60-year-old Bronwyn Davies from Hillingdon has been missing since New Year's Day.
She was captured on CCTV walking along the Grand Union Canal in West Drayton that morning, by the John Guest Ltd business premises, but hasn't been seen since.
She regularly walks her dogs along this towpath and is well known to other dog walkers and joggers.
She has diabetes but doesn't have any insulin with her.
Mrs Davies' daughter has appealed to her mum and anyone with information to get in touch,