Do you sometimes look in the mirror and wonder where that youthful glow has gone – the real one, not the one from filters? And have your joints started giving opinions every time you do a squat? Then we have a recipe for you that is neither a fad nor a marketing gimmick. It's homemade collagen, the good old bone elixir, approved by grandmothers and supported by nutritionists – a rare star that shines both in the kitchen and under the microscope.