Limonene: natural and organic
Limonene: natural and organic

An enlightening cutting from Tuesday’s London Lite just hit my desk: a review of “six of the best chemical-free deodorants.” Oh ho ho, I thought to myself. More chemical-free myths to debunk on the blog, trying to explain that, while natural and organic, limonene smells the same whether you get it from a citrus fruit or a separating funnel. For the record its molecular structure is to the left. Looks like a chemical to me, but what do I know?

So in this list there are a few of the standard “all-natural, 100% chemical-free” deodorants – the ones with ingredients lists like this. My favourite of the non-chemicals on this particular list is eugenol, which has the delightful alternative name eugenic acid.

But, even better than the chemical-containing 100%-chemical-free deodorants of a standard body-spray nature, there are two that really made me laugh – and think.

Tawas Crystal Deodorant is “a natural crystal of potassium alum, (nothing to do with aluminium) formed from non toxic minerals in mother earth.”

Umm. ChemSpidey-sense tingling, I performed a quick search on everyone’s favourite free chemical information source that revealed, of course, the chemical formula of potassium alum is KAl(SO4)2. Nothing to do with aluminium? Where did they think the name came from?

Perhaps the winner, though, is the Zielonka Bodystick. This comes closest to the “chemical-free” claim, as it doesn’t use a spray or wipe of chemicals to neutralise odour or act as an astringent (normally aluminium-based, to close pores and reduce sweating).

Instead the product comprises a steel stick in a plastic case. When wetted and rubbed under-arm, the steel “acts as a catalyst to the process of converting odour chain molecules into bland non-odour chains through the introduction of the alloy smell killer in conjunction with air and water.”

Whoa there – that’s swinging dangerously close to actual science. I’m almost convinced! I can believe that a nickel-iron-based alloy could catalyse… well something, anyway. What are these non-odour chains, though? Zielonka explains:

“If you then break the organic string, you are then only left with individual pearls and subsequently the pattern disappears. This, if you break the ‘odour chain’ then the scent disappears as well. Because odours are organic substances, no hazardous waste is created, except what could be regarded as below the measurable level of ‘odour compost’.”

Aha… so because the catalysed products are organic, they’re not hazardous. Off the top of my head I can think of quite a few small organic molecules I’d rather not wipe under my armpits, one being methanol (with which I have some experience, cleaning high-vacuum equipment in the Stavros lab at Warwick).

The helpful and polite lady at the end of the phone for Natural Figure, distributor of the Zielonka Bodystick, didn’t have the exact mechanism of the catalysis to hand. I’ve put in a few requests by email to the supplier and the manufacturer to see if I can find out more.

I’m intrigued, though – is there any way this could work? I don’t want to write it off until I’m shown some really bad pseudo-science as proof. Any nickel/steel catalysis experts out there want to voice an opinion?

UPDATE, 24.02.10 Thanks to commenter Mic, who has provided below a link and explanation that the active ingredient in the bodystick is not steel but nano-silver, well recognised as having antibacterial properties and definitively a chemical.