The short answer
Most conventional antiperspirants use aluminium salts to physically plug your sweat glands, stopping perspiration altogether. Si:zen takes a different approach: our natural deodorant is formulated with magnesium hydroxide, an ingredient that neutralises odour-causing bacteria instead of blocking your body's natural sweat process.
It's a small formulation choice with a big difference in how your skin feels and how your body functions day to day.
Why aluminium became the default in the first place
Aluminium-based antiperspirants became the norm because they're highly effective at stopping visible sweat, fast. But stopping sweat isn't the same as stopping odour, and for many people with sensitive skin, aluminium salts can cause irritation, especially with daily use over months and years.
Sweating is also a completely normal, healthy process your body uses to regulate temperature. Blocking it doesn't address the actual cause of body odour, which is bacteria breaking down sweat on your skin, not the sweat itself.
How magnesium hydroxide works instead
Magnesium hydroxide works by creating an environment on the skin that's inhospitable to odour-causing bacteria, without blocking sweat glands. That means:
- Your body keeps sweating and regulating temperature naturally
- Odour is neutralised at the source rather than masked with fragrance
- Skin stays less irritated than with aluminium-based formulas, especially for sensitive underarms
Combined with Vitamin E and plant-based oils, it's designed to be gentle enough for daily use while still holding up through a real day, not just a lab test.
What this means if you're switching from an antiperspirant
If you've used aluminium-based antiperspirant for years, your body may take a short adjustment period as it rebalances, generally around 1-2 weeks with consistent use. That's normal, and it's covered in more detail in our FAQs, along with answers on irritation, staining, and how long a natural deodorant actually lasts.
The bottom line
Choosing magnesium over aluminium was a deliberate decision, not a marketing angle: it's a gentler ingredient that supports your body's natural processes instead of interrupting them. You can find the full ingredient list and how it all comes together in our natural deodorant, made in Australia for sensitive skin.