Does stem cell therapy work against ageing in humans?
For one specific application, physical frailty in older adults, there is a first randomised trial with a positive result; for all other ageing-related applications it is too early for firm statements, and stem cell therapy cannot yet be considered a proven anti-ageing treatment.
One randomised trial in 148 older adults with frailty shows positive results. Participants who received an infusion of allogeneic bone marrow stem cells (laromestrocel) walked an average of 63 metres further in a walking test after nine months than the placebo group. That difference is clinically meaningful and statistically reliable. At the same time, patients also improved on a self-reported scale for physical functioning. This is the strongest direct evidence in humans that is currently available.
Beyond this single trial, the evidence is considerably thinner. Review articles describe promising results in ageing-related conditions such as Alzheimer's disease, osteoporosis and cardiovascular disease, but these are largely findings from the laboratory or small exploratory clinical studies, not large confirmatory trials. The step towards broad clinical application has not yet been taken.
Animal research in primates shows that genetically modified stem cells can slow down signs of ageing, without visible side effects. Interesting, but the distance from monkey to human is large: such research says nothing yet about what works in people. The same applies to reprogramming research in cells and animals, in which cells are effectively 'rewound' to a younger state. That research is still entirely in its early stages.
A practical problem highlighted in several studies: stem cells age themselves as well, both inside the body and during cultivation in the laboratory. Aged stem cells function less effectively. This makes it complicated to produce consistently working therapies and represents a genuine barrier to widespread application.
Stem cell therapy in humans is therefore not one single thing. For physical frailty in older adults, there is now one randomised trial with a hopeful result. For everything beyond that, from skin rejuvenation to dementia, the indications are preliminary and based on early research. Firm conclusions about life extension or broader health gains cannot yet be drawn in humans.
The strongest evidence comes from one randomised trial in 148 older adults. All other findings come from review articles, animal research in primates, and cell and laboratory studies. There is no systematic review incorporating multiple randomised trials. The researchers of the primate study themselves emphasise that the step to clinical use in humans is still missing; review authors point to unresolved problems such as immune reactions, cell death after administration and loss of stem cell quality during production.