Pre-orders for Deepinder Goyal’s Temple, a head-worn “fitness tracking” wearable priced at Rs. 85,000, opened on November 1. After these pre-bookings, the device’s founder, Deepinder Goyal, was in a public controversy once again with doctors who say the company has not shown the scientific evidence that Temple measures what it claims. The company had promised earlier that it would present the evidence first before selling the product to consumers. Goyal said that the Temple would release by the end of this year. 

Dr Cyriac Abby Philips, a hepatologist who is also known as TheLiverDoc online, leads the criticism. Goyal, who founded Eternal (formerly Zomato) and no longer runs it as chief executive, says Temple is “strictly a fitness + AI device” and not a medical device. He also claims that the company got the clearances from the relevant regulatory bodies where it is required. Goyal didn’t share more details. 

The ‘Temple’ controversy brings back the debate around where we should draw the line between a “fitness tracking” device and a medical device that might be construed for a clinical diagnostic report.

What is a Temple? Temple is an adhesive sensor worn on the side of the forehead. The company website says its main metric, Entropy, “measures how hard your body is working to shed heat, read from your temple.” In general, entropy could mean the measure of disorderliness. Similarly, the second metric of Temple, BrainFlow, is meant to track blood flow to the brain.

What happened? 

Temple’s pre-orders opened on November 1. The same day, Goyal claimed that “Temple is the most accurate HR tracker compared to all flagship wearables, even in Zone 4 & 5.”

However, on November 4, TheLiverDoc asked:

“So why are you already selling Temple device on preorder, that has not been proven to work for any of the claims made, for Rs 85,000? Usually people sell devices that work. Do explain.”

On November 5, Goyal answered in a post headed “Dear Concerned Indian Doctors”. He argued that a bad product would fail quickly, highlighting that Temple offers 14-day returns. He also said he had spent $30 million on Temple, of which $20 million out of own pocket. On evidence, Goyal said:

“Most wearable companies start with internal studies. Whoop shipped its band in 2015, and the first published validation followed a few years later. We hold ourselves to a higher standard; pre-prints are a step prior to peer reviewed publications, and they are coming up.”

He ended the post with: “If not, keep raging”. Hours later, TheLiverDoc replied that the post gave no evidence that the device can read brain flow from a superficial artery. He wrote: “Temple device is a scam. There is no doubt about it.” Goyal’s post had argued the opposite: “Scams don’t build that cap table.”

Additionally, on November 6, Goyal apologised for the tone of his earlier post:

“Apologies where they are due: last night, I should not have bucketed all Indian doctors into one single box.”

He added that his anger was aimed at “a few influencer doctors, who are more influencers than doctors.”

TheLiverDoc’s central objection is about the location of device. He argues that a sensor on the temple reads a surface artery that feeds the scalp, not the brain. On November 9, he wrote:

“Instead, Temple only reads a surface artery on the forehead that supplies the scalp and face, which flushes with heat or exercise independently of the brain.”

On Entropy, he argued on November 7:

A device can produce a number without proving that the number means what its advertising says. That is the central problem with Temple’s “Entropy.”

Goyal has so far backed its claims with company-led studies rather than peer-reviewed journal papers. Two preprints, a research paper published publicly before peer review, one in September that tested Temple’s Brain Flow index and another later that month about BrainFlow metric. Goyal clarified that these papers are submitted for peer review, but none has been published in a scientific journal yet. 

On November 5, he wrote that preprints “are a step prior to peer reviewed publications, and they are coming up”. Dr Cyriac Abby Philips, disputes what the papers showed by saying that heart-rate study “an unreviewed, in-house white paper funded, run, and analyzed entirely by Temple Private Limited”. He argues the brain-flow preprints cannot separate blood flow in the brain from blood flow in the scalp. He adds that none of the papers tests Entropy, the metric Goyal now positions as Temple’s Unique Selling Point.  He also alleged “data falsification” in an earlier post. These are his claims, not findings of an independent body.  

When should medical regulators enter into ‘fitness trackers’?

Denying Temple as a medical device, Goyal compares its approach with that of other health tracking wearables, citing Whoop’s 2015 launch that apparently produced the scientific evidence “years later.” TheLiverDoc disputes the comparison, arguing that Apple, Fitbit, Whoop and Oura launched with stronger prior evidence, some with regulatory clearances. 

Later, Nikhil Pahwa, MediaNama’s foudner and Editor and also an investor in Zomato, argued on November 10 that regulators should step in. He wrote:

I think India’s Health Ministry / Central Drugs Standard Control Organization which regulates medical devices should look into this.

“This should force us to look at the gap between medical devices and fitness devices: that’s a regulatory gap that some fitness devices exploit,” Pahwa added. He also asked investors to engage “@deepigoyal and venture arms of listed company @InfoEdgeVC should respond to this with science and not ad-hominem, especially since investor money is now involved.” Ad-hominem is a logical fallacy where the argument is directed against a person, rather than against what that person says.

Meanwhile, Goyal claimed that “Social media is not the regulator for Temple. Wherever we need regulatory clearances, we will have them before we make any claim needing them.”

TheLiverDoc calls it a “U-turn”, from a brain-tracking device to a fitness tracker and says a fitness claim would need head-to-head studies against existing wearables.

The disclosures and transparency: 

A separate dispute concerns disclosure as well. For instance, on November 8, TheLiverDoc wrote to podcaster Ranveer Allahbadia, who had defended Temple on X, asking him to disclose his interests and alleging that Allahbadia is an angel investor in Temple’s $54 million round. However, the size of any stake has not been made public.

Similarly, another influencer Raj Shamani hosted Goyal on a four-hour podcast in which Temple was discussed alongside various other topics, including Goyal’s childhood, Zomato’s growth and his other businesses such as LAT Aerospace. 

According to Inc42’s report, Raj Shamani has a 0.03% stake in Temple.

“In my entire history of building Zomato, Eternal, and now Temple – we have never asked anyone to post anything online, for money or otherwise…. we sometimes ask our internal teams to repost our posts if and when they want,” Goyal wrote on X.  

This could be in response to the allegations against Goyal by LiverDoc. He posted a portion of a Discord screenshot where an account named Deepinder Goyal asked someone to “amplify” some particular Tweets. 

A small timeline of events: How it all began? 

Temple’s origin lies in an idea Goyal published in November 2025, the “Gravity Ageing Hypothesis”. It suggests that gravity’s pull on blood flow to the brain contributes to ageing. MediaNama reported at the time that Goyal had been photographed wearing a white patch near his temple, which he described as an experimental device to measure brain flow.

Goyal introduced the hypothesis on X on November 15:

I’m not sharing this as the CEO of Eternal, but as a fellow human, curious enough to follow a strange thread.

Five days later, he apologised for how he had presented it:

I brought my consumer internet brain into a deep scientific field and I miscommunicated. I tried to compress years of research and thinking into a dramatic social media reveal.

The first round of criticism against Temple began in January. On January 6, TheLiverDoc posted a sequence of his exchanges with Goyal. He described Temple as:

“…an ancient, already debunked gravitational theory of ageing to “promote” his zero-evidence based wellness product that looks like a fat band-aid stuck to the temple.”

On January 9, Goyal replied to “concerned doctors and/or influencers”. He said no sale had been announced and no data released:

“We haven’t made any public commercial announcements about Temple yet. We haven’t released any official device benchmarking data. A lot of the work is still underway; we’re months away from introducing preview devices to the public, if at all.”

He continued:

“We will share all the science if and when we decide to sell the Temple. You can judge and give all your advice at that moment. Until then, be curious, and cheer Indian startups? Your skepticism is valuable, but at the right time.”

The podcast carries a similar line. In the transcript, Goyal says Temple was benchmarked against MRI and Transcranial Doppler (TCD), an ultrasound test of blood flow in brain arteries), with more validation under way. On a market launch, he says: “if and when we are going to market it, we’ll have third-party validations.” He adds that he would release Temple only if convinced it was useful: “Else tank it.”

Nikhil Pahwa, MediaNama’s founder, responded on January 11:

Especially for a product that claims to be somewhat scientific, the onus of proof is on YOU, not doctors.

On February 27, Goyal announced that Temple had raised $54 million at a post-money valuation of about $190 million. A hiring post the same day said: “we are building the ultimate wearable for elite performance athletes.” In October 2026, cricketer Shubman Gill was seen with a Temple device near his forehead. 

In June, Goyal introduced Entropy:

“We have discovered (literally discovered) a biomarker, only readable on the temple region, and nowhere else, that measures the real-time cost of you being alive. We are calling it Entropy”

Later in August this year, Temple acquired the London longevity practice Longevous. Its founders joined: Dr Robert Mohr as chief medical officer and Dr Avi Roy as head of science.

In September, Goyal posted two preprints. The first tested BrainFlow against TCD in 23 healthy adults, with Goyal noting: “One study, two interventions, healthy adults only, but it’s the first step.” The second compared it with near-infrared spectroscopy, a light-based method, in 60 participants. His summary was:

“Key takeaway: Temple tracks the brain, much more than the scalp”.

On October 21, Goyal announced that pre-orders would open on November 1.

By November 5, Goyal was describing Temple in different terms from the brain-flow pitch. He wrote: “Temple is a fitness tracker, and wellness device. We are not a medical device. If at some point, we clinically validate any of our metrics, we will let you know.”

On November 8, Goyal posted a 10-point response. On medical claims, he wrote: “We didn’t make any medical claim.” He said Brain Flow was where the project started, not its main point.

 Also read

The post Explained: Everything you need to know about Deepinder Goyal’s Temple controversy appeared first on MEDIANAMA.