Non-invasive blood glucose monitoring is a dream function in wearables, but it’s not likely to appear as a feature in the Apple Watch soon.

Bloomberg’s Mark Gurman said that Apple is still a long way to go in developing glucose sensing, citing on-board sensors and algorithms as hurdles that need to be overcome. A silicon photonics chip that’s ‘the size of a module’ is important so it can be integrated into an Apple Watch. Gurman concludes that this will take anywhere between three to seven years ‘at least’.
In February, Gurman said that Apple had made a sensor technology after twelve years of work, but apparently it was too large for it to be useful. Engineers are working to bring the prototype down to the size of an iPhone so it can fit into a user’s leg, but there’s still so much to do to further miniaturize it into something that can fit inside an Apple Watch.