Private Formula Advanced Night Cream
DR. LEWINN'S Private Formula Advanced Night CreamIngredients 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.
An odorless and colorless emollient ester (cetyl alcohol + ethylhexanoic acid) that gives a velvety and silky feel to the skin. It has great spreadability and a non-oily feel. It's a popular ingredient in makeup removers.
It's the yellow, solid stuff that you probably know from beeswax candles. It's a natural material produced by honey bees to build their honeycomb.
As for skincare, it's used as an emollient and thickening agent. It's super common in lip balms and lipsticks.
A clear, colorless emollient ester (oily liquid from isopropyl alcohol + palmitic acid) that makes the skin nice and smooth. It has very good spreading properties and gives a silky touch to the products.
- 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 at higher concentrations up to 20-40% (around 10% is a good usability-effectiveness sweet spot)
- High-glycerin moisturizers are awesome for treating severely dry skin
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 >>
A natural emulsifier that brings a soft and powdery feel to the formula. It's also very gentle and is recommended for sensitive or baby skin products.
A mainly oil loving molecule that helps water and oil to mix nicely, aka emulsifier. In itself, it can create water-in-oil emulsions (when water droplets are dispersed in oil), but it is used mostly next to water-loving emulsifiers to create nice and smooth oil-in-water creams. It can also function as a wetting and dispersing agent helping insoluble particles such as color pigments or inorganic sunscreens (zinc/titanium dioxide) to disperse nice and even in liquids.
Chemically speaking, this molecule is "halfway" between Sorbitan Oleate and Sorbitan Trioleate, meaning that it is also an attachment of sorbitan (a dehydrated sorbitol (sugar) molecule) with the unsaturated fatty acid Oleic Acid, but in a ratio of 2:3 hence the "Sesqui" part in the molecule's name.
A helper ingredient that is used as a bulking and viscosity controlling agent. It is also an emulsion stabilizer in water-in-oil emulsions, where water droplets are dispersed in the continuous oil phase and not the other way round.
It can also be used as a heat generating agent in water-less formulas as it has an instant heat-generating chemical reaction with water.
We don't have description for this ingredient yet.
It's an ester form of vitamin A (retinol + palmitic acid) that belongs to the "retinoid family". The retinoid family is pretty much the royal family of skincare, with the queen being the FDA-approved anti-aging ingredient tretinoin. Retinol is also a very famous member of the family, but it's like Prince William, two steps away from the throne. Retinyl palmitate will be then little Prince George, quite far (3 steps) away from the throne.
By steps, we mean metabolic steps. Tretinoin, aka retinoic acid, is the active ingredient our skin cells can understand and retinyl palmitate (RP) has to be converted by our metabolic machinery to actually do something. The conversion is a 3 step one and looks like this:
retinyl palmitate --> retinol -- > retinaldehyde --> all-trans-retinoic acid
As we wrote in our lengthy retinol description the problem is that the conversion is not terribly effective. The evidence that RP is still an effective anti-aging ingredient is not very strong, in fact, it's weak. Dr. Leslie Baumann in her fantastic Cosmetic Dermatology book writes that RP is topically ineffective.
What's more, the anti-aging effectiveness is not the only questionable thing about RP. It also exibits questionable behaviour in the presence of UV light and was the center of a debate between the non-profit group, EWG (whose intentions are no doubt good, but its credibility is often questioned by scientists) and a group of scientists and dermatologists lead by Steven Q. Wang, MD, director of dermatologic surgery at Memorial-Sloan Kettering Cancer Centre.
Dr. Leslie Baumann wrote a great review of the debate and summarized the research available about retinyl palmitate here. It seems that there is a study showing RP being photo protective against UVB rays but there is also a study showing RP causing DNA damage and cytotoxicity in association with UVA.
We think that the truth lies somewhere in the middle, and we agree with Dr. Baumann's conclusion: "sufficient evidence to establish a causal link between RP and skin cancer has not been produced. Nor, I’m afraid, are there any good reasons to recommend the use of RP". We would add especially during the day!
Bottom line: If you wanna get serious about retinoids, RP is not your ingredient (retinol or tretinoin is!). However, if you use a product that you like and it also contains RP, there is no reason to throw it away. If possible use it at night, just to be on the safe side.
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.
Super common soothing ingredient. It can be found naturally in the roots & leaves of the comfrey plant, but more often than not what's in the cosmetic products is produced synthetically.
It's not only soothing but it' also skin-softening and protecting and can promote wound healing.
We don't have description for this ingredient yet.
The chemically chopped up version of the big protein molecule, collagen. It is often derived from fish or bovine sources and works as a nice moisturizer and humectant that helps the skin to hold onto water.
To understand a bit more what Hydrolyzed Collagen is, you have to know that proteins are large chains of amino acids connected with so-called peptide bonds. These bonds can be broken up when a water molecule is added and the resulting thing is a mix of shorter length amino acids, also called peptides. So Hydrolyzed Collagen is not really collagen, it is rather an undefined and varying mix of largish peptides. Based on a manufacturer's data, the whole, soluble collagen has an average molecular weight of 300 000 Da, while this chopped up mixture has an average MW of 12 000 Da (still pretty big).
The main thing of these largish peptides is to act as water-binding agents, and to make the skin nice and smooth (aka emollient). Hydrolyzed Collagen is also often used in cleansers as it can make harsh surfactants milder and in hair conditioners as it improves the flexibility and manageability of hair.
If you wanna know more about collagen in cosmetics, we have a shiny explanation about soluble collagen here >>
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 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.
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.
It’s the most commonly used version of pure vitamin E in cosmetics. You can read all about the pure form here. This one is the so-called esterified version.
According to famous dermatologist, Leslie Baumann while tocopheryl acetate is more stable and has a longer shelf life, it’s also more poorly absorbed by the skin and may not have the same awesome photoprotective effects as pure Vit E.
The emollient plant oil coming from the kernel (the seed of the seed) of the delicious apricot fruit. Like other plant oils, it contains antioxidant vitamin E and nourishing fatty acids (mostly oleic acid 54-74%, linoleic acid 12-35%).
It's a nice general purpose emollient, has nourishing and moisturizing properties (as a high oleic oil it's ideal for dry skin types) and is quite easily absorbed into the skin.
- 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
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 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.
- 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
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!).
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.
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.
Ci 19140 or Tartrazine is a super common colorant in skincare, makeup, medicine & food. It’s a synthetic lemon yellow that's used alone or mixed with other colors for special shades.
FDA says it's possible, but rare, to have an allergic-type reaction to a color additive. As an example, it mentions that Ci 19140 may cause itching and hives in some people but the colorant is always labeled so that you can avoid it if you are sensitive.
|what‑it‑does||emollient | viscosity controlling | emulsifying | perfuming|
|irritancy, com.||0, 0-2|
|irritancy, com.||1, 3-4|
|what‑it‑does||skin-identical ingredient | moisturizer/humectant|
|irritancy, com.||0, 0|
|what‑it‑does||skin-identical ingredient | emollient|
|irritancy, com.||0, 1|
|irritancy, com.||0, 4|
|irritancy, com.||0, 0-1|
|what‑it‑does||colorant | moisturizer/humectant|
|irritancy, com.||0, 1|
|irritancy, com.||1-3, 1-3|
|irritancy, com.||0, 0|
|what‑it‑does||moisturizer/humectant | emollient|
|what‑it‑does||emollient | moisturizer/humectant|
|what‑it‑does||moisturizer/humectant | emollient|
|what‑it‑does||moisturizer/humectant | solvent|
|what‑it‑does||solvent | emulsifying | perfuming | surfactant/cleansing|
|irritancy, com.||0-1, 0-2|
|irritancy, com.||0, 0|
|irritancy, com.||0, 1-2|
|irritancy, com.||0-3, 0-3|
|irritancy, com.||0, 2|
|what‑it‑does||antioxidant | skin brightening | buffering|
|what‑it‑does||perfuming | solvent|