice film-forming, skin smoothing and moisturizing properties.​ [more]
what‑it‑does antioxidant | moisturizer/humectant
A big sugar molecule coming from an edible mushroom in China. Like hyaluronic acid, it contains Glucuronic acid and is claimed to be an awesome moisturizer. [more]
what‑it‑does skin-identical ingredient | antioxidant | moisturizer/humectant
A special, "cross-linked" from of hyaluronic acid (HA). Claimed to have five times the water-binding capacity of normal HA, also acts as an antioxidant and gives skin long-term moisture. [more]
what‑it‑does antioxidant
irritancy, com. 0, 0
A form of vitamin E that works as an antioxidant. Compared to the pure form it's more stable, has longer shelf life, but it's also more poorly absorbed by the skin. [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]
what‑it‑does solvent | emulsifying | perfuming | surfactant/cleansing
irritancy, com. 0-1, 0-2
Similar to other glycols, it's a helper ingredient used as a solvent, or to thin out thick formulas and make them more nicely spreadable.  Hexylene Glycol is also part a preservative blend named Lexgard® [more]
what‑it‑does buffering
It's a little helper ingredient that helps to set the pH of the products to be right. It has an alkaline pH and can neutralize acidic ingredients.
what‑it‑does viscosity controlling
irritancy, com. 0, 1
A handy white powder that magically converts a liquid into a nice gel formula. [more]
what‑it‑does viscosity controlling | emulsifying | surfactant/cleansing
A super commonly used thickener and emulsion stabilizer. [more]
A helper ingredient that usually comes to the formula coupled with PEG-40 Hydrogenated Castor Oil. The two together work as surfactants and oil solubilizers. [more]
what‑it‑does moisturizer/humectant | emollient
A handy multi-tasking ingredient that gives the skin a nice, soft feel and also boosts the effectiveness of other preservatives. [more]
what‑it‑does preservative
It can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too. [more]
what‑it‑does emulsifying | surfactant/cleansing
A mildly viscous, amber-colored liquid that works as an emulsifier and surfactant. [more]
what‑it‑does moisturizer/humectant
Fancy name for fruit sugar. It has nice water-binding properties and helps to keep skin hydrated. 
what‑it‑does chelating | viscosity controlling
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. [more]
what‑it‑does moisturizer/humectant
Sugar - as a skincare ingredient it has water-binding properties, which means that it helps to keep your skin nice and hydrated.  [more]
what‑it‑does viscosity controlling | moisturizer/humectant
A little helper ingredient that can be a thickener, a humectant, a foam booster, an adhesion promoter and a filler. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
The thing in the pee that is also a natural moisturizing factor (NMF) with mild keratolytic and strong skin moisturizing superpowers. [more]
what‑it‑does moisturizer/humectant | soothing
A type fo sugar, usually refined from cane or beet sugar. On the skin, it is water-binding properties and helps to keep your skin hydrated.
what‑it‑does moisturizer/humectant
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 [more]
what‑it‑does skin-identical ingredient
A non-essential amino acid  (important building block of collagen and elastin) that hydrates the skin. [more]
what‑it‑does emollient
It's an emollient and moisturizer. It also increases blood flow. [more]
what‑it‑does skin-identical ingredient
A non-essential amino acid (a building block of skin proteins like collagen or elastin) that hydrates the skin.