Yeah we see you flexin' Elon.

Elon Musk has a tough schedule. In an explosive interview published Thursday night, the Tesla CEO defended sometimes erratic behavior by revealing details about his 120 work weeks, factory all nighters on his birthday, and a sleep schedule that’s all but impossible to maintain without Ambien.

“It is often a choice of no sleep or Ambien,” Musk told the New York Times. Two people familiar with the board told the publication that some members are concerned about his use of the drug, with some noting that instead of going to sleep Musk stays up and posts on Twitter.

Tesla has faced intense pressure over the past year, after the $35,000 Model 3 entered production in July 2017. The relatively lower price, coupled with a backlog of nearly 500,000 orders, necessitated a production expansion from around 2,000 cars per week total to an end of June rate of 7,000. Tesla is also planning to boost production of its solar roof, and launch three new models of vehicle over the next two years.

Ambien, a brand name for zolpidem, works similar to benzodiazepines like Valium and Xanax in that it slows down brain activity. This is meant to induce sleep, but it can also lead to some unexpected behaviors while awake.

Musk has made some bizarre Twitter posts during Tesla’s high-pressure expansion, but Musk’s interview did not specify any tweets that were written under the influence of the drug. In March, he announced an “intergalactic media empire” called “Thud,” in April he claimed he had “prehensile eyebrows,” and in May he posted an image of a “woke frisbee.” Other posts have been less innocuous: Musk was forced to apologize after describing a Thai cave rescue hero as “pedo guy.”

It’s also not the first time Musk has mentioned Ambien use.

One post that Musk is serious about, though, is his plan to take Tesla private with a buyout offer of $420 per share. The offer was 20 percent higher than the share price on the day of the announcement, but the number is common in marijuana culture, which some interpreted as meaning that Musk was not serious about the offer. Tesla has shared more details about the plan since the post, and in the Thursday interview he rebuffed suggestions that there was any weed involved in the post.

“It seemed like better karma at $420 than at $419,” Musk said. “But I was not on weed, to be clear. Weed is not helpful for productivity. There’s a reason for the word ‘stoned.’ You just sit there like a stone on weed.”

Photos via Elon Musk