Ingredient glossary
Behentrimonium Methosulfate
On your shelf ✓What Behentrimonium Methosulfate does for your skin, who it suits, and what to watch for.
INCI: Behentrimonium Methosulfate · Also: BTMS-50, BTMS-25
In short: Behentrimonium Methosulfate delivers conditioning and softening, earns its place for hair, and the evidence behind it is moderate.
- What it does
- Conditioning, softening
- Best for
- Hair
- Evidence
- Moderate
- How long
- Straight away
The molecule
The two pieces are meant to be apart. Behentrimonium Methosulfate is a salt, and its parts are held to each other by opposite charges rather than by a bond.
The Glow take
Nice to have, and nothing to overthink.
Behentrimonium Methosulfate plays a quiet supporting role, rounding out a formula rather than being the reason you buy it.
— Maya
What it does
- conditioning
- softening
- slip
moderate evidenceSupplier data and regulatory reviews describe a quaternary ammonium compound safe for rinse off and leave on use, conditioning as well as older quats with less irritation. Reports of buildup on fine hair are anecdotal; controlled long term studies are lacking.
On a label: usually effective at 1-5%.
Who it's for, and who should skip it
Tends to suit
- hair
Approach with care
- very oily
- Irritation riskLow
How it fits each skin type
- DryNeutral
- CombinationNeutral
- OilyTake care
- SensitiveNeutral
Often chosen for hair.
Where it fits in your routine
This one works on contact — there is nothing to wait for.
What that covers, and what it does not
Measured on: surface friction dropping on contact - combing force on hair, slip on skin.
A cationic quat deposits onto negatively charged keratin as it is applied and lowers surface friction there and then, the same class of on-contact physical change as a silicone film, which is why conditioner detangling is judged during the rinse rather than weeks later. Nothing is being remodelled, so there is no later endpoint to wait for. The base points the ingredient at hair and its own note says controlled long-term studies are lacking; no skin trial measures anything beyond slip.
Supplier technical data and regulatory reviews cited in the base row; no controlled human study identified.
Plays well with
- fatty alcohols
- emollients
- film formers
Behentrimonium Methosulfate, answered
Is Behentrimonium Methosulfate safe during pregnancy?
Yes. Behentrimonium Methosulfate is considered safe to use during pregnancy and breastfeeding. As with anything, if you are unsure it is worth a quick word with your doctor or midwife.
Who should avoid Behentrimonium Methosulfate?
Approach Behentrimonium Methosulfate with care if any of these apply to you: very oily.
What concentration of Behentrimonium Methosulfate actually works?
Behentrimonium Methosulfate tends to do its job in the 1 to 5% range. Much lower and it is likely underdosed.
Does it clog pores?
No rating published; treated as 0, and used mostly on hair.
- This rating comes from old lab tests on the isolated ingredient, not the finished product.
- The full formula, how much is used, and your own skin all matter more than one number.
- If you are acne-prone it is worth noticing, not a reason to avoid it on sight.
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