This popular science piece is characteristic of a prevalent and hostile view of the growing practice of patient-funded clinical trials. In this model the patient pays a sizable portion of the costs, which certainly makes it a lot easier to gather larger amounts of data, as the trial organizers don't have to seek the funding themselves. On the other hand, it tends to rule out the ability to carry out a blind trial in which not everyone actually gets the treatment, as well as other similar refinements. That is a problem if the goal is to search for and quantify marginal effects, but if the point is to discover or rule out large effects, I'd argue that control groups are not necessary. The control in that case is the established progression for patients who do not get the treatment, or who undergo existing, marginal treatments. We are at the stage in the development of medicine to treat aging in which marginal effects, such as those resulting from the use of metformin as a calorie restriction mimetic, should be discarded as uninteresting. Once at the stage of trying things in human studies, the research community should be filtering for significant effects, such as those obtained by clearance of senescent cells. Given the poor state of funding for aging research in general, methods that can pull in more resources to obtain more data should be applauded.

In the case of the approach being trialed here by Ambrosia, I think our expectations should be low, and the outcome I expect is for there to be no significant benefit. The only ethical question worthy of consideration is whether those involved then do the right thing: publish the data, shut up shop, and move on to the next project - having done the good work of finding out that there is no large effect here. Transfusions of young blood to old individuals are not producing benefits in mice, and there is reason to think that the beneficial outcomes observed in old mice due to parabiosis, the linking of circulatory systems between an old and a young individual, are due to factors or circumstances not replicated by periodic transfusion. It isn't difficult to imagine that beneficial outcomes require the youthful system reacting in a dynamic way to the presence of aged signals, for example, or - as suggested by some researchers recently - that it is nothing more than a consistently maintained dilution of problem signals in the aged environment.