Everything You Need to Know About Alum Vs. Aluminium

When you're trying to find a good deodorant, you'll notice that most products have some sort of alum, aluminum, or aluminium in their ingredient list. Are all these ingredients the same thing? Not really. Alum and aluminium are two distinct ingredients that affect your personal health very differently. Explore our guide to learn the difference and find the right choice for you.

Alum is Not the Same Thing as Aluminium

Though alum and aluminium might sound similar, it's important to recognize that these are two entirely different ingredients. Called aluminium for short, aluminium chlorohydrate is a synthetic substance made from aluminum and bauxite. What is alum? It's a type of naturally occurring salt.

When people talk about alum, they're usually referring to potassium alum. It looks like a white, cloudy crystal or fine grains of salt. Historically, this compound has been used as a water purifier and baking powder. In modern times, it's also a popular deodorant and aftershave treatment.

Alum Vs. Aluminium Chlorohydrate

Both potassium alum and aluminium chlorohydrate are chemical compounds that contain the chemical element aluminum. However, just like sodium can be present in harmless table salt or deadly cyanide, aluminum exists in both beneficial and dangerous compounds. Here are the key differences between alum and aluminium chlorohydrate.

• Origin: Alum is a naturally-occurring rock that's been around since the times of the ancient Egyptians. Aluminium chlorohydrate is a synthetic substance made by antiperspirant manufacturers in the 1940s.
• Uses: Alum can stop stinky sweating, but it's also used for a variety of other things. It's been used to dye fabric, leaven bread, pickle fruit, stop bleeding, and reduce pain from insect stings. Besides being an antiperspirant, aluminium is mostly just used to dissolve organic matter during wastewater treatment.
• Side effects: Alum is safe on skin, but may cause an upset stomach if ingested in large amounts. High doses of aluminium can cause itching and irritation on the skin. It also interacts poorly with certain antibiotics, and some studies suggest that aluminium chlorohydrate may be linked to the development of certain cancers.
• Chemical composition: Alum has large, stable molecules, so it doesn't degrade into toxic substances. Meanwhile, aluminium chlorohydrate has very small molecules that can break down into even smaller pieces.
• Effects on clothing: Aluminium can leave a residue that stains clothes. It typically looks like yellow patches on light clothing or bleached patches on dark clothing. Alum is a gentler substance, so it doesn't damage clothes or set in stains.

Does Alum or Aluminium Work Better as a Deodorant?

If you want to smell fresh without all the downsides of aluminium, alum can be a great choice. These two substances work very differently. Aluminium chlorohydrate helps reduce smells by physically blocking pores. The tiny molecules sit in your sweat ducts and cause swelling that blocks any water from seeping through.

Meanwhile, alum works to reduce body odor by inhibiting the bacteria that cause bad smells. You apply it by dampening the stone and rubbing it on your underarms. This creates an invisible layer of alum that inhibits bacterial growth. Your sweat will be harmless water instead of smelling stinky. Ultimately, this ensures you smell great without risking health problems.