Unacademy co-founder Gaurav Munjal has given a largely positive review of Temple, the wearable brain-flow device from Deepinder Goyal, as the product faces sharp questions from Indian doctors over its scientific backing.
Munjal, who said he had used the device on and off for a few weeks, posted his verdict on X on Thursday. "I think it has true potential to be a global product built out of India," he wrote.
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I have used Temple for the last few weeks on and off. I think it has true potential to be a global product built out of India (we do need great global products from India apart from just Haldiram's Bhujia). Pros: - Extremely lightweight / before wearing I was concerned the presence I'll feel on my head / many times I got reminded that I am wearing one when others told me - It does not come off / not during sleep / not during workouts / out of 30-40 nights / it did come out once - In fact Whoop is quite irritating during sleep / I don't feel the presence of Temple at all - Food Tracking Feature is better than any app out there / no other device can capture chewing / it sent a nudge after every meal / love this - Entropy and Brain Flow are amazing - Sleep tracking is quite good Cons - Few minutes of every Meeting goes in explaining Temple / because everyone asks / but I guess that will change once it becomes more omnipresent - Whoop App has better UI and UX
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— Gaurav Munjal (@gauravmunjal) November 5, 2026
Among the pros, he called Temple extremely lightweight and said he stopped noticing it on his head. It stayed on through sleep and workouts, he said, coming off only once in 30-40 nights. He also said Whoop was "quite irritating" during sleep, while he did not feel Temple at all.
Munjal singled out the food tracking feature, saying it was better than any app available because the device can capture chewing and sent a nudge after every meal.
He also praised the Entropy and Brain Flow metrics and called the sleep tracking "quite good".
His cons were limited. A few minutes of every meeting go in explaining the device because everyone asks about it, he said, adding that this would likely change once it becomes more common.
He also said the Whoop app has a better user interface and experience.
The review followed a long post by Goyal, who stepped down as Eternal CEO to focus on Temple.
Addressing "Concerned Indian Doctors", Goyal rejected suggestions that the device was a scam. He said the company has spent $30 million on it, including $20 million of his own money, and offers 14-day, no-questions-asked returns.
Goyal said peer-reviewed publications would follow, noting that most wearable makers begin with internal studies, and that "pre-prints are a step prior" to them. Business Today reported that Temple opened for pre-orders on November 1 at Rs 85,000.
It also noted that a heart-rate accuracy study Goyal cited earlier this week was funded and conducted by Temple and had not been peer reviewed.
ALSO READ | 'If Not, Keep Raging': Deepinder Goyal's 7-Point Reply To Doctors Calling Temple A Scam
The criticism of the device predates its launch. In January, AIIMS Delhi radiologist Suvrankar Datta dismissed the then-prototype as a "toy", citing a lack of clinical data.
Earlier, hepatologist Cyriac Abby Philips, known online as The Liver Doc, called Temple a "Desi Theranos" in a post on X.
Oh right on time! Trust me, you dont want to miss my post on Desi Theranos. https://t.co/uhe961ypkP https://t.co/jDJ4UvFQQb
— TheLiverDoc™ (@theliverdoc) November 3, 2026
Philips went through two studies cited by Temple. He argued that the sensor sits on the outside of the head and can reach only skin and surface facial arteries, not the brain. He noted that one study, a medRxiv pre-print comparing the device with transcranial Doppler, has not been peer reviewed.
He alleged that a second study, co-authored by Temple staff including Goyal, used data processing that blended skin signals into its brain readings, and that the device's software feeds motion and temperature inputs into the Brain Flow score.
Philips also criticised the exclusion of female participants from the studies.
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