Aluminium and Good and Bad Bacteria
We’ve heard deodorant brands claim their products keep 'bad bacteria' in check while promoting 'good bacteria', and that aluminium is toxic. But is this the truth or just a marketing fairytale?
What are good and bad bacteria?
Classifying bacteria as good or bad is subjective and context-specific. Generally, good bacteria don’t cause body odor (BO), while bad bacteria do. Medically, bacteria that cause illness are deemed bad, while those that benefit our well-being are good. However, even good bacteria can become harmful if they end up in the wrong place. For instance, E. coli in the lower GI tract aids digestion, but in the upper GI tract, it can cause severe illness. What if a bacteria causes strong BO but prevents fungal infections—good or bad? Clearly, defining good and bad bacteria isn’t straightforward and depends on the context.
Can deodorants promote good bacteria?
Even the most advanced antibiotics can’t target specific bacterial species without affecting others. Similarly, no deodorant can differentiate between good and bad bacteria. However, there’s evidence that aluminium-free deodorants promote a healthier armpit microbiome with fewer BO-causing bacteria than aluminium-based deodorants. Aluminium-based products have been shown to encourage the growth of BO-producing bacteria. This difference is more related to sweat presence or absence (since aluminium-containing deodorants are antiperspirants) rather than actively promoting good bacteria.
Do natural deodorants kill bacteria?
Most deodorants don’t kill bacteria. Nanoparticle formulations of magnesium hydroxide can physically disrupt bacterial cell walls, but no deodorant on the market—including ours—uses this technology. Aluminium, baking soda, and magnesium hydroxide deodorants don’t kill bacteria in typical application amounts. Instead, they work through other mechanisms, as explained below.
Can natural deodorants prevent bacterial growth?
Yes! Bacteria generate energy using a system similar to mitochondria in human cells, relying on charged compounds crossing their cell walls. Ingredients like magnesium hydroxide create an environment that inhibits this process, slowing bacterial growth. This doesn’t kill bacteria outright but reduces their activity, meaning fewer bacteria metabolising sweat and releasing odour. This is the key to how our deodorants work—controlling the number and activity of both good and bad bacteria.
Magnesium Hydroxide vs. Sodium Bicarbonate
Both are common in aluminium-free deodorants and create an alkaline environment (high pH) that hinders bacterial growth. Magnesium hydroxide is gentler on the skin, making it suitable for sensitive skin, while sodium bicarbonate can be more irritating. A key difference is their solubility: 1 liter of water dissolves nearly 100 g of sodium bicarbonate but over 15,000 liters are needed to dissolve the same amount of magnesium hydroxide. This slower dissolution minimises skin irritation by releasing active ingredients gradually over time. It's also what makes our magnesium-based deodorants last longer during prolonged and excessive sweating.
Are aluminium salts toxic?
The idea that aluminium in antiperspirants is toxic has been widely discussed, particularly in connection with conditions like breast cancer and neurodegenerative diseases. However, multiple scientific studies have found no conclusive evidence linking aluminium-based personal care products to these health issues. Regulatory bodies, including the World Health Organization (WHO) and various health authorities, consider aluminium salts safe for use in personal care products. Despite this, some people prefer to avoid aluminium as a precautionary measure or to reduce their use of synthetic ingredients. For those seeking an alternative, natural deodorants offer an effective option.
Are aluminium-free deodorants always free from aluminium?
Not always. Some brands label their products as aluminium-free but only mean they’re free of aluminium salts. Hidden aluminium compounds like bentonite or kaolin may still be present. While these are considered safe, transparency is key. A truly aluminium-free deodorant should contain no added aluminium compounds. You won’t find any hidden aluminium in our products!
We hope this overview helps you to better understand marketing claims around aluminium-free products and making an informed decision when buying your next deodorant.
