Rejuvenation and Regeneration

Updated July 2026. Originally published February 2021.

Rejuvenation and regeneration are progressing rapidly toward becoming mainstream medical practices to extend healthspan and lifespan. Science fiction is becoming science.

“Every generation needs regeneration.” — Charles Spurgeon, 1800s Baptist preacher

“Walk into your local drugstore, you’re going to see about 50 products that claim to be anti-aging, and I can assure you that none of them are.” — Greg Bailey, CEO Juvenescence

Data from a 2020 experiment to restore vision loss in old mice indicates that mammalian tissues retain a record of youthful epigenetic information — encoded in part by DNA methylation — that can be accessed to improve tissue function and promote regeneration in vivo. — Dr. David Sinclair and the Life Biosciences team. As of June 9, 2026, Life Biosciences has now dosed the first human patient with a cellular reprogramming therapy — moving this vision from mice to people. Keep Health covers that milestone in depth in Reversing Aging.

“Lifespan is controlled by how well your body can repair and regenerate. Young and old people take the same damage. Young people can repair and regenerate better.” — Irina Conboy

How to look, feel and actually be physically younger

As noted in What Causes Aging, two main categories of factors influence biological aging: programmed and damage-related. Programmed factors follow a biological timetable, including those regulating childhood growth and development. Damage-related factors include internal and environmental assaults that induce cumulative impairment and dysfunction, including in our DNA.

Defying aging is a continuous four-part process:

For older adults, rejuvenate your body to its desired youthful state.
Stop the programmed aging process. (See Reversing Aging.)
Repair damage rapidly through healing and regeneration.
Don’t die. (See Brain and Body Protection.)

This article focuses on #1 (Rejuvenation) and #3 (Healing and Regeneration).

Rejuvenation targets

As people age, what do you notice most? Wrinkled skin? Loss of muscle tone and flexibility? Loss of hair? Dwindling eyesight? Impaired brain function?

Commercial research now targets multiple areas for whole-body rejuvenation:

Blood and Plasma (See Bloody Good Health)
Body Healing — growing tissues, organs and limbs
Brain
Cells (see Cellular Reprogramming)
Eyes (see 2020 Vision Eye Care)
Hair (see Keep Hair)
Muscles (see Strength Training: Power Up! and Flexibility and Pliability)
Skin (see Feel Comfortable in Your Own Skin)

This article covers Brain rejuvenation and Body Healing rejuvenation in detail. The latest scientific research on Blood and Plasma rejuvenation has produced the first positive human trial data — and its effects reach directly into the youthfulness of your brain, eyes, hair, muscles and skin.

Brain rejuvenation — avoid age-related functional and memory loss

Impaired brain function is perhaps the most frightening aspect of aging — losing the ability to think quickly, focus, recall words, and access memories. Here is the top research on what’s possible for brain rejuvenation today:

The strongest proven option for brain rejuvenation is also the least glamorous: aerobic exercise combined with resistance training. Combined aerobic and resistance training shows the largest cognitive benefits of any single lifestyle intervention, boosting brain-derived neurotrophic factor (BDNF), blood flow, and hippocampal volume. The hippocampus is the brain’s memory center, and it shrinks with age — but exercise reverses that. Twelve months of moderate aerobic activity, such as walking three times a week, increased anterior hippocampal volume by roughly 2% in older adults, effectively reversing one to two years of age-related shrinkage. The 2025 US POINTER trial — the largest multidomain lifestyle study yet conducted in adults at risk of cognitive decline — found that a structured two-year lifestyle intervention in 2,111 participants improved global cognition more than self-guided lifestyle change. The message is clear: movement is the most important thing you can do for your brain, and structured programs outperform casual intentions. For more on how exercise protects the brain and body together, see our article on Body and Brain Protection.

Sleep is a close second — and most people underestimate how badly poor sleep damages the brain over time. During deep sleep, the brain’s glymphatic system activates to flush out amyloid and tau proteins, the waste products linked to Alzheimer’s disease. Chronic sleep under six hours raises dementia risk by 25–30%. Targeting seven to nine hours of quality sleep is not optional for anyone serious about brain rejuvenation. Beyond sleep duration, nutrition matters too. The MIND diet — built around leafy greens, fatty fish, walnuts, berries, and olive oil — is linked to cognitive performance equivalent to being 7.5 years younger. B vitamins and omega-3 fatty acids add further benefit, especially if your homocysteine is elevated: B-vitamin supplementation slowed brain atrophy by roughly 30% overall and by around 50% in people with high homocysteine levels, according to the VITACOG trial. For a deeper look at how your genes shape your cognitive risk — including the APOE4 variant that significantly raises Alzheimer’s risk — see our article on Genetic Longevity.

For those who want to go further, targeted cognitive training offers more than most people expect. The ACTIVE study found that processing-speed training reduced dementia risk over 20 years — more than memory games. Digital brain training tools like BrainHQ have also shown results: a 2025 McGill-led study found that ten weeks of BrainHQ exercises restored cholinergic function in older adults — the neurotransmitter system most associated with memory and learning — effectively turning back the clock on aging brain systems. Hearing health is another overlooked lever: hearing intervention reduced cognitive decline by roughly 48% over three years in older adults at high risk, making it one of the most cost-effective brain protection strategies available. Together, these options form a layered approach — lifestyle first, targeted tools second — that gives your brain the best chance of staying sharp well into your 60s and beyond. For the full picture on what to track and measure, see our article on Outthink Your Brain.

Additionally,

As we age, increasing brain stiffness causes dysfunction of brain stem cells needed for normal function and the regeneration of myelin — the fatty sheath surrounding nerves. A protein called Piezo1 on the cell surface informs cells whether their surrounding environment is soft or stiff. Deleting Piezo1 in stem cells within elderly rat brains led to cellular rejuvenation, restoring their normal regenerative function.
The hypothalamus plays a crucial role in controlling aging. At the Albert Einstein College of Medicine, Dr. Dongsheng Cai’s team identified neural stem cells in the hypothalamus as responsible for the pace of aging, and showed the process can be counteracted by adding fresh stem cells — though that’s obviously not a practical consumer solution yet.
Healing scar tissue from brain injuries is now also possible. Research from Dr. Gong Chen showed glial tissue can be reversed back to neuronal tissue through neuroregenerative gene therapy involving four core molecular switches.
A 2020 study demonstrated that inhibiting intracellular brain stress restored youthful brain function in mice, adding another potential therapeutic pathway to the brain rejuvenation toolkit.

For more on protecting brain health, see Connect With Your Brain.

Healing and Regenerative Medicine: Growing Cells, Tissue, Organs, and Limbs

The human body replaces roughly 330 billion cells every day. Over about 80 days, it swaps out enough cells to match your entire body weight. For most of human history, that remarkable capacity stopped at soft tissue — broken bones heal, cuts close, but a damaged heart or failed kidney stays damaged. That’s changing fast. A new generation of researchers and companies is learning to grow replacement tissues, reprogram existing cells, and even transplant organs from other species. Here’s where the science stands today.

The world leader in lab-grown organs: Wake Forest Institute for Regenerative Medicine

The Wake Forest Institute for Regenerative Medicine (WFIRM), led by Dr. Anthony Atala, is the most established research institution in this field and the first in the world to engineer lab-grown organs that were successfully implanted in patients. With more than 550 researchers, WFIRM currently works on therapies for about 40 different tissues and organs, including heart valves, muscle tissue, livers, and kidneys. Fifteen of these technologies have already been used in patients, covering skin, urethras, cartilage, bladders, muscle, and more — all built using the patient’s own cells.

Most recently, WFIRM received a $24.8 million, five-year award from the Advanced Research Projects Agency for Health (ARPA-H) to develop bioprinted, on-demand kidney tissues. The goal is to produce implantable kidney tissue made from a patient’s own cells — eliminating both the organ shortage and the need for lifelong immunosuppressive drugs. As Atala puts it: “Every 30 seconds, a patient dies from diseases that could be treated with tissue replacement.” WFIRM is working to change that.

Xenotransplantation: pig organs for human patients

More than 100,000 people in the US wait for organ transplants at any given time. About 13 die each day while waiting. Xenotransplantation — transplanting genetically modified animal organs into humans — offers one of the most direct paths to solving that shortage, and 2025 marked a turning point for the field.

eGenesis leads the field with its EGEN-2784 genetically engineered porcine kidney, which carries 69 gene edits across three categories: removing antigens that trigger immune rejection, adding human genes to regulate the immune response, and inactivating pig retroviruses for safety. In January 2025, Tim Andrews, 67, received an EGEN-2784 kidney at Massachusetts General Hospital — and threw the first pitch at a Boston Red Sox game six months later, dialysis-free. A second patient followed in June 2025. The FDA cleared eGenesis’s Investigational New Drug (IND) application for a full Phase 1/2/3 clinical trial in September 2025, making it one of the most significant regulatory milestones in the history of organ transplantation.

United Therapeutics (NASDAQ: UTHR), parent company of Revivicor, received FDA clearance in February 2025 to start its own xenokidney clinical trial with UKidney, its competing gene-edited porcine kidney. United Therapeutics ultimately aims to use its technology as a platform for multiple organs. Both eGenesis and United Therapeutics are now in formal human trials — a milestone the field has worked toward for decades.

3D bioprinting: printing tissue to order

Rather than sourcing organs from animals, bioprinting builds them layer by layer from living cells. The technology remains several years away from printing complex solid organs like hearts or lungs, but it’s already producing clinically useful results in simpler tissues. The global 3D bioprinting market was valued at $3.07 billion in 2025 and is expected to reach $6.67 billion by 2033, driven largely by demand for tissue engineering in transplant medicine and drug testing.

Aspect Biosystems raised a $115 million Series B in January 2025, backed by Dimension and Novo Nordisk, to advance its bioprinted tissue therapeutics toward the clinic. Organovo continues to pioneer bioprinted liver and kidney tissues, with preclinical trials underway for liver disease treatment. Prellis Biologics focuses on the hardest unsolved problem in the field — vascularization, meaning how to build the tiny blood vessel networks that keep thick tissue alive. Without solved vascularization, complex solid organ printing remains a long-term goal. Prellis uses holographic printing to create these networks at speeds no other approach has matched.

The most concrete near-term applications are skin, cartilage, and soft-tissue reconstruction, along with drug testing models that let researchers test compounds on human tissue rather than animals. The FDA’s April 2025 guidance encouraging bioprinted tissue as a valid alternative to some animal testing reinforces how seriously regulators now take the field.

Bioelectric regeneration: using the body’s own signals

One of the most surprising research directions in regeneration comes from the Allen Discovery Center at Tufts University, led by Dr. Michael Levin. His lab studies how bioelectric signals — the tiny electrical currents that flow between cells — act as a kind of master blueprint that tells the body what shape to build and when to stop. Some animals, like planaria flatworms, can regrow their entire bodies from a small fragment. Levin’s team has used bioelectric manipulation to induce partial limb regeneration in frogs — animals that don’t normally regenerate limbs at all. The work is early-stage for humans, but it points toward a future where regeneration is triggered by the body’s own signaling systems rather than by introducing foreign cells or materials. For more on this topic, see our article on Your Bioelectric Body.

Meanwhile, Morphoceuticals is commercializing bioelectric approaches to regeneration, and Lygenesis is using lymph nodes as bioreactors — essentially repurposing nodes in the body as miniature factories to grow replacement liver tissue in place.

Stem cell therapies: early human trials show real promise

Stem cell therapy has long promised more than it delivered, but 2025 brought the first truly convincing human results. Clinical trials led by academic researchers were the first to show that stem cell therapy has clear potential to treat people with Parkinson’s disease, showing that the therapies were safe and reduced motor symptoms of the neurodegenerative disorder. Multiple other stem cell trials are now underway for neurological disorders, cardiovascular disease, and autoimmune conditions.

On the regulatory side, FDA guidance published in September 2025 enables regenerative medicine companies to use an expedited approval program, lowering the barrier for companies moving toward clinical use. That’s a meaningful shift — regenerative medicine has historically faced long, expensive regulatory timelines that slowed promising therapies.

For a broader look at how Cellular Reprogramming connects to these advances, see our dedicated article on that topic. And for the investment case around these companies and the field more broadly, see our article on Investment Opportunities in longevity science.

Hyperbaric oxygen therapy and red light therapy

For information on Hyperbaric Oxygen Therapy and Red Light Therapy for rejuvenation, Keep Health’s dedicated articles on each cover the research and practical applications.

The bottom line

Rejuvenation and regeneration have crossed a meaningful threshold since this article was first published. The first controlled human trial of therapeutic plasma exchange demonstrated measurable biological age reversal — 2.61 years on multi-omics biomarkers — in a placebo-controlled study published in 2025. Gene-edited pig kidneys moved from experimental procedures in deceased patients to FDA-approved clinical trials in living recipients across 2024 and 2025. On June 9, 2026, Life Biosciences dosed the first human participant in a cellular reprogramming trial.

None of these are ready for broad clinical use. Each represents an early-stage clinical milestone in a field where the gap between promising results and proven, durable human therapies remains substantial. However, the direction of travel is clear: the tools to rejuvenate and regenerate human bodies are advancing from concept to clinical trial at an accelerating pace.