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Kerastase Fortifying 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.
- It's a super common and super debated skincare ingredient
- It has several benefits: great solvent, penetration enhancer, creates cosmetically elegant, light formulas, great astringent and antimicrobial
- It can be very drying if it's in the first few ingredients on an ingredient list
- Some experts even think that regular exposure to alcohol damages skin barrier and causes inflammation though it's a debated opinion (read more in geeky details tab)
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.
A mildly viscous, amber-colored liquid with fatty odor, made from Castor Oil and polyethylene glycol (PEG).
If it were a person, we’d say, it’s agile, diligent & multifunctional. It’s mostly used as an emulsifier and surfactant but most often it is used to solubilize fragrances into water-based formulas.
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.
- 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.
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 super common and cheap fragrance ingredient. It's in many plants, e.g. rosemary, eucalyptus, lavender, lemongrass, peppermint and it's the main component (about 50-90%) of the peel oil of citrus fruits.
It does smell nice but the problem is that it oxidizes on air exposure and the resulting stuff is not good for the skin. Oxidized limonene can cause allergic contact dermatitis and counts as a frequent skin sensitizer.
Limonene's nr1 function is definitely being a fragrance component, but there are several studies showing that it's also a penetration enhancer, mainly for oil-loving components.
All in all, limonene has some pros and cons, but - especially if your skin is sensitive - the cons probably outweigh the pros.
We don't have description for this ingredient yet.
Linalool is a super common fragrance ingredient. It’s kind of everywhere - both in plants and in cosmetic products. It’s part of 200 natural oils including lavender, ylang-ylang, bergamot, jasmine, geranium and it can be found in 90-95% of prestige perfumes on the market.
The problem with linalool is, that just like limonene it oxidises on air exposure and becomes allergenic. That’s why a product containing linalool that has been opened for several months is more likely to be allergenic than a fresh one.
A study made in the UK with 483 people tested the allergic reaction to 3% oxidised linalool and 2.3% had positive test results.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
It’s a common fragrance ingredient that has a light floral smell. It’s one of the “EU 26 fragrances” that has to be labelled separately (and cannot be simply included in the term “fragrance/perfume” on the label) because of allergen potential. Best to avoid if your skin is sensitive.
A common fragrance ingredient that has a sweet, vanilla, nutty scent. When diluted it smells like freshly-mown hay.
It’s one of the “EU 26 fragrances” that has to be labelled separately (and cannot be simply included in the term “fragrance/perfume” on the label) because of allergen potential. Best to avoid if your skin is sensitive.
It’s a common fragrance ingredient that smells like lemon and has a bittersweet taste. It can be found in many plant oils, e.g. lemon, orange, lime or lemongrass.
It’s one of the “EU 26 fragrances” that has to be labelled separately (and cannot be simply included in the term “fragrance/perfume” on the label) because of allergen potential. Best to avoid if your skin is sensitive.
It's one of those things that help your cosmetics not to go wrong too soon, aka a preservative. It can be naturally found in fruits and teas but can also be made synthetically.
No matter the origin, in small amounts (up to 1%) it’s a nice, gentle preservative. Has to be combined with some other nice preservatives, like potassium sorbate to be broad spectrum enough.
In high amounts, it can be a skin irritant, but don’t worry, it’s never used in high amounts.
The main part of a moisturizing complex called Aquaxyl. Comes from two water-binding plant sugars, glucose and xylitol. According to the manufacturer, Aquaxyl is close to a magic moisturizer that not only simply moisturizes, but can "harmonize the skin's hydrous flow".
This means that on the one side it can optimize water reserves by increasing important NMFs (natural moisturizing factors - things that are naturally in the skin and help to keep it hydrated) - like hyaluronic acid and chondroitin sulfate - in the skin. On the other side, it also limits water loss by improving the skin barrier with increased lipid (ceramides and cholesterol) and protein synthesis.
In vivo (made on real people) tests show that 3% Aquaxyl not only increases the water content of the outer layer instantly and in the long run but it also visibly improves cracked, dry skin and smoothes the skin surface after a month of treatment.
The hydrating effect of Aquaxyl was also examined in a comparative study in the Journal of Cosmetic Dermatology. Four humectants were examined in combination with 5% glycerin in a hydrogel formula and one with 4% Aquaxyl performed as well as the well-known moisturizer, urea and somewhat better than the formula containing NMF components or hydrating plant extract called Imperata Cylindrica.
All in all, Aquaxyl is a goodie and if you have dehydrated, dry skin it's something to look at.
Citronellol is a very common fragrance ingredient with a nice rose-like odor. In the UK, it’s actually the third most often listed perfume on the ingredient lists.
It can be naturally found in geranium oil (about 30%) or rose oil (about 25%).
As with all fragrance ingredients, citronellol can also cause allergic contact dermatitis and should be avoided if you have perfume allergy. In a 2001 worldwide study with 178 people with known sensitization to fragrances citronellol tested positive in 5.6% of the cases.
There is no known anti-aging or positive skin benefits of the ingredient. It’s in our products to make it smell nice.
A common fragrance ingredient that has a faint sweet balsamic smell. It can also be a solvent and can fight against microbes and insects very well.
It's one of the “EU 26 fragrances” that has to be labelled separately because of allergen potential. Best to avoid if your skin is sensitive.
A sugar derived moisturizer that's part of a moisturizing trio called Aquaxyl. You can read more about its magic properties at xylitylglucoside.
A type of sugar that's part of a moisturizing trio called Aquaxyl. You can read more about its magic properties at xylitylglucoside.
The extract coming from ginger, the lovely spice that we all know from the kitchen. It is also a medicinal plant used both in Chinese and Ayurvedic medicine for pretty much everything you can imagine (muscular pain, sore throat, nausea, fever or cramps, just to give a few examples).
As for ginger and skincare, the root extract contains the biologically active component called gingerol that has potent antioxidant and anti-inflammatory properties. Combined with Bisabolol, the duo works synergistically to sooth the skin and take down redness.
Other than that, ginger also contains moisturizing polysaccharides, amino acids, and sugars, and it is also quite well known to increase blood circulation and have a toning effect.
Last but not least, Ginger also has some volatile, essential oil compounds (1-3%). Those are mostly present in ginger oil, but small amounts might be in the extract as well (around 0.5% based on manufacturer info).
If you are looking for a reason why red wine is good for you, good news, you have found it! Resveratrol, aka the "red grape antioxidant" is the thing that's suspected to keep the French from coronary heart disease despite their not so healthy eating habits (such as high saturated fat intake).
So resveratrol, found in the seed and skin of the red grape (and berries), is a pretty well-known and well-studied molecule that has potent antioxidant, anti-inflammatory, and anticarcinogenic abilities. Most of the studies were done examining resveratrol's promising anti-cancer properties, but as for skin care, it shows a potent protective effect against UV-caused oxidative stress as well as promising effects against multiple types of skin cancer including the most severe one, melanoma (as an adjuvant therapy).
When it comes to skincare and antioxidants, "the more the merrier", so resveratrol is definitely a nice addition to any skincare routine.
- 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 acronym for Butylated Hydroxy Toluene. It's a common synthetic antioxidant that's used as a preservative.
There is some controversy around BHT. It's not a new ingredient, it has been used both as a food and cosmetics additive since the 1970s. Plenty of studies tried to examine if it's a carcinogen or not. This Truth in Aging article details the situation and also writes that all these studies examine BHT when taken orally.
As for cosmetics, the CIR (Cosmetic Ingredient Review) concluded that the amount of BHT used in cosmetic products is low (usually around 0.01-0.1%), it does not penetrate skin far enough to be absorbed into the bloodstream and it is safe to use in cosmetics.
A little helper ingredient that is used to adjust the pH of the product. It also helps to keep products stay nice longer by neutralizing the metal ions in the formula (they usually come from water).
Exactly what it sounds: nice smelling stuff put into cosmetic products so that the end product also smells nice. Fragrance in the US and parfum in the EU is a generic term on the ingredient list that is made up of 30 to 50 chemicals on average (but it can have as much as 200 components!).
If you are someone who likes to know what you put on your face then fragrance is not your best friend - there's no way to know what’s really in it.
Also, if your skin is sensitive, fragrance is again not your best friend. It’s the number one cause of contact allergy to cosmetics. It’s definitely a smart thing to avoid with sensitive skin (and fragrance of any type - natural is just as allergic as synthetic, if not worse!).
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what‑it‑does | solvent |
what‑it‑does | antimicrobial/antibacterial | solvent | viscosity controlling |
what‑it‑does | skin-identical ingredient |
what‑it‑does | emulsifying | surfactant/cleansing |
what‑it‑does | buffering |
what‑it‑does | cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant |
what‑it‑does | antioxidant | perfuming |
what‑it‑does | perfuming | solvent |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | perfuming |
what‑it‑does | preservative | perfuming | solvent | viscosity controlling |
what‑it‑does | moisturizer/humectant |
what‑it‑does | perfuming |
what‑it‑does | solvent | perfuming | antimicrobial/antibacterial |
what‑it‑does | moisturizer/humectant |
what‑it‑does | moisturizer/humectant |
what‑it‑does | antioxidant | soothing |
what‑it‑does | antioxidant |
what‑it‑does | antioxidant |
irritancy, com. | 0-3, 0-3 |
what‑it‑does | antioxidant | preservative |
what‑it‑does | chelating | buffering |
what‑it‑does | perfuming |