Law enforcement agencies have been using breathalyzers to test motorists’ sobriety for decades, but a new startup is staking a claim to bring its cannabis version of the technology to market.
So far, the only reliable ways to test for cannabis use have been through saliva, blood, or urine, which aren’t always practical in a roadside setting. But more than that, Tetrahydrocannabinol (THC) is known to remain detectable in the system long after a user would be impaired from its use. This is why Hound Labs is developing its breathalyzer, given that THC is detectable in the breath for only a few hours after marijuana use.
Oakland-based cannabis breathalyzer startup Hound Labs is today announcing an $8.1 million funding round led by Benchmark, the renowned Silicon Valley VC firm that has made early-stage investments in a number of notable startups, including eBay, Uber, Dropbox, Snapchat, Twitter, and Instagram. So Hound Labs, it’s fair to say, is in good company.
Hound Labs field-tested its Hound breathalyzer with law enforcement in California last year, and clinical trials started this month at San Francisco General Hospital (SFGH). The company plans to begin manufacturing a market-ready device later this year.
June 5th: The AI Audit in NYC
Join us next week in NYC to engage with top executive leaders, delving into strategies for auditing AI models to ensure fairness, optimal performance, and ethical compliance across diverse organizations. Secure your attendance for this exclusive invite-only event.
“Over the past two and a half years, we have extensively tested our device with marijuana users and routinely correlated our results with state-of- the-art forensic laboratory equipment,” explained Hound Labs CEO Dr. Mike Lynn. “We are eager to demonstrate the Hound marijuana breathalyzer’s capabilities and to take the final steps toward commercial availability.”
The Hound breathalyzer is touted as being portable, as well as highly accurate, which means it could be used by police roadside or by employers in a place of work where drug-testing is standard.
Though the device is similar in look and feel to an alcohol breathalyzer, the Hound has to be more sensitive to detect THC — it claims to measure THC molecules in parts-per-trillion, as opposed to the parts-per-thousand measurement standard with alcohol.

Above: Hound Labs’ cannabis breathalyzer
Since the legal floodgates to sell cannabis have opened in several U.S. states, the fledgling weed industry has been gaining momentum. Indeed, a number of VC firms have plowed cash into marijuana startups — DCM Ventuers, Tusk Ventures, and 500 Startups are among the firms that have invested in medical marijuana delivery firm Eaze.
Elsewhere, Peter Thiel’s Founders Fund took a minority stake in Privateer Holdings, a Seattle-based company behind weed startup Leafly.com.
But while some VC firms have been investing in technology startups that enable cannabis intake, Benchmark is looking to tackle things from the other side. With as many as 55 million Americans reportedly using marijuana to some degree, Hound sees an opportunity to take on the problem of stoned drivers.
“Cannabis legalization has created a new global market for employee and law enforcement testing,” stated Benchmark general partner Mitch Lasky, who will also join Hound Labs’ board of directors. “In the past, employers and law enforcement professionals focused on possession and use. After legalization, impairment — whether behind the wheel or on the job — becomes the new enforcement paradigm. Groundbreaking science is necessary to make an accurate measurement of recently used cannabis, and Hound Labs is uniquely positioned to deliver a solution to the market that respects the needs of the enforcement community as well as the rights of legitimate cannabis users.”
In addition to the clinical trials that have kicked off in San Francisco, Hound Labs said that it will continue carrying out field studies with law enforcement agencies across the U.S.
Today’s funding takes Hound Labs total cash injection past the $14 million mark.