On October 20th, Dexcom announced FDA approval and immediate availability of the Share, a docking cradle for their G4 continuous glucose monitor that pushes glucose data through a nearby iPhone to the cloud.  This data can then be pushed to up to 5 designated “followers” who have the Dexcom iPhone app.


The Dexcom Share is an out-of-the-box, no-hassle solution for providing real-time glucose readings and emergency alerts for extreme hypoglycemia and hyperglycemia to loved ones and concerned family members.

However, the length of time it took for the Share to get approved reveals the struggles that the FDA faces in the brave new world of mobile and wireless health.

The Dexcom Share: Glucose In the Cloud


Currently available for iPhone only, the Dexcom Share ($399; Product Link) is a cradle/dock for the G4.  In addition to charging the G4, the Share cradle wirelessly transmits glucose data via bluetooth to a nearby iPhone, which in turn securely uploads the glucose data to the cloud.

The Dexcom Share is readily available now as an accessory to the G4 and does not require any prescription.  Furthermore, the cloud service is entirely free from any monthly service fees.

Up to 5 other people can then follow the user’s blood sugars in real-time using the corresponding free Dexcom Follow app. In addition to viewing the glucose reading and glucose trend direction, the followers can each set up notification alerts that get pushed out to users.

Thankfully, using the free Dexcom Share app, the primary Dexcom user has full control over who can follow their sugar data, and can set different permissions and visibility levels to individual followers.  For example, a college student can make it so that their parent can only be alerted when sugars reach critically low or high levels, without having access to their less severe daily variabilities.

A Seamless, Out-of-the-Box Solution for iPhone

Tech-savvy people with diabetes might be familiar with the Dexcom Share concept, as its not much different than the previously covered home-brew, do-it-yourself Nightscout solution.

One key improvement with the Dexcom Share is that it is useable out of the box, and requires little technological knowledge to setup. Furthermore, while the Nightscout requires a wired Android smartphone for uploading glucose data, the Dexcom Share uses bluetooth to wirelessly upload glucose data via an iPhone.

A significant downside of the Dexcom Share is that, unlike the Nightscout solution, it requires an iPhone for followers to view and monitor blood sugars from afar. (Nightscout data is accessible by any smartphone and even some smartwatches through a web-based interface).

The New Challenges of FDA Approval in the Wireless Health Era

Word of the Dexcom Share first started circulating in Spring 2013. A Dexcom executive proudly told me about the Share over a year ago, when it was fully functional and simply waiting for FDA approval.

When it comes to wireless transmission of sensitive patient data directly from a medical device, the FDA exercises extreme caution. Dexcom representatives are quick to remind readers that the Share is a transition step to the ultimate goal of glucose transmission directly from the continuous glucose monitor to the smartphone, without the need for a cradle/dock.

The FDA’s cautious approach is defensible, as strict regulations can protect the general population from unanticipated dangers from new medications and technologies. Surely, with something as valuable as glucose data in diabetes, the reliability, accuracy, and security of such information must be proven.

However, the fact that the home brew Nightscout solution beat the Dexcom Share to market by months represents the growing tension between an eager, tech-savvy diabetes community and wireless innovation.  With medical apps and a burgeoning digital health industry with  novel innovations in hardware and software, the FDA faces challenges that did not exist 10 years ago.

For now, let’s just be thankful that the Dexcom Share is finally available.