Transparent Lab Zi-K Cica Repairing Gel

The Cosmetic Ingredient Review panel has concluded this ingredient to be safe in cosmetics and found to be a non-ocular (eye) irritant at 100% in rabbits.

Usage levels vary depending on product type; industry surveys report it around 2.2% in baby products, 19.5% in hair sprays, and 1-20% in skincare.

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.

D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.

Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):

Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.

This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.

Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.

This ingredient is also referred to as pro-vitamin B5.

This ingredient is volatile which means it will mostly evaporate (but it evaporates slower than older cyclomethicones, like Cyclotetrasiloxane).

Typical concentration ranges from 1-30% depending on if it's being used to tweak the feel of a product or acting as the main emollient.

Besides holding formulas together, it also leaves a silky and lightweight feel on skin without the greasiness. A manufacturer also claims it can help with the controlled release of active ingredients.

The CIR Expert Panel found this ingredient to not be sensitizing in concentrations up to 15% in human maximazation testing and dimethicone-based compounds were not comedogenic.

It has a high molecular weight well above 1,000 g/mol which means it limits meaningful skin penetration.

A 2019 study specifically tested this ingredient and found no observable Malassezia growth in its presence.

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Isododecane's role as a solvent makes it a great texture enhancer. It spreads smoothly on skin and does not leave a sticky feeling behind. Isododecane also helps prevent color transfer in makeup products.

Isododecane is not absorbed into skin.

The chemical name for this ingredient is 2,2,4,6,6-PENTAMETHYLHEPTANE.

Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

Madecassoside pairs well with other hydrating or antioxidant ingredients like Ascorbic Acid or Hyaluronic Acid.

You'll usually find this in concentrations between 0.2-5%.

First, it turns down inflammation so it helps with things like redness and general upset skin.

Second, it acts as an antioxidant which means it helps protect skin from daily stress and damage.

And third, it nudges the skin to make more collagen and rebuild its support structure.

That combination is why the whole Centella family is known for calming skin, strengthening the barrier, fading redness, and giving anti-aging benefits.

It's worth being honest about the evidence here; a lot of the strongest data is on the full extract or a Madecassoside/Asiaticoside rather than Madecassic Acid alone. Reviewers also note more long-term clinical trials are needed to confirm the full potential.

Concentration-wise, this ingredient is rarely used pure and usually shows up as part of a standardized centella extract where reported content ranges from 0.02-3.06%.

Finished products typically run somewhere in the 0.1-10% range depending on the format.

In real-world tolerance tests, a repeat-insult patch test on an eye lotion with 0.2% Centella extract showed no irritation or allergic contact dermatitis in 54 subjects. And a mascara with 0.5% Madecassoside caused neither irritation nor sensitization in 109 subjects.

Allergy risk is very low, but not zero. Centella and its constituents are classified as weak contact sensitizers and some rare cases of allergic contact dermatitis exist.

It also calms inflammation and acts as an antioxidant so it can help skin heal faster, rebuild itself, and repair a damaged barrier.

And on naming, even though "acid" is in the name, it's nothing like an AHA or BHA exfoliant. It's a gentle firming and soothing ingredient that supports your skin barrier.

Concentration-wise, Asiatic Acid is potent at very low doses and usually shows up as a small fraction of a broader centella extract.

Analyses of centella material put Asiatic Acid reported in the range of 0.2-3% of the extract.

This ingredient is non-sensitizing and guinea pig sensitization testing also found it to be a weak sensitizer. That means the risk of acquiring contact sensitivty is quite low.

Allergic contact dermatitis does exist but is also very rare; documented cases tend to involve prolonged use on broken skin plus co-sensitization to fragrance ingredients.

These compounds allow centella to dial back inflammation, encourage the skin to build and hold onto collagen, support the barrier and hydration, and bring solid antioxidant activity to protect against signs of aging.

Centella also carries a nice supporting cast of Vitamin A, vitamin C, several B vitamins, and amino acids. Put it all together and you get an ingredient that soothes, hydrates, and protects, all at once.

Most of centella's magic comes from the four big compounds (Asiaticoside, Madecassoside, Asiatic Acid, and Madecassic Acid). These are the actives doing the heavy lifting in almost every centella study.

Here is the short version of what they do in the skin:

So it is not just soothing for the sake of soothing. Centella calms the skin AND helps it rebuild.

Just FYI, not all centella on an ingredient list is the same. What you are getting actually depends on the extract:

Fun fact on the ratios: the leaves tend to be richest in Madecassoside and Asiaticoside, and lower in the two acids. The exact amounts shift with where the plant is grown and how it is processed. This means purity really does vary brand to brand.

Centella is one of the most easygoing actives out there.

It layers well with basically everything: niacinamide, hyaluronic acid, peptides, and vitamin C, and also pairs nicely with stronger actives like retinoids and exfoliating acids where it can help take the edge off irritation.

On the safety side, centella and its triterpenes are classified as weak sensitizers, meaning allergic reactions are possible but uncommon.

Patch tests at 1% and 5% came back negative in test panels, and creams at typical use levels did not cause allergic reactions across large groups of people.

But as with any new active, a patch test is still a smart move for very reactive skin.

Centella is widely used because it is effective at low percentages. For context, human safety testing found no meaningful irritation from creams containing centella extract at everyday use levels (the tested amounts were well under 1%).

The irritancy threshold in animal testing was also above 30% (so real-world formulas sit far below anything concerning).

In collagen lab studies, higher concentrations drove more collagen synthesis, so serums built around centella tend to feature it more prominently.

Bottom line: you will find centella working nicely anywhere from a fraction of a percent up to hero-ingredient levels depending on whether it is a supporting soother or the main event.

Fun fact: Centella has been used as a medicine and in food for many centuries. As a medicine, it is used to treat burns, scratches, and wounds.

This root juice also contains antioxidant compounds (like chlorogenic acid and caffeic acid).

Just so you know, Yacon belongs to the daisy family so be sure to patch test if you have a known allergy to plants in that family.

Copper has wound healing properties due to its role in creating new blood vessels and tissue repair.

As a co-emulsifier, its "head" and "tail" sit at the oil-water interface. But overall, the short C8 tail and not being water soluble means it doesn't really have the muscle to emulsify a formula on its own. That's why you'll often see it paired with a primary emulsifier like Cetearyl Glucoside.

Interestingly, Glyceryl Caprylate acts as a preservative booster. This is because its fatty-acid backbone disrupts microbial lipid membranes. It shows excellent activity against bacteria and yeast but is weaker against mold.

Typical concentrations range from 0.5-1% and this ingredient is generally non-irritating.

Because this ingredient has a C8 fatty acid chain, it is outside the range that the Malassezia yeast metabolizes (making it fungal acne safe).

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%.

Fun fact: Mannitol can be found in foods as a sweetener. It can be naturally found in mushrooms, algae, fruits, and veggies.

In skincare, PC pulls double duty:

The linoleic acid it carries gets incorporated into skin ceramides and helps reinforce the lipid matrix.

Interestingly, it can help top of the omega-6 fatty acid that's often low in acne-prone and atopic skin. There's a sizeable body of literature that supports its use in dry, barrier-impaired, and breakout-prone skin.

There are two kinds of PC you'll see on ingredient lists.

Use levels range from <1% as a liposomal carrier and between 20-40% in lamellar matrix sytems.

The good news is: studies show applying this ingredient topically replenishes ubiquinone levels in our skin. This also comes with a ton of skin benefits. These benefits include:

Ubiquinone is considered a large molecule and cannot be absorbed into the lower layers of skin. This is why it is believed to be such an effective antioxidant: it protects our skin in the upper layers and prevents damage in the deeper layers.

When used in sunscreen, ubiquinone is shown to increase ingredient stability, increase SPF factor, and add to infrared protection.

Fun fact: ubiquinone is fat-soluble.

On the emulsifier side, it keeps your formula smooth and well-mixed by playing peacekeeper for ingredients that don't naturally get along (like oil and water).

Because it has a C12 (lauric acid) fatty acid chain, this ingredient can potentially feed the Malassezia yeast that causes fungal acne. The Malassezia yeast prefers esters with C11-C24 fatty acids.

This ingredient is an ester of lauric acid and Polyglycerin-10.

Though it has "alcohol" in the name, it is not related to denatured alcohol or ethyl alcohol.

The FDA allows products labeled "alcohol-free" to have fatty alcohols.

This ingredient may not be fungal acne safe. It is a primary fatty alcohol with a chain length above 12 carbons. A study from 2019 show Malassezia can feed on fatty alcohols in this range, so it may trigger fungal acne in those prone to it.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Read more about some other popular AHA's here:

Both potassium sorbate and sorbic acid can be found in baked goods, cheeses, dried meats, dried fruit, ice cream, pickles, wine, yogurt, and more.

You'll often find this ingredient used with other preservatives.

Sodium benzoate works as a preservative by inhibiting the growth of bacteria inside of cells. It prevents the cell from fermenting a type of sugar using an enzyme called phosphofructokinase.

It is the salt of benzoic acid. Foods containing sodium benzoate include soda, salad dressings, condiments, fruit juices, wines, and snack foods.

Studies for using ascorbic acid and sodium benzoate in cosmetics are lacking, especially in skincare routines with multiple steps.

We always recommend speaking with a professional, such as a dermatologist, if you have any concerns.

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.