Follow us on our new Insta page »
Lab Series Rescue Serum

Rescue Serum

High-performance, concentrated, anti-aging treatment. This serum defends skin against environmental aggressors and combats visible signs of aging.
Uploaded by: elliereid on

Highlights

Skim through

Ingredient name what-it-does irr., com. ID-Rating
Water\Aqua\Eau solvent
Butylene Glycol moisturizer/​humectant, solvent, viscosity controlling 0, 1
Bis-PEG-18 Methyl Ether Dimethyl Silane emollient, moisturizer/​humectant, surfactant/​cleansing
Alcohol Denat antimicrobial/​antibacterial, solvent, viscosity controlling icky
Biosaccharide Gum - 1 soothing, moisturizer/​humectant goodie
PEG-6 moisturizer/​humectant, solvent
Glycerin skin-identical ingredient, moisturizer/​humectant 0, 0 superstar
Acetyl Hexapeptide-8 cell-communicating ingredient, moisturizer/​humectant goodie
Sigesbeckia Orientalis (St. Paul'S Wort) Extract
Plankton Extract
Algae Extract emollient, moisturizer/​humectant goodie
Lactobacillus Ferment soothing, preservative goodie
Micrococcus Lysate
Yeast Extract\Faex\Extrait De Levure moisturizer/​humectant goodie
Scutellaria Baicalensis Root Extract soothing, antioxidant, antimicrobial/​antibacterial, moisturizer/​humectant goodie
Morus Nigra (Mulberry) Root Extract
Lycium Chinense (Wolfberry) Fruit Extract antioxidant
Acetyl Glucosamine skin-identical ingredient, skin brightening goodie
Vaccinium Macrocarpon (Cranberry) Fruit Extract
Vaccinium Angustifolium (Blueberry) Fruit Extract soothing
Vitis Vinifera (Grape) Fruit Extract soothing, antioxidant, moisturizer/​humectant goodie
Camellia Sinensis (Green Tea) Leaf Extract antioxidant, soothing superstar
Aminopropyl Ascorbyl Phosphate antioxidant, skin brightening goodie
Ergothioneine antioxidant
Biosaccharide Gum-4
Tocopheryl Acetate antioxidant 0, 0
Caffeine antioxidant, perfuming goodie
Nylon-12 viscosity controlling
Trehalose moisturizer/​humectant goodie
Sodium Hyaluronate skin-identical ingredient, moisturizer/​humectant 0, 0 goodie
Sucrose moisturizer/​humectant, soothing goodie
Polysorbate 20 emulsifying, surfactant/​cleansing 0, 0
PEG-11 Methyl Ether Dimethicone emulsifying
Xanthan Gum viscosity controlling
Fragrance (Parfum) perfuming icky
Lecithin emollient, emulsifying goodie
Ammonium Acryloyldimethyltaurate/VP Copolymer viscosity controlling
Citric Acid buffering
Silica viscosity controlling
Disodium EDTA chelating, viscosity controlling
BHT antioxidant, preservative
Phenoxyethanol preservative

Lab Series Rescue Serum
Ingredients explained

Also-called: Aqua;Water | What-it-does: solvent

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. 

What-it-does: moisturizer/humectant, solvent, viscosity controlling | Irritancy: 0 | Comedogenicity: 1

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. 

Bis-PEG-18 Methyl Ether Dimethyl Silane is a silicone that is water dispersible (as opposed to most other silicones that are usually oil dispersible). It makes the skin smooth and nice (emollient), moisturizes, helps to reduce tackiness, and also has some foam boosting properties. It is often used in light, watery formulas to give them an extra silky feel

  • It's a super common and super debated skincare ingredient
  • It has several benefits: great solvent, penetration enhancer, creates cosmetically elegant, light formulas, great astringent and antimicrobial
  • It can be very drying if it's in the first few ingredients on an ingredient list
  • Some experts even think that regular exposure to alcohol damages skin barrier and causes inflammation though it's a debated opinion (read more in geeky details tab)
Read all the geeky details about Alcohol Denat. here >>

Biosaccharide Gum-1 is a pretty interesting kind of sugar ingredient that is created from sorbitol via bacterial fermentation. 

According to the manufacturer it’s a “S.M.A.R.T.” sugar: it has Soothing, Moisturizing, Anti-aging, Restructuring and Touch properties. Let’s look at them quickly one by one.

Soothing: the manufacturer tested out the soothing effect in vivo (meaning on humans that is always a good thing!) by measuring how 3% Biosaccharide Gum-1 decreased the tingling sensation caused by 10% lactic acid. The result was good: the tingling was decreased by 47%.

Moisturizing: Compared to famous hyaluronic acid, it turns out that the two are great together. HA has a quicker effect and provides more instant hydration (much more hydration was measured after 1h of application), while our nice sugar has a somewhat delayed effect demonstrating stronger hydration after 3h of application. After 8 hours both had similar moisturizing effect. 

Anti-aging: According to ex-vivo tests (meaning not on humans, so do not trust it too much) Biosaccharide Gum-1 can stimulate a protein in our skin called sirtuin-1. This is supposed to help our skin cells to live longer, and function better. 

Resurfacing:  The sirtuin-1 stimulation also results in quicker cell renewal - something that happens anyway but slows down as we age. And the quicker cell renewal is good because it helps the regeneration of the barrier function. That is especially nice for fragile, sensitive skin.

Touch: our fermented sugar is not only good to the skin, but it also feels great on the skin. It gives a nice “soft touch” feeling and makes the products pleasant to use. 

The bottom line is that the above info is from the manufacturer (and we could not find any relevant independent research) so obviously take it with a grain of salt. But Biosaccharide Gum-1 does look as an interesting and promising ingredient that’s why it earned our goodie rating. 

A  clear viscous polymer (a molecule from repeated subunits) liquid that works as a solvent and humectant.

According to manufacturer info, it's recommended for all kinds of washing products (like hand dishwashing detergents or fine-fabric washing powders) and is ideal as a viscosity regulator, detergent booster, and solubilizer.

Glycerin - superstar
Also-called: Glycerol | What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0
  • 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
Read all the geeky details about Glycerin here >>

Also-called: Argireline, Acetyl Hexapeptide-3 | What-it-does: cell-communicating ingredient, moisturizer/humectant

If you see a cosmetic product that claims that it has "Botox-like effect" then two things are almost certain: one, the product overpromises and two, it contains Argireline. 

So this one is the famous peptide that's marketed by its manufacturer as the "Botox in a jar". The basis for this claim is that it targets the same wrinkle forming mechanism (wrinkles caused by facial muscle movement) as Botox, but the way it works is very different. In addition, the extent to which it can prevent muscles from contracting (and to smooth wrinkles) is very different (otherwise why would anyone use still Botox?). 

The manufacturer did several studies to prove that Argireline really works and it does (just not as well as Botox). In-vivo (made on real people) tests showed that using 10% Argireline solution around the eyes for 15 days decreased wrinkles depth by 17%. A Spanish University also did some research and found that Argireline increased the level of skin moisturization and decreased both the depth and width of wrinkles "significantly". 

This means, Acetyl Hexapeptide-8 does have some ability to smooth wrinkles (but not as well as Botox - sorry, if we sound like a broken record). Also, we have to agree with TruthInAging, that it's not a collagen builder and not a preventer of structural aging (think vitamin C, AHAs or retinol); it's just a quick fix. If you are looking for one, this could be your thing. If you are more of a "let's treat this aging thing properly" type, then it's probably not your thing.

We don't have description for this ingredient yet.

We don't have description for this ingredient yet.

Algae Extract - goodie

We have to admit that Algae Extract is not our favorite ingredient name. It does comply with the INCI standard (the official list about how ingredients on the product labels have to be called, the thing we help you to decode here :)), but there are about 20 000 different kinds of algae and an extract from them can be made in another 10 000 ways.

So, Algae Extract can be anything from La Mer's "Miracle Broth" to a simple brown algae extract that helps to smooth the hair. The official description in the Europiean Cosmetic Ingredient listing is this: "an extract of various species of Algae; Extract of the Seaweed, Fucus vesiculosus, Furaceae". Its official functions include being a humectant (helps skin to attract water), emollient (makes skin feel smooth and nice) and skin conditioner (a catchall phrase for saying it does something good for the skin).

A 2015 research paper on the potential of uses of algae in cosmetics summarizes that algae are rich sources of biologically active metabolites including antioxidants, anti-inflammatory agents, alginates, polysaccharides, and carotenoids. Currently, algae extracts are mostly used as moisturizing and thickening agents, but algae also have great potential to combat skin aging, pigmentation as well as working as an antimicrobial.

We have also browsed through Prospector to see what manufacturers say about their algae. There is, for example, an algae extract trade-named Lanablue that comes from blue-green algae (green algae is rare, less than 1% of the total macroalgae in the world) and is claimed to have retinoid like effects (i.e. reduce wrinkles, smooth skin) but without the side effects (though it seems now that the INCI name of Lanablue was changed to Aphanizomenon Flos-Aquae Extract). 

There is another algae extract from another manufacturer that comes from red algae (much more common, about 40% of total macroalgae worldwide) and is claimed to have not only moisturizing but also skin smoothing and densifying effects. 

Here is a brown algae extract (the most common type, about 59% of macroalgae), also just called Algae Extract on the product label that is simply claimed to be a free radical scavenger, aka antioxidant. These were just three random examples from three manufacturers all called Algae extract even though they all come from different algae with different claims.

Anyhow, the point is this; there are tons of different types of Algae Extracts out there. Unless the brand tells you what they use, it's impossible to know for sure. The most probable scenario for the Alge Extract is that it works as a moisturizer and emollient and it might have some additional anti-aging properties.

What-it-does: soothing, preservative

Lactobacillus ferment is an interesting probiotic ingredient with some promising properties. 

First, according to a 2009 Estee Lauder patent, it’s a DNA repair enzyme and it can help to protect the skin against environmental aggressors.

Second, still according to Estee Lauder research but now from 2012 the ingredient has anti-microbial and anti-inflammatory properties and holds promise in the treatment of acne and rosacea. For the former one 5% was needed to show effectiveness, but for reducing skin sensitivity already 1% showed results. 

The anti-acne effect is confirmed also by US manufacturer, Barnet, that says that Lactobacillus ferment is helpful in killing harmful bacteria and creating a healthy balanced microflora. Compared to well-known anti-acne and anti-inflammatory salicylic acid the probiotic worked faster at reducing the size and redness of acne lesions. 

It also goes by the trade name Leucidal Liquid SF and can serve in the formula as a natural preservative. 

Bottom line: It’s not the most proven ingredient (yet) but definitely a very promising one especially if you have sensitive skin, acne or rosacea.  

We don't have description for this ingredient yet.

What-it-does: moisturizer/humectant

You probably know yeast from the kitchen where you put it into milk with a little sugar and then after a couple of minutes brownish bubbles form. That is the fungi fermenting the sugar

As for skin care, yeast contains beta-glucan that is a great soothing ingredient and also a mild antioxidant.  The yeast extract itself is a silky clear liquid that has some great moisturizing, skin protecting and film-forming properties on the skin. 

Also-called: Skullcap Root Extract | What-it-does: soothing, antioxidant, antimicrobial/antibacterial, astringent, moisturizer/humectant

A traditional Chinese herbal medicine loaded with potent antioxidant and anti-inflammatory flavonoids such as baicalin, baicalein, and wogonin.

If that would not be enough, Skullcap Root is also claimed to have antimicrobial and antifungal properties (also against P.acnes and Malassezia furfur) as well as some skin-brightening activity. A multi-functional skin-goodie.

We don't have description for this ingredient yet.

What-it-does: antioxidant

We don't have description for this ingredient yet.

An amino acid sugar that can be found in the skin and does there good and important things. One of them is that it's a precursor for the biosynthesis of superstar moisturizer, hyaluronic acid. So acetyl glucosamine itself is also an important skin-identical ingredient and natural moisturizing factor.

But that is not all, acetyl glucosamine has two other great properties proved by double-blind clinical trials. First, it's a promising ingredient against wrinkles:  2% can improve wrinkles, particularly in the eye area.

Second, the same amount can also fade - always stubborn - brown spots. (Do not expect magic, though - the photos from the study show the difference after 8 weeks of daily use. The difference is visible, but not that big. It's always good to have realistic expectations. :))  Combined with skincare superstar niacinamide the duo is synergistic and is more effective at improving hyperpigmentation, so if you are after the skin-lightening benefit look out for products that contain both. 

Also-called: Cranberry Fruit Extract | What-it-does: astringent

We don't have description for this ingredient yet.

Also-called: Blueberry Extract | What-it-does: soothing

We don't have description for this ingredient yet.

Also-called: Grape Fruit Extract | What-it-does: soothing, antioxidant, moisturizer/humectant

When it comes to grape and skincare, the seed extract and the seed oil steals most of the show. The reason for that is that the seed contains the majority of the skin goodies, the antioxidant superstar polyphenols. 

The fruit also contains some, but it's less potent. However - according to manufacturer info - the fruit extract is not only an antioxidant, but it's also a soothing, moisturizing and nourishing agent

Also-called: Green Tea | What-it-does: antioxidant, soothing
  • 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
Read all the geeky details about Camellia Sinensis Leaf Extract here >>

Also-called: Form of Vitamin C | What-it-does: antioxidant, skin brightening

A vitamin C derivative that's created by combining ascorbic acid (pure vitamin C) with a molecule called 3-APPA (it stands for 3-aminoproply dehydrogen phosphate). If you do not know what the big deal about vitamin C is, you are missing out, and you have to click here and read all the geeky details about it.

So now, you know that vitamin C is awesome. It's proven to have antioxidant, collagen-boosting and skin-brightening magic abilities, but the problem is that it's really really unstable. To solve the stability issue, the cosmetic industry is coming up with derivatives and Aminopropyl Ascorbyl Phosphate (AAP) is a newish version created by a Korean company.

According to the manufacturer, AAP is a water soluble, stable derivative that has both anti-wrinkle and whitening effects. They conducted an in-vivo (made on real people) study with 33 participants and found that the test formula, with just 0.5% AAP, "significantly" reduced hyperpigmentation (age spots) after 8 weeks (by 29-33%).  They also measured a "dramatic" decrease in the total number of wrinkles, about 23% after 8 weeks. (If that's dramatic, we are not sure. Also, be patient because after 4 weeks, the wrinkle reduction was only a couple of percent.)

As for published studies on AAP, we found hardly anything. We found one done by Estee Lauder that briefly mentions AAP as an antioxidant that adds additional UV protection to sunscreen formulas. Another one done by Oriflame reviewed skin-whitening ingredients and also briefly mentioned AAP as a skin-lightening active.

Overall, there is not much data on Aminopropyl Ascorbyl Phosphate, but it does seem like a promising derivative with antioxidant, anti-wrinkle and skin-brightening properties. If you are into vitamin C derivatives and are happy to experiment, it's worth a go.

What-it-does: antioxidant

We don't have description for this ingredient yet.

We don't have description for this ingredient yet.

Also-called: Vitamin E Acetate | What-it-does: antioxidant | Irritancy: 0 | Comedogenicity: 0

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. 

Caffeine - goodie
What-it-does: antioxidant, perfuming

Hello, our favorite molecule that helps us wake up in the morning and then keeps us going through the day. As a super well-known stimulant from coffee, tea and plenty of other soft drinks, Caffeine needs no introduction. So we will skip right to the part where we talk about what the hell it does in so-so many cosmetic products.

Looking at the research, we were surprised to find how versatile Caffeine is. It is a small, water-loving molecule with pretty good skin penetration abilties. Once in the skin, it has nice antioxidant properties, meaning that it reduces the formation of evil free radicals and it might even be useful in preventing UV-induced skin cancers. 

A well-known thing about Caffeine is that it improves the microcirculation of the blood vessels. Though conventional wisdom and anecdotal evidence says that this property is helpful for dark under-eye circles and puffy eyes, we have to mention that the double-blind research we have found about a 3% caffeine gel concluded that "the overall efficacy of the selected caffeine gel in reducing puffy eyes was not significantly different from that of its gel base."  But you know, the proof is in the pudding.

Another thing Caffeine is used for in body care products is its anti-cellulite effects. In theory, it can speed up the lipolysis process (the "fat burning"  by our cells) and stimulate the draining lymph system that might lead to the improvement of cellulite. But here again, the evidence that it actually makes a measurable, let alone visible,  improvement on actual human beings is limited (we could find only some animal skin studies or caffeine being combined with other actives). 

Last, but not least, we have to write about caffeine and hair growth. The theory is that it can inhibit the activity of the 5-α-reductase enzyme that plays an important role in hair loss and allows a renewed growth phase of the hair. We have found some recent and promising research to back this up. A 2017 study compared a 0.2% caffeine liquid with a 5% Minoxidil  (an FDA approved active to treat baldness) solution and found that  "a caffeine-based topical liquid should be considered as not inferior to minoxidil 5% solution in men with androgenetic alopecia", or English translation means that the caffeine liquid was pretty much as good as the FDA-approved Minoxidil stuff. Not bad!

Overall, we think that caffeine is a very versatile and biologically active ingredient. Even though some of its effects are more hyped up than backed up, it is still a nice to have on many ingredient lists. 

What-it-does: viscosity controlling

An  odorless, slightly yellowish powder that's used as a polymer microsphere (a tiny little ball from repeated subunits). It gives products an elegant, silky texture and better slip. It can also scatter light to blur fine lines while letting enough light through so that the skin still looks natural.

Trehalose - goodie
What-it-does: moisturizer/humectant

A type of sugar that has water-binding properties and helps to keep your skin hydrated

What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0

It’s the - sodium form - cousin of the famous NMFhyaluronic 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).

Sucrose - goodie

A type fo sugar, usually refined from cane or beet sugar. On the skin, it has water-binding properties and helps to keep your skin hydrated

What-it-does: emulsifying, surfactant/cleansing | Irritancy: 0 | Comedogenicity: 0

It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula. 

What-it-does: emulsifying

We don't have description for this ingredient yet.

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). 

Also-called: Fragrance, Parfum;Parfum/Fragrance | What-it-does: perfuming

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!). 

Lecithin - goodie
What-it-does: emollient, emulsifying

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

Also-called: Aristoflex AVC | What-it-does: viscosity controlling

A kind of polymer (big molecule from repeated subunits) that helps to create beautiful gel-like textures. It's also a texturizer and thickener for oil-in-water emulsions. It gives products a good skin feel and does not make the formula tacky or sticky. 

It works over a wide pH range and is used between 0.5-1.2%.

What-it-does: buffering

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 white powdery thing that's the major component of glass and sand. In cosmetics, it’s often in products that are supposed to keep your skin matte as it has great oil-absorbing abilities. It’s also used as a helper ingredient to thicken up products or suspend insoluble particles. 

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.

Also-called: Butylated Hydroxy Toluene | What-it-does: antioxidant, preservative

It's the acronym for Butylated Hydroxy Toluene. It's a common synthetic antioxidant that's used as a preservative.

There is some controversy around BHT. It's not a new ingredient, it has been used both as a food and cosmetics additive since the 1970s. Plenty of studies tried to examine if it's a carcinogen or not. This Truth in Aging article details the situation and also writes that all these studies examine BHT when taken orally.

As for cosmetics, the CIR (Cosmetic Ingredient Review) concluded that the amount of BHT used in cosmetic products is low (usually around 0.01-0.1%),  it does not penetrate skin far enough to be absorbed into the bloodstream and it is safe to use in cosmetics.

What-it-does: preservative

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.

You may also want to take a look at...

what‑it‑does solvent
Normal (well kind of - it's purified and deionized) water. Usually the main solvent in cosmetic products. [more]
what‑it‑does moisturizer/humectant | solvent | viscosity controlling
irritancy, com. 0, 1
An often used glycol that works as a solvent, humectant, penetration enhancer and also gives a good slip to the products. [more]
what‑it‑does emollient | moisturizer/humectant | surfactant/cleansing
A type of silicone that makes the skin smooth and nice (emollient), moisturizes and helps to reduce the tackiness of the products. [more]
what‑it‑does antimicrobial/antibacterial | solvent | viscosity controlling
Alcohol with some additives to make it unconsumable. It is great solvent, penetration enhancer, creates cosmetically elegant, light formulas, great astringent, and antimicrobial. In large amounts, it can be very drying to the skin. [more]
what‑it‑does soothing | moisturizer/humectant
Biosaccharide Gum-1 is a pretty interesting kind of sugar ingredient that is created from sorbitol via bacterial fermentation.  According to the manufacturer it’s a “S.M.A.R.T.” sugar: [more]
what‑it‑does moisturizer/humectant | solvent
A  clear viscous polymer (a molecule from repeated subunits) liquid that works as a solvent and humectant.According to manufacturer info, it's recommended for all kinds of washing products (like hand dishwashing detergents or fine-fabric washing powders) and is ideal as a viscosity regulator, detergent booster, and solubilizer. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
A real oldie but a goodie. Great natural moisturizer and skin-identical ingredient that plays an important role in skin hydration and general skin health. [more]
what‑it‑does cell-communicating ingredient | moisturizer/humectant
Argireline - famous peptide that's often referred to as "Botox in a jar". In reality, it's nowhere near that powerful, but it can smooth wrinkles to some extent by preventing facial muscles from contracting. [more]
what‑it‑does emollient | moisturizer/humectant
An extract that comes from one or more of the 20 000 kinds of algae out there. In general algae extracts serve as moisturizing, emollient and thickening agents, and many of them also have additional anti-aging properties. [more]
what‑it‑does soothing | preservative
A probiotic ingredient that might protect the skin against environmental aggressors, have anti-acne and anti-inflammatory properties. Also works as a natural preservative. [more]
what‑it‑does moisturizer/humectant
A silky clear liquid that has great moisturizing, skin protecting and film-forming properties on the skin. [more]
what‑it‑does soothing | antioxidant | antimicrobial/antibacterial | moisturizer/humectant
A traditional Chinese herbal medicine loaded with potent antioxidant and anti-inflammatory flavonoids such as baicalin, baicalein, and wogonin.If that would not be enough, Skullcap Root is also claimed to have antimicrobial and antifungal properties (also against P.acnes and Malassezia furfur) as well  [more]
what‑it‑does antioxidant
what‑it‑does skin-identical ingredient | skin brightening
An amino sugar that helps the skin to stay hydrated, is also promising against wrinkles and can help to fade brown spots particularly when combined with niacinamide. [more]
what‑it‑does soothing
what‑it‑does soothing | antioxidant | moisturizer/humectant
Grape fruit extract - less potent antioxidant than the seed extract, but it's also a soothing and moisturizing agent. [more]
what‑it‑does antioxidant | soothing
Green Tea - one of the most researched natural ingredients that contains the superstar actives called catechins. It has proven antioxidant, anti-inflammatory, antimicrobial and anticarcinogenic properties. [more]
what‑it‑does antioxidant | skin brightening
A water-soluble vitamin C derivative with promising antioxidant, anti-wrinkle, and skin-brightening abilities. [more]
what‑it‑does antioxidant
what‑it‑does antioxidant
irritancy, com. 0, 0
A form of vitamin E that works as an antioxidant. Compared to the pure form it's more stable, has longer shelf life, but it's also more poorly absorbed by the skin. [more]
what‑it‑does antioxidant | perfuming
The well-known stimulant from coffee. It has nice antioxidant properties and can improve the microcirculation. Might be helpful for dark circles, puffy eyes, as well as cellulite and hair loss. [more]
what‑it‑does viscosity controlling
A polymer microsphere that gives products an elegant, silky texture. Can also scatter light to blur fine lines. [more]
what‑it‑does moisturizer/humectant
A type of sugar that has water-binding properties and helps to keep your skin hydrated. 
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
It's the salt form of famous humectant and natural moisturizing factor, hyaluronic acid. It can bind huge amounts of water and it's pretty much the current IT-moisturizer. [more]
what‑it‑does moisturizer/humectant | soothing
A type fo sugar, usually refined from cane or beet sugar. On the skin, it is water-binding properties and helps to keep your skin hydrated.
what‑it‑does emulsifying | surfactant/cleansing
irritancy, com. 0, 0
It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula. 
what‑it‑does emulsifying
what‑it‑does viscosity controlling
A super commonly used thickener and emulsion stabilizer. [more]
what‑it‑does perfuming
The generic term for nice smelling stuff put into cosmetic products so that the end product also smells nice. It is made up of 30 to 50 chemicals on average. [more]
what‑it‑does emollient | emulsifying
It's quite the multi-tasker: an emollient and water-binding ingredient but also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes.  [more]
what‑it‑does viscosity controlling
A kind of polymer (big molecule from repeated subunits) that helps to create beautiful gel-like textures. It's also a texturizer and thickener for oil-in-water emulsions. [more]
what‑it‑does buffering
An AHA that comes from citrus fruits. It is usually used as a helper ingredient to adjust the pH of the formula. [more]
what‑it‑does viscosity controlling
A white powdery thing that can mattify the skin and thicken up cosmetic products. [more]
what‑it‑does chelating | viscosity controlling
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. [more]
what‑it‑does antioxidant | preservative
It's the acronym for Butylated Hydroxy Toluene. It's a common synthetic antioxidant that's used as a preservative.There is some controversy around BHT. [more]
what‑it‑does preservative
Pretty much the current IT-preservative. It’s safe and gentle, and can be used up to 1% worldwide. [more]