COLDZYME MOUTH SPRAY

20ml, £17.50, boots.com

CLAIM: This is said to work against the cold virus itself — rather than just treat symptoms.

Once sprayed in the throat, the manufacturer says it forms a protective barrier that traps the virus in the throat and stops it infecting cells; the body then gets rid of the virus naturally.

It also claims that ColdZyme can shorten cold duration if used at the first sign of symptoms. To use, spray into the throat — one dose every second hour up to six times daily during the time you are exposed to the cold virus or until symptoms decline. EXPERT VERDICT: The main ingredients of ColdZyme include glycerol, a colourless and odourless thick liquid that traps viruses in the throat. It also contains trypsin, an enzyme that, it is also claimed, inhibits the virus’s ability to bond with and infect healthy cells.

But the evidence is mixed. Some studies show it may offer little protection — but a paper earlier this year in the european Journal of Sport Science suggested it could shorten cold duration by up to a third.

Additionally, it is only a treatment for the mouth and it does not stop viruses entering through the nose.

7/10