Two products dominate the market for nasal sprays that claim to reduce symptons of a cold - Vicks ‘First Defence’ and Boots ‘Dual Defence’. But do they work?

Listener Leah got in touch because she catches lots of colds from her young son and wants to know if they can help her get over them more quickly. She also wants to know if they’re safe to use regularly and how long you should take them for.

Presenter Greg Foot sniffs out the evidence and talks to a leading expert who’s dedicated most of his career to investigating cold remedies.

This series, we’re testing and investigating your suggested wonder-products. If you’ve seen an ad, trend or fad and wonder if there’s any evidence to back up a claim, drop us an email to sliced.bread@bbc.co.uk or you can send us a voice note to our new WhatsApp number: 07543 306807.

PRESENTER: Greg Foot PRODUCER: Simon Hoban