With shorter days, longer nights, and bad weather leading to the winter blues for many, and for some the more severe Seasonal Affective Disorder, Sliced Bread investigates whether specially designed lights can really help improve how we feel.

Listener Ross got in touch on WhatsApp after he’d read claims Wake Up Lights and SAD Lamps can boost our mood, and wanted to know what “medically certified” means when accredited to them, and if it’s worth paying extra for it?

Greg Foot finds out by speaking to a leading expert in light therapy, as well as by visiting a manufacturer of these lights, to ask them to explain their claims, and whether they’re medically recognised in the UK.

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: Kate Holdsworth