Z. Bigatti Silk Toner

Dipropylene glycol is technically an alcohol, but it belongs to the glycol family (often considered part of the ‘good’ alcohols). This means it is hydrating and gentle on skin unlike drying solvent alcohols like denatured alcohol.

As a masking agent, Dipropylene Glycol can be used to cover the smell of other ingredients. However, it does not have a scent.

Studies show Dipropylene Glycol is considered safe to use in skincare.

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.

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.

Antioxidants help fight free-radical molecules. Free-radical molecules are capable of damaging our cells and other genetic material. Antioxidants help stabilize free-radicals by donating extra electrons. Grape seed extract may help reduce the signs of aging.

The antimicrobial properties of grape seed may help treat acne. However, more research is needed to support this claim.

Grape seed has also been found to help absorb UV rays. Grape seed extract should not replace your sunscreen.

Antioxidant components in chamomile help fight free-radical molecules. These unstable molecules may damage your skin cells. By stabilizing them, antioxidants may help reduce the signs of aging.

Ancient Greeks, Romans, and Egyptians used Chamomile to treat skin redness and dryness. Chamomile has also been used to help with stomach issues.

Last, the phytochemicals found in apples are strong antioxidants. These antioxidants help with anti-aging as they protect your skin cells against oxidative damage.

And of course, lemons are rich in Vitamin C. Vitamin C helps with skin-brightening and increasing collagen production.

The acidity of lemons may work as an astringent for acne.

However, lemons can also cause skin sensitivity due to its limonene content. It can also increase photosensitivity, or sensitivity to the sun.

This ingredient is also used to add a lemon scent to products.

It can also be mildly exfoliating due to the citric acid, an AHA.

Citrus fruits are rich in flavonoids, alkaloids, and vitamin C.

Glycolic acid is a derivative of sugarcane. While glycolic acid is an AHA with exfoliating properties, sugarcane is not an AHA.

A study from 2021 found the compounds in sugarcane extract to have antioxidant, antimicrobial, and anti-inflammatory activity. The study also suggests these compounds can inhibit skin ageing enzymes and promote collagen synthesis.

Antioxidants help fight free-radical molecules that may damage your skin's DNA. This may help with the signs of aging. Due to its antioxidant property, it is used to help treat chronic inflammation.

In cosmetics, SOD is usually obtained from marine phytoplankton, bovine liver, horseradish, cantaloupe, and certain bacteria.

The three major families of SOD include: Copper/Zinc, Iron/Manganese, and Nickel.

When eating SOD-rich foods, our bodies break it down into amino acids before absorption. Foods that contain SOD include: melons, citrus, spinach, broccoli, kale, almonds, sunflower seeds, and blue-green algae.

Tocopheryl Acetate is commonly found in both skincare and dietary supplements.

First, Retinyl palmitate is created from palmitic acid and retinol. It is a retinol ester and considered one of the weaker forms of retinoid.

This is because all retinoids have to be converted to Tretinoin, AKA retinoic acid. Retinyl Palmitate is pretty far down the line and has to go through multiple conversions before its effects are seen.

Due to this long and ineffective conversion line, the benefits of Retinyl Palmitate are debated.

Studies show Retinyl Palmitate to help:

Dermatologists say this ingredient is ineffective because it isn't used in high enough concentrations in cosmetics.

This ingredient used to be found in sunscreens to boost the efficacy of sunscreen filters.

The downfall of Retinyl Palmitate was due to released reports about the ingredient being correlated to sun damage and skin tumors.

While there is a study showing this ingredient to cause DNA damage when exposed to UV-A, there is no concrete proof of it being linked to skin cancer. It is safe to use when used correctly.

All retinoids increase your skin's sensitivity to the sun in the first few months of usage. Be especially careful with reapplying sunscreen when using any form of retinoid.

Currently, this ingredient is still allowed in cosmetics all over the world. In Canada, cosmetics must have a warning label stating the product to contain Retinyl Palmitate

Fun fact: This ingredient is often added to low-fat milk to increase the levels of Vitamin A.

Menthol also has antimicrobial properties.

As a humectant, Sorbitol helps draw water to the skin. This helps keep the skin hydrated. Sorbitol also helps create a thicker texture in products. You might find sorbitol in your toothpaste and other gels.

It is a non-irritating ingredient that is great for those with dry skin.

Sorbitol is a prebiotic. It helps promote the growth of healthy bacteria on your skin. The bacteria on your skin form a microbiome. This microbiome helps protect your skin from infection and harmful bacteria.

The CIR Expert Panel has confirmed this ingredient to be nontoxic and clinical studies show no sensitization at cosmetic use concentrations.

True allergic reactions are quite rare: a 15-year retrospective study of 6,751 patients found only 0.31% had a positive reaction (and less than half were considered clinically relevant).

It seemed that when sensitization does occur, it's most commonly linked to topical medication (like corticosteroids) and not cosmetics. Allergic contact dermatitis also appears largely limited to individuals with underlying skin conditions.

Overall, propylene glycol is a well-studied ingredient that most people can tolerate without issue.

Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.

This is also one of the most heavily studied preservatives out there and major regulatory bodies have repeatedly given it the green light.

In 2023, the EU's Scientific Committee on Consumer Safety (SCCS) confirmed that this ingredient is safe up to 0.4% on its own, of up to 0.8% when mixed with other paraben esters.

Here's the science behind the noise behind parabens/hormones as well:

Methylparaben shows very weak estrogen-like activity in vitro tests (more than 1,000x weaker than your body's own estradiol). In vivo (live-organism) studies don't support a meaningful endocrine-disrupting effect either.

You get a stronger estrogenic effect from eating tofu, actually.

It's also a low sensitizer and allergic reactions are uncommon; they usually happen on damage or broken skin.

There is a caveat: France has proposed to formally re-examine its endocrine classification in 2025 so the regulatory conversation isn't fully closed as of yet.

But as it stands today, this ingredient is considered safe at permitted levels.

PH adjusters are common in cosmetic products. The pH of a product can affect the effectiveness of other ingredients. A product with a high pH may also irritate the skin.

If you are looking for the tea leaf ingredient, click here.

The FDA requires batch-to-batch certification for this ingredient that is held to a pretty rigorous standard. That means the CI 17200 in your cosmetics has been tested and approved before it ever reaches you.

Contact allergy to cosmetic-grade dyes used at low concentrations are uncommon but has been documented before.

This ingredient also goes by the name D&C RED NO. 33.

CI 17200 has a comedogenic rating of 1 and an irritancy rating of 2 on a scale of 0-5. This is based on peer-reviewed research from the man who invented the comedogenic scale.

A 1 on the comedogenic scale is about as low as it gets without being a flat zero, and makes sense for CI 17200.

It's a water-soluble dye used at very small concentrations (typically 0.001-0.1%), so it dissolves into the water phase of a formula rather than sitting on your skin the way an oil or wax would.

The irritancy rating of 2 reflects that, like most synthetic dyes, there's a small possibility of mild irritation ( particularly for people with existing dye sensitivities).

For the vast majority of people, it's a non-issue at typical use levels.

It's also worth keeping in mind that comedogenic and irritancy ratings are tested on individual ingredients, not finished formulas. The final product's formulation, concentration, and other ingredients all play a role in how something actually behaves on your skin.

Just so you know, the FDA ban on Red Dye No. 3 refers to CI 45430, not this ingredient. CI 45430 and CI 17200 are different chemical compounds with distinct safety and regulatory histories.

It's also worth noting that Red No. 3 (CI 45430) was already banned from cosmetics back in 1990, so the 2025 action just extended the ban to food and oral drugs. CI 17200 was never part of any of this.

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

You'll likely see it paired with methylparaben to cover the full range (including gram-negative bacteria).

This ingredient is effective at low concentrations (~0.2-0.5%) and stable across a wide pH range (4.5-7.5 pH). It's effectiveness drops off above pH 8 and it can lose potency when combined with non-ionic surfactants like polysorbate 80 due to micellization.

The regulatory bodies have concluded this ingredient to be safe as used in cosmetics. The EU has capped it at 0.14% and combined parabens are not to exceed 0.8%.

While parabens do cross the stratum corneum, only about 1% remains for absorption into the body. This is because most of it is metabolized within living skin.