xAI Co-founder Greg Yang Steps Back After Lyme Diagnosis

Greg Yang, a co-founder of Elon Musk's artificial intelligence startup xAI, is shifting into an advisory role following a diagnosis of Lyme disease. The move, announced in a post on X, marks a significant change for the researcher who joined the company in June 2023.

Yang stated he will move into an informal advisory role immediately to focus on his recovery. The decision comes after months of battling unexplained symptoms that he attributed to the bacterial infection, which is notoriously difficult to diagnose.

The health challenges began subtly in early 2025. Yang initially experienced an illness he believed he had recovered from, only to notice lingering fatigue and a sharp drop in energy and creativity weeks later.

Over time, the symptoms intensified significantly. Ordinary activities became debilitating, with Yang noting that workouts or certain foods would leave him exhausted for days.

"There was a week where I slept 12 hours a day and still couldn't recover,"

he added, highlighting the severity of his condition. After multiple rounds of testing, his doctor diagnosed him with Lyme disease, a bacterial infection typically transmitted by ticks that is known for symptoms that can linger or worsen over time.

The diagnosis came as a surprise to Yang, who did not recall a tick bite. He theorized that the infection may have been dormant for some time before being triggered by the intense demands of his work.

"Likely I contracted Lyme a long time ago, but until I pushed myself hard building xAI and weakened my immune system, the symptoms weren't noticeable," he explained.

Despite the setback, Yang expressed a sense of optimism regarding his prognosis. He noted that he felt "lucky" to have caught the condition relatively early, viewing the discovery as an opportunity to address the issue before it worsened.

Yang's decision to step back is framed as a proactive measure to prioritize his well-being. He described the transition as an opportunity to "go founder mode on my health," applying the same dedication to his recovery that he applied to building the company.

His goal is to fully address the condition so he can return to his work with renewed vigor. "Fix it so I can push myself even harder when I rebound," he stated.

The move has drawn support from the company's leadership. In response to Yang's announcement, Elon Musk replied on X, wishing him a swift recovery and adding, "Maybe Grok will find a cure!"

Yang's departure represents a notable shift in the leadership structure of the rapidly evolving AI startup. He joined xAI as a co-founder in June 2023, bringing expertise from a nearly six-year tenure as a researcher at Microsoft.

His exit follows the departure of two other co-founders over the past year. Igor Babuschkin and Christian Szegedy both left the company in 2024, leaving Yang as the third co-founder to step away from daily operations.

As Yang transitions to his advisory role, the company continues its work in the competitive artificial intelligence landscape, though it now faces the challenge of navigating further leadership changes.

Greg Yang's health journey highlights the intense pressures often associated with founding and scaling high-stakes technology companies. His decision to prioritize recovery serves as a reminder of the physical toll that relentless innovation can exact.

For xAI, the transition marks another chapter in its ongoing evolution. While Yang steps back to focus on his health, the company's remaining leadership faces the dual challenge of maintaining momentum and ensuring stability amidst shifting personnel dynamics.

Observers will be watching closely to see how the startup navigates this period of transition and whether Yang's recovery will eventually lead to a return to the forefront of the company's strategic direction.