Stem Cells
Cell types, regenerative therapies, regulatory status, and disease-by-disease evidence for stem cell medicine, from FDA-approved bone marrow transplants to unproven clinic infusions.
n=1 self-experiments or animal studies
Athletes and Stem Cells: Documented vs Anecdote
Five famous athlete stem cell stories get repeated as proof stem cells work. The primary sources show a range from solidly confirmed to media speculation, and regulators say none of it counts as evidence.
Large human RCTs or meta-analyses
EMA Regulation of Stem Cell Therapies
The EU treats stem cell products as Advanced Therapy Medicinal Products; only Holoclar remains fully approved after Alofisel's 2024 withdrawal, and roughly a fifth of all approved ATMPs have left the market.
Small human pilot studies or cohorts
Embryonic Stem Cells (ESC)
Pluripotent cells taken from early-stage embryos remain the most flexible stem cell type in research but the most regulated in practice, with only a handful of human trials and no full approval anywhere.
Medium human RCTs or systematic reviews
Exosomes vs Stem Cells: What's the Difference
Exosomes are cell-free nanoparticles, not living stem cells, but the FDA says clinics market them the same way, and zero exosome products carry approval anywhere.
Medium human RCTs or systematic reviews
Exosomes: Therapy, Longevity, and Regulatory Status
Cell-to-cell messengers that carry proteins and RNA between cells. Young and stem-cell-derived exosomes rejuvenate old tissue in mice, but zero FDA-approved exosome products exist and adverse events are documented.
Large human RCTs or meta-analyses
FDA Regulation of Stem Cell Therapies
The FDA has fully licensed roughly 43 cell and gene therapy products, almost none of them stem cell products beyond cord blood, while running an escalating enforcement campaign against unapproved stem cell clinics.
Large human RCTs or meta-analyses
Hematopoietic Stem Cells (HSC)
Bone-marrow-derived blood-forming stem cells behind the oldest and most FDA-approved stem cell therapy in medicine, the transplant used against leukemia and other blood disorders.
Small human pilot studies or cohorts
Induced Pluripotent Stem Cells (iPSC)
Lab-reprogrammed adult cells that behave like embryonic stem cells without requiring an embryo, now entering human trials for Parkinson's disease and diabetes, though no iPSC therapy is yet approved.
n=1 self-experiments or animal studies
Athletes and Stem Cells: Documented vs Anecdote
Five famous athlete stem cell stories get repeated as proof stem cells work. The primary sources show a range from solidly confirmed to media speculation, and regulators say none of it counts as evidence.
Large human RCTs or meta-analyses
EMA Regulation of Stem Cell Therapies
The EU treats stem cell products as Advanced Therapy Medicinal Products; only Holoclar remains fully approved after Alofisel's 2024 withdrawal, and roughly a fifth of all approved ATMPs have left the market.
Small human pilot studies or cohorts
Embryonic Stem Cells (ESC)
Pluripotent cells taken from early-stage embryos remain the most flexible stem cell type in research but the most regulated in practice, with only a handful of human trials and no full approval anywhere.
Medium human RCTs or systematic reviews
Exosomes vs Stem Cells: What's the Difference
Exosomes are cell-free nanoparticles, not living stem cells, but the FDA says clinics market them the same way, and zero exosome products carry approval anywhere.
Medium human RCTs or systematic reviews
Exosomes: Therapy, Longevity, and Regulatory Status
Cell-to-cell messengers that carry proteins and RNA between cells. Young and stem-cell-derived exosomes rejuvenate old tissue in mice, but zero FDA-approved exosome products exist and adverse events are documented.
Large human RCTs or meta-analyses
FDA Regulation of Stem Cell Therapies
The FDA has fully licensed roughly 43 cell and gene therapy products, almost none of them stem cell products beyond cord blood, while running an escalating enforcement campaign against unapproved stem cell clinics.
Large human RCTs or meta-analyses
Hematopoietic Stem Cells (HSC)
Bone-marrow-derived blood-forming stem cells behind the oldest and most FDA-approved stem cell therapy in medicine, the transplant used against leukemia and other blood disorders.
Small human pilot studies or cohorts
Induced Pluripotent Stem Cells (iPSC)
Lab-reprogrammed adult cells that behave like embryonic stem cells without requiring an embryo, now entering human trials for Parkinson's disease and diabetes, though no iPSC therapy is yet approved.
Medium human RCTs or systematic reviews
Mesenchymal Stem Cells (MSC)
MSCs are multipotent adult stem cells that work mainly through secreted signaling molecules, not by becoming new tissue, and they dominate the commercial stem cell market despite almost no full drug approvals.
n=1 self-experiments or animal studies
Neural Stem Cells for Traumatic Brain Injury: Nonhuman-Primate Evidence
A 2026 bioRxiv study in 18 marmosets reported dose-dependent behavioral and MRI improvements after transplantation of a cryopreserved human neural stem-cell product, but no human efficacy data exist.
n=1 self-experiments or animal studies
Partial Epigenetic Reprogramming
Altos Labs and Life Biosciences are testing Yamanaka-factor-based partial reprogramming to reverse cellular aging markers without creating pluripotency, a mechanism distinct from stem cell transplantation despite using the same discovery.
In vitro or mechanistic only
Stem Cell Clinic Pricing by Country: What It Actually Costs
Offshore stem cell clinics charge $2,000 to $50,000+ per treatment, but almost every published number comes from the clinics or the brokers selling them.
Large human RCTs or meta-analyses
Stem Cell Evidence Tiers: Our Methodology
A five-level framework, from tier 1 regulatory-grade human evidence to tier 5 unsupported hypothesis, that we apply consistently across every stem cell page in this encyclopedia.
Large human RCTs or meta-analyses
Stem Cell Safety and Red Flags
Pew Charitable Trusts documented roughly 360 adverse events linked to unapproved US stem cell interventions between 2004 and 2020, and the ISSCR's patient handbook lists specific marketing red flags to check before any procedure.
Large human RCTs or meta-analyses
Stem Cell Types: A Comparison Overview
Five stem cell types used in medicine differ in origin, potency, and regulatory status; only cord-blood-derived hematopoietic cells and two European ATMPs carry full approval.
Medium human RCTs or systematic reviews
Stem Cells for Alzheimer's Disease
Longeveron's CLEAR MIND Phase 2a trial found laromestrocel slowed brain volume decline by up to 61.9% in mild Alzheimer's disease, but the trial was safety-focused and too small to prove a cognitive benefit.
Medium human RCTs or systematic reviews
Stem Cells for Diabetes
Vertex's stem-cell-derived islet therapy zimislecel achieved insulin independence in 83% of evaluable type 1 diabetes patients at one year, the strongest human efficacy signal in this entire encyclopedia section.
Medium human RCTs or systematic reviews
Stem Cells for Frailty
Longeveron's laromestrocel is the most rigorously tested MSC therapy for aging-related frailty, showing a 63.4-meter six-minute-walk improvement at nine months, but it remains unapproved.
Small human pilot studies or cohorts
Stem Cells for Hair Loss
A 2024 systematic review of 12 RCTs and 514 patients found stem cell and stem-cell-secretome injections modestly boost hair density, but no randomized trial of exosomes for pattern hair loss existed as of that review, and clinics still sell exosome hair packages off that evidence gap.
Medium human RCTs or systematic reviews
Stem Cells for Knee Osteoarthritis
The largest meta-analyses show MSC injections modestly outperform placebo for knee osteoarthritis pain and function, but a 2025 study estimates that 50-66% of the apparent benefit comes from placebo and contextual effects, not the cells themselves.
n=1 self-experiments or animal studies
Stem Cells for Stroke
The MASTERS trial program tested an allogeneic adult stem cell product in over 300 acute ischemic stroke patients and found no significant benefit on the primary endpoint, making stroke the weakest evidence case in this section.
Medium human RCTs or systematic reviews
Tendon/Ligament Stem Cell for Spinal Stenosis
A Cell study identified a tendon/ligament stem-cell population in mice and humans and linked calcium-dependent differentiation changes to ligamentum-flavum hypertrophy; this is mechanism research, not an injection therapy.
Medium human RCTs or systematic reviews
Umbilical Cord Stem Cells: Legitimate Use vs Clinic Products
Cord-blood stem cells are the only FDA-approved stem cell product on the US market, but that approval covers blood-disorder transplants only; the umbilical cord products sold for pain, aging, and joints caused a 12-to-20-patient bacterial infection outbreak in 2018 and continue to draw FDA warning letters, most recently in February 2026.
Medium human RCTs or systematic reviews
iPSC Epigenetic Age Reset
In 99 healthy donors, reprogramming blood cells into iPSCs largely reset age-related DNA methylation clocks; this is a cell-culture finding, not whole-body rejuvenation.