Pro Retinal-plus Treatment
Ingredients overview
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Key Ingredients
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Lira Clinical Pro Retinal-plus TreatmentIngredients 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
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 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.
An often used emollient with a light and silky feel. It's very mild to both skin and eyes and spreads nicely and easily. It's often used in sunscreens as it's also an excellent solvent for sunscreen agents.
Aloe Vera is one of today’s magic plants. It does have some very nice properties indeed, though famous dermatologist Leslie Baumann warns us in her book that most of the evidence is anecdotal and the plant might be a bit overhyped.
What research does confirm about Aloe is that it’s a great moisturizer and has several anti-inflammatory (among others contains salicylates, polysaccharides, magnesium lactate and C-glucosyl chromone) as well as some antibacterial components. It also helps wound healing and skin regeneration in general. All in all definitely a goodie.
An ester that comes from Cetearyl alcohol and the fatty acids of olive oil. It often comes to the formula coupled with Sorbitan Olivate as the two together form the well-known, natural emulsifier trade named Olivem 1000.
Other than helping oil and water to blend, the main thing of Olivem 1000 is generating liquid crystal structures that are similar to the lipid structures of the stratum corneum (the outermost layer of the skin). Thanks to this, Olivem 1000 doubles as an active ingredient with significant moisturizing, barrier-repairing and soothing properties.
It also helps to deliver water-soluble actives such as caffeine more effectively, and can even boost SPF in sunscreen formulas. Its typical use level is 1-5% and has wide compatibility with other actives and oils.
Overall, a real multi-tasker with nice sensorial properties. No wonder it is so popular.
An ester coming from sorbitol and the fatty acids of olive oil. It is part of the popular emulsifier trade named Olivem 1000 that is well-known for generating biomimetic liquid crystal structures. We have more info on Olivem 1000 at Cetearyl Olivate >>
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.
We don't have description for this ingredient yet.
A clear, colorless and odorless oily liquid that works as a fast-spreading emollient with a dry skin feel.
We don't have description for this ingredient yet.
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).
Hydroxyapatite is a mineral found naturally in our bones and teeth. As for cosmetics, it is claimed to act as a sunscreen booster as well as a soft-focus agent.
- 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 white, waxy emollient that gives "body" to skincare formulas. Comes from coconut or palm kernel oil.
A creamy solid that helps water and oil to mix, aka emulsifier. Its solid, wax-like nature is useful for oil-based formulas where some rigidity is needed.
A super common, medium-spreading emollient ester that gives richness to the formula and a mild feel during rubout. It can be a replacement for mineral oil and is often combined with other emollients to achieve different sensorial properties.
It's a water-hating, fumed silica that works as a thickener for oils and it can also suspend particles in oils.
Also, increases the gloss of castor oil that can be useful for makeup products.
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).
At first glance, you could think that Bakuchiol is your average plant extract. It is derived from the seeds of Psoralea Corylifolia, aka Babchi, a plant important in Indian and Chinese medicine. The molecule was first isolated in 1973 and several anti-something properties are known about it: it has anti-inflammatory, antioxidant, anti-tumor, anti-bacterial and hepatoprotective magical abilities like plenty of other Ayurvedic plant extracts.
What makes Bakuchiol a special snowflake is the recent discovery that it behaves on the skin in a way very similar to well-known skincare superstar, retinol. While chemically, it has nothing to do with the vitamin-A family, aka retinoids, comparative gene expression profiling (a fancy way of saying that they compared how retinol and bakuchiol modify the way skin cells behave and produce important skin proteins such as collagen) shows that retinol and bakuchiol regulate skin cell behavior in a similar way.
To be more specific, both Bakuchiol and retinol upregulate collagen I, III and IV production and downregulate MMP, the evil collagen attacking enzyme in our skin. This means more collagen stays in our skin and we all know that more collagen equals firmer, more wrinkle-free skin. A 12-week clinical study using a 0.5% Bakuchiol formula with 17 people using it twice a day confirmed a significant improvement in lines and wrinkles, elasticity, firmness and an overall reduction in photo-damage. Also, the test formula was very well tolerated, without any retinol-like side effects.
What's more, a 2018 double-blind study with 44 people compared 0.5% Bakuchiol with 0.5% retinol cream and found that "bakuchiol is comparable to retinol in its ability to improve photoaging and is better tolerated than retinol". A super promising result after 12 weeks.
If you are not a daredevil-type who doesn't want to stop using a super well-proven retinol for a newbie like Bakuchiol, we have good news. The two also work very nicely together and Bakuchiol can actually help to stabilize the otherwise unstable and hard to formulate retinol.
And we are still not done, as Bakuchiol shows not only anti-aging properties but also nice anti-acne effects. 1% Bakuchiol seems to be very effective in itself (57% reduction in acne after 6 weeks treatment) and even better when combined with 2% salicylic acid (67% reduction in acne after 6 weeks). We like that Bakuchiol is such a good team player! The molecule works against acne in multiple ways: It downregulates 5α-reductase (a sebum-controlling enzyme), it is antibacterial (including P. acnes), anti-inflammatory and it inhibits lipid-peroxidation, an evil oxidative process that is recently thought to be a very early trigger in the acne process.
We feel that this description is becoming very long so we will just mention that Bakuchiol also seems to positively regulate hydration-related genes such as Aquaporin 3 and also shows some melanin-inhibiting properties.
Overall, we think Bakuchiol is an awesome molecule with lots of promise both for anti-aging and anti-acne. But the proof compared to the well-established superstars is far from solid, so in a skincare routine, we would rather add Bakuchiol next to retinol than straight up replace it. Unless you are a gimme-the-newest-shiny-thing-under-the-sun-type.
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
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.
If you are reading here, we are pretty sure the words retinoids and retinol ring a bell, but if not, you are seriously missing out, please click here immediately to catch up. The TL;DR version is that retinoids are the royal family of skincare with tretinoin being the king, the only FDA-approved ingredient to treat the signs of photoaging. Retinol is like a grandkid, it has to be converted (through two steps) in the skin to become retinoic acid. The conversion means retinol is both less effective and less harsh on the skin.
So where does our current molecule, Retinal, aka Retinaldehyde fit into the family (btw, here is a nice visual family tree about who is who)? Remember that retinol needed two conversion steps to become retinoic acid? Yes, you are right, Retinal is the intermediate step between retinoic acid and retinol, meaning it needs only one conversion step to become active in the skin. If we go with our royal family analogy, Retinal is Prince William, directly next in line to the throne.
Once retinal is converted, it becomes retinoic acid and does the same things we detailed in our tretinoin description. In a nutshell, it is everything you expect from an anti-aging superstar such as decreased wrinkles, smoother, firmer and more elastic skin.
This sounds good, but how does Retinal compare to retinoic acid? Good question! We found a study (a pretty good one with 125 patients) that compared 0.05% retinal with 0.05% retinoic acid (and vehicle). They concluded that "at week 18, a significant reduction of the wrinkle and roughness features was observed with both retinaldehyde and retinoic acid." and the difference between the two was not statistically significant. (Interestingly, in both groups, the results were less significant at week 44, so it might be a good idea to have a retinoid break from time to time?) Also, our guy, Retinal was much better tolerated than retinoic acid known for its harshness.
The good tolerability of retinal was also confirmed by another study that compared retinol (ROL), retinal (RAL) and retinoic acid (RA). They found that "the natural retinoids ROL and RAL do have a good tolerance profile, in contrast with the irritating potential of RA", meaning retinal is an awesome alternative if you have irritation and flaking issues with prescription products, such as Retin-A.
Last, but not least, we want to mention a pretty big (but subjectively evaluated), Avene (the French pharmacy brand famous for its Retinal products) sponsored study that examined the tolerability and efficacy of a 0.1 Retinal + 6% glycolic acid product in the treatment of acne. The product was added next to the standard anti-acne regimen of 1,709 patients for 90 days and the study concluded that the formula was both very well tolerated as well as effective next to other standard anti-acne medications such as benzoyl peroxide and antibiotics.
Overall, if you are into retinoids, Retinal is a really awesome and well-proven member of the family that is absolutely worth trying.
It's a special "cross-linked" from of IT-moisturizer, hyaluronic acid (HA). Cross-linked means that "normal" HA pieces (1-2 million Da molecular weight) are chemically bound togeather to create a big, "infinite" mesh.
The special HA mesh has a remarkable water-binding capacity, 5 times more than the already crazy water-binding capacity of "normal" HA. This water filled crosslinked HA gel forms a smooth film on the skin and continuously delivers the bound water, so it gives long-term moisturizing benefits.
Btw, crosslinking HA was developed for dermal fillers (as crosslinking helps their longevity), and this guy is the topical version of FDA approved dermal filler called Hylan B gel. Smearing crosslinked version all over ourselves is a newish thing, and incoming evidence so far suggests that it's a great idea, even better than normal HA.
A very recent, 2016 research article compared the topical moisturizing effect of crosslinked HA (not Hylan B gel specifically, but something called Resilient HA or RHA), HMW-HA and LMW-HA and found that "TEWL (that is trans-epidermal water loss, the water that evaporates from the skin) was reduced by 27.8% with RHA, and by 15.6% with HMW HA, but increased by 55.5% with LMW HA." (You can read much more about HMW and LMW HA here in the geeky details section.)
All in all, we think Sodium Hyaluronate Crosspolymer is an awesome version of HA, probably superior to traditional versions, so be happy to spot it on the ingredient list.
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 film-forming and thickening polymer (a large molecule composed of many repeated subunits) that comes to the formula usually as part of an emulsifier, thickener trio (with C13-14 Isoparaffin and Laureth-7, trade named Sepigel 305). This trio is an easy-to-use liquid that helps to create nice, non-tacky gel formulas.
It's a petroleum derived emollient and thickener. It often comes to the formula as part of an emulsifier, thickener trio (with Polyacrylamide and Laureth-7). This trio is an easy-to-use liquid that helps to create nice, non-tacky gel formulas.
A not-very-interesting helper ingredient that is used as an emulsifier and/or surfactant. Comes from a coconut oil derived fatty alcohol, lauryl alcohol.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
The extract of summer lilac or butterfly-bush in itself is a nice ingredient with some antioxidant and anti-inflammatory properties and the manufacturer claims that the meristem cell culture is even better.
It contains among others verbascoside and isoverbascoside that have not only antioxidant and anti-inflammatory but also photoprotective activity. What’s more, it has phytosterols, amino acids and polysaccharides, all useful for skin moisture.
We don't have description for this ingredient yet.
- 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
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
Cucumber is a nice, non-irritating plant extract that’s known for it’s soothing and emollient properties. It’s not something new to put it on our face: even Cleopatra used it to “preserve her skin”.
It’s commonly believed that cucumber is the answer to puffy eyes, but there is no research confirming this. What research does confirm is that it contains amino acids and organic acids that’s helpful for the skin’s acid mantle. There is also an enzyme (called shikimate dehydrigenase) in the pulp that’s shown to have anti-inflammatory properties.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
Apple needs no introduction as one of the most common fruits on planet Earth. It's not only a healthy fruit snack, it's also a goodie if you put in all over your face.
It's loaded with proteins, starch, sugars, acids, vitamins and salts. The sugars (mainly fructose, glucose, sucrose) give apple fruit extract nice moisturizing and smoothing properties, while the acids (mainly malic and gallic acid) give it mild exfoliant, skin brightening and antibacterial properties.
We don't have description for this ingredient yet.
Raspberry is one of the colorful berries that’s not only delicious but contains many biologically active, healthy compounds. It has polyphenols including anthocyanins and ellagitannins that have antioxidant and anti-inflammatory properties.
According to skin care expert Paula Begoun, it’s antibacterial as well but due to its tannin content it can cause also irritation to the very sensitive skinned.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
We don't have description for this ingredient yet.
The salt form of one of the main anti-inflammatory ingredients in the licorice plant, monoammonium glycyrrhizinate. It’s a yellowish powder with a nice sweet smell.
It’s used mainly for its soothing and anti-inflammatory properties, but according to manufacturer info, it’s also sebum regulating so it's a perfect ingredient for problem skin products.
Read more about licorice and why it's a skincare superstar here.
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.
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.
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.
Similar to other glycols, it's a helper ingredient used as a solvent, or to thin out thick formulas and make them more nicely spreadable.
Hexylene Glycol is also part a preservative blend named Lexgard® HPO, where it helps the effectiveness of current IT-preservative, phenoxyethanol.
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 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.
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.
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.
A helper ingredient that helps to make the products stay nice longer, aka preservative. It works mainly against fungi.
It’s pH dependent and works best at acidic pH levels (3-5). It’s not strong enough to be used in itself so it’s always combined with something else, often with potassium sorbate.
It's one of those things that help your cosmetics not to go wrong too soon, aka a preservative. It’s not a strong one and doesn’t really work against bacteria, but more against mold and yeast. To do that it has to break down to its active form, sorbic acid. For that to happen, there has to be water in the product and the right pH value (pH 3-4).
But even if everything is right, it’s not enough on its own. If you see potassium sorbate you should see some other preservative next to it too.
BTW, it’s also a food preservative and even has an E number, E202.
An Ecocert-approved, natural preservative that counts as gentle and non-irritating to the skin. Usually, it comes to the formula as part of a preservative blend as it's not enough on its own.
- 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
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.
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 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.
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.
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| what‑it‑does | solvent |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | skin-identical ingredient | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | emollient |
| what‑it‑does | emollient | antimicrobial/antibacterial |
| what‑it‑does | soothing | moisturizer/humectant |
| what‑it‑does | emulsifying |
| what‑it‑does | emulsifying |
| what‑it‑does | emollient | viscosity controlling | emulsifying | surfactant/cleansing |
| irritancy, com. | 1, 2 |
| what‑it‑does | emollient |
| what‑it‑does | emollient | solvent |
| what‑it‑does | emollient |
| irritancy, com. | 0, 1 |
| what‑it‑does | abrasive/scrub |
| what‑it‑does | cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant |
| what‑it‑does | emollient |
| irritancy, com. | 0, 0 |
| what‑it‑does | emulsifying |
| what‑it‑does | emollient |
| irritancy, com. | 0, 2-4 |
| what‑it‑does | emollient | viscosity controlling |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | cell-communicating ingredient | antioxidant | antimicrobial/antibacterial |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | antioxidant |
| what‑it‑does | cell-communicating ingredient |
| what‑it‑does | skin-identical ingredient | antioxidant | moisturizer/humectant |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | viscosity controlling |
| what‑it‑does | emollient | viscosity controlling | solvent |
| what‑it‑does | emulsifying | surfactant/cleansing |
| what‑it‑does | moisturizer/humectant | solvent |
| what‑it‑does | perfuming |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | antioxidant |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | soothing | emollient |
| what‑it‑does | perfuming |
| what‑it‑does | surfactant/cleansing | perfuming |
| what‑it‑does | surfactant/cleansing |
| what‑it‑does | moisturizer/humectant |
| what‑it‑does | antioxidant | soothing |
| what‑it‑does | perfuming | viscosity controlling |
| what‑it‑does | perfuming |
| what‑it‑does | soothing | moisturizer/humectant |
| what‑it‑does | soothing |
| what‑it‑does | moisturizer/humectant | emollient |
| what‑it‑does | preservative |
| what‑it‑does | solvent | emulsifying | perfuming | surfactant/cleansing |
| irritancy, com. | 0-1, 0-2 |
| what‑it‑does | viscosity controlling |
| what‑it‑does | viscosity controlling |
| irritancy, com. | 0, 1 |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | preservative |
| what‑it‑does | preservative |
| what‑it‑does | preservative |
| what‑it‑does | preservative |
| what‑it‑does | antioxidant |
| irritancy, com. | 0-3, 0-3 |
| what‑it‑does | buffering |
| what‑it‑does | buffering |
| what‑it‑does | perfuming | solvent |
| what‑it‑does | perfuming |