Correcting Intensive Renewal Glycolic 15
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KERSTIN FLORIAN Correcting Intensive Renewal Glycolic 15Ingredients 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 the most researched AHA with the most proven skin benefits
- It gently lifts off dead skin cells to reveal newer, fresher, smoother skin
- It can help skin’s own collagen production that results in firmer, younger skin
- It can fade brown spots caused by sun damage or PIH
- Choose a product where you know the concentration and pH value because these two greatly influence effectiveness
- Don’t forget to use your sunscreen (in any case but especially so next to an AHA product)
- Slight stinging or burning with a stronger AHA product is normal
- If your skin is very sensitive, rosacea prone choose rather a BHA or PHA product
The unfancy name for it is lye. It’s a solid white stuff that’s very alkaline and used in small amounts to adjust the pH of the product and make it just right.
For example, in case of AHA or BHA exfoliants, the right pH is super-duper important, and pH adjusters like sodium hydroxide are needed.
BTW, lye is not something new. It was already used by ancient Egyptians to help oil and fat magically turn into something else. Can you guess what? Yes, it’s soap. It still often shows up in the ingredient list of soaps and other cleansers.
Sodium hydroxide in itself is a potent skin irritant, but once it's reacted (as it is usually in skin care products, like exfoliants) it is totally harmless.
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.
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 waxy solid material that helps oil and water to mix together, aka emulsifier. It is derived from the fatty alcohol, stearyl alcohol by ethoxylating it and thus making the molecule a little water-soluble. This version has only a small amount of ethoxylation and thus the molecule is still largely oil soluble. It is often mixed with more water-soluble emulsifiers (such as Steareth-20) to create stable emulsion systems.
A waxy solid material that helps oil and water to mix together, aka emulsifier. It is super similar to Steareth-20 with just a little more ethoxylation and thus a little more water solubility. It works very well when combined with mostly oil-soluble emulsifiers such as Steareth-2 and the two together can form exceptionally stable emulsions.
- 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
A common multi-tasker fatty acid. It makes your skin feel nice and smooth (emollient), gives body to cream type products and helps to stabilize water and oil mixes (aka emulsions).
A 100% natural and plant-derived moisturizer that mimics the natural carbohydrate fraction found in the upper layer of the skin. Its special magic power is to bind to the skin stronger and longer than other moisturizer ingredients do so it can keep the skin hydrated longer than usual.
Probably the most common silicone of all. It is a polymer (created from repeating subunits) molecule and has different molecular weight and thus different viscosity versions from water-light to thick liquid.
As for skincare, it makes the skin silky smooth, creates a subtle gloss and forms a protective barrier (aka occlusive). Also, works well to fill in fine lines and wrinkles and give skin a plump look (of course that is only temporary, but still, it's nice). There are also scar treatment gels out there using dimethicone as their base ingredient. It helps to soften scars and increase their elasticity.
As for hair care, it is a non-volatile silicone meaning that it stays on the hair rather than evaporates from it and smoothes the hair like no other thing. Depending on your hair type, it can be a bit difficult to wash out and might cause some build-up (btw, this is not true to all silicones, only the non-volatile types).
We don't have description for this ingredient yet.
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 so-called fatty (the good, non-drying kind of) alcohol that does all kinds of things in a skincare product: it makes your skin feel smooth and nice (emollient), helps to thicken up products and also helps water and oil to blend (emulsifier). Can be derived from coconut or palm kernel oil.
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.
It's one of the most commonly used thickeners and emulsion stabilizers. If the product is too runny, a little xanthan gum will make it more gel-like. Used alone, it can make the formula sticky and it is a good team player so it is usually combined with other thickeners and so-called rheology modifiers (helper ingredients that adjust the flow and thus the feel of the formula). The typical use level of Xantha Gum is below 1%, it is usually in the 0.1-0.5% range.
Btw, Xanthan gum is all natural, a chain of sugar molecules (polysaccharide) produced from individual sugar molecules (glucose and sucrose) via fermentation. It’s approved by Ecocert and also used in the food industry (E415).
A 100% natural and plant-derived moisturizer that mimics the natural carbohydrate fraction found in the upper layer of the skin. Its special magic power is to bind to the skin stronger and longer than other moisturizer ingredients do so it can keep the skin hydrated longer than usual.
- It's a helper ingredient that improves the freeze-thaw stability of products
- It's also a solvent, humectant and to some extent a penetration enhancer
- It has a bad reputation among natural cosmetics advocates but cosmetic scientists and toxicology experts do not agree (read more in the geeky details section)
It's one of the active parts of Chamomile that contains about 30% of bisabolol. It's a clear oily fluid that is used in skincare as a nice anti-inflammatory and soothing ingredient.
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.
Titanium Dioxide is one of the two members of the elite sunscreen group called physical sunscreens (or inorganic sunscreens if you’re a science geek and want to be precise).
Traditionally, UV-filters are categorized as either chemical or physical. The big difference is supposed to be that chemical agents absorb UV-light while physical agents reflect it like a bunch of mini umbrellas on top of the skin. While this categorization is easy and logical it turns out it's not true. A recent, 2016 study shows that inorganic sunscreens work mostly by absorption, just like chemical filters, and only a little bit by reflection (they do reflect the light in the visible spectrum, but mostly absorb in the UV spectrum).
Anyway, it doesn't matter if it reflects or absorbs, Titanium Dioxide is a pretty awesome sunscreen agent for two main reasons: it gives a nice broad spectrum coverage and it's highly stable. Its protection is very good between 290 - 350 nm (UVB and UVA II range), and less good at 350-400 nm (UVA I) range. Regular sized Titanium Dioxide also has a great safety profile, it's non-irritating and is pretty much free from any health concerns (like estrogenic effect worries with some chemical filters).
The disadvantage of Titanium Dioxide is that it's not cosmetically elegant, meaning it's a white, "unspreadable" mess. Sunscreens containing Titanium Dioxide are often hard to spread on the skin and they leave a disturbing whitish tint. The cosmetic industry is, of course, really trying to solve this problem and the best solution so far is using nanoparticles. The itsy-bitsy Nano-sized particles improve both spreadability and reduce the whitish tint a lot, but unfortunately, it also introduces new health concerns.
The main concern with nanoparticles is that they are so tiny that they are absorbed into the skin more than we want them (ideally sunscreen should remain on the surface of the skin). Once absorbed they might form unwanted complexes with proteins and they might promote the formation of evil free radicals. But do not panic, these are concerns under investigation. A 2009 review article about the safety of nanoparticles summarizes this, "to date, in-vivo and in-vitro studies have not demonstrated percutaneous penetration of nanosized particles in titanium dioxide and zinc oxide sunscreens". The English translation is, so far it looks like sunscreens with nanoparticles do stay on the surface of the skin where they should be.
All in all, Titanium Dioxide is a famous sunscreen agent and for good reason, it gives broad spectrum UV protection (best at UVB and UVA II), it's highly stable, and it has a good safety profile. It's definitely one of the best UV-filter agents we have today, especially in the US where new-generation Tinosorb filters are not (yet) approved.
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).
The essential oil coming from the rind of the grapefruit. In general, the main component of citrus peel oils is limonene (86-95% for grapefruit peel), a super common fragrant ingredient that makes everything smell nice (but counts as a frequent skin sensitizer).
Other than that, citrus peel also contains the problematic compound called furanocoumarin that makes them mildly phototoxic. In general, the more sour-bitter the fruit, the more problematic it is regarding phototoxicity: orange and clementine peel contain less of it while lemon, grapefruit, and bergamot contain some more. Be careful with it if it is in a product for daytime use.
The essential oil coming from the sweet orange. In the case of orange (and citruses in general), the essential oil is mainly in the peel of the fruit, so it's pretty much the same as the orange peel oil (also has the same CAS number - a unique ID assigned to chemicals).
Its main component is limonene (up to 97%), a super common fragrant ingredient that makes everything smell nice (but counts as a frequent skin sensitizer).
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.
A white to beige powder that is described as the golden standard emulsifier for emulsions (oil+water mixtures) that are difficult to stabilize. It is especially popular in sunscreens as it can boost SPF protection and increase the water-resistance of the formula.
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 smallish polymer molecule (created from repeated units of Polyethylene glycol, aka PEG) that's used as a solubilizer and viscosity control agent.
It is a clear, colorless liquid that is water-soluble and water-binding (aka humectant) and can help to solubilize sparingly-water soluble things (e.g. vanilla, perfumes) into water-based formulas. Thanks to its water-binding ability, it also prevents the drying out of formulas, especially when combined with the fellow hygroscopic agent, sorbitol.
- 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
A form of skincare superstar, vitamin C. Even though we are massive vitamin C fans, Ascorbyl Palmitate (AP) is our least favorite. (Btw, if you do not know what the big deal with vitamin C is then you are missing out. You must go and read our geeky details about it.)
So, AP is one of the attempts by the cosmetics industry to solve the stability issues with vitamin C while preserving its benefits, but it seems to fall short on several things.
What's the problem?
Firstly, it's stability is only similar to that of pure ascorbic acid (AA), which means it is not really stable. A great study in the Journal of Cosmetic Dermatology compared a bunch of vitamin C derivatives and this derivative was the only one where the study said in terms of stability that it's "similar to AA". Not really that good.
Second, a study that examined the skin absorption of vitamin C found that ascorbyl palmitate did not increase the skin levels of AA. This does not mean that ascorbyl palmitate cannot penetrate the skin (because it can, it's oil soluble and the skin likes to absorb oil soluble things) but this means that it's questionable if ascorbyl palmitate can be converted into pure Vit C in the skin. Even if it can be converted, the palmitate part of the molecule is more than the half of it, so the efficacy will not be good and we have never seen a serum that contains a decent (and proudly disclosed) amount of AP. We are highly skeptical what effect a tiny amount of AP has in a formula.
Third, another study that wanted to examine the antioxidant properties of AP was surprised to find that even though AP does have nice antioxidant properties; following UVB radiation (the same one that comes from the sun) it also promotes lipid peroxidation and cytotoxicity. It was only an in-vitro study meaning that it was done on cell cultures and not on real people, but still, this also does not support the use of AP too much.
The only good thing we can write about Ascorbyl Palmitate is that there is an in-vitro (made in the lab, not on real people) study showing that it might be able to boost collagen production.
Regarding the skin-brightening properties of pure vitamin C, this is another magic property AP does not have, or at least there is no data, not even in-vitro, about it.
Overall, Ascorbyl Palmitate is our least favorite vitamin C derivative. It is there in lots of products in tiny amounts (honestly, we do not really understand why), however, we do not know about any vitamin C serum featuring AP in high amounts. That is probably no coincidence. If you are into vitamin C, you can take a look at more promising derivatives here.
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.
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.
- Works best between a concentration of 5-20%
- Boosts the skin’s own collagen production
- Fades pigmentation and brown spots
- If used under sunscreen it boosts its UV protection
- Extremely unstable and oxidizes very easily in presence of light or air
- Stable in solutions with water only if pH is less than 3.5 or in waterless formulations
- Vit E + C work in synergy and provide superb photoprotection
- Ferulic acid doubles the photoprotection effect of Vit C+E and helps to stabilize Vit C
- Potent Vit. C serums might cause a slight tingling on sensitive skin
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| what‑it‑does | solvent |
| what‑it‑does | exfoliant | buffering |
| what‑it‑does | buffering |
| what‑it‑does | emollient |
| what‑it‑does | emollient |
| what‑it‑does | emulsifying | surfactant/cleansing |
| irritancy, com. | 2, 2 |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | emollient | viscosity controlling |
| irritancy, com. | 0, 2-3 |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 1, 2 |
| what‑it‑does | emollient | viscosity controlling |
| irritancy, com. | 2, 2 |
| what‑it‑does | moisturizer/humectant | emollient |
| what‑it‑does | viscosity controlling |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 0 |
| what‑it‑does | soothing |
| what‑it‑does | perfuming | solvent |
| what‑it‑does | sunscreen | colorant |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | chelating |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | buffering |
| what‑it‑does | moisturizer/humectant | solvent |
| what‑it‑does | antioxidant |
| irritancy, com. | 0-3, 0-3 |
| what‑it‑does | antioxidant |
| irritancy, com. | 0, 2 |
| what‑it‑does | perfuming |
| what‑it‑does | perfuming |
| what‑it‑does | antioxidant | skin brightening | buffering |