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Rohto Skin Aqua UV Super Moisture Milk SPF 50+

Skin Aqua UV Super Moisture Milk SPF 50+

Super waterproof sunscreen with moisturizing ingredients. Made in Japan.
Uploaded by: littlemushroomboy on

Rohto Skin Aqua UV Super Moisture Milk SPF 50+
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. 

What-it-does: emollient, solvent

A super commonly used 5 unit long, cyclic structured silicone that is water-thin and does not stay on the skin but evaporates from it (called volatile silicone). Similar to other silicones, it gives skin and hair a silky, smooth feel

It's often combined with the non-volatile (i.e. stays on the skin) dimethicone as the two together form a water-resistant, breathable protective barrier on the skin without a negative tacky feel.

Zinc Oxide - goodie
What-it-does: sunscreen | Irritancy: 0 | Comedogenicity: 1

When it comes to sunscreen agents, Zinc Oxide is pretty much in a league of its own. It's a physical (or inorganic) sunscreen that has a lot in common with fellow inorganic sunscreen Titanium Dioxide (TiO2) but a couple of things make it superior even to TiO2.

If physical sunscreens don't tell you anything, go ahead and read about the basics here. Most of what we wrote about Titanium Dioxide is also true for Zinc Oxide so we will focus here on the differences. 

Also-called: Octinoxate, Octyl Methoxycinnamate | What-it-does: sunscreen | Irritancy: 0 | Comedogenicity: 0

A clear, oil-soluble, "cosmetically-elegant" liquid that is the most commonly used chemical sunscreen. It absorbs UVB radiation (at wavelengths: 280-320 nm) with a peak protection at 310nm. 

It only protects against UVB and not UVA rays (the 320-400 nm range) – so always choose products that contain other sunscreens too. It is not very stable either, when exposed to sunlight, it kind of breaks down and loses its effectiveness (not instantly, but over time - it loses 10% of its SPF protection ability within 35 mins). To make it more stable it can be - and should be - combined with other sunscreen agents to give stable and broad-spectrum protection (the new generation sunscreen agent, Tinosorb S is a particularly good one for that).

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.

What-it-does: emollient, solvent | Irritancy: 0 | Comedogenicity: 2

We don't have description for this ingredient yet.

spherical texturizing powder that's used as a texture enhancer and soft focus agent. It's claimed to give silicone type softness to the formula and also works as a (temporary) wrinkle filler. 

We don't have description for this ingredient yet.

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 for dry skin at higher concentrations up to 20-40%
  • High-glycerin moisturizers are awesome for treating severely dry skin
Read all the geeky details about Glycerin here >>

What-it-does: viscosity controlling

We don't have description for this ingredient yet.

The snappily named Lauryl Peg-9 Polydimethylsiloxyethyl Dimethicone is a silicone emulsifier fluid whose main thing is being a good dispersant for powders such as mineral UV filters or color pigments. 

According to the manufacturer Kobo, this partly water- and partly oily soluble form of dimethicone helps filters like Titanium Dioxide and Zinc Oxide disperse more evenly and thus provide better UV protection while also minimizing any white-cast that often comes hand-in-hand with mineral filters.

Also-called: Uvinul A Plus, DHHB | What-it-does: sunscreen

Diethylamino Hydroxybenzoyl Hexyl Benzoate is a new generation, chemical sunscreen agent (not available in the US due to impossible FDA regulations) that's designed for high UVA protection and high photostability. It gives sun protection in the whole UVA range (320-400 nm) with peak protection at 354nm. It can be used up to 10% worldwide except for the US and Canada. 

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". 

What-it-does: viscosity controlling

A big polymer molecule that has a bunch of different versions and thus different uses. It can act as a film former,  as thickening agent, or it can increase the water-resistance in sunscreens. It is also used to entrap pigments/inorganic sunscreens within a micron size matrix for even coverage and easy application.

A silicone molecule that is half-way between Dimethicone and Methicone, meaning that some of the methyl (-CH3) groups are replaced with a hydrogen atom (in Methicone half of the CH3 groups are replaced). This makes Hydrogen Dimethicone a handy pigment bonding agent used for the hydrophobization treatment of powders as the H atoms can absorb traces of water from the surface of pigments.

It almost always comes stuck together with either Titanium Dioxide, Zinc Oxide or Mica. In suncare products, it binds to physical UV filters to maximize their protection while minimizing any white casts. It also has good chemical stability with no irritation. In makeup, it is often paired with Mica where it offers nice hydrophobic properties and improves skin adhesion - meaning it will make it easier for products to stay where they should be.

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. 

A silicone fluid used mainly to treat insoluble powders (such as mineral sunscreen agents or pigments) so that they are easily and evenly dispersable both in the formula and on the skin. 

What-it-does: preservative | Irritancy: 0 | Comedogenicity: 0

The most common type of feared-by-everyone-mostly-without-scientific-reason parabens. It's a cheap, effective and well-tolerated ingredient to make sure the cosmetic formula does not go wrong too soon

Apart from the general controversy around parabens (we wrote about it more here), there is a 2006 in-vitro (made in the lab not on real people) research about methylparaben (MP) showing that when exposed to sunlight, MP treated skin cells suffered more harm than non-MP treated skin cells. The study was not done with real people on real skin but still - using a good sunscreen next to MP containing products is a good idea. (Well, in fact using a sunscreen is always a good idea. :))

What-it-does: chelating

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.

What-it-does: moisturizer/humectant

Sodium Acetylated Hyaluronate is a variation of current IT moisturizer, Hyaluronic acid, where some water-loving -OH groups are replaced by amphipathic (partly water-loving and partly water-hating) acetyl groups. The modified molecule is claimed to have even better moisture retention ability than normal HA and better affinity to the skin surface. 

The better affinity comes from the acetyl groups that act as tiny "anchors" to attach the HA molecule to the skin. Staying on top of the skin better and longer means longer-lasting surface hydration and improved elasticity. It is also less sticky and more cosmetically elegant than normal HA, so no wonder the nickname of this molecule is super hyaluronic acid. 

The chemically chopped up version of the big protein molecule, collagen. It is often derived from fish or bovine sources and works as a nice moisturizer and humectant that helps the skin to hold onto water.  

To understand a bit more what Hydrolyzed Collagen is, you have to know that proteins are large chains of amino acids connected with so-called peptide bonds. These bonds can be broken up when a water molecule is added and the resulting thing is a mix of shorter length amino acids, also called peptides. So Hydrolyzed Collagen is not really collagen, it is rather an undefined and varying mix of largish peptides. Based on a manufacturer's data, the whole, soluble collagen has an average molecular weight of 300 000 Da, while this chopped up mixture has an average MW of 12 000 Da (still pretty big). 

Arginine - goodie

A semi-essential (infants cannot synthesize it, but adults can) amino acid that is one of the primary building blocks of hair keratin and skin collagen. It's a natural moisturizing factor, a skin hydrator and might also help to speed up wound healing

Arginine usually has a positive charge (cationic) that makes it substantive to skin and hair (those are more negatively charged surfaces) and an excellent film former.  Thanks to the positive charge, it also creates a complex with AHAs (AHAs like to lose a hydrogen ion and be negatively charged, so the positive and the negative ions attract each other) that causes a "time-release AHA effect" and reduces the irritation associated with AHAs

Also-called: RonaCare AP, HDBM | What-it-does: antioxidant

A clear, colorless liquid that gives advanced protection for the skin lipids and truly photostabilizes UV filters, at least according to its manufacturer. It's as effective of an antioxidant as pure Vitamin E, aka tocopherol and as stable as its esterified version tocopheryl acetate.

It's claimed to efficiently and continuously work over 24 hours by a continuous three-phase mechanism: it dims oxidative stress, builds up protection from ROS (evil free radicals) and prevents the formation of further reactive species.

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 | solvent
It's a super commonly used water-thin volatile silicone that gives skin and hair a silky, smooth feel.  [more]
what‑it‑does sunscreen
irritancy, com. 0, 1
A physical/inorganic sunscreen with the broadest spectrum (UVB and UVA II, less good at UVA I) protection available today. It also has good stability and also works as a skin protectant, anti-irritant. Might leave some whitish tint on the skin, though. [more]
what‑it‑does sunscreen
irritancy, com. 0, 0
Octinoxate - an old-school chemical sunscreen that absorbs UVB radiation (wavelengths: 280-320 nm). Not photostable and does not protect against UVA. [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 emollient | solvent
irritancy, com. 0, 2
A spherical texturizing powder that's used as a texture enhancer and soft focus agent. [more]
what‑it‑does abrasive/scrub | viscosity controlling
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 viscosity controlling
what‑it‑does emulsifying | surfactant/cleansing
The snappily named Lauryl Peg-9 Polydimethylsiloxyethyl Dimethicone is a silicone emulsifier fluid whose main thing is being a good dispersant for powders such as mineral UV filters or color pigments. According to the manufacturer Kobo, this partly water- and partly oily soluble form of dimethicone helps filters like Titanium Dioxide and Zinc Oxide disperse more evenly and thus provi [more]
what‑it‑does sunscreen
Uvinul A Plus - A new generation, chemical sunscreen agent (not available in the US due to impossible FDA regulations) that's designed for high UVA protection and high photostability. [more]
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 viscosity controlling
A big polymer molecule that has a bunch of different versions and thus different uses. It can act as a film former,  as a thickening agent, or it can increase the water-resistance in sunscreens. [more]
A silicone molecule that is half-way between Dimethicone and Methicone, meaning that some of the methyl (-CH3) groups are replaced with a hydrogen atom (in Methicone half of the CH3 groups are replaced). [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]
A silicone fluid used mainly to treat insoluble powders (such as mineral sunscreen agents or pigments) so that they are easily and evenly dispersable both in the formula and on the skin. 
what‑it‑does preservative
irritancy, com. 0, 0
The most common type of feared-by-everyone-mostly-without-scientific-reason parabens. It's a cheap, effective and well-tolerated ingredient to make sure the cosmetic formula does not go wrong too soon.  Apart from the general controversy around parabens (we wrote about it more here), there is a 2006 in-vitro (made in the lab not on real people) research about methylparaben (MP) sho [more]
what‑it‑does chelating
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
Sodium Acetylated Hyaluronate is a variation of current IT moisturizer, Hyaluronic acid, where some water-loving -OH groups are replaced by amphipathic (partly water-loving and partly water-hating) acetyl groups. [more]
what‑it‑does emollient | moisturizer/humectant
The chemically chopped up version of the big protein molecule, collagen. It is often derived from fish or bovine sources and works as a nice moisturizer and humectant that helps the skin to hold onto water.   To understand a bit more what Hydrolyzed Collagen is, you have to know that proteins are large chains of amino acids connected with so-called peptide bonds. [more]
what‑it‑does skin-identical ingredient
An amino acid that is one of the primary building blocks of hair keratin and skin collagen. It's a natural moisturizing factor and might also help to speed up wound healing.  [more]
what‑it‑does antioxidant
A clear, colorless liquid that gives advanced protection for the skin lipids and photostabilizes UV filters. It's also a promising ingredient for acne pevention. [more]