BTMS-50 | Behentrimonium Methosulfate Conditioning Emulsifier

• INCI Name: Behentrimonium Methosulfate (and) Cetearyl Alcohol
• CAS Number: 81646-13-1 (Behentrimonium Methosulfate); 67762-27-0 (Cetearyl Alcohol)
• Common Name: BTMS-50, Conditioning Emulsifier BTMS-50
• Active Concentration: 50% Behentrimonium Methosulfate / 50% Cetearyl Alcohol
• Charge Type: Cationic (positively charged) — this is what delivers conditioning to negatively charged hair
• Grade: Cosmetic Grade
• Appearance: White to off-white waxy flakes or pellets
• Odour: Faint characteristic waxy — essentially odourless in formulation
• Melting Point: 55–65°C
• pH (as supplied): Not applicable (solid); produces slightly acidic to neutral pH in formulation (5.5–7.0 typical)
• HLB Value: Approximately 11–13 (suitable for oil-in-water emulsions)
• Solubility: Dispersible in warm water above melting point; soluble in oils at elevated temperature
• Phase: Oil phase / emulsifier phase — melt with oil-phase ingredients at 70–75°C
• Shelf Life: 2+ years when stored correctly
• Storage: Store sealed in a cool, dry place away from moisture and heat. In hot Australian conditions store below 30°C to prevent softening
• Butylene Glycol Free: Yes — this formulation contains no butylene glycol

HOW IT WORKS — THE CATIONIC CONDITIONING MECHANISM

Understanding why BTMS-50 outperforms other emulsifiers in hair care requires understanding the electrical charge principle:

Hair is negatively charged. Healthy hair has a net negative surface charge from the keratin protein structure. Damaged, chemically treated, or bleached hair has an even more strongly negative charge as the cuticle layer is lifted and disrupted, exposing more anionic binding sites.

BTMS is positively charged (cationic). The Behentrimonium Methosulfate molecule carries a permanent positive charge. Opposite electrical charges attract — so BTMS is drawn to and adsorbs onto the hair shaft with high substantivity (sticking power). This is called a "depot effect" — the conditioner deposits onto hair and stays there even through rinsing.

The result: A smooth, continuous conditioning film deposits on every hair fibre. This film lubricates the cuticle surface, reducing friction between hairs (eliminating frizz and tangles), reflecting light more evenly (adding shine), reducing static electricity, and creating the silky, soft, manageable feel that defines a high-quality conditioner.

In skin care: The same mechanism applies to a lesser degree on skin — BTMS deposits a mild conditioning film that reduces tackiness, improves after-feel, and contributes to a light, non-greasy moisturised skin feel. It is not as dramatically skin-conditioning as it is hair-conditioning, but it does contribute to the elegant skin feel of O/W creams and lotions.

Self-emulsifying: BTMS-50 is self-emulsifying — it can create stable oil-in-water emulsions without the need for a separate emulsifying wax. The cetearyl alcohol component provides the fatty alcohol backbone that supports emulsion structure, while the behentrimonium methosulfate component stabilises the interface between oil and water droplets. At 4–8% in a standard O/W formulation, BTMS-50 creates a stable, elegant emulsion without additional emulsifiers.

RECOMMENDED USAGE RATES

Rinse-Off Hair Conditioner

• BTMS-50: 4–8% of total formulation
• Melted with the oil phase at 70–75°C
• Typical conditioner formula: 4–6% BTMS-50 + 1–3% cetyl alcohol + 0.5–2% conditioning oils + water + actives (panthenol, hydrolysed proteins) + preservative

Leave-In Conditioner (lightweight)

• BTMS-50: 1–3% of total formulation
• Lower rate for a lighter, non-weighing-down feel in fine or oily hair

Detangling Spray

• BTMS-50: 0.5–2% in a water-based spray formulation
• Fully melts and disperses in hot water phase; produces a clear to slightly cloudy light-weight spray

Hair Mask (intensive)

• BTMS-50: 5–10% for a rich, deeply conditioning mask
• Combine with conditioning butters, oils, and hydrolysed proteins for maximum treatment effect

Body Lotion and Light Cream

• BTMS-50: 3–6% as the sole emulsifier in O/W formulations
• Produces a lightweight, slightly conditioning skin feel — appropriate for body and hand lotions

Rich Body Cream

• BTMS-50: 4–8% combined with additional co-emulsifiers or waxes for richer texture

Baby Lotion

• BTMS-50: 2–4% for gentle, mild emulsification suitable for baby skin

Shaving Cream

• BTMS-50: 4–6% for cushioning, glide, and post-shave skin feel

• Cationic conditioning mechanism — positively charged BTMS deposits conditioning film onto negatively charged hair with high substantivity; no anionic or non-ionic emulsifier can replicate this effect
• Self-emulsifying — creates stable O/W emulsions at 4–8% without requiring a separate emulsifying wax; reduces formulation complexity
• 50% active concentration — use at approximately half the rate of BTMS-25 to achieve equivalent conditioning and emulsification; more efficient and cost-effective per application
• Outstanding detangling performance — dramatically reduces wet and dry combing friction, improving manageability in both fine and coarse, damaged hair
• Anti-static — cationic conditioning neutralises static charge on hair fibres, eliminating frizz in dry climates and during winter
• Shine enhancement — smoothed cuticle surface reflects light more evenly, producing noticeable shine without silicone
• Compatible with all cosmetic ingredients — works alongside anionic, non-ionic, and amphoteric actives; note cationic/anionic incompatibility in the same phase at high concentrations
• Butylene glycol free — cleaner formulation profile; important for brands marketing free-from or clean beauty positioning
• Produces elegant, non-greasy skin feel in lotion and cream applications
• Suitable for all hair types — particularly beneficial for damaged, chemically treated, bleached, and high-porosity hair
• Vegan — derived from plant-based behenic acid (rapeseed)
• Available in 100g, 1kg, and 5kg — suitable from hobby formulators to professional production.

When to use BTMS-50: Any formulation where hair conditioning is the goal — conditioners, leave-ins, masks, detangling sprays, conditioning body washes. Also suitable for skin care where a mild conditioning skin feel is desired.

When to use Emulsifying Wax instead: Body lotions and creams where no conditioning claim is needed and you want a straightforward, neutral emulsion without any cationic activity.

TYPICAL APPLICATIONS

• Rinse-off hair conditioners
• Leave-in conditioners
• Deep conditioning hair masks
• Detangling sprays
• Argan oil and coconut oil hair treatments
• Conditioning hair oils (emulsified)
• Body lotions and lightweight creams
• Baby lotions
• Shaving creams and shaving balms
• After-sun and soothing skin products
• Colour-protecting hair conditioners
• Scalp treatments
• Beard conditioners and beard balms (emulsified)

• Cosmetic grade — safe for hair and skin contact in formulations at recommended usage rates
• Cationic emulsifier — avoid direct high-concentration mixing with anionic surfactants (SLS, SLES, SCS) in the same phase as this can cause precipitation or destabilisation
• Avoid contact with eyes; if contact occurs rinse thoroughly with water for several minutes and seek medical advice if irritation persists
• Perform a patch test before use in new formulations intended for sensitive skin
• Melt carefully — working temperature of 70–75°C presents burn risk; use heatproof equipment and a double boiler
• Keep out of reach of children
• Store sealed at room temperature below 30°C — in hot Australian summer conditions keep in a cool location to prevent softening of the flakes
• Biodegradable — behentrimonium methosulfate is readily biodegradable

What is the INCI name for BTMS-50?
The correct INCI name is Behentrimonium Methosulfate (and) Cetearyl Alcohol. Both components must be listed on your finished cosmetic product ingredient list in their INCI forms. Behentrimonium Methosulfate is the conditioning active; Cetearyl Alcohol is the fatty alcohol emollient component.

What is the difference between BTMS-50 and BTMS-25?
The number refers to the percentage of Behentrimonium Methosulfate (the active conditioning ingredient) in the blend. BTMS-50 is 50% Behentrimonium Methosulfate + 50% Cetearyl Alcohol. BTMS-25 is 25% Behentrimonium Methosulfate + 75% Cetearyl Alcohol. BTMS-50 is more concentrated — you use approximately half the amount to achieve equivalent conditioning and emulsification compared to BTMS-25. BTMS-50 is the preferred professional grade for efficiency and formulation control.

Can BTMS-50 emulsify without a separate emulsifying wax?
Yes — BTMS-50 is self-emulsifying. At 4–8% of total formulation it creates stable oil-in-water emulsions without additional emulsifying wax. The cetearyl alcohol component provides the fatty alcohol backbone for emulsion structure. For richer creams you may add additional cetyl alcohol or cetearyl alcohol as co-emulsifiers and texture modifiers, but this is optional — not required for basic emulsification.

Why is BTMS-50 better than regular emulsifying wax for conditioners?
Standard emulsifying wax (typically polysorbate 60 based) is non-ionic — it has no electrical charge and cannot deposit conditioning actives onto hair. BTMS-50 is cationic — it is positively charged and is attracted to the negatively charged surface of hair fibres, depositing a conditioning film with high substantivity that remains on the hair even after rinsing. This is the fundamental difference: emulsifying wax gives you an emulsion; BTMS-50 gives you an emulsion plus genuine hair conditioning chemistry.

How do I use BTMS-50 in a basic conditioner recipe?
A simple starter conditioner formula: Add 4–6% BTMS-50 + 1–2% cetyl alcohol to your oil phase. Melt together at 70–75°C. Heat your water phase (distilled water + optional water-phase actives like panthenol or hydrolysed silk protein) to the same temperature. Slowly add the water phase to the oil phase while mixing continuously. Mix until fully emulsified and cooled to below 40°C. Add heat-sensitive actives, fragrance, and preservative at below 40°C. Adjust pH to 4.5–5.5 and package.

Can I use BTMS-50 with anionic surfactants like SLS or SCS?
BTMS-50 is cationic. Mixing cationic and anionic ingredients in high concentrations can cause precipitation or complex formation — the opposite charges attract and neutralise each other. In practice, at the low usage rates typical in conditioner formulations (4–8%), BTMS-50 can coexist with traces of anionic surfactant carry-over from rinsing, but it should not be deliberately combined with anionic surfactants in the same phase. If formulating a combined shampoo-conditioner or 2-in-1, use an amphoteric or non-ionic surfactant system instead.

How do I store BTMS-50 in Australian conditions?
Store in a sealed container in a cool, dry location below 30°C. In hot Queensland, Northern Territory, or Western Australian conditions during summer, keep in a temperature-controlled location such as an air-conditioned storeroom. BTMS-50 has a melting point of 55–65°C so it will not melt at Australian ambient temperatures, but prolonged exposure to heat can cause the flakes to clump or partially soften. Shelf life is 2+ years in correct storage conditions.

YOU MAY ALSO NEED

• Cetyl Alcohol (Vegetable) — co-emulsifier and thickener that pairs with BTMS-50 in conditioners and creams for richer texture
• Castor Oil (Hexane Free) — adds shine and conditioning to BTMS-50 hair conditioner formulations
• Sweet Almond Oil — lightweight conditioning oil for BTMS-50 body lotion formulations
• Shea Butter (Refined & Organic) — enriches BTMS-50 body cream formulations for deeper conditioning
• Aloe Vera Juice — hydrating water-phase ingredient for BTMS-50 conditioner and lotion formulations
• Hair Supplies Collection — shop all hair care ingredients for shampoo bars, conditioners, and treatments
• Wax and Emulsifiers Collection — shop all emulsifying waxes and conditioning agents
• Caprylic/Capric Triglyceride (MCT Oil) — lightweight oil phase addition to BTMS-50 leave-in conditioners