In a Netflix documentary released in January, Bryan Johnson, a tech entrepreneur turned longevity guru, walked people through his morning routine. After tracking his sleep, he would wake up early to conduct audio therapy and hair therapy, do an hour of exercise and take 54 different pills with a drink called “the green giant,” he said.

Mr. Johnson also talked about his long-life start-up, Blueprint, which sells health supplements, blood-testing equipment and other products tied to his personal diet and recommendations.

“By doing Blueprint, one of the key objectives is to achieve the lowest possible biological age,” he declared. He added that his health regimen had “reversed my biological age 5.1 years.”

The Netflix feature was a breakout moment in Mr. Johnson’s five-year campaign to become the face of one of Silicon Valley’s most oddball fascinations: the pursuit of everlasting youth. The 47-year-old former Mormon missionary has become known for experimenting on his own body to defy aging, captivating the media and his nearly four million social media followers by receiving the blood plasma of his then-17-year-old son and repeatedly shocking his penis to increase his erections.

His fame has also appeared to catapult Blueprint to success. In January, Mr. Johnson hailed his start-up as “one of the fastest-growing companies in the world, fueled by word of mouth.”

But away from the cameras, his carefully curated profile and Blueprint’s business are starting to show cracks — especially with a brewing fight over Mr. Johnson’s use of a legal document: confidentiality agreements.

For nearly a decade, Mr. Johnson has wielded confidentiality agreements to control his image and the companies he built atop that image. His employees, sexual partners, vendors and contract workers have all had to sign the documents, sometimes in exchange for settlements, severance or continued employment at his firms, according to people close to him and his start-ups, internal documents and court records.

Now those agreements, which were supposed to keep people silent on Mr. Johnson’s personal life and businesses, are backfiring as some of his workers band together to challenge them.

At least three of Mr. Johnson’s former employees — including a former fiancée who worked for him — have recently filed complaints with the National Labor Relations Board, a federal watchdog agency, about his confidentiality agreements. They said the terms they signed were “overbroad” and accused Mr. Johnson of violating federal laws that protect workers who want to speak about their workplace conditions, according to copies of two of the complaints and six people with knowledge of them.

People close to Mr. Johnson and Blueprint have increasingly chafed at the agreements as the start-up has faced mounting financial and product-quality questions that some thought should be made public, former employees and others with knowledge of the company said.

Oliver Zolman, Mr. Johnson’s longtime longevity doctor, who was featured in the Netflix documentary, quietly left Blueprint last year after having concerns about some of its health supplements, the people said. Last fall, Mr. Johnson also told Blueprint executives that the company was running out of money.

Mr. Johnson’s goal was “to use these contractual agreements to keep everyone quiet,” and that effort “kind of was a house of cards,” said Matt Bruenig, the lawyer for the former employees who filed the N.L.R.B complaints.

Jamie Contento, who was Mr. Johnson’s personal assistant and who filed one of the N.L.R.B. complaints, said she “definitely felt coerced into signing the agreements” because she thought she would lose her job if she did not do so.

The New York Times interviewed 30 people close to Mr. Johnson and his start-ups, including current and former employees. Many spoke on the condition of anonymity because they were bound by the confidentiality terms and feared retaliation from Mr. Johnson. The Times also reviewed copies of the agreements, court records, internal documents, photos and the N.L.R.B. complaints.

Mr. Johnson declined to answer many questions from The Times. In a post on X before this article was published, he said confidentiality agreements “try to create clear boundaries and expectations, so that trust isn’t left to chance.”

After The Times contacted Mr. Johnson, he privately pushed people in his orbit to abide by the agreements, people familiar with his outreach said. One legal letter sent last month reminded a former employee that they were “strictly prohibited from using, disclosing or misappropriating any confidential, proprietary or trade secret information belonging to the company or Bryan R. Johnson,” according to a copy.

Publicly, Mr. Johnson focused on other things. This month, he announced his own religion, which is named after his longevity slogan, “Don’t Die.” It would save the human race, he said.

Eternal life

Mr. Johnson founded the payments company Braintree in 2007 and became a multimillionaire when PayPal bought the start-up in 2013. He soon shed his Mormon roots and began a phase of exploration.

Mr. Johnson divorced his wife, with whom he has three children, and left the Mormon Church. He hired prostitutes, according to friends, former employees and court documents, and took drugs including acid, Ibogaine and DMT.

Mr. Johnson has not publicly addressed his use of acid, but is a proponent of psychedelics like DMT and has the shape of its chemical structure tattooed on his arm.

He also started using confidentiality agreements. The terms mandated that people could not speak publicly about his escapades, or talk to their friends or family about him.

In 2016, Mr. Johnson founded Kernel, a brain technology start-up. He had turned down the chance to establish a similar company with Elon Musk, who created his own such firm, Neuralink.

Mr. Johnson increasingly fixated on his reputation, according to former friends and employees, and wondered why he was not getting as much publicity as Mr. Musk. He turned more to confidentiality agreements. In 2020, he required a date to sign one before the two used acid together, two former friends said. She signed but left early, incensed by the agreement.

The confidentiality terms were typically attached to broader employment agreements at Mr. Johnson’s business. At the time, a Kernel employee agreement with confidentiality clauses was four and a half pages long, with few specifics about what workers could not talk about.

But as Mr. Johnson transitioned into the longevity industry and focused on his health, losing more than 50 pounds, the terms mushroomed. The change was driven partly by the founding of Blueprint, a start-up at Mr. Johnson’s Los Angeles home, in 2021 to sell health products to his legions of death-averse fans. (He stepped down from Kernel in 2023 but remains on the board.)

Blueprint’s brand is tied to Mr. Johnson’s image, with pop-ups of his face promoting the Netflix documentary and supplements called “Bryan’s favorites” listed for sale on the website. “He is the healthiest person on the planet,” Blueprint’s site claims.

By last year, a Blueprint employment agreement with confidentiality terms was 20 pages long and listed dozens of restrictions.

Among them: Workers must keep confidential “any nonpublic information regarding Bryan’s home, office, personal effects in his home or office, any spaces rented or owned by Bryan, any vehicles/planes/automobiles/boats/other methods of transportation that are not publicly accessible, or areas of his home or such space that are not publicly accessible,” according to a copy.

In his X post, Mr. Johnson said the agreements “have evolved, just like everything else I iterate & improve upon.” He added, “The goal is precision.”

Employees at Blueprint, which has a staff of about 30, sometimes had to sign as many as three separate agreements. That is atypical for employee agreements, according to legal experts.

One was an unusual “opt-in” document, which is not a confidentiality contract but aims to protect the company from potential lawsuits over what employees might witness in the workplace.

Under that agreement, employees had to attest that they were OK with Mr. Johnson’s wearing “little and sometimes no clothing/no underwear” and with hearing “discussions of sexual activities, including erections,” according to a copy. They also had to agree that Mr. Johnson’s behavior was not “unwelcome, offensive, humiliating, hostile, triggering, unprofessional or abusive.”

The opt-in agreement was “fair to all concerned and is in everyone’s best interest,” Mr. Johnson posted on X.

Many wealthy individuals and companies use confidentiality agreements. But Cliff Palefsky, an employment lawyer in San Francisco, said some aspects of Mr. Johnson’s agreements were overly broad and unenforceable.

Mr. Johnson and his company are “counting on people being afraid and not violating it because they’re afraid,” said Mr. Palefsky, who reviewed the documents for The Times.

Longevity mix

By early last year, some Blueprint employees were growing frustrated with the confidentiality agreements as the company experienced problems, people who have worked there said.

Among them were questions about Blueprint’s health supplements. The company sells about a dozen different proprietary supplements, including a $49 “longevity mix,” according to its website. Supplements are subject to lighter regulation than medicines.

At the time, Mr. Johnson and his leadership team, including Dr. Zolman, asked for volunteers to join a study of the supplements and meals called “The Blueprint Stack.” The goal was to examine the effects of the products on people’s health, according to the people and internal documents viewed by The Times.

Some executives, including Dr. Zolman, wanted to follow standard clinical testing procedures for the study and choose users to test at random, the people said. But Mr. Johnson had customers pay more than $2,100 to participate, they said. He promised them he would release the results by the summer of 2024.

Of the roughly 1,700 participants in the study, about 60 percent experienced at least one side effect, according to internal emails, spreadsheets and other documents. Blood tests revealed that participants saw their testosterone levels drop and became prediabetic after following Mr. Johnson’s diet plan. It’s unclear how severe the side effects were.

“Longevity mix: A lot of comments about hating this as it is making them sick, vomit, have heartburn, etc.,” one Blueprint employee wrote to a colleague in February 2024.

Allulose, an ingredient in the longevity mix and a sugar alternative that Mr. Johnson has pitched to his social media followers, also caused issues. “TONS of people saying it’s causing nausea, bloating,” wrote an employee.

In an email to The Times, Mr. Johnson said the results showed “common side effects with any food, beverage or supplement.” Blueprint products are always improved, he said, and are tested for safety. He added that it was typical in a self-experimentation study to not cover participants’ costs.

Employees felt they could not share the findings because of the confidentiality agreements, according to the emails and text messages.

Last summer, Dr. Zolman left Blueprint after raising concerns about the study’s results, people familiar with his departure said. He had signed a nondisclosure agreement, but Mr. Johnson wanted him to sign another one in return for a month of severance, they said. Dr. Zolman declined because of the stringent terms.

Mr. Johnson did not publish the study’s results by the summer of 2024, as he had told customers he would. In January, he released some data for about 300 participants, showing positive results. The supplements continue to be sold.

In an email to The Times, Mr. Johnson said metrics about Blueprint’s supplements “transitioned to or stayed in the normal range throughout the entirety of the study.” He added that Dr. Zolman had resigned “to seek professional help for his serious mental health concerns,” without providing evidence. Dr. Zolman did not leave for those reasons, people with knowledge of his departure said.

At the same time, Blueprint ran into financial challenges. While revenue increased last year to about $40 million and the company has about 40,000 customers, it was falling below its break-even point by at least $1 million a month, people with knowledge of the business said. Mr. Johnson, who had put in $25 million as Blueprint’s sole investor, warned executives that the company was running out of money. Its current finances are unclear.

This year, a recruiting email described Blueprint as “already profitable,” according to a copy of the message.

Mr. Johnson has also sometimes cherry-picked the rosiest metrics for his own health experiments, former employees and others said, particularly to spotlight his “biological age,” which refers to how well his organs and other body parts are functioning.

In the Netflix documentary, which was largely filmed in 2023, Mr. Johnson said his biological age had reversed 5.1 years. But the results of a range of internal studies of his health between January 2022 and February 2024 showed it had increased by as much as 10 years, according to charts of the blood test results. It’s unclear what his current tests show.

In an email, Mr. Johnson said that the “decision to highlight the 5.1 year reduction was made entirely by the documentary’s production team” and that the statistic came from an experiment conducted in early 2023. He said “biological age measurements fluctuate” depending on the test and other factors.

‘Just didn’t feel right’

Employee concerns flared last spring when Blueprint sent the opt-in agreement, requiring workers to say they were OK with many workplace behaviors. It landed in email inboxes with instructions to sign as a normal course of business.

Many employees signed, but their concerns mounted. With Blueprint run from Mr. Johnson’s home, the line between his personal life and business sometimes was hazy, former employees and others close to Mr. Johnson said.

During workdays, Mr. Johnson frequently walked around with little clothing on, and sometimes flirted with Blueprint’s largely female staff, they said. But because of the opt-in agreement, no one felt able to could complain.

Ms. Contento, who had also worked at Kernel, said she had been at Blueprint for a year when she was asked to sign the opt-in agreement. She agreed because she did not want to lose her job, she said, but “the document just didn’t feel right.”

Last fall, Ms. Contento left Blueprint. At the time, she emailed human resources to raise concerns about the work environment, which she said “began to change in ways that made me feel uncomfortable,” according to a copy of her message.

“There were certain professional boundaries that, from my perspective, seemed to blur over time,” she wrote.

It’s unclear if Blueprint investigated Ms. Contento’s concerns. She did not sign another of Mr. Johnson’s confidentiality agreements upon exiting the company.

Mr. Johnson said in an email that Ms. Contento had “raised no material complaints or concerns regarding the work environment or her role to my knowledge” while at Blueprint.

A call for action

Even as concerns grew over what Mr. Johnson was saying publicly versus privately, many employees were afraid to challenge him and his confidentiality agreements.

They had a cautionary tale: Taryn Southern.

Ms. Southern, 38, was Mr. Johnson’s former fiancée and an employee of his brain-technology start-up, Kernel. In February 2020, Mr. Johnson fired Ms. Southern from the company after breaking up with her while she had Stage 3 breast cancer, according to a 2021 lawsuit she filed against him.

Mr. Johnson had pressured her to sign an employment separation agreement with confidentiality terms, the lawsuit said. One version of the confidentiality terms included a $500,000 penalty each time she broke the rules.

“It’s all he seemed to care about, that agreement,” Ms. Southern said in her first interview about the experience.

Many Blueprint employees followed the developments in Ms. Southern’s lawsuit, in which she contended that Mr. Johnson had breached a promise to pay her $150,000 in exchange for rent and moving out of their home after their breakup.

Mr. Johnson successfully moved the lawsuit to arbitration. In 2023, an arbitrator ruled that Ms. Southern must adhere to her employment separation agreement, which included terms that said she could not sue Mr. Johnson.

He then countersued for his legal fees, with Ms. Southern ordered to pay more than $584,000 to him.

Mr. Johnson took the legal battle public. In 2023, he posted a 16-minute YouTube video saying he was a victim of “the dark underground accusation economy.” He followed on Valentine’s Day 2024 with a 2,400-word post on X naming Ms. Southern, saying that he feared she would try to kill him with a pair of scissors and that his health regimen had saved her from cancer. It got more than 500,000 views.

Ms. Southern felt she could not respond because of the confidentiality terms. (Four people close to the couple said that they had never heard Ms. Southern threaten to kill Mr. Johnson and that his health regimen did not save her from cancer.) Her social media accounts and email inbox filled with attacks from Mr. Johnson’s fans.

“Cancer treatment and my termination and everything I had to go through — that was all awful,” said Ms. Southern, whose cancer is in remission. “But what felt worse was not being able to share the truth when I was being publicly attacked.”

Mr. Johnson has not paid Ms. Southern the $150,000. In his YouTube video, he said he would set up a trust so payments from “his accuser” for his legal fees would go toward her medical expenses. Emails viewed by The Times showed he opened the trust last year, then closed it without putting money into it.

Last summer, Ms. Southern filed a complaint against Kernel and Mr. Johnson to the N.L.R.B., saying the confidentiality terms violated a provision of labor law that protects employees who want to speak about workplace conditions.

While Ms. Southern is still bound by the agreement’s terms, she said she chose to speak to The Times about her working conditions to represent Mr. Johnson’s employees.

Other employees heard about Ms. Southern’s legal strategy. In February, Ms. Contento, the former assistant to Mr. Johnson, filed a similar complaint to the N.L.R.B. through the same lawyer, Mr. Bruenig. Ms. Southern said Ms. Contento had learned about him through her complaint. A third former employee of Mr. Johnson’s soon filed a complaint similar to the other two.

Because the employees filed in a concerted effort against Mr. Johnson, federal law protects their ability to speak about workplace conditions, Mr. Bruenig said. He added that the N.L.R.B. was investigating Ms. Southern’s complaint.

The N.L.R.B. did not return requests for comment. Ryan Field, Kernel’s chief executive, said the company was cooperating with the investigation. Mr. Johnson has brought in David Broderdorf, an employment lawyer at Morgan Lewis, according to filings with the N.L.R.B.

Some of Mr. Johnson’s current and former employees are now regularly chatting with one another about their experiences at his companies, Ms. Southern said.

“We hope to bring some kind of positive ending for other employees,” she said.

Kirsten Noyes contributed research.