Labo-H Scalp Skincare Hair Line Ampoule

Basically, Peg-60 Hydrogenated Castor Oil helps hold ingredients together.

Studies show green tea extract and its catechins (like epigallocatechin gallate (EGCG)) help your skin cells product energy more efficiently and reducing the number of free-radicals that can damage your skin from the inside.

In lab-grown skin models, this translated to younger, healthier, and stronger skin.

There's also good sun protection data; researchers saw less DNA damage and redness on human skin when green tea was applied before UVB exposure. And the more they applied, the better the protection.

Needless to say, this ingredient shouldn't replace your sunscreen. But it is a great supportive ingredient that you can already find in many sunscreens and antioxidant serums.

A 2009 study found a 2% green tea lotion was effective for mild-to-moderate acne thanks to its anti-inflammatory and mild antimicrobial activity.

The quality of the extract matters a lot here:

Good extracts contain 50-90% catechins while lower quality ones are mostly there for marketing. We recommend reaching out to the brand if you have questions about the quality or source of their ingredients.

Human Repeated Insult Patch Testing showed no irritation or sensitization at use concentrations (0.86% in leave-on products and up to 30% as leaf water).

A high amount of carbomer can cause pilling or balling up of products. Don't worry, most products contain 1% or less of carbomer.

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

Tromethamine helps balance the pH level of a product. Normal pH level of skin is slightly acidic (~4.75-5.5). The acidity of our skin is maintained by our glands and skin biome. Being slightly acidic allows our skin to create an "acid mantle". This acid mantle is a thin barrier that protects our skin from bacteria and contaminants.

Oral Tromethanmine is an anti-inflammatory drug but plays the role of masking, adding fragrance, and/or balancing pH in skincare.

1,3-Propanediol, 2-amino-2-(hydroxymethyl)-

Studies show coating UV filters with dextrin prevents these ingredients from being absorbed. This helps UV ingredients last longer on the skin.

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

Menthol also has antimicrobial properties.

At higher doses or for those with sensitive skin, methol-type cooling can quickly turn into burning/irritation. It can also trigger irritant dermatitis or even allergic contact dermatitis. In a large patch-test dataset, peppermint oil had a low but positive rate for this.

In cosmetics, Cosmetic Safety Reviews (CIR) concludes that peppermint oil is safe to use when formulated to be non-sensitizing with some restrictions; for instance, pulegone, a naturally occurring component of peppermint oil, should not exceed 1%.

Since peppermint oil contains fragrance allergens such as limonene, linalool, and menthol, it can be sensitizing for those with rosacea, eczema, a broken skin barrier, or just sensitive skin in general.

In Japan, this ingredient is known as Hakka Yu.

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:

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%.

This oil also contains antioxidant and antimicrobial properties. As an antioxidant, it may protect you skin against damage. This can help slow down the signs of aging.

Studies show this ingredient can help calm redness and may help treat the signs of photoaging; however, the evidence is inconclusive and further studies are needed.

Lactobacillus Ferment is generally considered safe for fungal-acne prone skin. The key thing to understand is that it comes from bacteria, not yeast or fungus.

Yeast-derived ferments (like galactomyces) have been shown to activate a protein that's linked to Malassezia-related skin issues whereas lactobacillus doesn't have that problem.

Its byproducts also don't contain the types of fatty acids (C11-24 chain lengths) that Malassezia feeds on.

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.

The "cooling" sensation from mint isn't a real temperature change; menthol actives a nerve receptor in skin that gets triggered by cold. Your brain essentially gets a "cool" signal from it.

Just so you know, allergic contact dermatitis to menthol is documented in literature (but it's kind of uncommon). This is why the percentages allowed in leave-on products are quite low (0.2%). Be sure to patch test if you have sensitive skin.

Though this ingredient is not listed as an EU allergen, it's cousins (Mentha Piperita Oil, menthol and Mentha Viridis Leaf Oil) are.

Due to the high Menthol content of this ingredient, brands are required to label "menthol" as a separate ingredient on the list. The EU regulation labels the allergenic substance, not just the source ingredient, so the menthol carried in this ingredient still has to be declared.

Studies show soy may help fade hyperpigmentation from UVB. It does so by disrupting the melanin process caused by UVB induced skin inflammation.

Two powerful components found in the wild soybean include genistein and diadzein. These two isoflavones are potent antioxidants with anti-inflammatory properties. Genistein in particular has been found to prevent redness caused by UV exposure.

Soybeans are rich in proteins and are part of the legume family. Foods made with soybeans include tofu, soymilk, edamame, miso, and soy sauce.

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.

In-vitro studies have demonstrated activity against acne-causing bacteria.

The antioxidant properties help protect your body from free-radicals. Free-radicals are molecules that may damage your skin cells. As a result, ginger may help slow down signs of aging such as hyperpigmentation and wrinkles.

Studies show ginger inhibits the enzyme that breaks down collagen. It also helps with:

This ingredient has no negative side-effects and is safe to use unless one has a specific allergy to it.

Ginger originates from Southeast Asia but has spread throughout the world. It is now a common spice used in many cultures.

More research is needed on applying biotin topically. However, taking biotin orally has been shown to help nourish the skin, hair, and nails. They play a role in forming skin-hydrating fatty acids.

Biotin is water-soluble. It can be found in foods such as fish, eggs, dairy, nuts, and meat. Vitamin H stands for "haar" and "haut". These are the German words for hair and skin.

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.

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.

Because hydrolyzed hyaluronic acid is smaller in size, it can slip past your outermost layer of skin more easily than full-sized HA.

Most formulations will combine all sizes to get the best of both worlds.

Typical usage levels range from 0.01-1%. Any percentage higher than 2% might become goopy and tacky.

A follow-up clinical trial found that a topical crosslinked HA serum applied after fillers, microneedling, or chemical peels was well-tolerated and enhanced skin quality at 14 / 28 days.

More recent research suggests that concentrations as low as 0.03% can act as a penetration enhancer for other skincare actives.

The only catch is that HA isn't a single thing; it actually comes in a wide range of molecular weights (~50 - 2,000+ kDA) and size matters.

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

This is why the best HA serums blend the two sizes together so you get the best of both worlds.

The majority of cosmetic HA is produced by bacterial fermentation, typically using Streptococcus or Bacillus strains. Typical use levels in skincare sit around 0.1-2%.

A clinical study using a 0.2% low-molecular weight HA gel showed improvement in facial seborrheic dermatitis with excellent tolerance.

These are some other common types of Hyaluronic Acid:

This ingredient is incredibly gentle and often used to counter more irritating ingredients.

While our skin does have collagen, this ingredient is not used by the skin for anti-aging. Applying collagen topically has not been linked to helping with collagen loss in skin. All the benefits of soluble collagen are related to hydration.

Fun fact: The name "soluble collagen" refers to its ability to dissolve in water.

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

Read about common types of Hyaluronic Acid here: