Aluminium vs Bi carb vs Magnesium Hydroxide What's the Story?

by Jo-anne Maree Srbinovski

Recently we received this question:

"But doesn't the magnesium act like aluminium and block the sweat ducts...Isn't it just a non toxic version of aluminium. It's acting like an anti-perspirant right?"

Let's break this down a little! Both aluminium and magnesium hydroxide are commonly used in deodorants for their ability to help control odour, but they work in slightly different ways.

Aluminium based antiperspirants: Aluminium based compounds (such as aluminium chlorohydrate or aluminium zirconium) are commonly used in conventional antiperspirants. They work by temporarily blocking sweat ducts, thereby reducing the amount of sweat that reaches the skin's surface. This helps to reduce perspiration.

Magnesium Hydroxide: Magnesium hydroxide, on the other hand, is often used in natural deodorants as an alternative to aluminium compounds. It doesn't block sweat ducts like aluminium based compounds. Instead, it works by adjusting the pH of the skin, creating an environment that is less hospitable to the bacteria that cause odour. It helps to neutralise odour causing bacteria rather than blocking sweat.

In summary, while aluminium based compounds in antiperspirants primarily work by blocking sweat ducts, magnesium hydroxide in natural deodorants operates by neutralising odor causing bacteria through its pH adjusting properties. This means that while magnesium hydroxide won't prevent you from sweating, it can help to keep odour at bay.

Another common ingredient used, especially in natural deodorants is Bicarbonate (Bi Carb or Baking Soda).

Bicarbonate (Baking Soda/Bi Carb) Containing Deodorants: Baking soda, or sodium bicarbonate, is an ingredient commonly found in natural deodorants. It works by neutralising odour causing bacteria due to its alkaline nature. Baking soda can also help to absorb moisture.

Why Bicarbonate (Baking Soda) Can Cause Irritations: Bicarbonate based deodorants can sometimes cause skin irritation for a few reasons:

Alkalinity: Baking soda is alkaline whilst our skin has a slightly acidic pH. Using a highly alkaline substance like baking soda on sensitive skin can disrupt this natural balance, leading to irritation, redness, and discomfort.

Abrasive Texture: Baking soda has a gritty texture, which can be abrasive on the skin. This abrasiveness may lead to irritation, especially in people with sensitive skin.

Overuse: Using too much baking soda in a deodorant formulation can increase the likelihood of irritation. Some people may be more sensitive to higher concentrations of baking soda.

Pre Existing Skin Conditions: Individuals with pre existing skin conditions like eczema or dermatitis may be more susceptible to irritation from baking soda.

Magnesium hydroxide is less likely to cause irritation compared to baking soda because it is less alkaline.

Remember that everyone's skin is different and not everyone will experience irritation from baking soda. What works for one person may not work for another. Additionally, individual skin sensitivities may play a role in how well each ingredient is tolerated. Finding the right deodorant for your skin may involve some trial and error. It's also a good idea to perform a patch test before using a new product to check for any adverse reactions.