Deodorant
Its astringent film limits the growth of odor-causing bacteria. It does not block sweat the way an antiperspirant does.
MineralMoroccan heritage
Alum stone
The ore a mineral salt, potassium alum.
The crystal it forms perfect octahedrons.
The stone cut, polished, translucent.
The ritual moistened, it glides over the skin.
INCI · POTASSIUM ALUMCreate my alum range
- INCI name
- POTASSIUM ALUM
- Other names
- Potassium alum, chebba
- Family
- Mineral
- Formula
- KAl(SO₄)₂·12H₂O
- Form
- Stone, powder or solution
- Areas
- Underarms, face after shaving, feet
In short
Alum stone in 30 seconds
By the Carmel Cosmetics Labs R&D team · updated October 2, 2026
- INCI namePOTASSIUM ALUM
- What it isa mineral salt, a double sulfate of aluminum and potassium
- Usesdeodorant, aftershave, foot care
- Key differencepotassium alum is natural, ammonium alum (AMMONIUM ALUM) is synthetic
- Safetythe SCCS considers aluminum safe in non-spray deodorants up to 6.25%
( A )WHAT IT IS
What is alum stone?
Alum stone is a crystal of potassium alum, a mineral salt with the formula KAl(SO₄)₂·12H₂O, a double sulfate of aluminum and potassium. Moistened and glided over the skin, it leaves a thin film with astringent properties. In cosmetics, it is used as a deodorant, as an aftershave and in foot care.
Crystal composition
Mass proportions calculated from the formula KAl(SO₄)₂·12H₂O, rounded to the nearest unit.
Potassium alum or ammonium alum: the difference
Potassium alum
INCI POTASSIUM ALUM. The natural mineral of the traditional alum stone. This is the one we use.
Ammonium alum
INCI AMMONIUM ALUM. A synthetic salt, sometimes sold as "alum stone". The INCI list tells them apart.
( B )BENEFITS
01 02 03
Alum stone benefits as a deodorant and aftershave
Aftershave
Glided over damp skin after shaving, it tightens the skin and soothes razor burn. A traditional barber's ritual.
Feet and hands
As a powder or solution, it is used in foot care for its drying, refreshing effect.
How to use alum stone
- Underarms
Moisten the stone and glide it over clean, dry skin, morning or evening.
- Aftershave
Glide it over damp skin right after shaving, then rinse if needed.
- Storage
Dry it after use: it dissolves in water and cracks if left wet.
( C )IN OUR PRODUCTS
Launch your alum stone range
We add it as a powder or solution to products ready to carry your brand. Choose a category to see the formulas.
( D )FORMULATOR NOTES
How we formulate with it
What our formulators consider when alum stone goes into your product.
- 01Aluminum dosage
We stay within the limits set by the European SCCS assessment for each product type.
- 02Potassium, not ammonium
We use potassium alum and state it clearly in the INCI list.
- 03Honest claims
"Natural", yes; "aluminum-free", never: alum is an aluminum salt.
- 04Formats
Raw stone, stick, powder or solution: the format depends on your product and your sales channel.
Did you know?
A mineral used for centuries
- Octahedrons
Potassium alum naturally crystallizes into octahedrons, eight-sided crystals.
- Chebba
This is the Moroccan name for alum stone, found in barber kits and hammams.
- Dyeing
Before cosmetics, alum was used as a mordant to fix colors on wool and leather.
Alum stone: your questions
An alum stone project?Our product specialist answers you on WhatsApp.Message us on WhatsApp
Is alum stone dangerous?
Alum is an aluminum salt. In 2020, the EU Scientific Committee on Consumer Safety (SCCS) concluded that aluminum is safe in non-spray deodorants and antiperspirants up to 6.25% aluminum. Avoid applying it to broken skin or right after hair removal.
Is alum stone a good deodorant?
It limits odor thanks to its astringent effect, but it does not block sweat. It is a deodorant, not an antiperspirant.
What is the difference between potassium alum and ammonium alum?
Potassium alum (POTASSIUM ALUM) is the natural mineral. Ammonium alum (AMMONIUM ALUM) is made synthetically. The INCI list tells them apart.
Does alum stone contain aluminum?
Yes. Potassium alum is a double sulfate of aluminum and potassium. A product made with alum therefore cannot be called "aluminum-free".
How do you use alum stone after shaving?
Glide it over the still-damp skin right after shaving. It tightens the skin and soothes razor burn.
What is the INCI name of alum stone?
Its INCI name is POTASSIUM ALUM. This is the name that appears in the ingredient list.
Can I create an alum stone range with Carmel Cosmetics Labs?
Yes. We add it as a powder or solution to white label men's care, lotions and body care, or to an exclusive private label formula, made in our factory in Morocco.
Sources
Your alum stone range, formulated in Morocco
Send your brief: we formulate and manufacture in our ISO 22716 factory in Aït Melloul. Formula selection and detailed quote, with no commitment.