Caffeine Cooling Eye Serum Stick
Ingredients overview
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Dēpology Caffeine Cooling Eye Serum StickIngredients 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.
We don't have description for this ingredient yet.
A light emollient ester (C8-10 fatty acids connected to C12-18 fatty alcohols) that absorbs quickly and leaves a dry but silky finish on the skin. In terms of skin feel, it is similar to Dicaprylyl Carbonate, another commonly used light emollient.
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 solid emollient that melts at skin temperature and gives a silky but non-oily skin-feel.
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.
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 multi-functional skincare superstar with several proven benefits for the skin
- Great anti-aging, wrinkle smoothing ingredient used at 4-5% concentration
- Fades brown spots alone or in combination with amino sugar, acetyl glucosamine
- Increases ceramide synthesis that results in a stronger, healthier skin barrier and better skin hydration
- Can help to improve several skin conditions including acne, rosacea, and atopic dermatitis
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
Propanediol is a natural alternative for the often used and often bad-mouthed propylene glycol. It's produced sustainably from corn sugar and it's Ecocert approved.
It's quite a multi-tasker: can be used to improve skin moisturization, as a solvent, to boost preservative efficacy or to influence the sensory properties of the end formula.
A so-called dispersant or dispersing agent that's used in inorganic (titanium dioxide/zinc oxide based) sunscreens or in make-up products to help to distribute the pigments nicely and evenly on the skin. It's also claimed to increase the UV absorption of the sunscreen formula as well as to reduce the annoying white cast left behind by inorganic sunscreens.
We don't have description for this ingredient yet.
Sodium chloride is the fancy name of salt. Normal, everyday table salt.
If (similar to us) you are in the weird habit of reading the label on your shower gel while taking a shower, you might have noticed that sodium chloride is almost always on the ingredient list. The reason for this is that salt acts as a fantastic thickener in cleansing formulas created with ionic cleansing agents (aka surfactants) such as Sodium Laureth Sulfate. A couple of percents (typically 1-3%) turns a runny surfactant solution into a nice gel texture.
If you are into chemistry (if not, we understand, just skip this paragraph), the reason is that electrolytes (you know, the Na+ and Cl- ions) screen the electrostatic repulsion between the head groups of ionic surfactants and thus support the formation of long shaped micelles (instead of spherical ones) that entangle like spaghetti, and viola, a gel is formed. However, too much of it causes the phenomenon called "salting out", and the surfactant solution goes runny again.
Other than that, salt also works as an emulsion stabilizer in water-in-oil emulsions, that is when water droplets are dispersed in the outer oil (or silicone) phase. And last but not least, when salt is right at the first spot of the ingredient list (and is not dissolved), the product is usually a body scrub where salt is the physical exfoliating agent.
The oil coming from the pulp of the sea buckthorn berry. It has a pretty unique fatty acid composition: 65% is a combination of the rare Omega-7, aka palmitoleic acid and the more common palmitic acid. Fatty acids give the oil nice moisturizing and skin-protecting abilities.
But that's not all the goodness of sea buckthorn oil. It contains antioxidant superstar, Vitamin E (in multiple forms), antioxidant (and orange color giving) pigments beta-carotene and lycopene, as well as skin-soothing and replenishing beta-sitosterol.
Btw, used undiluted, it will make your skin orange.
All in all, a goodie emollient plant oil.
We don't have description for this ingredient yet.
- 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 organic derivative of hectorite clay, Disteardimonium Hectorite is used as a viscosity controller - it thickens up formulations to make them less runny.
It’s most popular use in cosmetics is in sunscreens, under the trademarked name Bentone 38 from Elementis. According to the manufacturer info, it is a real multi-tasker, including the ability to prevent pigments settling during storage, stabilizing a formula for longer, creating a light and smooth skin feel and enhancing the water-resistance of sunscreen formulas.
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 >>
Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate is an antioxidant molecule used in small amounts (less than 0.8%) to help products stay nice longer. More specifically, it is great at preventing discoloration or other types of oxidative degradation. It is a trendy alternative to often bad-mouthed synthetic antioxidant and stabilizer, BHT.
- 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
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
Adenosine is an important little compound in our body that has a vital cell-signalling role. Research on smearing it on our face is also promising and shows so far a couple of things:
- It can help with wound healing
- It’s a good anti-inflammatory agent
- It might even help with skin’s own collagen production and improve skin firmness and elasticity
- It helps with barrier repair and protection
- It might be even useful for the hair helping with hair thickness and hair growth
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.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
A nice plant extract that's used as a traditional oriental medicine in China and Korea. A 2006 study examined the cosmetic properties of the polysaccharide extract and found a couple of promising things:
The main components of the extract are water-binding sugars, namely rhamnose, galactose, and glucose. After this, it's not very surprising that the extract itself is also a great skin moisturizer almost as good as superstar NMF, hyaluronic acid. But that's not all: the researchers also found that Ulmus extract has promising anti-inflammatory and photoprotective properties. Seems like a goodie plant extract.
We don't have description for this ingredient yet.
- Primary fat-soluble antioxidant in our skin
- Significant photoprotection against UVB rays
- Vit C + Vit E work in synergy and provide great photoprotection
- Has emollient properties
- Easy to formulate, stable and relatively inexpensive
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).
We don't have description for this ingredient yet.
Hydrolyzed Hyaluronic Acid is a low molecular weight, chemically chopped up version of the naturally big molecule and current IT-moisturizer, Hyaluronic Acid (HA). 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 retain water, making it plump and elastic. As HA is a polymer, the subunits can be repeated many times (as a high-molecular-weight version), or just a few times (as a low-molecular-weight version).
We wrote in detail at HA about how different molecular weight versions do different things both as a component of the skin and as a skincare ingredient, so click here and read about all the details. Hydrolyzed Hyaluronic Acid can also come in different molecular-weight versions with different properties:
- 100-300 kDa version: apart from moisturizing, this size might also help the skin to repair itself by increasing its self-defense. It is also claimed to boost the wound healing process and is especially helpful for sensitive skin types (acne, rosacea, inflammation-related skin diseases).
- 50k Da version: this is the size that is claimed to be able to absorb into the skin and plump up wrinkles, so it is used mainly as an "anti-aging ingredient"
- below 50k, around 10k Da version: there is a Japanese version trade named Hyalo-Oligo that has only a 10k molecular weight and is claimed to penetrate the skin very well, have a unique touch and give deep and long-lasting moisturization. Based on the Evonik-research and the natural role of LMW-HA in the body working as a pro-inflammatory signal molecule, this ultra-low molecular weight version is a controversial ingredient.
If you wanna become a real HA-and-the-skin expert, you can read much 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).
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.
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.
- It’s naturally in our skin and behaves there like a sponge
- It can bind up to 1000 times its own weight in water
- It is a big molecule from repeated subunits (polymer) so different molecular weight versions exist (unfortunately there is no way to determine MW from INCI list only)
- High-molecular-weight-HA (>500 kDa) is an excellent surface hydrator, skin protectant and can act as an osmotic pump helping water-soluble actives to penetrate deeper into the skin
- Low-molecular-weight-HA (< 500 kDa) can hydrate the skin somewhat deeper though it is still a big molecule and works mainly in the epidermis (outer layer of the skin)
- Low-molecular-weight-HA might also help the skin to repair itself by increasing its self-defense (~ 200kDa used in the study)
- Ultra-low-molecular-weight-HA (<50kDa) is a controversial ingredient and might work as a pro-inflammatory signal molecule
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
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.
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.
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.
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.
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.
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| what‑it‑does | solvent |
| what‑it‑does | emollient | viscosity controlling |
| what‑it‑does | emollient |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | emollient |
| irritancy, com. | 0, 4 |
| what‑it‑does | antioxidant | perfuming |
| what‑it‑does | emollient |
| what‑it‑does | solvent |
| what‑it‑does | cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant |
| what‑it‑does | surfactant/cleansing |
| what‑it‑does | viscosity controlling |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | emulsifying |
| what‑it‑does | emulsifying |
| what‑it‑does | emulsifying |
| what‑it‑does | viscosity controlling |
| what‑it‑does | antioxidant | emollient |
| what‑it‑does | emulsifying |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | viscosity controlling |
| what‑it‑does | skin-identical ingredient | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | antioxidant | preservative |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | soothing | emollient | moisturizer/humectant |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | antioxidant |
| what‑it‑does | antioxidant |
| irritancy, com. | 0-3, 0-3 |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | skin brightening |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | skin-identical ingredient | antioxidant | moisturizer/humectant |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | preservative |