A Stinging Study is used to learn if products intended to be used on the face such as cleansers, moisturisers, make-up etc. are capable of causing delayed stinging or smarting when applied to the skin of known 'stingers', i.e. people likely to show this response. Although these products may not cause visual irritation they may cause stinging sensations to certain consumers. Only female subjects are studied.
Volunteers are asked to expose their face to steam emitted from a facial sauna for 5-10 min or until sweating on their face is obvious. A swab of cotton wool soaked in the test material is then wiped over the side of their nasolabial fold and cheek. The volunteer is then asked to place their face into the steam for a further 5 minutes. At various time intervals, test subjects are asked to describe facial sensations at various intervals throughout the exposure.
The assessment scores recorded at 2.5 min and 5.0 min for each product are totalled for the whole panel giving the total cumulative score.