NEW DELHI: Temple, a head-worn wellness wearable whose team includes Eternal founder Deepinder Goyal, is not yet on sale, but its website lays out what the device measures and who is building it. The early access page says Temple "will soon be available for pre-order" and asks interested buyers to join a waitlist. It gives no price and no pre-order date.
The company, registered as Temple Private Limited, describes the idea on its home page in plain terms. Habits such as exercise, sleep, cold exposure and meditation, it says, raise something it calls BrainFlow, which it describes as a proxy for cerebral blood flow. Temple, worn at the temple, is meant to show whether those habits are working.
What BrainFlow is, and the evidence on offer
The science and research page is the closest thing to a technical claim sheet. It names three studies on the device itself. In the first, by Gulati D and colleagues, Temple BrainFlow was compared with time-domain NIRS, an optical reference method, in healthy young men put through three physiological challenges. The company reports a correlation of 0.84 to 0.91 with brain blood volume, against a lower figure for scalp blood volume. In the head-down tilt test the brain figure was 0.91 and the scalp figure 0.49.
The second, by Kumar A and colleagues, set the device against transcranial Doppler, a clinical ultrasound method for measuring blood flow velocity in the brain. Across 23 healthy adults doing cycling and a stand-to-supine shift, the page reports a within-person correlation of about 0.8. The third, by Liu D and colleagues, looked at 89 features of the optical pulse waveform and found 14 strongly related to age at the temple, against 3 at the wrist.
These are the company's summaries. The page does not say where the three device studies were published or whether they have been peer reviewed, and all three used healthy volunteers. That limits what they can say about people with medical conditions, and Temple presents itself as a wellness product, not a diagnostic one.
The people involved
The team page describes Goyal as a first-generation founder who built Eternal, which encompasses Zomato, Blinkit, District, Hyperpure and Feeding India. Mayank Ladia and Vikram Kumar, both described as long-time builders of Zomato's systems, are listed alongside him. The science side is led by Dr Avi Roy as Head of Science, with Dr Sachin Nadig on algorithms and Dr Ajay Bhat on hardware. A scientific advisory board lists academics from institutions including Boston University, Harvard Medical School and EPFL.
What the privacy policy says
A wearable that reads signals from the head will draw questions about data. Temple's privacy policy, dated 26 August 2025, says the company does not sell personal or health data and does not share it with insurers or employers without separate, explicit consent. It says data may be stored and processed in India or other countries where it or its service providers operate. The device is meant for adults only.
The policy also says some app features use third-party generative AI services, and that only de-identified metrics are shared with those partners, who are not allowed to store the data or train models on it. Users are told not to enter personal data into prompts. Support and privacy queries go to support@temple.com and privacy@temple.com.
A price, a ship date and full study details are all still unpublished.
