Versus

Isshi The Hair Milk Dx Deep Repair Moist Leave-In Treatment Versus Hair Theory Lab Milk Serum

Leave-in Treatment
Hair Serum
Japanese Brand Japan
Japanese Brand Japan

Updated on April 24, 2025

Overview

What they are

These products are both reef safe . They have a total of 21 ingredients in common

Cool Features

They both contain ceramides and hyaluronic acid

Suited For

They're both likely to be good for anti aging, dry skin, brightening skin, sensitive skin and scar healing

Free From

They both do not contain any parabens

What's Inside

They both contain harsh alcohols, fragrances and silicones

We independently verify ingredients, and our claims are backed by peer-reviewed research. Spot a product that needs an update? Let us know.

Ingredient Info

Click any item below to learn more and see relevant ingredients

About this product

About this product

At a glance

Click on any of the items below to learn more

Key Ingredients

Benefits

Concerns

Benefits

Concerns

Ingredients Side-by-side

found in both products
The Hair Milk Dx Deep Repair Moist Leave-In Treatment

Water

Skin Conditioning

Dimethicone

Emollient
1 / 0 Silicon Icon

Methyl Trimethicone

Skin Conditioning
Silicon Icon

Ethylhexyl Palmitate

Emollient
2-3 / 0 May worsen Oily Skin IconBad for Acne Prone Skin IconNot safe for Fungal Acne Icon

Glycerin

Humectant
0 / 0 Helps hydrate Dry Skin IconHelps brighten skin Icon

Dipropylene Glycol

Masking

Aminopropyl Dimethicone

Silicon Icon

Heptanol

Perfuming
Fragrance Icon

Hematin

Aphanothece Sacrum Polysaccharide

Absorbent

Polyquaternium-64

Polyquaternium-61

Skin Conditioning

Sodium Lauroyl Glutamate

Steardimonium Hydroxypropyl Hydrolyzed Keratin

Skin Conditioning

Cetearamidoethyl Diethonium Hydrolyzed Rice Protein

Phytosteryl/Octyldodecyl Lauroyl Glutamate

Skin Conditioning

Dimethiconol

Emollient
Silicon Icon

Amodimethicone

Silicon Icon

Gamma-Docosalactone

Skin Conditioning

Meadowfoam Delta-Lactone

Skin Conditioning

Hydrolyzed Keratin

Humectant

Hydrolyzed Silk

Humectant

Polylysine

Sodium Hyaluronate

Humectant
0 / 0 Hyaluronic Acid Icon

Squalane

Emollient
1 / 0 Helps hydrate Dry Skin Icon

Hydrolyzed Collagen

Emollient
Helps hydrate Dry Skin IconHelps with Anti-Aging Icon

Ceramide AP

Skin Conditioning
Ceramide IconHelps hydrate Dry Skin IconHelps reduce irritation IconHelps with Anti-Aging Icon

Ceramide NP

Skin Conditioning
Ceramide IconHelps hydrate Dry Skin IconHelps reduce irritation IconHelps with Anti-Aging Icon

Ceramide Ng

Skin Conditioning
Ceramide IconHelps hydrate Dry Skin IconHelps reduce irritation IconHelps with Anti-Aging Icon

Anthemis Nobilis Flower Extract

Masking
Fragrance Icon

Lavandula Angustifolia Flower Extract

Cleansing
May cause irritation IconEU Allergen Icon

Scutellaria Baicalensis Root Extract

Astringent

Oryza Sativa Bran Oil

Emollient
Oil IconNot safe for Fungal Acne Icon

Argania Spinosa Kernel Oil

Emollient
Oil IconHelps hydrate Dry Skin IconNot safe for Fungal Acne Icon

Macadamia Integrifolia Seed Oil

Skin Conditioning
Oil IconNot safe for Fungal Acne Icon

Simmondsia Chinensis Seed Oil

Emollient
0-2 / 0 Oil IconHelps hydrate Dry Skin IconNot safe for Fungal Acne Icon

Olea Europaea Fruit Oil

Masking
0-2 / 0 Fragrance IconOil IconNot safe for Fungal Acne Icon

Rosa Canina Fruit Oil

Emollient
Oil IconGood for Scar Healing IconNot safe for Fungal Acne Icon

Helianthus Annuus Seed Oil

Emollient
0 / 0 Oil IconHelps hydrate Dry Skin IconNot safe for Fungal Acne Icon

Cholesterol

Emollient
0 / 0 Helps hydrate Dry Skin Icon

Steartrimonium Chloride

Preservative
Preservative Icon

Dicocodimonium Chloride

Emulsifying

Ceteth-20

Cleansing

Diethyl Sebacate

Emollient

Cetearyl Alcohol

Emollient
2 / 1 Fatty Alcohol IconMay worsen Oily Skin IconBad for Acne Prone Skin IconNot safe for Fungal Acne Icon

Glyceryl Stearate

Emollient
1 / 0 Not safe for Fungal Acne Icon

Sorbitan Stearate

Emulsifying
0 / 1 Not safe for Fungal Acne Icon

Polyacrylate-13

PCA Ethyl Cocoyl Arginate

Moisturising

Polyisobutene

Polysorbate 20

Emulsifying
0 / 0 Not safe for Fungal Acne Icon

Sorbitan Isostearate

Emulsifying
1-2 / 0 Not safe for Fungal Acne Icon

Glyceryl Caprate

Emollient

Polyglyceryl-2 Laurate

Emulsifying
Not safe for Fungal Acne Icon

Polyglyceryl-10 Laurate

Skin Conditioning
Not safe for Fungal Acne Icon

Hydrogenated Lecithin

Emulsifying

Tocopherol

Antioxidant
0-3 / 0-3 Vitamin E IconAntioxidant IconHelps hydrate Dry Skin IconHelps with Anti-Aging IconGood for Scar Healing Icon

Butylene Glycol

Humectant
1 / 0 Helps hydrate Dry Skin Icon

Alcohol Denat.

Antimicrobial
Alcohol IconCan worsen Dry Skin IconMay worsen Oily Skin IconMay cause irritation IconMay worsen Eczema IconMay worsen Rosacea Icon

Pentylene Glycol

Skin Conditioning

PEG-60 Hydrogenated Castor Oil

Emulsifying
Oil IconNot safe for Fungal Acne Icon

Disodium EDTA

Phenoxyethanol

Preservative
Preservative Icon

Parfum

Masking
Fragrance IconMay worsen Eczema IconMay worsen Rosacea Icon
Milk Serum

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Skin Conditioning, Solvent

Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Stay hydrated!

Learn more about Water
Emollient, Skin Conditioning, Skin Protecting

Dimethicone is a type of synthetic silicone created from natural materials such as quartz.

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
Masking, Solvent

Dipropylene Glycol is a synthetically created stabilizer and solvent. It is a part of the glycol class in the alcohol family.

Dipropylene Glycol helps dissolve and evenly distribute ingredients. It also helps decrease viscosity and thin out texture.

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.

Learn more about Dipropylene Glycol

Aminopropyl Dimethicone is a type of silicone.

Perfuming

Heptanol is a fragrance.

Sodium Lauroyl Glutamate is the sodium salt from the lauric acid of glutamic acid.

It is a surfactant and helps cleanse the skin. Surfactants gather oil, dirt, and other pollutants from your skin so they may be washed away easily.

Emollient, Moisturising

Dimethiconol is a silicone that resembles the popular dimethicone. Like other silicones, it is an emollient. Emollients create a thin film on skin to prevent moisture from escaping.

This ingredient helps to create a silky texture and improve spreadability. Due to its high molecular weight and thickness, it is often combined with cyclopentasiloxane.

This water-soluble silicone is used for its hydrating and softening properties. It is used to add a silky feel to skincare products and has great benefits for haircare.

In haircare, this ingredient:

  • Adds shine
  • Protects color
  • Offers thermal protection
  • Boosts hair strength
  • Does not build up as easily
Skin Conditioning

We don't have a description for Gamma-Docosalactone yet.

Humectant, Skin Conditioning

Sodium Hyaluronate is hyaluronic acid's salt form. It is commonly derived from the sodium salt of hyaluronic acid.

Like hyaluronic acid, it is great at holding water and acts as a humectant. This makes it a great skin hydrating ingredient.

Sodium Hyaluronate is naturally occurring in our bodies and is mostly found in eye fluid and joints.

These are some other common types of Hyaluronic Acid:

Learn more about Sodium Hyaluronate
Emollient, Humectant, Skin Conditioning

Hydrolyzed collagen has a misleading name because it is actually a mixture of various proteins/peptides. This ingredient has skin hydrating properties.

Collagen is the most abundant type of structural protein found in your body. In your skin, it is responsible for keeping it firm and youthful.

Hydrolyzed Collagen is created by breaking up proteins into smaller peptide bonds. These peptides act as humectants and emollients.

Humectants are great at holding onto water, keeping skin hydrated. Emollients create a thin barrier on the skin to prevent moisture from escaping.

There is ongoing debate about whether hydrolyzed collagen works because it increases skin hydration. Skin hydration is also linked to elasticity and the appearance of wrinkles.

Collagen or peptide ingredients can be used in the morning or night. They will not increase sun sensitivity, but you should always wear sunscreen during the day.

According to a manufacturer, this ingredient is a great hair conditioner as well.

This ingredient can be extracted from different sources, including:

Vegan collagen is derived from yeast, bacteria, or plant sources. Vegan collagen would go by a different INCI name, such as hydrolyzed soy protein.

The results are varied.

A study from 2021 found hydrolyzed collagen increased elasticity and improved wrinkles in 1,125 participants between age 20 and 70. Another study found increased skin thickness in participants between the ages of 45 to 59.

However, It is difficult to prove that oral collagen will end up working on your skin. Many of the studies using hydrolyzed collagen also add several vitamins and nutrients into the test mixture as well.

Further studies are needed at this time.

Learn more about Hydrolyzed Collagen
Skin Conditioning

Ceramide NG is a type of Ceramide. The NG stands for a sphinganine base.

Ceramides are intercellular lipids naturally found in our skin that bonds dead skin cells together to create a barrier. They are known for their ability to hold water and thus are a great ingredient for dry skin.

Ceramides are an important building block for our skin barrier. A stronger barrier helps the skin look more firm and hydrated. By bolstering the skin ceramides act as a barrier against irritating ingredients. This can help with inflammation as well.

If you would like to eat ceramides, sweet potatoes contain a small amount.

Read more about other common types of ceramides here: Ceramide AP Ceramide EOP Ceramide NP

Learn more about Ceramide Ng

Steartrimonium Chloride is a preservative.

We don't have a description for Dicocodimonium Chloride yet.

Cleansing, Emulsifying

We don't have a description for Ceteth-20 yet.

Emollient, Emulsifying, Emulsion Stabilising

Cetearyl alcohol is a mixture of two fatty alcohols: cetyl alcohol and stearyl alcohol. It is mainly used as an emulsifier. Emulsifiers help prevent the separation of oils and products. Due to its composition, it can also be used to thicken a product or help create foam.

Cetearyl alcohol is an emollient. Emollients help soothe and hydrate the skin by trapping moisture.

Studies show Cetearyl alcohol is non-toxic and non-irritating. The FDA allows products labeled "alcohol-free" to have fatty alcohols.

This ingredient is usually derived from plant oils such as palm, vegetable, or coconut oils. There is debate on whether this ingredient will cause acne.

Due to the fatty acid base, this ingredient may not be Malassezia folliculitis safe.

Learn more about Cetearyl Alcohol
Humectant, Masking, Skin Conditioning

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

  • It is a solvent, meaning that it helps to dissolve other ingredients. This also enhances the absorption of the product into one's skin.
  • It is a humectant, which means that it helps attract moisture into the skin.
  • It helps improve product application.
  • It has mild preservative properties.

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Skin Conditioning, Solvent

Pentylene glycol is typically used within a product to thicken it. It also adds a smooth, soft, and moisturizing feel to the product. It is naturally found in plants such as sugar beets.

The hydrophilic trait of Pentylene Glycol makes it a humectant. As a humectant, Pentylene Glycol helps draw moisture from the air to your skin. This can help keep your skin hydrated.

This property also makes Pentylene Glycol a great texture enhancer. It can also help thicken or stabilize a product.

Pentylene Glycol also acts as a mild preservative and helps to keep a product microbe-free.

Some people may experience mild eye and skin irritation from Pentylene Glycol. We always recommend speaking with a professional about using this ingredient in your routine.

Pentylene Glycol has a low molecular weight and is part of the 1,2-glycol family.

Learn more about Pentylene Glycol

Disodium EDTA plays a role in making products more stable by aiding other preservatives.

It is a chelating agent, meaning it neutralizes metal ions that may be found in a product.

Disodium EDTA is a salt of edetic acid and is found to be safe in cosmetic ingredients.

Learn more about Disodium EDTA
Preservative

Phenoxyethanol is a preservative that has germicide, antimicrobial, and aromatic properties. Studies show that phenoxyethanol can prevent microbial growth. By itself, it has a scent that is similar to that of a rose.

It's often used in formulations along with Caprylyl Glycol to preserve the shelf life of products.

Masking, Perfuming

Parfum is a catch-all term for an ingredient or more that is used to give a scent to products.

Also called "fragrance", this ingredient can be a blend of hundreds of chemicals or plant oils. This means every product with "fragrance" or "parfum" in the ingredients list is a different mixture.

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.

Learn more about Parfum