Mac Cosmetics Eye Brows Big Boost Fibre Gel Thunder

Mac Cosmetics Eye Brows Big Boost Fibre Gel

Color: Thunder

Eyebrow with 35 ingredients that contains exfoliants and Vitamin E

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What's inside

Ingredients List

Key Ingredients

Benefits

Concerns

Ingredients Explained

Emollient, Skin Conditioning

Hydrogenated Polyisobutene is a synthetic polymer. Polymers are compounds with high molecular weight. Hydrogenated Polyisobutene is an emollient and texture enhancer.

In one study, Hydrogenated Polyisobutene showed better skin hydration levels than Caprylic/Capric Triglyceride. As an emollient, it helps keep your skin soft and hydrated by trapping moisture in.

Hydrogenated Polyisobutene is often used as a mineral oil replacement.

Learn more about Hydrogenated Polyisobutene
Emulsion Stabilising

Microcrystalline Wax is derived from petroleum through a de-oiling process, then highly refined and purified before use in cosmetics.

In skincare formulations, it is used to improve texture and create a smooth, even consistency. It also helps stabilize products by preventing ingredients from separating.

Skin Conditioning

Paraffin is a solid wax that pulls its weight as an emollient, occlusive, and consistency-booster.

It softens skin and lays down a protective film to slow water loss and gives products a stable body and structure.

The cosmetic grade stuff is highly refined with a solid safety record. The CIR Expert Panel has repeatedly reaffirmed this ingredient to be safe in current practices of use and concentration.

The worry about carcinogenic compounds only applies to industrial grades, not the purified version used in skincare.

Despite its reputation, the highly reformed form is non-comedogenic and doesn't penetrate deeply into skin.

The good news for fungal-acne prone folks: the Malassezia yeast feeds on fatty acids and lipids and paraffin doesn't contain any of these (so there's nothing for the yeast to metabolize). This ingredient is considered fungal acne safe.

Learn more about Paraffin
Abrasive

Polyethylene is a synthetic ingredient that helps the skin retain moisture. It is a polymer.

It is also typically used within product formulations to help bind solid ingredients together and thicken oil-based ingredients. When added to balms and emulsions, it helps increase the melting point temperature.

This ingredient comes as a powder made up of small, porous, microbeads. It is used to add a silky feel to products and also helps absorb oil.

Emollient, Skin Conditioning, Surfactant

Diisostearyl Malate is an emollient and most often used in lip products. It comes from isostearyl alcohol, a fatty acid, and malic acid, an AHA.

As an emollient, Diisostearyl Malate helps create a thin film on your skin to trap moisture in. This helps keep your skin soft and smooth.

We don't have a description for Copernicia Cerifera Wax Extract yet.

We don't have a description for Nylon-6 yet.

Disteardimonium Hectorite comes from the clay mineral named hectorite. It is used to add thickness to a product.

It can also help stabilize a product by helping to disperse other ingredients.

Hectorite is a rare, white clay mineral.

Learn more about Disteardimonium Hectorite
Emollient, Emulsifying

Glyceryl Diisostearate isn't fungal acne safe.

Emollient, Skin Conditioning, Skin Protecting

Dimethicone is a type of synthetic silicone created from natural materials such as quartz. It is also known as polydimethylsiloxane.

What it does:

Dimethicone comes in different viscosities:

Depending on the viscosity, dimethicone has different properties.

Ingredients lists don't always show which type is used, so we recommend reaching out to the brand if you have questions about the viscosity.

This ingredient is unlikely to cause irritation because it does not get absorbed into skin. However, people with silicone allergies should be careful about using this ingredient.

Note: Dimethicone may contribute to pilling. This is because it is not oil or water soluble, so pilling may occur when layered with products. When mixed with heavy oils in a formula, the outcome is also quite greasy.

Learn more about Dimethicone

We don't have a description for Nylon-66 yet.

Emollient, Humectant, Skin Protecting

Aluminum Hydroxide is a form of aluminum. It can be naturally found in nature as the mineral gibbsite. In cosmetics, Aluminum Hydroxide is used as a colorant, pH adjuster, and absorbent.

As a colorant, Aluminum Hydroxide may add opacity, or reduce the transparency. Aluminum hydroxide is contains both basic and acidic properties.

According to manufacturers, this ingredient is an emollient and humectant. This means it helps hydrate the skin.

In medicine, this ingredient is used to help relieve heartburn and help heal ulcers.

There is currently no credible scientific evidence linking aluminum hydroxide in cosmetics to increased cancer risk.

Major health organizations allow the use of aluminum hydroxide in personal care products and have not flagged it as a carcinogenic risk at typical usage levels.

Learn more about Aluminum Hydroxide
Emulsifying, Surfactant

We don't have a description for Dextrin Myristate yet.

Abrasive, Absorbent

Silica, also known as silicon dioxide, is a naturally occurring mineral. It is used as a fine, spherical, and porous powder in cosmetics.

Though it has exfoliant properties, the function of silica varies depending on the product.

The unique structure of silica enhances the spreadability and adds smoothness, making it a great texture enhancer.

It is also used as an active carrier, emulsifier, and mattifier due to its ability to absorb excess oil.

In some products, tiny microneedles called spicules are made from silica or hydrolyzed sponge. When you rub them in, they lightly polish away dead skin layers and enhance the penetration of active ingredients.

Learn more about Silica
Skin Conditioning, Solvent

Pentylene Glycol (1,2-pentanediol) is a multitasking little diol with three main roles in a formula:

Research on alkanediols (the family pentylene glycol belongs to) show they work by disrupting microbial cell membranes. This disruption helps the primary preservative system in a product work more effectively at lower doses.

On the safety side, the Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe as used in current cosmetic practices + concentrations.

Typical use levels in a formula run about 1-5%.

Learn more about Pentylene Glycol
Antimicrobial, Astringent, Masking

This ingredient is also called ethanol or ethyl alcohol. It is denatured, meaning made undrinkable for cosmetic use.

In formulas, it:

Is it bad for your skin?

The answer comes down to concentration. Patch and wash studies have found highly concentrated alcohol-based hand rubs (60-100%) cause less barrier disruption than washing with a basic detergent like SLS. The only measurable effect in these studies was a temporary dip in skin hydration.

Concentrations below 12-15% in leave-on cosmetics is generally well-tolerated. Concentrations above start to see increased transepidermal water loss (TEWL) and reduced hydration.

In concentrations about 58%, it creates temporary channels in your skin's lipid layers to become more permeable and allow other ingredients to slip through easily.

This ingredient can be up to 80% of the formula in alcohol-based perfumes.

Overall, this ingredient is probably harmless if found lower down an ingredients list but worth side-eyeing if it's high up (especially if your barrier is already struggling).

Alcohol can worsen dry skin, eczema, and oily skin, especially at higher concentrations. This is because it can increase transepidermal water loss and decrease hydration to disrupt the skin barrier.

According to the National Rosacea Society based in the US, you should be mindful of products with these alcohols in the top half of ingredients.

True allergic contact dermatitis to ethanol is uncommon, but be sure to patch test if you have dry or sensitive skin.

Learn more about Alcohol
Antioxidant, Masking, Skin Conditioning

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

Learn more about Tocopherol
Preservative

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Learn more about Phenoxyethanol
Cosmetic Colorant

Mica is a naturally occurring mineral used to add shimmer and color in cosmetics. It can also help improve the texture of a product or give it an opaque, white/silver color.

Serecite is the name for very fine but ragged grains of mica.

This ingredient is often coated with metal oxides like titanium dioxide. Trace amounts of heavy metals may be found in mica, but these metals are not harmful in our personal products.

Mica has been used since prehistoric times throughout the world. Ancient Egyptian, Indian, Greek, Roman, Aztec, and Chinese civilizations have used mica.

Learn more about Mica
Cosmetic Colorant

Ci 77891 is a white pigment from Titanium dioxide. It is naturally found in minerals such as rutile and ilmenite.

It's main function is to add a white color to cosmetics. It can also be mixed with other colors to create different shades.

Ci 77891 is commonly found in sunscreens due to its ability to block UV rays.

Learn more about CI 77891
Cosmetic Colorant

Ci 77491 is also hydrated iron III oxide. It's sole purpose is to give a red/pink hue to products.

Iron III oxides are classified as inorganic chemicals for coloring.

Synthetically created Ci 77491 is considered safer than those naturally found. This is because the synthetically created version may contain less impurities. Iron oxides are generally non-toxic and non-allergenic.

Learn more about CI 77491
Cosmetic Colorant

CI 77492 is also hydrated iron III oxide. It's sole purpose is to give a yellow hue to products.

Iron III oxides are classified as inorganic chemicals for coloring.

Synthetically created CI 77492 is considered safer than those naturally found. This is because the synthetically created version may contain less impurities. Iron oxides are generally non-toxic and non-allergenic.

Learn more about CI 77492
Cosmetic Colorant

Ci 77499 is also hydrated iron III oxide. It is created from mixing red and black iron oxides. This helps give shades of darkness to a product.

Iron III oxides are classified as inorganic chemicals for coloring.

Cosmetic Colorant

We don't have a description for CI 77000 yet.

Cosmetic Colorant

This synthetic powder is used to add a pearly/white color in cosmetics.

Cosmetic Colorant

Ci 42090 is a synthetic dye created from petroleum. It is used to give a bright blue color to cosmetics, medicine, and food.

Cosmetic Colorant

We don't have a description for CI 77400 yet.

Cosmetic Colorant, Masking

Ci 75470 is a bright-red pigment. It is AKA carmine.

Carmine is derived from insects such as the cochineal beetle. This ingredient has been used as a natural dye for over 2000 years.

Cosmetic Colorant

We don't have a description for CI 77289 yet.

Cosmetic Colorant

Ci 77288 is used to add green pigment to products.

Cosmetic Colorant

This ingredient is used to impart a blue color. It is not water-soluble.

It goes by two different names:
1. Ferric Ferrocyanide: a synthetic dark blue pigment
2. Ferric Ammonium Ferrocyanide: a synthetic blue pigment, also called Prussian blue

In the EU, both of these colors must be labeled as 'CI 77510'.

Learn more about CI 77510
Cosmetic Colorant

This ingredient is used to add a violet color to cosmetics.

It is created by reacting phosphoric acid, ammonium dihydrogen orthophosphate, and manganese dioxide.

Cosmetic Colorant

This pigment is called Ultramarine blue lazurite. It gives a saturated blue color, but can be used to create other colors as well.

According to the manufacturer, it is usually made from kaolin, sodium sulfate, sodium carbonate, sulfur, and charcoal.

Cosmetic Colorant

CI 19140 is also known as Tartrazine. Tartrazine is a synthetic dye used in cosmetics, foods, and medicine to add a yellow color.

Tartrazine is created from petroleum and is water-soluble.

Some people may experience allergies from this dye, especially asthmatics and those with an aspirin intolerance.

Learn more about CI 19140

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· Updated May 6, 2025 Added by anemone