Deepinder Goyal's ?85,000 wearable device, Temple, is facing questions from doctors over its scientific credibility. While the former Eternal CEO maintains that the product is a fitness and AI device rather than a medical device, doctors argue that its claims about measuring blood flow to the brain have not been adequately established. The controversy has also drawn attention to the product's changing positioning and Goyal's combative responses to criticism.

Temple began as an experiment to measure blood flow to the brain and understand ageing. It was subsequently associated with a new biomarker called entropy, before being positioned as a fitness tracker. Goyal has more recently described it as an AI-powered personal companion that uses vibrations to capture the wearer's speech, calling it "humanity's last personal device".

Pre-orders opened on November 1, but questions remain about what the device actually measures, how reliable its readings are and what evidence supports its claims.

In an interview with CNBC-TV18, Harish Bijoor, Founder of Harish Bijoor Consults; Dr Sanjeev Bagai, Padma Shri awardee and Chairman of Nephron Clinics; and Prakash Dadlani, Co-Founder of Topsail Appliances, discussed the scientific, business and communication challenges facing Temple.

What does Temple actually measure, and why are doctors questioning it?

The central scientific question is whether Temple's sensor can measure cerebral blood flow or, more specifically, the blood supply within the brain.

Dr Bagai argues that a sensor placed on the temporal region of the skin can measure the superficial temporal artery, but this is not the same as measuring blood flow within the brain. The arterial and venous blood supply of the brain lies much deeper and is considerably more complex.

According to him, the device's design raises questions about its ability to measure cerebral blood flow accurately. An incorrect reading could also give a user a false sense of security about their health when an underlying problem may be developing.

Bagai has also questioned the research being cited in support of Temple. He pointed to a pre-review article involving 22 participants — 15 men and seven women — who were medically fit and studied at rest in an ambient temperature of 25 degrees Celsius.

He argued that such a small sample, studied under controlled conditions, cannot establish how the device would perform in real-world situations. He also questioned the research funding, saying that studies sponsored by the company need independent verification before their findings can be relied upon.

His objection is not to innovation itself, but to presenting a product as scientifically robust without sufficient evidence.

"I am all for innovation. That is the greatest thing India can do for itself," Bagai said, while insisting that Temple's claims must stand the test of medical science.

Does calling Temple a fitness tracker resolve the concerns?

Goyal has maintained that Temple is a fitness and AI device, not a medical device, and that it does not make medical claims. He has also said that peer-reviewed studies are on the way.

However, Bagai believes this description does not resolve the questions surrounding the product. He pointed to Goyal's earlier references to brain function, cognitive function, cerebral blood flow and the future of health, arguing that the product's positioning has changed repeatedly.

"You cannot keep changing the goalposts. You don't even know what your product is," Bagai said.

The issue, therefore, is not simply whether Temple is classified as a medical device or a fitness tracker. It is whether the capabilities associated with the product have been established through reliable research.

Bagai also raised questions about the data collected by Temple, including who would monitor and analyse it, how it would be used and who would be responsible in the event of a data breach. These concerns become particularly important when a device collects personal information related to the human body.

Has Goyal's communication strategy made matters worse?

The scientific debate has increasingly been accompanied by a separate controversy over Goyal's responses to criticism.

Harish Bijoor believes the founder's combative approach is counterproductive, particularly when the product operates in the wellness space. He argues that a founder's personal views should not become the brand's public voice.

Goyal's statements about having enough money to last generations, not needing the Indian market and asking sceptics not to buy the device may reflect his personal confidence. However, Bijoor believes such responses do little to build consumer trust.

He draws a distinction between founder language and brand language. While a founder may react defensively when a venture is criticised, the brand needs to communicate with customers in a more measured manner.

"What is missing is brand language. What is missing is brand humility," Bijoor said.

He also believes Goyal is overlooking the importance of doctors. In the wellness space, doctors are not merely critics or stakeholders; they could become important distribution channels and sources of credibility for a product.

Alienating the medical fraternity could therefore make it harder for Temple to establish trust among consumers. Bijoor's advice is that Goyal should step back from the public confrontation and engage with doctors rather than treat their questions as attacks.

Is the criticism discouraging innovation, or is scrutiny necessary?

Prakash Dadlani takes a different view of the controversy. While agreeing that Temple's science needs to be scrutinised, the Co-Founder of Topsail Appliances believes the criticism directed at Goyal risks becoming a witch-hunt against an entrepreneur attempting to build an innovative hardware product.

Dadlani, who has manufactured products in China for around 30 years and in India for the past decade, argues that the country needs to move beyond assembling products designed elsewhere and develop its own innovations.

He believes entrepreneurs attempting to build new products should be encouraged, even as they are expected to explain their technology and respond to questions about its capabilities.

However, he does not believe India should be dismissed as a market for an expensive product. He pointed out that Indian consumers are willing to spend on premium devices and argued that entrepreneurs should look to leverage this demand.

Bijoor, too, does not consider Temple's ?85,000 price tag a problem in itself. He describes it as a "belief product", where consumers are willing to pay a premium if they believe the product serves their purpose.

In his assessment, the bigger concern is what the price communicates about the product's quality and credibility. A premium price raises consumer expectations, making it important for the product's capabilities to match its positioning.

What does the controversy mean for Temple's future?

Goyal has defended the project by highlighting the investment behind it and its 14-day, no-questions-asked return policy. He has said that $30 million has been spent on building Temple, of which $20 million is his own money. He has also argued that selling a few thousand devices would recover only a small fraction of that investment.

Bijoor believes the controversy could affect Temple itself, although he does not expect it to automatically spill over into Goyal's other business ventures, including Eternal.

Dadlani, meanwhile, believes the market will ultimately decide the product's fate. He has acknowledged that Goyal's communication strategy could hurt him, but maintains that scrutiny and encouragement for entrepreneurs need not be mutually exclusive.

For Temple, the immediate challenge is to establish precisely what the device can measure and provide credible evidence to support those capabilities. Its premium positioning and the founder's personal investment may demonstrate the ambition behind the project, but they cannot substitute for scientific validation.

Until those questions are addressed, Temple's ability to convince consumers will depend not just on how Goyal presents the product, but on how convincingly it can demonstrate what it actually does.