4C Only Too Soft Leave-In Conditioner

4C Only Too Soft Leave-In Conditioner

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Leave-in conditioner with 14 ingredients

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What's inside

Benefits

Concerns

Ingredients Explained

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. Remember to stay hydrated!

Learn more about Water
Humectant, Skin Conditioning, Skin Protecting

Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.

Topically, glycerin does several things at once:

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.

Learn more about Glycerin

Behentrimonium Methosulfate is a gentle, positively-charged conditioning agent made from rapeseed oil.

It's the opposite of a harsh cleansing sulfate despite having "sulfate" in its name; its a detangler/softener in haircare and helps keep oil/water blended into a creamy texture as an emulsifier.

Concentration-wise, safety review reports the wider trimonium family shows up between 0.0005% to 10% in rinse-off products and 0.001% to 4% in leave-on products.

This ingredient is commonly used at ~1–5% when acting as the emulsifier.

Allergies to this ingredient are rare; the CIR panel noted the literature lacks clinical reports of irritation or sensitization and patch tests on finished products containing it came back clean.

Learn more about Behentrimonium Methosulfate
Emollient, Emulsifying, Emulsion Stabilising

Cetyl Alcohol is a fatty alcohol. Fatty Alcohols are most often used as an emollient or to thicken a product.

Its main roles are:

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.

Learn more about Cetyl Alcohol

This ingredient is also known as Slippery Elm Bark Extract.

Emollient, Skin Conditioning

Squalane is the hydrogenated and shelf-stable form of squalene (a lipid that naturally occurs in human sebum).

It is an emollient and skin conditioning agent that is able to integrate seamlessly into the skin's lipid barrier without clogging pores.

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.

Learn more about Squalane

Althaea Officinalis Root Extract is from a plant called the Marsh Mallow plant. This plant is indigenous to Europe, West Asia, and North Africa.

Marsh Mallow root is an emollient and antioxidant. It helps sooth and soften the skin. When applied to the skin, it blocks enzymes that break down hyaluronic acid.

The marshmallow we eat today is based on an ancient Egyptian dessert made from this plant (Marshmallows do not contain this plant anymore).

Learn more about Althaea Officinalis Root Extract
Humectant, Masking, Skin Conditioning

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

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

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.

Learn more about Butylene Glycol

Phenethyl Alcohol is a colorless and aromatic alohol. It is naturally occuring in essential oils.

The scent of this ingredient is floral and often compared to rose.

Like other alcohols, this ingredient helps prevent the growth of bacteria. However, its main purpose is to impact a fragrance.

Learn more about Phenethyl Alcohol
Skin Conditioning, Solvent

Pentylene Glycol (1,2-pentanediol) is a multitasking little diol with three main roles in a formula:

Research on alkanediols (the family pentylene glycol belongs to) show they work by disrupting microbial cell membranes. This disruption helps the primary preservative system in a product work more effectively at lower doses.

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%.

Learn more about Pentylene Glycol
Solvent

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin. 

It’s often used to:

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.

Learn more about Propanediol
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
Perfuming

Linalool is a fragrance and helps add scent to products. It's derived from common plants such as cinnamon, mint, citrus, and lavender.

Like Limonene, this ingredient oxidizes when exposed to air. Oxidized linalool can cause allergies and skin sensitivity.

This ingredient has a scent that is floral, spicy tropical, and citrus-like.

Learn more about Linalool
Perfuming

Citral is the molecule responsible for the fresh lemon scent in lemon, lime, and lemongrass. It is a fragrance ingredient that can be created from plant essential oils or synthetically.

Though Citral has documented antimicrobial activity against acne bacteria (which is where the marketing claims about it being good for acne-prone skin originate), real formulas use it at fragrance-level concentrations under 1% so there's likely no skin benefit.

You should know this ingredient is a known EU fragrance allergen.

Animal studies classifies this ingredient as a weak-to-moderate skin sensitizer and clinical patch testing on eczema patients confirmed it to be both a contact allergen and irritant.

The term 'citral' is a collective term for two geometric isomers: geranial/Citral A and neral/Citral B.

The term '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.

Learn more about Citral

Reviews

Where it's from

4C Only is a American brand

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· Updated July 20, 2026 Added by jnm