Neurologist dismantles Zomato founder's brain wearable claims

Deepinder Goyal's Temple headband, marketed to hundreds of millions of followers as a tracker of brain blood flow, stress and fatigue, has drawn a pointed rebuttal from one of India's senior neurologists. Dr Praveen Gupta, chairman of neurosciences at Marengo Asia Hospitals in Gurugram, told Times Now Tech that the device lacks the clinical evidence to support any health claim.

Goyal himself has conceded the framing problem, posting on X that Temple is a "fitness and wellness tracker and not a medical device" while insisting its Brain Flow Index is "backed by research and published data." Gupta's response to that data is precise: no large peer-reviewed studies exist apart from the company's own, and the company's own figures — a 0.80 correlation during controlled physiological changes — may be encouraging but establish nothing about stroke, dementia, stress or migraine.

The anatomy is where the claim falls apart. Gupta notes the temple is indeed a convenient place for optical sensors, because the superficial temporal artery and its branches sit close to the surface. But convenience is not coverage. The brain's regions have different blood supplies, and a reading taken from one temple says nothing reliable about the opposite hemisphere, the brainstem, the cerebellum or the thalamus. Migraine alone can change superficial blood flow over the temple enough to confound whatever the sensor thinks it sees. No data exist, Gupta says, showing the device can separate signals originating in the brain from those originating in the scalp — or from one brain region versus another.

Then there is the hardware's relationship with the head it sits on. The temple's thin soft tissue and dense superficial nerves mean prolonged pressure risks tenderness, skin irritation and headache in susceptible users — a cost borne entirely by the wearer.

The deeper issue is who funds and who verifies. A billionaire founder who finances the research, controls the data and promotes the conclusion through his own distribution channel occupies every seat at the table: investigator, publisher and marketing department. When the only studies that exist come from the seller, the buyer runs the experiment.

Gupta's remedy is the one the industry never volunteers: independent, peer-reviewed replication. Until then, the device measures blood flow in the skin of the temple, and calls it the brain.