While Apple continues research into what should one day result in its own rumored non-invasive continuous glucose reader for Apple Watch, industry watchers have cautioned that the Cupertino tech giant is probably years away from a commercial product.

The New York Times reported yesterday that Apple is “continuing research” into this potentially revolutionary first-party health accessory that would allow patients to use an Apple Watch for measuring their blood sugar levels without having to prick their finger to draw blood.

The accessory would take advantage of tiny sensors to pierce the skin in order to track blood sugar levels, relaying those readings through a wireless transmitter back to the watch.

The newspaper described how the project began:

In the last months of Steve Jobs’s life, the Apple co-founder fought cancer while managing diabetes. Because he hated pricking his finger to draw blood, Mr. Jobs authorized an Apple research team to develop a noninvasive glucose reader with technology that could potentially be incorporated into a wristwatch.

It was one of many medical applications that Apple considered for Apple Watch, which debuted in 2015. Yet because many of the health features proved unreliable or required too many compromises in the watch’s size or battery life, Apple ended up positioning the device for activity tracking and notifications instead.

Citing two sources familiar with the project and industry watchers, the paper cautioned that a real product is likely years away from being commercialized.

“Separately, Apple is continuing research on a noninvasive continuous glucose reader, according to two people with knowledge of the project,” notes NYT. “The technology is still considered to be years away, industry experts said.”

Tim Cook was spotted around Apple’s campus in the summer, wearing a non-invasive glucose tracker prototype on his body. According to CNBC, he was testing the prototype accessory to understand how his blood sugar responded to factors like food and exercise.

The Cupertino company is also looking at potentially building an electrocardiogram into future watch models, triggered by squeezing the device’s frame, as earlier reported by Bloomberg.