Many of us invest money on gym memberships or skincare to look - and feel - our best, but that's nothing compared to the amount one tech entrepreneur spends to 'reverse aging'.
You might have seen Bryan Johnson doing the rounds on social media, as people truly cannot believe the lengths he's going to get the body of a teenager and reverse his biological age.
Johnson, 46, believes 'biohacking' can get him there - and has embarked on what he calls 'Project Babyface' (yes, that's the real name) to achieve his goals.
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It all comes as part of his larger anti-aging initiative called Project Blueprint - and he reportedly forks out $2 million (£1.59 million) a year for it.
Well, at least the tech entrepreneur has money to spend - he sold his payment processing tech business, Braintree, to PayPal for $800 million (then £492 million) a decade ago.
And he does all manner of wild things to reverse his biological age, including wearing a baseball cap that shoots red light into his scalp and even undergoing plasma transfusions, with his son being one of the donors.
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As you can probably imagine, his fitness regime is gruelling to say the least. Johnson works out for at least an hour a day, including using a machine that he says puts his body through the equivalent of 20,000 sit ups in just half an hour.
And his diet? It's hardly like Johnson is indulging in the odd takeaway.
Instead, what he eats is just as regimented as everything else in his life.
He's done away with calling meals 'breakfast', 'lunch' and 'dinner', but instead uses 'first meal', 'second meal', and so on.
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In an interview with Time, he revealed that his first meal is a decidedly non-delicious sounding 'nutty pudding', which is made from macadamia-nut milk, ground macadamia and walnuts, chia seed, flaxseed, Brazil nuts, sunflower lecithin, ceylon cinnamon, and pomegranate juice.
Time journalist Charlotte Alter had a taste, and said: "It’s the color of a pencil eraser and tastes a little dusty, but it’s not too different from a vegan yogurt, if you like that sort of thing."
Another typical meal would be steamed vegetables and lentils that had been "blended until they resemble a mush the color of a sea lion", Alter wrote.
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A whopping 15% of his daily diet apparently consists of allegedly cholesterol-reducing olive oil, sold by his Blueprint company.
And Johnson apparently doesn't even miss treating himself, and told Insider in another interview: "I no longer have arousal from eating junk food."
Apparently the idea of eating pizza and donuts makes him "nauseous to even think about".
Johnson has even suggested death might not be inevitable - but not everyone is so convinced.
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Dr. Pinchas Cohen, dean of the Leonard Davis School of Gerontology at the University of Southern California, told Time: “Death is not optional; it’s written into our genes."