I went to a private longevity night hosted by Bryan Johnson in San Francisco. I needed a cookie afterward.

The only topic these days that gets people in San Francisco to stop talking about AI is living forever.

When Baseten, an AI startup (what else?), announced a few weeks ago, it was hosting a "private evening" with tech entrepreneur and longevity evangelist Bryan Johnson and VC Sarah Guo at its SF office, over 3,000 people applied to get in for just 100 slots.

For the uninitiated, Johnson made hundreds of millions selling his payment startup to PayPal and now spends millions a year on a wellness regime that he shares with his 2.7 million Instagram followers. Johnson has been in the news a lot this summer, after he revealed he has autoimmune gastritis, an incurable chronic condition of the stomach. Then, last month, he said, "he might have taken 'this whole longevity thing too far."

When I arrived, the registration table was swarmed by people condemned to the waitlist trying to angle their way in.

"Don't bother," said the person at the desk. "It's full."

Once I squeezed past the crowds, I was handed a color-coded schedule with three stations: Breathwork, Bioage tests, and a Q&A with Dr. Carl Seger, Johnson's lead doctor.

"Nothing you measure tonight is a verdict," I was told. "It's a baseline, and every one of these markers can be moved."

But first, it was time for happy hour! No hors d'oeuvres or wine here. Instead, can I interest you in raw vegetables and mocktails to take the edge off? I opted for a refreshing "Tumeric Elixir" with orange juice, carrot juice, ginger, and tumeric.

As soon as I walked in, I noticed everyone seemed overwhelmingly youthful. One tech founder in his fifties told me he felt ancient. So either Johnson's routine is working wonders or this crowd was emblematic of Silicon Valley's "youthquake."

I asked an enthusiastic young machine learning engineer who works at Uber why he was there.

"Bryan Johnson is just so cool!" he said.

But enough chitchat. It was time to get my face scanned to learn my "face age." After a few minutes, a reading popped up. I was in the 80th percentile for wrinkles (which is apparently very good), but my "face age" was older than my real age.

Feeling a little dejected, I walked over to the bioage stations, where participants underwent a series of tests, such as grip strength, push-ups, and a one-leg stand, to measure their biological age. Johnson, accompanied by his new guard dog, Katara, strode by, playfully encouraging people to do a few more push-ups.

A few feet away, engineers were coding on giant screens. We were in an office after all, not a gym, and the work must go on.

Before Johnson's interview, it was time for a dinner "guided" by his personal chef, Tara Amanya. There were box meals with chicken and vegetables, but I opted for the salmon, which was tasty but left me a bit hungry.

Anything that gets people to exercise more or eat healthier should be commended. Still, I was struck by how many questions throughout the night came down to people wanting easy shortcuts to essentially hack life, as if it were an algorithm to be exploited.

Again and again, people kept asking: "What is the one thing I can do to live longer?"

I kept thinking about my grandparents, who never heard of peptides or biohacking. They drank wine with dinner every night and mostly ate whatever they wanted. They all lived well into their nineties.

Johnson is far more self-aware than he can seem on Instagram, and when he was interviewed by Guo to end the evening, he said: "We all know I'm going to die, but it's going to be being hit by a bus or choking on broccoli."

"I give you permission to revel in the joy of it," he continued. "That is irony, and my ultimate foe is irony."

After the talk ended, I walked back to my hotel and ordered a chocolate chip cookie.

Do you have a tip about life in Silicon Valley? Contact reporter Ben Bergman securely on Signal at @BenBergman.11