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EltaMD Uv Daily Broad-Spectrum Spf 40
EltaMD

Uv Daily Broad-Spectrum Spf 40

Untinted hydrating combination sunscreen with hyaluronic acid
Uploaded by: elasmo4 on 16/03/2019

Ingredients explained

Also-called: Aqua;Water | 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. 

Also-called: Petroleum jelly, Vaseline | What-it-does: emollient

The famous Vaseline or Petroleum Jelly. Just like mineral oil, it is also a by-product of refining crude oil, aka petroleum, and it is also a mixture of hydrocarbons but with bigger (C18-90+) carbon chain length.

The unique thing about petrolatum is that it is the most effective occlusive agent known today. While the occlusivity of mineral oil is in the same league as the occlusivity of plant oils, petrolatum is in a league of its own. It sits on top of the skin and hinders so-called transepidermal water loss (TEWL) like nothing else.

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This comes in handy healing cracked lips or severely dry skin patches, though overdoing it (i.e. reducing TEWL by more than 40%) is not good as it can create a nice moist place for fungi and bacteria to grow.  

As for petrolatum and safety, we can write here pretty much the exact same thing as we have written at mineral oil. There is no evidence whatsoever that cosmetic, USP grade petrolatum is carcinogenic. It also does not absorb into the skin but sits on top of it and that in itself greatly minimises health risks. It also has a long history of safe use, as it was first used as a skincare product more than 100 years ago, in 1872 to be precise. 

It is also non-comedogenic, though its pure form is very heavy and greasy so combination and oily skin types might want to avoid it anyway. 

Overall, it is the gold-standard occlusive agent known today and a tub of Vaseline comes in handy in any household to heal cracked lips or other severely dry skin patches.

What-it-does: emollient | Irritancy: 1 | Comedogenicity: 3-4

A clear, colorless emollient ester (oily liquid from isopropyl alcohol + palmitic acid) that makes the skin nice and smooth. It has very good spreading properties and gives a silky touch to the products.

A sugar based emulsifier that's especially great for low viscosity lotions or even sprays. It's effective in small amounts, only 1-1.5% is needed to form an emulsion. The resulting cream or lotion has great cosmetic properties with good spreadability and an enhanced soft skin feel. 

What-it-does: emollient | Irritancy: 0 | Comedogenicity: 1

Probably the cheapest and 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. 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. 

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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). 

Also-called: Sepinov EMT 10 | What-it-does: viscosity controlling, emulsion stabilising

This long-named, polymer molecule (big molecule from repeated subunits) is a helper ingredient that's good at emulsifying and stabilizing oils into water-based formulas. It also acts as a thickening and gelling agent that creates nice, non-sticky and supple textures. It works over a very wide pH range (3-12) and can be used to thicken up low-ph formulas, such as exfoliants.

What-it-does: viscosity controlling

A polymer (big molecule from repeated subunits) that's used as a gloss improver for lipsticks and lipglosses. Its stickiness also helps lip products to stay on longer. 

Combined with polyacrylate-13 and polysorbate 20, it forms a very effective tickener-emulsifier trio.

We don't have description for this ingredient yet.

What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0

It’s the - sodium form - cousin of the famous NMFhyaluronic 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". 

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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).

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: viscosity controlling

We don't have description for this ingredient yet.

Citric Acid - goodie
What-it-does: exfoliant, buffering

Citric acid comes from citrus fruits and is an AHA. If these magic three letters don’t tell you anything, click here and read our detailed description on glycolic acid, the most famous AHA. 

So citric acid is an exfoliant, that can - just like other AHAs - gently lift off the dead skin cells of your skin and make it more smooth and fresh. 

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There is also some research showing that citric acid with regular use (think three months and 20% concentration) can help sun-damaged skin, increase skin thickness and some nice hydrating things called glycosaminoglycans in the skin. 

But according to a comparative study done in 1995, citric acid has less skin improving magic properties than glycolic or lactic acid. Probably that’s why citric acid is usually not used as an exfoliant but more as a helper ingredient in small amounts to adjust the pH of a formulation. 

What-it-does: surfactant/cleansing, emulsifying | Irritancy: 2 | Comedogenicity: 2

A partly water, partly oil soluble molecule created by the attachment of (ethoxylated) oleic acid (oil-soluble part) and phosphoric acid (water-soluble part). 

It works as an emulsifier helping water and oil to mix and as a dispersing agent helping insoluble solid particles (such as mineral UV filters or pigments) to be evenly dispersed in cosmetic formulas.  

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: moisturizer/humectant, solvent | 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. 

What-it-does: preservative

It's one of those things that help your cosmetics not to go wrong too soon, aka a preservative. Its strong point is being effective against yeasts and molds, and as a nice bonus seems to be non-comedogenic as well.

It is safe in concentrations of less than 0.1% but is acutely toxic when inhaled, so it's not the proper preservative choice for aerosol formulas like hairsprays. Used at 0.1%, Iodopropynyl Butylcarbamate has an extremely low rate of skin-irritation when applied directly for 24 hours (around 0.1% of 4,883 participants) and after 48 hours that figure was 0.5%, so it counts as mild and safe unless your skin is super-duper sensitive.

A clear, light yellow liquid that is used to coat pigments (such as inorganic sunscreen agents or colorants) in cosmetic products.  The coating helps to stabilize pigments in the formulas and also helps them to spread easily and evenly on 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 emollient
The famous Vaseline or Petroleum Jelly. Just like mineral oil, it is also a by-product of refining crude oil, aka petroleum, and it is also a mixture of hydrocarbons but with bigger (C18-90+) carbon chain length.The unique thing about petrolatum is that it is the most effective occlusive agent known today. [more]
what‑it‑does emollient
irritancy, com. 1, 3-4
A clear, colorless emollient ester (oily liquid) that makes the skin nice and smooth. [more]
what‑it‑does emulsifying | surfactant/cleansing
A sugar based emulsifier that's especially great for low viscosity lotions or even sprays. [more]
what‑it‑does emollient
irritancy, com. 0, 1
A very common silicone that gives both skin and hair a silky smooth feel. It also forms a protective barrier on the skin and fills in fine lines. Also used for scar treatment. [more]
what‑it‑does viscosity controlling
A helper ingredient that's good at stabilizing water-based formulas and also serves as a thickener. [more]
what‑it‑does viscosity controlling
A polymer (big molecule from repeated subunits) that's used as a gloss improver for lipsticks and lipglosses. Combined with polyacrylate-13 and polysorbate 20, it forms a very effective tickener-emulsifier trio. [more]
what‑it‑does emulsifying | surfactant/cleansing
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
It's the salt form of famous humectant and natural moisturizing factor, hyaluronic acid. It can bind huge amounts of water and it's pretty much the current IT-moisturizer. [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 viscosity controlling
what‑it‑does exfoliant | buffering
An AHA that comes from citrus fruits. It is usually used as a helper ingredient to adjust the pH of the formula. [more]
what‑it‑does surfactant/cleansing | emulsifying
irritancy, com. 2, 2
A partly water, partly oil soluble molecule created by the attachment of (ethoxylated) oleic acid (oil-soluble part) and phosphoric acid (water-soluble part). It works as an emulsifier helping water and oil to mix and as a dispersing agent helping insoluble solid particles (such as mineral UV filters or pigments) to be evenly dispersed in cosmetic formulas. [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 moisturizer/humectant | solvent
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 preservative
It's one of those things that help your cosmetics not to go wrong too soon, aka a preservative. Its strong point is being effective against yeasts and molds, and as a nice bonus seems to be non-comedogenic as well.It is safe in concentrations of less than 0.1% but is acutely toxic when inhaled, so it's not the proper preservative choice for aerosol formulas like hairsprays. [more]
A clear, light yellow liquid that is used to coat pigments (such as inorganic sunscreen agents or colorants) in cosmetic products.  [more]