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Breaking Down Behentrimonium Methosulfate in Hair Products

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Table of Contents

Image of the Mielle hydrating conditioner containing behentrimonium methosulfate.

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Beginning a natural hair journey can feel like stepping into a complex new world, especially when confronted with intimidating-sounding ingredients like Behentrimonium Methosulfate. But what if I told you that this unpronounceable entity could actually be the superhero your curls have been waiting for? Yes, diving into the ingredient list of your hair products is an essential step, but not all tongue twisters are foes in disguise.

Behentrimonium Methosulfate in hair products are gentle, plant-based conditioning agent derived from rapeseed oil. Forget the stereotypes attached to ‘chemical-sounding’ terms; this ingredient is renowned for its exceptional detangling capabilities and is often used to add slip and softness to natural hair products.

I’ve joined forces with my trusted friend, a hair scientist and cosmetic formulator who holds a Chemistry for a deep dive into the complexities of this ingredient. Trust me, he’s the authority on this subject!

What is Behentrimonium Methosulfate?

Behentrimonium Methosulfate is a quaternary ammonium salt. It is a plant-based cationic conditioning agent frequently found in hair care products such as rinse-off conditioners, hair conditioners, leave-in conditioners, deep conditioners, or hair masks.1

The word “Behen” denotes the length of the carbon chain attached to the quaternary nitrogen group. The Behen group comprises a 22-carbon straight chain while “trimonium” describes the nitrogen group attached at the end.

This molecule carries a unit positive charge at its nitrogen center, which is further stabilized by the counter ion of chloride or methosulfate.

The “Methosulfate” part refers to the counter ion stabilizing the unit positive charge at the molecule’s nitrogen center.

This ingredient is renowned for its efficacy in personal care formulations, owing largely to its positive charge and the length of its carbon chain.

Benefits of Behentrimonium Methosulfate for Hair

  • Detangles Hair Effectively: Makes it easier to comb through your hair strands, reducing breakage and split ends. Behentrimonium Methosulfate acts as a cationic surfactant, meaning it carries a positive charge that attracts negatively charged hair strands, aiding in detangling and conditioning.
  • Enhances Manageability: Helps to control frizz and unruly strands, making hair more manageable throughout the day.
  • Improves Ease of Styling: Works as an excellent base for styling products, allowing for smoother application and better hold. It also reduces the surface tension in cosmetic products, ensuring a uniform distribution upon application.
  • Provides Water-Repellent Coating: Forms a protective layer on the hair that repels water, thus preserving the hair’s natural oils and reducing moisture loss.
  • Boosts Product Stability: Helps in stabilizing the formulation of hair care products, making them more effective over time.
  • Increases Product Viscosity: Contributes to the rich and creamy texture of conditioners and masks, improving their spreadability.
  • Offers Anti-Static Properties: Counters static electricity, helping to manage flyaways and frizziness more effectively.
  • Helps Hair Retain Moisture: Aids in locking in essential moisture, contributing to conditioned and resilient hair. It leaves hair softer and shinier.
  • Targets Damaged Cuticle Layer: Restores surface lubricity and detangles hair fibers, aiding in the repair of damaged hair.
  • Generally Safe and Gentle on Hair and Scalp: While efficacy is high, it is typically gentle enough for regular use without irritation.

What is Behentrimonium Chloride?

Like its Methosulfate counterpart, Behentrimonium Chloride is also a cationic conditioning agent common in hair care formulations.

The “Chloride” functions as the counter ion stabilizing the positive charge at the nitrogen center. Behentrimonium Chloride is highly effective in enhancing the viscosity, texture, and ease of application in personal care products.

The Similarities: A Chemical Bond

Both Behentrimonium Chloride and Behentrimonium Methosulfate share fundamental structural components—a quaternary nitrogen group attached to a long 22-carbon chain.

The dual nature of behentrimonium chloride or methosulfate, being hydrophilic at one end (nitrogen end) and a long carbon chain (hydrophobic) at the other end makes them a cationic surfactant. Therefore, they can be used as emulsifiers in hair care or skin care products.

They can emulsify oils in water- making an emulsion, stabilizing the product, enhancing its viscosity, and boosting the aesthetic texture of the product with ease of application.

The structural difference is highlighted by the chemical structures below:

Image of behentrimonium chloride and behentrimonium methosulfate structure. Breaking Down Behentrimonium Methosulfate in Hair Products.

The Role in Hair Care: More Than Just Conditioners

Hair is often subjected to a range of damaging factors, such as heat styling and chemical treatments, that compromise the integrity of the cuticle layer. This results in dry, frizzy, and difficult-to-manage hair.2,3,4

Regular conditioning is crucial for detangling and smoothing the hair, making it easier to style. Over time, without proper care, the damaged cuticle can lead to long-term structural issues.

Here’s where Behentrimonium Chloride and Methosulfate come to the rescue. They target the damaged cuticle layer, restore its surface lubricity, and detangle hair fibers through electrostatic chemical bonding.

This bonding occurs when the positively charged nitrogen group in these ingredients attaches to the negatively charged amino acids in hair.

Furthermore, the long hydrophobic carbon chain creates a water-repellent layer on the hair, facilitating easier detangling of damaged strands. This protective coating also simplifies the combing process for wet and dry hair, leaving your locks feeling soft and smooth.5

Additional Benefits: Anti-Static Effects

A frequently overlooked advantage of using these cationic conditioning agents is their ability to neutralize electrical charges, effectively combatting static electricity.

Given their positively charged ends, both ingredients can counteract or neutralize static cling, making them ideal choices for treating damaged hair, reduced frizz, or flyaways.

Now, let’s take a look at the possible drawbacks of using both cationics and any potential side effects they might inflict on the hair shaft or skin.

Potential Concerns: Safety and Side Effects

Although these ingredients offer major advantages in hair care formulations, their heavy and regular use has raised concerns about their safety, toxicity risks, and potential side effects on both skin and hair.

Behentrimonium Methosulfate is generally regarded as safe for use in both rinse-off and leave-in products when applied within recommended guidelines. Nonetheless, some individuals may experience allergic reactions, or skin and eye irritation.

Ongoing scientific research aims to clarify these aspects, providing a more comprehensive understanding of their overall impact on personal care.

By understanding the roles and characteristics of Behentrimonium Methosulfate and Behentrimonium Chloride, it’s clear that these ingredients have much to offer in the realm of hair care.

Their benefits far outweigh the complexities of their chemical names, making them key components in crafting superior, effective hair care products. 

Behentrimonium Methosulfate in Hair Products: Conditioners

Here are a few curly hair products that contain Behentrimonium Methosulfate or Behentrimonium Chloride (or both). There are a lot more on the market, but these are some of my go-to’s.

Note: Cetearyl alcohol is often combined with Behentrimonium Methosulfate to create an emulsion, enhancing the texture and stability of hair care products.

I use the following conditioners regularly and they’ve never failed me yet:

Image of the ingredient list of Righteous Roots Conditioner showing behentrimonium chloride in the product. Breaking Down Behentrimonium Methosulfate in Hair Products.

Image of the ingredient list of Mielle Hydrating Conditioner showing behentrimonium chloride and behentrimonium methosulfate in the product. Breaking Down Behentrimonium Methosulfate in Hair Products.

Image of the ingredient list of Bounce Curl Moisture Balance leave in conditioner showing behentrimonium methosulfate in the product. Breaking Down Behentrimonium Methosulfate in Hair Products.

Image of the ingredient list of Giovanni Conditioner showing behentrimonium chloride in the product. Breaking Down Behentrimonium Methosulfate in Hair Products.

Safe Assessment: Potential Side Effects

Behentrimonium Methosulfate and Behentrimonium Chloride belong to a large family of cationic hair conditioning actives.

They have been in use for years and have been subject to numerous scientific studies to establish their safety and toxicity to human consumers.

Recent studies conducted by the European Union (EU), Food and Drug Administration (FDA), and the International Journal of Toxicology have concluded that the topical use of Behentrimonium chloride in skin or hair care formulations is safe.6,7

A maximum allowed concentration limit has been set for each specific product type, as listed below:

  • Rinse-Off Hair Care Products max limit – 5.0%
  • Leave-on Hair Care & Skin Care Products max limit – 3.0%

“Relying solely on a product label and their concentrations may not provide a complete picture of its effectiveness or suitability for your skin or hair. Instead of scrutinizing the ingredients list and percentages, look for clinical evidence that supports the product’s claims, whether it’s objective data from scientific studies or testimonials from consumers who have had firsthand experience using it.”

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Research has been conducted on Behentrimonium Chloride at high concentrations to assess its potential for skin irritation or discomfort with repeated topical use.

The results demonstrated that it is safe and does not pose any threat to skin quality or cause any irritation or discomfort.8

In short, both Behentrimoium Chloride and Behentrimonium Methosulfate are safe under current concentration limits and usage regulations.

Are They Bad for Hair or Skin?

The frequent usage of both ingredients in hair care formulations reflects their remarkable effectiveness and ability to effectively boost hair quality.

Both ingredients have been extensively examined and compared to other hair cationic conditioning ingredients.

The reports published demonstrate that the behenyl group offers superior hair conditioning, slip, and detangling properties.

Nevertheless, it is important to remember that too much of anything can be bad.

“To ensure safety, the FDA requires a warning advisory label to be included on any products that have not been reviewed by their expert panels. Considering they’ve already closely examined thousands of ingredients and shared their outcomes with the public, the industry can draw upon these reviews when formulating new products.”


Continuous use of cationic ingredients like Behentrimonium Chloride or Methosulfate can lead to product buildup on your hair. These ingredients are particularly prone to sticking to the hair fiber because of their positive-negative charge interaction.

Over time, this accumulation can weigh down damaged or fragile hair, making it appear limp or heavy. To counteract this, it’s advisable to use a clarifying shampoo to remove excess cationic buildup.

Natural Alternatives

There have been attempts to develop green, and plant-derived cationic conditioning emulsifiers, surfactants, and hair active ingredients.

Several manufacturers have come up with different options using plant-extracted natural oils that are modified to make a cationic molecule.

Some examples are listed below:

  • Brassicamidopropyl Dimethylamine – developed using oils from the Brassica plant family. This has shown good hair affinity, conditioning, and detangling benefits. 
  • Disunfloweroylethyl Dimonium Chloride – a sunflower oil-derived cationic conditioner, offers good slip and makes wet or dry combing hair a much more pleasant experience.
  • Arachidyl/Behenyl Betainate Esylate (and) Arachidyl/Behenyl Alcohol – a mildly cationic ingredient developed from green biomass. 


Behentrimonium Chloride and Behentrimonium Methosulfate in hair products are two of the most commonly used and reliable cationic conditioning agents in formulations.

These actives are a strong backbone to any conditioner while remaining safe, gentle, and free from any potential damage to skin or hair fibers.


What is a Quaternary Ammonium Compound (QACs)?

It is a broad category of compounds that includes Behentrimonium Methosulfate. It is an organic salt with a positively charged nitrogen atom at its core.

This structure allows it to act as a surfactant, commonly used for its disinfecting, conditioning, and emulsifying properties in various applications, including hair care products. It also reduces the surface tension in cosmetic products, ensuring a uniform distribution upon application.

Does Betrimonium Methosulfate have anything to do with the hair follicle?

While mainly interacting with the hair strands, Behentrimonium Methosulfate does not generally have a direct impact on the hair follicle itself.

To which phase does Behentrimonium Methosulfate belong—oil phase or water phase?

Behentrimonium Methosulfate belongs to the oil phase.


  1. E, K., Hair Conditioning Ingredients Developed with Focusing on Hair Surface Structure. SOFW Journal 2012, 138, 28-36. ↩︎
  2. Jeong, M.-S.; Lee, C.-M.; Jeong, W.-J.; Kim, S.-J.; Lee, K.-Y., Significant damage of the skin and hair following hair bleaching. The Journal of Dermatology 2010, 37 (10), 882-887. ↩︎
  3. Boswell, H.; Marsh, J.; Park, J.; Olshavsky, M. Oxidative treatment of hair with reduced hair damage. US, 20070107143A1, 2007. ↩︎
  4. Yuen, C.; Kan, C.; Cheng, S., Evaluation of keratin fibre damages. Fibers and Polymers 2007, 8 (4), 414-420. ↩︎
  5. Schueller, R.; Romanowski, P., Conditioning Agents for Hair and Skin. Taylor & Francis: 1999. ↩︎
  6. Becker, L. C.; Bergfeld, W. F.; Belsito, D. V.; Hill, R. A.; Klaassen, C. D.; Liebler, D.; Marks, J. G.; Shank, R. C.; Slaga, T. J.; Snyder, P. W.; Andersen, F. A., Safety Assessment of Trimoniums as Used in Cosmetics. International Journal of Toxicology 2012, 31 (6 suppl), 296S-341S. ↩︎
  7. OPINION ON ALKYL (C16, C18, C22) TRIMETHYLAMMONIUM CHLORIDE For other uses than as a preservative. Safety, S. C. o. C., Ed. Directorate General for Health and Consumers: 2009. ↩︎
  8. Cameron, D. M.; Donahue, D. A.; Costin, G. E.; Kaufman, L. E.; Avalos, J.; Downey, M. E.; Billhimer, W. L.; Gilpin, S.; Wilt, N.; Simion, F. A., Confirmation of in vitro and clinical safety assessment of behentrimonium chloride-containing leave-on body lotions using post-marketing adverse event data. Toxicology in Vitro 2013, 27 (8), 2203-2212. ↩︎


I’m just a girl who transformed her severely damaged hair into healthy hair. I adore the simplicity of a simple hair care routine, the richness of diverse textures, and the joy of sharing my journey from the comfort of my space.

My mission? To empower others with the tools to restore, and maintain healthy hair, and celebrate the hair they were born with!

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