Deepinder Goyal’s Temple wearable may open pre-orders next week: What it can actually track

Deepinder Goyal’s Temple wearable is moving closer to its India launch, with pre-orders potentially opening as early as next week. People who joined the early-access waitlist are expected to get priority. The unusual device is designed to sit on the side of the head and track changes in blood flow linked to the brain using a system called BrainFlow.

Unlike a smartwatch or smart ring, Temple is a small, pill-shaped wearable that attaches to the skin around the temple. The company says it can remain attached during activities including running, showering and swimming, although it does not recommend using it while scuba diving.

How does the Temple wearable work?

Temple is attached using disposable Grips, essentially adhesive tapes designed to keep the device against the skin. The company says a Grip can last for up to seven days, broadly matching the wearable's claimed battery life. However, Temple recommends replacing the Grip every two to three days, particularly after exposure to sweat or dust. The device is also designed to fit underneath glasses. Its smooth edges are intended to prevent it from catching on clothing. The launch edition is expected to be available in six colours: True Gold, Rose Gold, Black Mirror, Real Jade, Deep Blue and Purple Funk.

What does Temple actually measure?

Temple uses a PPG (photoplethysmography) sensor, an optical sensing technology also found in smartwatches. The difference is where the sensor is positioned. Instead of measuring from the wrist, Temple places the sensor at the temple. The company says its BrainFlow system continuously tracks changes in cerebral blood-flow-related signals. Goyal says this data could provide insights related to sleep, recovery, exercise and the body's response to stress. However, there is an important distinction: Temple does not directly read brain activity and is not presented as a device that can diagnose health conditions. It uses optical sensing to track blood-flow-related signals rather than the electrical signals measured by an EEG.

What do the studies say?

Goyal has shared two studies supporting the technology. One involved 23 healthy adults and compared BrainFlow readings with Transcranial Doppler measurements during cycling and changes in posture. Another analysed 60 sessions involving 44 healthy men, comparing BrainFlow with time-domain near-infrared spectroscopy. The results shared by Goyal indicated stronger correlations with changes in brain blood volume than scalp blood volume. However, both studies are preprints and require further research and peer review.

Temple price and India launch

The final India price has not been confirmed. Goyal has previously indicated a price of around $1,000, or roughly Rs 1 lakh, while earlier reports suggested a figure closer to Rs 80,000.

The expected price is said to include an unlimited supply of disposable Grips. For now, the key date is next week, when pre-orders could open for waitlist users. The exact shipping date remains unconfirmed.