Could the fountain of youth be flowing through the veins of young adults? A new human cell study shows that blood serum from young donors (those under age 30) can reverse signs of aging in skin tissue. But the effect only occurs when bone marrow cells are involved. Without them, the youthful serum has no visible impact.
The research, published in Aging on July 25, 2025, is the first to demonstrate that young human blood can trigger rejuvenation in human skin, provided the right biological systems are in place to translate its signals.
Serum Alone Doesn’t Rejuvenate Skin
Researchers led by Johanna Ritter and Elke Grönniger at Beiersdorf AG began by treating 3D skin models with human serum from donors under 30. On its own, the young serum didn’t improve gene expression, skin structure, cell proliferation, or biological age. Even after three weeks in dynamic culture, the skin showed no meaningful change.
That changed when the researchers added a bone marrow model. In a co-culture setup that mimics real circulation, skin and bone marrow models were connected in a fluidic chip and exposed to the same young serum. The result: skin cell proliferation increased, and DNA methylation-based age clocks showed the tissue had become biologically younger.
“We were able to reproduce systemic rejuvenating effects of circulating blood factors on the human skin, which have been so far only demonstrated in rodent heterochronic parabiosis studies,” the authors wrote.
Bone Marrow Translates Blood Signals Into Skin Renewal
The bone marrow wasn’t just along for the ride, it played an active role in rejuvenation. When treated with young serum, bone marrow cells began producing 55 secreted proteins, several of which are already known to influence tissue regeneration, immune balance, and skin remodeling.
Seven of these proteins were tested directly on aged human skin cells. The results were striking:
- Increased proliferation in fibroblasts and keratinocytes
- Enhanced production of collagen and hyaluronic acid
- Improved gene expression patterns linked to youth
- Elevated mitochondrial membrane potential and cellular plasticity
One protein, CHI3L1, improved all six hallmarks of aging measured in the study, outperforming even the widely studied GDF-11. Others, like MMP-9 and CD55, aided in tissue repair, reduced inflammatory signals, and helped recruit regenerative cells.
Why Bone Marrow Is the Missing Link
The findings explain why earlier experiments in mice showed systemic rejuvenation after young blood exposure: organs need intermediary cells to interpret and relay those youthful cues. In this study, bone marrow-derived immune and progenitor cells acted as messengers, converting circulating signals into skin-specific effects.
Without bone marrow, the skin model didn’t respond to young serum. “Rejuvenation of skin tissue is dependent on the presence of bone marrow-derived blood cells in the circulation,” the authors noted.
From Discovery to Therapy
This preclinical breakthrough could pave the way for new treatments that harness or mimic the effects of systemic youth-associated factors. By identifying proteins that rejuvenate aged skin, researchers hope to develop future therapies that avoid the need for transfusions and instead deliver only the active components.
The team is also exploring how other molecules in young serum, such as exosomes and microRNAs, might enhance these effects. Their microphysiological system offers a powerful new tool to investigate not just aging skin, but whole-body aging across multiple organs.
Next Steps and Broader Implications
As the population ages, demand for interventions that slow or reverse biological aging continues to grow. This study offers the first direct evidence that youthful circulating factors can rejuvenate human skin, but only under the right cellular conditions. Bone marrow, it turns out, may be the essential relay station for turning systemic signals into regeneration.
“Our study lays a basis for future therapeutic approaches using systemic factors to reverse signs of aging in the human skin,” the authors concluded.
Author and Publication Info
Study Title: Systemic factors in young human serum influence in vitro responses of human skin and bone marrow-derived blood cells in a microphysiological co-culture system
Authors: Johanna Ritter, Cassandra Falckenhayn, Minyue Qi, Leonie Gather, Daniel Gutjahr, Johannes Schmidt, Stefan Simm, Stefan Kalkhof, Janosch Hildebrand, Thomas Bosch, Marc Winnefeld, Elke Grönniger, Annette Siracusa
Institutions: Beiersdorf AG (Hamburg), Coburg University of Applied Sciences, Fraunhofer IZI, Kiel University
Journal: Aging (Aging-US), Volume 17, Issue 7
DOI: https://doi.org/10.18632/aging.206288
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There are many ways for age regression:
https://www.printernational.co.uk/timmann/age_regression.htm
Like me, you’ll have to wait. Probably I’m more in need than you.
I already showed that one particular constituent of young blood rejuvenates human skin – and it was published in Current Aging Science, last year (or the year before)/
Indeed, we’d love to learn more and where things stand with a commercial product.