Six months ago, venture capitalist Marc Andreessen stopped drinking alcohol. And although he feels much better, he’s “mad as hell about it,” as he wrote in his Substack post, “On Pausing Alcohol,” on Wednesday.

Andreessen, founder of the venture firm Andreessen Horowitz, claims he didn’t really drink in his 20s and 30s, but grew fond of whiskey in his 40s—pointing to “a thousand academic studies that proved that alcohol is actually good for you.” Many of those studies, however, have since been debunked. Instead, excessive alcohol use has been linked to increased risk of injury, poor sleep, depression and other long-term health issues, such as high blood pressure, heart disease and certain types of cancer.

The 51-year-old was even quoted as once saying “the perfect day is 10 hours of caffeine followed by 4 hours of alcohol,” which he still stands by. But after reading the show notes from podcast by neuroscientist Andrew Huberman about what alcohol does to your body, brain and health, Andreessen became “enraged.” In the conclusion, Huberman said “the best amount of alcohol to drink is no alcohol.”

“Since I stopped drinking, I feel much better. I don’t need as much sleep, but my sleep is better. I’m more alert through the day. I’m cogent and focused at all times. I have more energy when I exercise, and it’s easier to control my diet,” Andreessen writes. “It’s great, and I am super mad about it.”

In his Substack, Andreessen touches on some of the downsides he’s experienced as a result of quitting alcool, saying he feels like the “color has drained out” of his evenings.

“Spending time with people is still fun, but now it’s hard to sit still and watch a movie or read a book and unwind at the end of a hard day,” he writes. “I’m more prone to just work until bedtime. Grump grump grump.”

Andreessen also shares that he has no plans to substitute alcohol with cannabis or hallucinogens; however, he’s having a hard time finding a quality alcohol-free whiskey. He jokes that one day, he’s going to get “deeply, seriously, hammered … But not today!”