Retinol Face Serum
Ingredients overview
- This ingredient list contains several ingredient names that do not follow the INCI nomenclature. Read here for more detail.
- This ingredient list seems to miss preservatives necessary for creating safe products. Read here for more detail.
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Key Ingredients
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Kizenka Retinol Face 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.
Witch hazel is a smallish tree (up to 5m) that's native to North-America, has nice yellow flowers and is similar to the hazelnut bush (hence the name).
As for skincare, it's loaded with active components that have a bunch of magic properties, like astringent, anti-inflammatory, antioxidant and anti-bacterial. It's also a well-known vasoconstrictor (it makes the blood vessels narrower) and promotes the healing of broken skin by tightening up the skin proteins and thus creating a protective covering.
The complication, however, is that different extracts and distillates can be made from different parts of the plant (bark, twigs, and leaves are typically used) and different extraction methods from different parts produce different results. So if you see only Witch Hazel Extract or Witch Hazel Water on the ingredient list, it's a bit hard to know what you're actually getting but we will try to summarize the possibilities to give an idea.
The main biologically active components in Witch Hazel are hamamelitannin (a potent astringent and antioxidant), catechins (anti-inflammatory and antioxidant) and gallic acid (antibacterial). The bark extract contains by far the most hamamelitannin and it has the most gallic acid and catechins. The twigs contain fewer catechins, less gallic acid, and much less hamamelitannin (4.77% vs 0.18%). The leaves contain hardly any tannins (0.04%) or catechins and contain a medium amount of gallic acid (compared to the bark and twigs).
Witch Hazel also contains tiny amounts of the essential oil and fragrance component eugenol, but the amount is so small that it's probably not significant for the skin.
Apart from the differences in active components in different parts of the Witch Hazel bush, the extraction methods also vary. Witch Hazel Distillate contains 14% added alcohol according to the USP specifications and alcohol is, at best drying, and at worst skin-damaging. Luckily, there are also alcohol-free distillates, so if you prefer no alcohol check the ingredient list carefully. Witch Hazel Extracts can also be made in different ways: browsing Ulprospector, we could find hydroglycolic, hydroalcoholic and glicerine/water based extracts.
Well-known skin care expert, Paula Begoun rates witch hazel as poor and says, "depending on the form of witch hazel, you’re exposing your skin either to a sensitizing amount of alcohol or to tannins, or both." This might be the case if you are dealing with an alcoholic witch hazel bark water or extract, but looking at CosIng (the official INCI name listing of the EU), witch hazel bark water or witch hazel bark extract are not listed ingredients. Bark and leaf or bark and twig or all three are used together to create extracts, so the chance that there is too much hamamelitannin in the final cosmetic ingredient seems small. Also alcohol-free extracts and distillates exist; actually, the majority seem to be alcohol-free nowadays. So all in all, we think "Hamamelis Virginiana Extract" on the ingredient list is nothing to worry about.
We even found a German study that compared the efficacy of Hamamelis ointment to panthenol ointment for soothing the skin in children (from 27 days to 11 years old). They observed 309 children and concluded that both ointments were similarly effective but the one with Hamamelis was even better tolerated (98.2% vs. 92.3% tolerated well the ointments in the two groups).
All in all, Witch Hazel Extract is a sloppy INCI name (btw, not in the CosIng listing), and you do not really know what you're getting. Most probably though, you are getting a goody with nice astringent, soothing, antibacterial, and even antioxidant properties.
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.
It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula.
Jojoba is a drought resistant evergreen shrub native to South-western North America. It's known and grown for jojoba oil, the golden yellow liquid coming from the seeds (about 50% of the weight of the seeds will be oil).
At first glance, it seems like your average emollient plant oil: it looks like an oil and it's nourishing and moisturizing to the skin but if we dig a bit deeper, it turns out that jojoba oil is really special and unique: technically - or rather chemically - it's not an oil but a wax ester (and calling it an oil is kind of sloppy).
So what the heck is a wax ester and why is that important anyway? Well, to understand what a wax ester is, you first have to know that oils are chemically triglycerides: one glycerin + three fatty acids attached to it. The fatty acids attached to the glycerin vary and thus we have many kinds of oils, but they are all triglycerides. Mother Nature created triglycerides to be easily hydrolyzed (be broken down to a glycerin + 3 fatty acid molecules) and oxidized (the fatty acid is broken down into small parts) - this happens basically when we eat fats or oils and our body generates energy from it.
Mother Nature also created wax esters but for a totally different purpose. Chemically, a wax ester is a fatty acid + a fatty alcohol, one long molecule. Wax esters are on the outer surface of several plant leaves to give them environmental protection. 25-30% of human sebum is also wax esters to give us people environmental protection.
So being a wax ester results in a couple of unique properties: First, jojoba oil is extremely stable. Like crazy stable. Even if you heat it to 370 C (698 F) for 96 hours, it does not budge. (Many plant oils tend to go off pretty quickly). If you have some pure jojoba oil at home, you should be fine using it for years.
Second, jojoba oil is the most similar to human sebum (both being wax esters), and the two are completely miscible. Acne.org has this not fully proven theory that thanks to this, jojoba might be able to "trick" the skin into thinking it has already produced enough sebum, so it might have "skin balancing" properties for oily skin.
Third, jojoba oil moisturizes the skin through a unique dual action: on the one hand, it mixes with sebum and forms a thin, non-greasy, semi-occlusive layer; on the other hand, it absorbs into the skin through pores and hair follicles then diffuses into the intercellular spaces of the outer layer of the skin to make it soft and supple.
On balance, the point is this: in contrast to real plant oils, wax esters were designed by Mother Nature to stay on the surface and form a protective, moisturizing barrier and jojoba oil being a wax ester is uniquely excellent at doing that.
We don't have description for this ingredient yet.
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).
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.
A type of lipid that's the major (about 75%) component of all cell membranes. As for skincare, it works as an emollient and skin-identical ingredient.
It has a water-loving head with two water-hating tails and this structure gives the molecule emulsifying properties. It is also often used to create liposomes, small spheres surrounded by phospholipid bi-layer designed to carry some active ingredient and help its absorption.
- Retinol (pure Vitamin A) is probably the most proven anti-aging ingredient available OTC
- It has to be converted in the skin to retinoic acid to work its magic
- Once converted, it has the same effect as all-trans-retinoic acid, aka tretinoin
- A generally accepted ballpark number is that retinol is 10-to-20 times less potent than retinoic acid
- It makes skin less wrinkled, smoother, firmer and tighter
- It might also be helpful for acne prone skin as it normalizes keratinization and makes the pores produce less sebum
- Possible side effects and irritation are also much less than with retinoic acid
- Do not use whilst pregnant
The emollient plant oil coming from the soybean. It is considered to be a nice, cost-effective base oil with moisturizing properties. As for its fatty acid profile, it contains 48-59% barrier-repairing linoleic acid, 17-30% nourishing oleic acid and also some (4.5-11%) potentially anti-inflammatory linolenic acid.
A cellulose (the big molecule found in the cell wall of green plants) derivative that is used as an emulsion stabilizer and thickener.
Though its long name does not reveal it, this polymer molecule (big molecule from repeated subunits or monomers) is a relative to the super common, water-loving thickener, Carbomer. Both of them are big molecules that contain acrylic acid units, but Acrylates/C10-30 Alkyl Acrylate Crosspolymer also contains some other monomers that are hydrophobic, i.e. water-hating.
This means that our molecule is part water- and part oil-loving, so it not only works as a thickener but also as an emulsion stabilizer. It is very common in gel-type formulas that also contain an oil-phase as well as in cleansers as it also works with most cleansing agents (unlike a lot of other thickeners).
We don't have description for this ingredient yet.
It’s a little helper ingredient that helps to set the pH of a cosmetic formulation to be just right.
A nice little helper ingredient that can thicken up cosmetic products and create beautiful gel formulas. It's derived from cellulose, the major component of the cell wall of green plants. It is compatible with most co-ingredients and gives a very good slip to the formulas.
This ingredient name is not according to the INCI-standard. :( What, why?!
- 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
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.
A water-soluble, colorless, odorless humectant liquid that makes your skin nice and smooth (aka emollient) and gives a dry, non-tacky skin feel. It also has great instant and some longer-lasting moisturizing effect and works in synergy with fellow moisturizer, sorbitol.
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| what‑it‑does | solvent |
| what‑it‑does | soothing | antioxidant | antimicrobial/antibacterial |
| what‑it‑does | soothing | emollient | moisturizer/humectant |
| what‑it‑does | emulsifying | surfactant/cleansing |
| irritancy, com. | 0, 0 |
| what‑it‑does | emollient |
| irritancy, com. | 0, 0-2 |
| what‑it‑does | emollient | moisturizer/humectant |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | skin-identical ingredient | emollient |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | emollient | perfuming |
| irritancy, com. | 0, 3 |
| what‑it‑does | viscosity controlling |
| irritancy, com. | 0, 0 |
| what‑it‑does | viscosity controlling |
| what‑it‑does | buffering |
| what‑it‑does | viscosity controlling |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | moisturizer/humectant | emollient |
| what‑it‑does | solvent | moisturizer/humectant | emollient |