"4head contains a powerful natural painkiller - 90% levomenthol - that can help block pain signals caused by tension headaches and relax the muscles in the head."

"In fact, a clinical trial with tension headache, sufferers confirmed that after applying 4head they could feel the effects of its powerful natural painkiller, pure levomenthol (peppermint), getting to work in just two minutes."

Update 2015-01-13

The company sent me information regarding the clinical trial that they had cited, and wrote:

"The skin sensations have a very fast speed of onset. For example, attached is a summary report of a clinical evaluation of 4head stick involving headache sufferers. The aim of the first part of the study, performed in a controlled laboratory setting, was to establish the average speed of onset, and duration, of the skin sensations felt after single applications (4 wipes) of the product. This showed that the skin sensations were felt remarkably quickly, within 1.5 minutes for 90% of patients, and lasted for in the region of half an hour. The product’s approved dosage regimen provides for it to be reapplied as required, and in the second part of the study where patients used the product at home to treat 130 headache episodes altogether, 4head’s effectiveness was generally very favourable – with over 80% reporting that they were likely to carry on using it after the trial."

Unfortunately they gave little information re: participant selection or drop out rates, the sample size was just 20 people, it was not comparative (no alternative treatment or placebo) and was therefore open label. More a focus group than a trial...

They also attached an article published in the NHS Journal of Healthcare Professionals which gives a historical review of the use of (and evidence for) levomenthol as a treatment for relieving headaches. In their reply they wrote:

"In simple terms it works by a counter-irritant action – the process by which an induced bearable stimulus (in this case cold sensation) suppresses the perception of a less bearable painful stimulus."

Attached file

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