R-Retinoate® Eye Serum
Ingredients overview
Highlights
Key Ingredients
Skim through
Medik8 R-Retinoate® Eye 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.
A super common emollient that makes your skin feel nice and smooth. It comes from coconut oil and glycerin, it’s light-textured, clear, odorless and non-greasy. It’s a nice ingredient that just feels good on the skin, is super well tolerated by every skin type and easy to formulate with. No wonder it’s popular.
A clear, colorless and odorless, highly volatile (meaning it does not absorb into the skin but evaporates from it) liquid that's used as an emollient. It gives a nice non-oily light skin feel and it can improve the slip of the formula without leaving a tacky residue behind.
It's also popular in make-up products as its volatility makes mascaras and foundations last longer. If that would not be enough, it's also an excellent solvent, and it's a regular not only on the ingredients lists of make-ups but also on makeup removers.
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 really multi-functional helper ingredient that can do several things in a skincare product: it can bring a soft and pleasant feel to the formula, it can act as a humectant and emollient, it can be a solvent for some other ingredients (for example it can help to stabilize perfumes in watery products) and it can also help to disperse pigments more evenly in makeup products. And that is still not all: it can also boost the antimicrobial activity of preservatives.
- 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
An ester that comes from Cetearyl alcohol and the fatty acids of olive oil. It often comes to the formula coupled with Sorbitan Olivate as the two together form the well-known, natural emulsifier trade named Olivem 1000.
Other than helping oil and water to blend, the main thing of Olivem 1000 is generating liquid crystal structures that are similar to the lipid structures of the stratum corneum (the outermost layer of the skin). Thanks to this, Olivem 1000 doubles as an active ingredient with significant moisturizing, barrier-repairing and soothing properties.
It also helps to deliver water-soluble actives such as caffeine more effectively, and can even boost SPF in sunscreen formulas. Its typical use level is 1-5% and has wide compatibility with other actives and oils.
Overall, a real multi-tasker with nice sensorial properties. No wonder it is so popular.
A copolymer is a big molecule that consists not of one but of two repeating subunits. This particular copolymer is a handy helper ingredient to form nice gel textures.
It usually comes to the formula combined with emollients (such as C13-14 Isoparaffin, Isohexadecane, Isononyl Isononanoate or Squalane) and can be used as an emulsifier and/or thickener to produce milky gel emulsions with a soft and non-tacky skin feel.
An ester coming from sorbitol and the fatty acids of olive oil. It is part of the popular emulsifier trade named Olivem 1000 that is well-known for generating biomimetic liquid crystal structures. We have more info on Olivem 1000 at Cetearyl Olivate >>
It seems to us that squalane is in fashion and there is a reason for it. Chemically speaking, it is a saturated (no double bonds) hydrocarbon (a molecule consisting only of carbon and hydrogen), meaning that it's a nice and stable oily liquid with a long shelf life.
It occurs naturally in certain fish and plant oils (e.g. olive), and in the sebum (the oily stuff our skin produces) of the human skin. As f.c. puts it in his awesome blog post, squalane's main things are "emolliency, surface occlusion, and TEWL prevention all with extreme cosmetic elegance". In other words, it's a superb moisturizer that makes your skin nice and smooth, without being heavy or greasy.
Another advantage of squalane is that it is pretty much compatible with all skin types and skin conditions. It is excellent for acne-prone skin and safe to use even if you have fungi-related skin issues, like seborrhea or fungal acne.
The unsaturated (with double bonds) and hence less stable version of Squalane is Squalene, you can read about it here >>
Retinyl Retinoate (RR) is a less well known but super interesting member of the retinoids (vitamin A derivatives), aka the "royal family of skincare". Unless you live under a skincare-news-shielding rock, you must have heard about tretinoin, the FDA-approved anti-aging superstar, and retinol, the most common OTC version of tretinoin. You can read more about whos-who in the retinoid family here.
Enter Retinyl Retinoate, a molecule that is created by attaching retinol to retinoic acid. The attachment makes the molecule more stable (pure retinol is unstable and hard to formulate) as well as more active. If you read our shiny description about retinol you will know that it is not active and has to be converted by our metabolic machinery to become retinoic acid, the biologically active molecule. The conversion is not very effective and takes two steps. Retinyl Retinoate also has to be converted, but in the first step, our cells break up the molecule to become retinoic acid (the active) and retinol, meaning that it becomes active both after the first conversion step as well as later on once retinol is further converted.
The Korean research group, who invented the molecule, did several studies published in well-respected journals to prove that Retinyl Retinoate has better anti-aging activity than retinol. In marketing materials, RR is often touted to be 8 times as active as retinol, but as far as research goes we can cite that "the biological activity of retinyl retinoate was in between the properties of retinol and retinoic acid. Retinyl retinoate showed higher biological activity than that of retinol, such as RAR activity and collagen synthesis. Also, retinyl retinoate showed a similar side-effect to that of retinol, and not retinoic acid."
As for in-vivo, aka done on real people studies, there is one from 2010 that compares 0.06% Retinyl Retinoate to placebo and to 0.075% retinol. The conclusion of this study was that 0.06% RR is "significantly" more effective than placebo or retinol, and RR also had a faster-acting effect. Another study (in test tubes + mouse skin) concluded that RR increases the Hyaluronic acid production more than other retinoids and is also less of an irritant.
RR shows promise for treating acne. In an 8 week, double-blind clinical study, 0.05% retinyl retinoate "showed a significant decrease in both inflammatory and non-inflammatory lesions, and in sebum amount". It even had some activity against P.acnes that makes it a promising ingredient for acne prone skin, especially when combined with other actives.
Overall, we find Retinyl Retinoate a very interesting and promising member of the retinoid family. It is not as proven as good old retinol (the multiple studies on RR come from the same research guys), but it promises several advantages (more stable, more active, less irritating), so we say that if you like retinoids, RR is worth trying.
We don't have description for this ingredient yet.
A cholesteric ester (cholesterol + nonanoic acid) that has a unique liquid crystal structure (in between solid and liquid state). Mixed with other cholesteric esters, it can produce beautiful iridescent colors.
We don't have description for this ingredient yet.
Hello, our favorite molecule that helps us wake up in the morning and then keeps us going through the day. As a super well-known stimulant from coffee, tea and plenty of other soft drinks, Caffeine needs no introduction. So we will skip right to the part where we talk about what the hell it does in so-so many cosmetic products.
Looking at the research, we were surprised to find how versatile Caffeine is. It is a small, water-loving molecule with pretty good skin penetration abilties. Once in the skin, it has nice antioxidant properties, meaning that it reduces the formation of evil free radicals and it might even be useful in preventing UV-induced skin cancers.
A well-known thing about Caffeine is that it improves the microcirculation of the blood vessels. Though conventional wisdom and anecdotal evidence says that this property is helpful for dark under-eye circles and puffy eyes, we have to mention that the double-blind research we have found about a 3% caffeine gel concluded that "the overall efficacy of the selected caffeine gel in reducing puffy eyes was not significantly different from that of its gel base." But you know, the proof is in the pudding.
Another thing Caffeine is used for in body care products is its anti-cellulite effects. In theory, it can speed up the lipolysis process (the "fat burning" by our cells) and stimulate the draining lymph system that might lead to the improvement of cellulite. But here again, the evidence that it actually makes a measurable, let alone visible, improvement on actual human beings is limited (we could find only some animal skin studies or caffeine being combined with other actives).
Last, but not least, we have to write about caffeine and hair growth. The theory is that it can inhibit the activity of the 5-α-reductase enzyme that plays an important role in hair loss and allows a renewed growth phase of the hair. We have found some recent and promising research to back this up. A 2017 study compared a 0.2% caffeine liquid with a 5% Minoxidil (an FDA approved active to treat baldness) solution and found that "a caffeine-based topical liquid should be considered as not inferior to minoxidil 5% solution in men with androgenetic alopecia", or English translation means that the caffeine liquid was pretty much as good as the FDA-approved Minoxidil stuff. Not bad!
Overall, we think that caffeine is a very versatile and biologically active ingredient. Even though some of its effects are more hyped up than backed up, it is still a nice to have on many ingredient lists.
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).
Tetrahexyldecyl Ascorbate is a stable, oil-soluble form of skincare big shot Vitamin C. If you do not know, why Vitamin C is such a big deal in skincare, click here and read all about it. We are massive vitamin C fans and have written about it in excruciating detail.
So now, you know that Vitamin C is great and all, but it's really unstable and gives cosmetics companies many headaches. To solve this problem they came up with vitamin C derivatives, and one of them is Tetrahexyldecyl Ascorbate (let's call it THDA in short).
It's a really promising candidate (see below), but while reading all the goodness about it in a minute, do not forget that derivatives not only have to be absorbed into the skin but also have to be converted to pure vitamin C (ascorbic acid or AA) and the efficacy of the conversion is often unknown. In addition, vitamin C's three magic properties (antioxidant, collagen booster, skin brightener) are all properly proven in-vivo (on real people), but for the derivatives, it's mostly in-vitro studies or in the case of THDA, it's in-vitro and done by an ingredient supplier.
With this context in mind let's see what THDA might be able to do. First, it is stable (if pH < 5), easy to formulate, and a joy to work with for a cosmetic chemist.
Second, because it's oil-soluble, its skin penetration abilities seem to be great. So great in fact, that it surpasses the penetration of pure vitamin C threefold at the same concentration and it penetrates successfully into the deeper layers of the skin (that is usually important to do some anti-aging work). There is also in-vitro data showing that it converts to AA in the skin.
Third, THDA seems to have all three magic abilities of pure vitamin C: it gives antioxidant protection from both UVB and UVA rays, it increases collagen synthesis (even more than AA) and it has a skin brightening effect by reducing melanogenesis by more than 80% in human melanoma cell cultures.
So this all sounds really great, but these are only in-vitro results at this point. We could find Tetrahexyldecyl Ascorbate mentioned only in one published in-vivo study that examined the anti-aging properties of a silicone formula containing 10% AA and 7% THDA. The authors theorized that the 10% AA is released slowly from the silicon delivery system and probably stays in the upper layer of the skin to give antioxidant benefits, while THDA penetrates more rapidly and deeply and gives some wrinkle-reducing benefits. The study was a small (10 patients), double-blind experiment, and the formula did show some measurable anti-aging results. However, it is hard to know how much pure vitamin C or THDA can be thanked.
Bottom line: a really promising, but not well-proven vitamin C derivative that can be worth a try especially if you like experimenting (but if you like the tried and true, pure vitamin C will be your best bet).
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.
A chelating agent that helps to preserve cosmetic products by neutralizing the metal ions (especially iron) in the formula (that usually get into there from water). Its special thing is that it also acts as a biostatic and fungistatic agent and remains active even at high pH.
It is often coupled with antimicrobial glycols (such as propanediol) to create a "preservative free preservative system" for cosmetic products.
A traditional Chinese herbal medicine loaded with potent antioxidant and anti-inflammatory flavonoids such as baicalin, baicalein, and wogonin.
If that would not be enough, Skullcap Root is also claimed to have antimicrobial and antifungal properties (also against P.acnes and Malassezia furfur) as well as some skin-brightening activity. A multi-functional skin-goodie.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
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.
We don't have description for this ingredient yet.
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.
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.
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.
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| what‑it‑does | solvent |
| what‑it‑does | emollient |
| what‑it‑does | emollient | solvent |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 1, 2 |
| what‑it‑does | solvent |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | emulsifying |
| what‑it‑does | viscosity controlling |
| what‑it‑does | abrasive/scrub |
| what‑it‑does | emulsifying |
| what‑it‑does | skin-identical ingredient | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | emollient |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | antioxidant | perfuming |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | antioxidant | skin brightening |
| what‑it‑does | antioxidant |
| irritancy, com. | 0, 0 |
| what‑it‑does | chelating |
| what‑it‑does | emollient |
| what‑it‑does | soothing | antioxidant | antimicrobial/antibacterial | moisturizer/humectant |
| what‑it‑does | perfuming |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | chelating |
| what‑it‑does | buffering |