Since hanging up his boots, the Frenchman has transformed from professional footballer to activist and entrepreneur.
The same passion Flamini had on the football pitch is still evident now and particularly when speaking about his latest venture - a supplement’s range created by his and Mesut Özil’s company UNITY.
His first answer is a full 25 minutes long as he barely breaks stride, only briefing stopping to catch his breath and have a sip of water.
The passion is there too when Flamini talks about Arsenal, who he had two spells with during his playing career.
“I am watching every game,” Flamini tells Standard Sport. “It is like this club is part of me.
“I played for nearly eight years at the club. I am more than a fan; it is like I am part of the family.
“You are always in contact with your family, and you choose your friends, but you don’t choose your family!
“Obviously, you are happy when things go well and you’re a bit disappointed and frustrated when things don’t go well.
“I have been following the season, the games, the ups and downs like every fan. I am not just part of the family; I am now also a fan because I have to live it from outside.
“There is frustration and I understand that. Myself, I am frustrated because once you are a fan, once you love the club, once you are part of the family, we all want it to be successful.
“Obviously, it hurts me when we are not in the Champions League, the Europa League and we are fighting for a place in the Premier League that should not be ours.
“But at the end of the day, I think it is important to stick together and to work hard to get back on track.
“I don’t believe we (Arsenal) should be in this position. We should be near the top of this League. But beliefs are not enough, you need to work hard and you need to deliver.”
Flamini admits he has “the easy role” by simply watching the games and it is why he isn’t keen to wade in on how things can improve at Arsenal.
Instead, the 37-year-old’s main focus these days is his work as an activist and entrepreneur.
His latest venture, alongside Özil, is the U ULTRA supplement range - which they developed alongside University of Westminster scientists at Europe’s first Centre for Nutraceuticals.
Flamini worked with experts in every field during his playing career - be that psychologists, physiotherapists or fitness coaches - and now he is using what he learned to break into the supplement range market.
“If I am talking also about these energy drinks, you have these being used by kids starting at five years old to professional athletes that are supposed to be experts at what they do,” says Flamini.
“Through the years, I had experienced it was very hard for me to find products that would be delivering, not only the performance, but also be natural - using less chemical substances and sugar.
“When you take products full of colourant, it’s a disaster. When you take products full of sugar, that’s a disaster. If you take products which are full of chemicals that are harmful to you, and the planet, it’s a disaster.”
Flamini plans to extend UNITY’s range into the energy drink market in the future, with their supplement range being just the start.
Both he and Özil use the supplement range, with a tennis player also due to come on board in using the product.
“We want to give back. How do we give back? It’s by sharing trust and reliable information, and by bringing products to the market which people can trust because they trust us,” says Flamini.
“They will trust also the University of Westminster, who are experts in that field.
“What we want to do is to support millions of people out there and maybe help them in their everyday life.
“If we can change the life of even one person, at the end of the day it will have been an exciting and successful journey.”
Flamini has been involved in sustainability a long time. He is a vegan and also works with Uefa on their Cleaner Air, Better Game campaign.
The environment, and sustaining it, is close to his heart and he has been inspired by the likes of Greta Thunberg.
“When I see these kids, 10, 12, 15 years old, being in a street, fighting for their future, that’s the most inspiring,” he says.
“So how can I make the sure the next generation have better life conditions than what we have today?
“Growing up by the sea, I’ve always been exposed to the impact made by humankind.
“Also I had the opportunity to travel to Greenland, to see with my own eyes the impact on this part of the world.
“I have experienced that with my own eyes and, once you see it, it’s difficult to forget it or pretend you’ve never seen it.”
UNITY co-founders, Mathieu Flamini and Mesut Özil, have launched their new U ULTRA supplement range, developed in collaboration with leading University of Westminster scientists at Europe’s first Centre for Nutraceuticals. They are available to purchase at unityperformancelab.com now.