Kao Segreta Premier Shampoo

Fatty alcohols are usually derived from natural fats and oils and therefore do not have the same drying or irritating effect as solvent alcohols.

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

While succinic acid posesses antimicrobial, antioxidant, and anti-inflammatory properties, these properties have not been studied in skincare products.

Fun fact: Succinic acid was known as the 'spirit of amber' in the past. This is because it used to be derived from distilling amber.

Typical usage concentrations range from 1-5%.

Human testing shows it's non-irritating and non-sensitizing, and the EU Scientific Committee on Consumer Safety (SCCS) has cleared it at very high levels (79% in leave-on products).

The one thing worth knowing about its comedogenic score of 3-4 is to keep it in perspective: these ratings come from old rabbit-ear tests using 100% of pure ingredient and doesn't reflect how it behaves at low levels in a finished product.

Because it is an ester of palmitic acid (C16), it falls into the range that the Malassezia yeast can feed on and is considered not fungal acne safe.

This is due to how structurally similar it is to what your skin already produces.

Though it is mostly an emollient that helps soften and hydrate skin, it also has some humectant and occlusive action. Humectants help the skin retain moisture while occlusives seal it in, making squalane a triple-threat moisturizer.

Research shows it has antioxidant capabilities that help protect against stressors like UV exposure, specifically UVA induced oxidative stress. This study also found that it supports collagen biosynthesis in human dermal fibroblasts.

No clinical study has reported significant adverse effects and irritation reactions are very rare from this ingredient (even at 100% concentration).

Overall, it's a fantastic ingredient for hydration and is suitable for all skin types.

This depends on the source. Squalane can be derived from both plants and animals. Most squalane used in skincare comes from plants.

Please note: the source of squalane is only known if disclosed by the brand. We recommend reaching out to the brand if you have any questions about their squalane.

Read more about squalene with an "e".

Though squalane is often called an oil, it’s technically not one. It is a hydrocarbon, meaning it is only made of carbon and hydrogen. True oils are triglycerides and made of fatty acids and glycerol.

The term “oil-free” isn’t regulated so companies can define it however they want. Some exclude all oils, while others just avoid mineral oil or comedogenic oils.

Squalane has a comedogenic rating of 1 from the original 1972 study that tested raw ingredients under occlusion on rabbit ears. This system is not standardized or peer-reviewed, and using the raw ingredients is very different from how diluted cosmetic formulations are used on human skin.

A comedogenic rating of 1 means it is "unlikely to clog pores" according to the original rating system.

The overall formula of a product matters more than the individual ingredients on whether or not it will cause clogged pores.

Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.

A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.

Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.

One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.

Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.

Research on a hydrogel with serine confirmed this serine got delivered to your stratum corneum and demonstrated enhanced skin moisturization.

Interestingly serine also helps your skin produce filaggrin, a protein that keeps your skin barrier strong and used to create collagen.

This ingredient can either be derived from an animal product or be synthetically created.

Reviews of this ingredient have found it to be neither a dermal irritant nor a sensitizer.

Fun fact: Proline can be found in protein-rich foods like meat, fish, eggs, and dairy.

One study found histidine and carnosine to be a dynamic duo for your skin:

Oral histidine has also been found to help with filaggrin-deficit skin disorders such as atopic dermatitis.

Why is it considered a semi-essential amino acid? This is because adults are able to create it but children must get it from their diet.

Two structures of phenylalanine exist: L-phenylalanine and D-phenylalanine. L-phenylalanine is essential, this means our bodies cannot produce it naturally and we must get it from foods. Our bodies convert D-phenylalanine to neurotransmitters, and D-phenylalanine is found in our bodies naturally.

Some foods that contain L-phenylalanine include eggs, soybeans, beef, milk.

This ingredient has skin conditioning, anti-inflammatory, and humectant properties. Humectants help hydrate your skin by drawing moisture from the air. This helps keep your skin moisturized.

High percentages of Sodium Lactate can have an exfoliating effect.

Fun fact: Sodium Lactate is produced from fermented sugar.

Studies show Royal Jelly to contain amino acids, fatty acids, and a variety of vitamins, including Vitamin Bs. Many of these components are antioxidants, which help with anti-aging. The fatty acids in Royal Jelly make it a hydrating ingredient.

Several animal studies show Royal Jelly to boost collagen production and reduce inflammation.

The Vitamin Bs found in Royal Jelly include:

Royal Jelly is derived from honeybees. This means it is not vegan.

Vitamins C and E are potent antioxidants and may help with anti-aging. The fatty acids are emollients that help soften and hydrate your skin.

Another potent vitamin found in rosehip is Vitamin A, or retinol. Retinol encourages collagen production in the skin.

Rosehip extract may help with brightening the skin. Several components, such as beta-carotene, are able to reduce pigmentation caused by sun damage.

Interestingly, the size of the molecule affects its behavior:

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.

You'll typically see concentrations between 0.1-2% for this ingredient.

The reason this ingredient is so effective is because it forms a thin film on the skin that reduces transepidermal water loss (TEWL) while supplying linoleic acid to the stratum corneum to improve barrier strength.

The high linoleic acid content is particularly noteworthy for acne-prone skin.

Research suggests that acne-prone skin tends to be deficient in linoleic acid in sebum. Topical application may help replenish this to support a healthier follicular environment and less comedone-promoting sebum.

One randomized study found sunflower seed oil preserved skin barrier integrity in adult volunteers with and without atopic dermatitis (outperforming olive oil).

This ingredient is well-studied, gentle, and an effective emollient suitable for most skin types.

On fungal acne: This ingredient may not be Fungal acne (Malassezia folliculitis) safe. This is because it contains fatty acids with carbon chain lengths in the C11-C24 range.

As an occlusive, it forms a protective layer on the skin that locks in moisture and prevents transepidermal water loss (TEWL). This makes it especially great for compromised skin barriers.

The "it clogs your pores" myth has been around for decades; a study found that industrial-grade mineral oil may be comedogenic but cosmetic-grade mineral oil is not (these two are very, very different).

A 2017 review concluded that cosmetic use of mineral oils and waxes does not present a risk to consumers due to absorption.

Mineral oil got a bad rap from the old rabbit ear studies. When tested on actual human skin, cosmetic-grade mineral oil showed no comedogenic activity. The rating of 0 is a correction of outdated science.

Mineral oil is an inert substance with no fatty acids so there's nothing to feed Malassezia. This ingredient is fungal acne safe.

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.

Lab studies have found that lauric acid is surprisingly good at killing acne-causing bacteria. However, these tests were done on bacteria in a petri dish and not on real skin, so we can't say for certain it works the same in a formulation on a real face.

The comedogenic rating of 4 comes from the 1972 rabbit ear model using undiluted ingredients. Comedogenicity is highly individual and one comedogenic ingredient cannot predict how a formula will behave on skin.

This ingredient is not fungal acne safe and research has confirmed Malassezia can use it as a food source.

For haircare friends: this ingredient is not a silicone.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

Using high concentrations of Potassium Hydroxide have shown to irritate the skin.

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

Its main job is chelation; this is a fancy word to say it grabs onto metal ions and neutralizes them. This is because even purified water in cosmetics contains trace amounts of metals that can cause big problems in a formula.

These trace metals can break down actives faster, cause discoloration, promote rancidity in oils, and make preservatives less effective. Trisodium EDTA binds to these metals and takes them out of the equation so your products can stay stable and effective for longer.

There's also an added bonus: by neutralizing the metals ions that bacteria need to thrive, this ingredient also acts as a preservative booster.

The Cosmetic Ingredient Review has concluded this ingredient to be safe as used in cosmetic formulations. It is not considered an irritant, sensitizer, and is barely absorbed through the skin.

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.

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.

For instance, Habanolide is a proprietary trade name for a specific aroma chemical. When used as a fragrance ingredient in cosmetics, most aroma chemicals fall under the broad labeling category of “FRAGRANCE” or “PARFUM” according to EU and US regulations.

The term 'parfum' or 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term.

For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance by INCI standards.

One example is Calendula flower extract. Calendula is an essential oil that still imparts a scent or 'fragrance'.

Depending on the blend, the ingredients in the mixture can cause allergies and sensitivities on the skin. Some ingredients that are known EU allergens include linalool and citronellol.

Parfum can also be used to mask or cover an unpleasant scent.

The bottom line is: not all fragrances/parfum/ingredients are created equally. If you are worried about fragrances, we recommend taking a closer look at an ingredient. And of course, we always recommend speaking with a professional.