Today's Life/Style section in the Herald on Sunday brings us the latest 'beauty trend' to hit our shores: the snail facial.
Yes, you read that correctly. Apparently one can (if one has a sufficiency of funds) already purchase Snail Soap, which contains "snail slime, virgin olive oil, honey and extracts from medicinal plants". The slime component supposedly helps 'beat' wrinkles (what's wrong with a bit of character?) & reduces scarring. We're told that "No one has come back and said it is rubbish or doesn't work," but then, it might be a tad embarassing to have to 'fess up to spending $25/bar on soap that didn't meet one's expectations.
Apparently the next contribution gastropods have to make to our outer beauty is the snail facial: snails crawl about over your face, leaving their silvery mucus trails behind them. This probably does leave your face feeling a bit tighter, when the trails dry. But saying that "snail facials are believed to be very good" may well be an example of wishful thinking, especially in the absence of supporting data.
Snail slime does contain lectins, which are a class of glycoprotein; the amount & type of this substance vary with the species of snail. (Many years ago now, my Significant Other used to go out collecting them on dewy mornings, so that the lectin could be extracted and analysed.) It also contains other proteins such as collagen & elastin, which probably comes in helpful for the slug species that indulge in balletic aerial s*x at the end of a mucous bungee cord. But as far as I can see the claims that smearing one's face with this slimy mix will encourage skin cells to make more of these proteins lack support. And indeed, quite why putting protein molecules (which are highly unlikely to be absorbed through your skin) on the dead outer surface of your skin would encourage the cells beneath to spring into activity, is not immediately clear.
Lectins are 'sticky' molecules produced by plants (& algae), animals, fungi & prokaryotes, and are involved in communication between cells, defence against pathogens, fertiliation, metastasis of tumours, and appear to generate an inflammatory response (something that's picked up on by various 'alt.health' sites such as mercola.com). Those from snail slime may have anti-microbial activity, but in absence of actual infection that would not be a burning reason to use it on one's face. And indeed, I think there's need for caution in their use, as it seems that bacteria such as E.coli can survive for quite some time in snail faeces: I'd certainly want to be sure that the snails had been kept long enough to evacuate their bowels prior to crawling over my skin!
NB It was good to see a skeptical comment from a dermatologist, at the end of the Herald article – but more as an afterthought than an an attempt at investigative journalism :(
PS And 'thank you!' to my friends in the Skeptics for riffing on this in the first place :)
EDIT: one Smut Clyde has since expanded on this very subject. He notes that one can search in vain for the chemical known as "Helix Asperia Muller" – and this is not surprising, as the phrase is actually a typo (?) for the old taxonomic name of the actual garden snail, Helix aspersa (Muller), Muller being the chap who first described it. The species has now apparently been reclassified as Cornu aspersum. I didn't know that.