Biohacker who is 'reverse aging' reveals horrifying side-effect of procedure to make him look younger

A biohacker who is 'reverse aging' has revealed the horrifying side effect of a procedure he is taking to make him look younger.

Bryan Johnson is taking part in a lengthy and intense experimental medical program in the hope of reversing ageing.

Whether it be following a strict diet, or using his son's blood, the biohacker is doing every he can to look a lot younger than he actually is.

In addition to his restrictive lifestyle centred around diet and exercise, Johnson, 47, has spent close to $2 million on 'treatments' he hopes will keep him looking young for years to come.

Bryan Johnson has gone to extreme measures to reverse the aging process (Instagram/@bryanjohnson_)

Johnson recently underwent a "first therapy: injecting a fat-derived extracellular matrix to restore volume by stimulating my body’s natural fat growth."

Donor fat was subsequently used, which caused Johnson's face to swell to concerning levels, while the biohacker suffered from blurred vision.

Speaking of what happened after the procedure, Johnson penned on social media: "Immediately following the injections, my face began to blow up."

Johnson had suffered a severe allergic reaction to the procedure, which came shortly before an interview with Bloomberg’s Ashlee Vance.

I called him and said, 'Hey, so that you’re not alarmed, you may not recognize me today. I think I’m ok. I hope I’m ok. If I’m not ok, are you by chance trained to perform any life-saving actions?'" Johnson said of a conversation between himself and the journalist.

Thankfully, Johnson's face is now back to its normal size - though it was seven days of much worry before the swelling came down.

The biohacker suffered an allergic reaction (Twitter/@bryan_johnson)

Earlier this year, Johnson spoke about a $20k medical procedure that 'edits his DNA' so he 'lives forever'.

Johnson explained in a YouTube video: "Humans have a 120-year ceiling and so far no one can punch through it - gene therapy might be the answer. I never imagined I would be doing gene therapy on an island off the coast of Honduras."

He added: "Their target: follistatin gene therapy. A pioneering technology with the potential to improve muscle and strength [and] slow the speed of aging and many more benefits."

The biohacker explained how the procedure involves an injection in the stomach and in the buttocks at a cost of $20,000.

Johnson previously said how he avoided treatment involving DNA due to concerns around cancer.

"If a therapy caused say cancer in my body there'd be nothing I could do to reverse the process," he said.