Micro Dose Retinol
Ingredients overview
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Kiehl’s Micro Dose RetinolIngredients 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 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
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 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 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
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.
A light, velvety, unique skin feel liquid that is a good solvent and also makes the skin feel nice and smooth (aka emollient). It's often used in makeup products mixed with silicones to give shine and slip to the product. It's also great for cleansing dirt and oil from the skin as well as for taking off make-up.
An emollient ester with a rich and creamy but non-greasy skin feel. It makes skin supple and protects dry skin.
A clear, colorless, practically odorless, light liquid that works as a handy helper ingredient in sunscreen formulas. It helps to create high-SPF formulas with reduced concentrations of UV-filters and it also helps to create cosmetically elegant formulas (and that's no easy feat when it comes to sunscreens). It absorbs rapidly, makes the product easily spreadable and reduces greasiness coming from the oil-soluble sunscreen agents.
We don't have description for this ingredient yet.
A soothing molecule whose special feature is to instantly decrease stinging and burning sensations. According to the manufacturer's impressive numbers, it can reduce stinging up to 78% and burning sensation by up to 80% after just 3 minutes.
It is so effective because it works at a cellular level via intercepting the signals caused by the irritation before they can reach the neuro-receptor. This means that we feel stinging and burning sensations much less and the skin's tolerance threshold is increased.
The effectiveness of SymSitive was also backed up by a comparative study. It found that both 4‐t‐Butylcyclohexanol and fellow cell-communicating, soothing molecule acetyl dipeptide‐1 cetyl ester works, but 4‐t‐Butylcyclohexanol works better.
A soothing dipeptide (tyrosine + arginine) based molecule that functions as a "messenger of tranquility and muscle relaxation". It works via stimulating the skin nerve cells to release met-enkephalin, which is an opioid (i.e. relaxing, pain-relieving) messenger molecule.
This means that Acetyl Dipeptide-1 Cetyl Ester can "signal" our skin cells to "relax" and it can instantly decrease skin irritations coming from heat, chemical stinging or mechanical stresses. It is also claimed to be able to prevent the onset of wrinkles and expression lines thanks to its muscle relaxation properties.
Regarding the research, we could find one study that compared the calming effects of our guy with the soothing molecule called 4-T-Butylcyclohexanol. They irritated the skin with Capsaicin (the active in chili peppers) and examined how the test products relieved the burning/stinging sensation. They found that both molecules worked, but 4-t-Butylcyclohexanol worked somewhat better.
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
One of the many types of ceramides that can be found naturally in the upper layer of the skin. Ceramides make up about 50% of the goopy stuff that's between our skin cells and play a super important role in having a healthy skin barrier and keeping the skin hydrated. It works even better when combined with its pal, Ceramide 1.
We wrote way more about ceramides at ceramide 1, so click here to know more.
Unlike most other ceramides, this is a tricky one to recognize by name, but Hydroxypalmitoyl Sphinganine is a type of ceramide. The TL;DR version of ceramides is that along with cholesterol and fatty acids, the lipid trio (in a 50%, 25% and 15% ratio) is in the outermost layer of the skin helping to maintain a healthy skin barrier. This means keeping nasty things out, and important things such as water in. We have a more detailed description of ceramides here.
So as a ceramide, Hydroxypalmitoyl Sphinganine is a nice skin-identical ingredient that supports a healthy skin barrier. More specifically, a promising in-vitro study on reconstructed human skin shows that applying our molecule helps the skin to make some more ceramides (types 1,2 and 3). Interestingly, the extra ceramide production does not happen in the usual pathway, but the skin seems to process and transform Hydroxypalmitoyl Sphinganine into these other ceramides.
Clinical, aka made on real people studies, have confirmed that products with Hydroxypalmitoyl Sphinganine improve skin hydration, reduce trans epidermal water loss (the amount of water that evaporates out of the skin), and increase the ceramide content of the skin in people with atopic dermatitis or who are being treated with topical tretinoin. A real goodie in our book.
We don't have description for this ingredient yet.
A clear, slightly yellow, odorless oil that's a very common, medium-spreading emollient. It makes the skin feel nice and smooth and works in a wide range of formulas.
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.
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.
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 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 helper ingredient that helps to neutralize the metal ions in the formula (they usually come from water) so it stays nice longer. The special property of this particular ingredient is that it's more effective against more problematic ions, like Cu (copper) and Fe (iron) compared to less problematic ones like Ca (calcium) and Mg (magnesium).
- 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
- 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 clear, colorless and odorless oily liquid that works as a fast-spreading emollient with a dry skin feel.
There is not much info about this guy in itself other than it helps to thicken up products and stabilize oil-in-water emulsions. It usually comes to the formula as part of some thickener complex. For example, coupled with isohexadecane and polysorbate 80, the trio forms an instant gel upon mixing with water.
A fatty alcohol (the non-drying type with a long oil loving chain of 22 carbon atoms) that is used to increase the viscosity of the formula and it also helps the oily and the watery parts to stay nicely mixed together (called emulsion stabilizing).
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 big molecule created from repeated subunits (a polymer of acrylic acid) that magically converts a liquid into a nice gel formula. It usually has to be neutralized with a base (such as sodium hydroxide) for the thickening to occur and it creates viscous, clear gels that also feel nice and non-tacky on the skin. No wonder, it is a very popular and common ingredient. Typically used at 1% or less in most formulations.
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 sugar based emulsifier that's especially great for low viscosity lotions or even sprays. It's effective in small amounts, only 1-1.5% is needed to form an emulsion. The resulting cream or lotion has great cosmetic properties with good spreadability and an enhanced soft skin feel.
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.
Sunflower does not need a big intro as you probably use it in the kitchen as cooking oil, or you munch on the seeds as a healthy snack or you adore its big, beautiful yellow flower during the summer - or you do all of these and probably even more. And by even more we mean putting it all over your face as sunflower oil is one of the most commonly used plant oils in skincare.
It’s a real oldie: expressed directly from the seeds, the oil is used not for hundreds but thousands of years. According to The National Sunflower Association, there is evidence that both the plant and its oil were used by American Indians in the area of Arizona and New Mexico about 3000 BC. Do the math: it's more than 5000 years – definitely an oldie.
Our intro did get pretty big after all (sorry for that), so let's get to the point finally: sunflower oil - similar to other plant oils - is a great emollient that makes the skin smooth and nice and helps to keep it hydrated. It also protects the surface of the skin and enhances the damaged or irritated skin barrier. Leslie Bauman notes in Cosmetic Dermatology that one application of sunflower oil significantly speeds up the recovery of the skin barrier within an hour and sustains the results 5 hours after using it.
It's also loaded with fatty acids (mostly linoleic (50-74%) and oleic (14-35%)). The unrefined version (be sure to use that on your skin!) is especially high in linoleic acid that is great even for acne-prone skin. Its comedogen index is 0, meaning that it's pretty much an all skin-type oil.
Truth be told, there are many great plant oils and sunflower oil is definitely one of them.
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.
A very common ingredient that can be found in all cell membranes. In cosmetics it's quite the multi-tasker: it's an emollient and water-binding ingredient but it's also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes.
A colorless liquid used in small amounts as a so-called masking ingredient, meaning it can hide the natural not-so-nice smell of other cosmetic ingredients. It has a nice rose-like scent and can be found in several essential oils such as rose, neroli or geranium. It also has some antimicrobial activity and can boost the performance of traditional preservatives.
A synthetic big copolymer molecule that is used as a solubilizer, mild cleansing agent and foam booster or stabilizer.
If you want to understand poloxamers more, we have a shiny description at Poloxamer 184 and Poloxamer 407. This particular poloxamer, the 188 is quite similar to the 184 version, but it is more water-soluble (80% water-soluble parts) so it can act more as a solubilizer helping to dissolve oil-loving things in water-based formulas. Similar to 184, this one also works as a mild cleansing agent, but while 184 is claimed to be more effective at cleansing, the 188 is better at foaming.
We don't have description for this ingredient yet.
An ingredient that helps water and oil to mix together, aka emulsifier. Chemically speaking, it comes from the attachment of sorbitan (a dehydrated sorbitol (sugar) molecule) with the fatty acid Lauric Acid, that creates a partly water (the sorbitan part) and partly oil soluble (lauric part) molecule.
Sorbitan Laurate is a good team player that likes to work with many other emulsifiers and is compatible with a wide range of other ingredients.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
A little helper ingredient that works as a preservative. It works against bacteria and some species of fungi and yeast. It's often combined with IT-preservative, phenoxyethanol.
It’s pretty much the current IT-preservative. It’s safe and gentle, but even more importantly, it’s not a feared-by-everyone-mostly-without-scientific-reason paraben.
It’s not something new: it was introduced around 1950 and today it can be used up to 1% worldwide. It can be found in nature - in green tea - but the version used in cosmetics is synthetic.
Other than having a good safety profile and being quite gentle to the skin it has some other advantages too. It can be used in many types of formulations as it has great thermal stability (can be heated up to 85°C) and works on a wide range of pH levels (ph 3-10).
It’s often used together with ethylhexylglycerin as it nicely improves the preservative activity of phenoxyethanol.
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| what‑it‑does | solvent |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant |
| what‑it‑does | emollient | viscosity controlling |
| irritancy, com. | 2, 2 |
| what‑it‑does | emollient | solvent |
| what‑it‑does | emollient |
| what‑it‑does | emollient | solvent |
| what‑it‑does | soothing | cell-communicating ingredient |
| what‑it‑does | cell-communicating ingredient | soothing |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | skin-identical ingredient |
| what‑it‑does | skin-identical ingredient |
| what‑it‑does | viscosity controlling |
| what‑it‑does | emollient | perfuming |
| what‑it‑does | antioxidant | preservative |
| what‑it‑does | viscosity controlling |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | buffering |
| what‑it‑does | chelating |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | antioxidant |
| irritancy, com. | 0-3, 0-3 |
| what‑it‑does | emollient | solvent |
| what‑it‑does | viscosity controlling |
| what‑it‑does | emollient | viscosity controlling |
| what‑it‑does | moisturizer/humectant | emollient |
| what‑it‑does | viscosity controlling |
| irritancy, com. | 0, 1 |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 1, 2 |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | emollient | perfuming |
| irritancy, com. | 0, 3 |
| what‑it‑does | emollient |
| irritancy, com. | 0, 0 |
| what‑it‑does | viscosity controlling |
| what‑it‑does | emollient | emulsifying |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | emulsifying |
| irritancy, com. | 1-2, 1-2 |
| what‑it‑does | viscosity controlling | surfactant/cleansing |
| irritancy, com. | 0, 0 |
| what‑it‑does | colorant |
| what‑it‑does | preservative | antimicrobial/antibacterial |
| what‑it‑does | preservative |