Explaining Temple, Deepinder Goyal’s head-worn health monitoring wearable

Temple, which is Goyal’s other venture other than Eternal (the holding company of Zomato), aims to get into wearable fitness. Unlike most competitors, Temple avoids adding another screen to your daily routine. Instead, it focuses on screenless, “wear-and-forget” technology, echoing Google’s approach with the Fitbit Air.

Temple has been developing a head-worn wearable designed to non-invasively monitor real-time cerebral blood flow, oxygenation, and cognitive physiological signals. For months, Goyal has worn his bean-shaped ‘Temple’ on his… temple, and now, he says that the company is ready to release the production version.

So, what is Temple?

Temple is a small, clip-like device worn on the side of the head, sitting directly over the temple area between the forehead and the ear.

Unlike conventional health devices, Temple moves away from basic physical activity metrics like heart rate, calories, sleep tracking, etc. It focuses on brain health, neurological feedback, and continuous physiological demand.

In his recent post on X (formerly Twitter), Goyal updated his followers about another major development on the product prior to its commercial release. “Temple is now less than half the size of what you’ve seen so far. Volumetrically, Temple is now the smallest wearable on the market, and the most^10 powerful,” wrote Goyal. 

“Living and training with Temple is going to change your life. We will start taking pre-orders for our limited launch edition @temple very soon – shipping before the end of 2026.” he added.

Key highlights of Temple

While Temple is yet to reveal all the crucial details about the wearable product, here are a couple of major pointers we have observed so far.

It’s small: The latest design iteration, as shown on Goyal’s social media post, is less than half the size of original prototypes. By volume, Temple is now positioned as the smallest wearable on the market.

Not a fashion fitness accessory: Temple is being positioned primarily as a high-performance tracker for athletes, researchers, founders, and high-stress professionals.

How does Temple work?

One of the key reasons Temple works is where it is worn, i.e., on the temple. The temple region gives sensors proximity to temporal arterial blood flow and superficial cerebral circulation, allowing non-invasive monitoring of brain-level signals.

Now Temple doesn’t reveal the exact proprietary sensor technology at work here, but it is evident that the device relies on continuous optical or physiological monitoring—similar to near-infrared spectroscopy. It could be tracking how blood flow and oxygenation shift in real time.

Temple will measure your “Entropy”

One of the major concerns we all had was what Temple will measure. Goyal’s team claims to have identified a unique biomarker readable specifically at the temple region, which they have branded Entropy.

Entropy is described by Temple as the live “real-time cost” your body pays to stay alive and function at any given second. 

Resting Entropy: The device will care for resting entropy, which is essentially a measure of metabolic and sympathetic effort required when the body is at rest. A lower Resting Entropy shows higher physiological efficiency.

Max Entropy: This measures the maximum output or effort the body can sustain when pushed to its limits during intense physical or mental load. A higher Max Entropy represents greater physiological capacity.

Entropy updates continuously, responding to factors like stress, physical exertion, deep focus, caffeine intake, cold immersion, and sleep quality.

PV Sindhu and others have tested Temple

Temple first went viral when Goyal appeared on podcaster Raj Shamani‘s “Figuring Out” wearing a prototype clipped to his head. Since then, the device has undergone early-access testing among a select group of 100 “founding users” — a mix of doctors, scientists, entrepreneurs, and elite athletes.

Badminton champion PV Sindhu was recently spotted wearing the Temple tracker during major tournaments, marking one of the first high-profile uses of continuous head-worn monitoring in professional sports.

Price, pre-orders, and expected launch timeline

While final pricing remains unconfirmed, industry reports suggest a premium positioning ranging between Rs 75,000 to Rs 100,000 ($1,000). Goyal is yet to hint at what the device will cost and whether there will be a subscription fee for accessing the processed data insights.

Goyal, however, stated that pre-orders for the Limited Launch Edition are opening soon via their official channels, and shipments are officially targeted before the end of 2026.