By Vivonyx · Last reviewed: October 2026
If you've started reading about "stem cells" for joints, you've probably run into two names again and again: Wharton's jelly and bone marrow. Both are sources of mesenchymal stromal cells, usually shortened to MSCs. Both are studied. And both get described online in ways that range from careful to wildly overconfident.
This article lays them side by side: where the cells come from, how they're collected, what the research actually shows, and what is still unknown. It's education, not medical advice, and it isn't a recommendation for either one.
First, what are MSCs?
MSCs are a type of cell found in many tissues, including bone marrow, fat, and umbilical cord tissue. Scientists use a shared set of lab criteria to define them: they stick to plastic in a culture dish, carry certain surface markers, and can turn into bone, cartilage, and fat cells in the lab [1]. That shared definition matters, because it means "MSC" describes a family of cells, not one identical product.
Much of the current thinking is that MSCs may act mainly by sending signals (calming inflammation, influencing nearby cells) rather than by turning into new cartilage. That idea is still being studied.
If you're new to Wharton's jelly, our explainer What Is Wharton's Jelly MSC Therapy? covers the basics.
Where each one comes from
Wharton's jelly is the soft, gel-like tissue inside the umbilical cord. It's collected after a healthy birth from tissue that would otherwise be discarded. The cells come from a donor, so they're called allogeneic. For the person receiving them, there's no harvesting procedure.
Bone marrow MSCs usually come from the person themselves, so they're autologous. Marrow is drawn with a needle, most often from the back of the hip bone (the iliac crest). That's a minor procedure, but it is still a procedure, with some soreness and a small risk of bleeding or infection.
Bone marrow products also come in two very different forms:
BMAC (bone marrow aspirate concentrate): marrow is spun in a centrifuge the same day and the concentrate is injected. It contains many cell types, and only a small fraction are MSCs.
Culture-expanded bone marrow MSCs: cells are grown in a lab for weeks to reach a set dose. In the U.S., this is generally limited to clinical trials.
Keeping those two apart is one of the most useful things you can do when reading studies.
Donor age and cell numbers
This is where the two sources differ most.
In bone marrow, both the number of MSCs and their "fitness" appear to decline with age. A study across a wide range of donor ages found fewer MSCs in adults than in children, along with more markers of cellular aging and oxidative damage. The authors flagged this as a possible problem for using older adults' own cells [2]. For many readers in their 50s, 60s, and beyond, that's a fair question to raise.
Wharton's jelly cells come from newborn tissue, so donor age isn't the same issue. Lab comparisons have found that cord-derived MSCs tend to multiply faster than bone marrow MSCs [3][4]. But "faster in a dish" is not the same as "works better in a knee." The same lab work found bone marrow MSCs were more efficient at becoming bone and fat cells, while Wharton's jelly MSCs leaned toward genes tied to blood-vessel growth [4]. Different, not simply better or worse.
Educational summary of the sources cited in this article.
At a glance
| Wharton's jelly MSCs | Bone marrow MSCs | |
|---|---|---|
| Source | Umbilical cord tissue from a donor (allogeneic) | Usually your own marrow (autologous) |
| How collected | From donated cord tissue after birth; no harvest for the recipient | Needle draw from the hip bone; a minor procedure |
| Donor age | Newborn tissue | Your age; MSC numbers and fitness decline with age [2] |
| Cell counts / expansion | Multiply quickly in the lab [3][4]; dose depends on lab processing | BMAC: few MSCs, same-day. Cultured: lab-grown to a set dose |
| Research that exists | Lab studies; small early-phase human trials, e.g., knee OA [5][6] | Longest history; several knee OA trials of both BMAC and cultured cells [7][8] |
| Known risks / limits | Donor screening, lab quality, immune reaction questions [9]; small trials | Harvest discomfort; age-related cell decline; mixed placebo results for BMAC [8] |
| FDA status | Not FDA-approved for any orthopedic use [10] | Not FDA-approved for any orthopedic use [10]; one donor bone marrow MSC product is approved for a pediatric transplant complication [11] |
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What the knee research shows
Knee osteoarthritis is where both sources have been tested most. For a broader tour, see Stem Cells vs. PRP for Knee Arthritis.
Wharton's jelly / umbilical cord. In a randomized phase I/II trial in Chile, 26 people with knee osteoarthritis received either hyaluronic acid, one dose of umbilical cord MSCs, or two doses six months apart. No serious adverse events were reported. At 12 months, the two-dose group reported lower pain than the hyaluronic acid group [5]. That's encouraging, but it's a small study. A 2024 review concluded that Wharton's jelly looks safe in published studies, that its effectiveness for knee OA is "still controversial," and that adequately powered randomized trials are needed [6]. (Several of that review's authors list ties to biologics organizations, which is worth knowing.)
Culture-expanded bone marrow MSCs. A Spanish randomized phase I/II trial gave 30 patients hyaluronic acid alone or with one of two doses of their own lab-grown marrow MSCs. No adverse effects were reported, and the MSC groups reported more pain improvement over 12 months [7]. Again: small, early-phase.
BMAC. A Mayo Clinic trial injected BMAC into one arthritic knee and saline into the other in 25 patients. Pain dropped in both knees, with no significant difference between them at six months [8]. That's an important reminder of how strong the placebo effect can be with knee injections.
Head-to-head in people? We did not find a large, published randomized trial directly comparing Wharton's jelly MSCs with bone marrow MSCs in the same patients. Most "which is better" claims are drawn from lab studies or from comparing separate trials, which is shaky ground.
The "immune privileged" question
You'll often read that Wharton's jelly cells are "immune privileged," meaning the body won't react to them. The fairer picture is more nuanced. A widely cited review argued that MSCs are better described as "immune evasive, not immune privileged": they may provoke less reaction, but studies have found antibodies against donor MSCs and signs of immune rejection. The same review noted that no clear clinical advantage of a person's own MSCs over donor MSCs had been shown [9].
So donor cells aren't automatically risky, and they aren't automatically invisible to the immune system either.
Safety and regulation
The FDA states that regenerative medicine therapies have not been approved for any orthopedic condition, including osteoarthritis, knee, hip, back, and shoulder pain, and that it regulates these products [10]. That applies to both Wharton's jelly and bone marrow products marketed for joints.
There is one real MSC approval worth knowing about. In December 2024, the FDA approved Ryoncil, a donor bone marrow-derived MSC product, for steroid-refractory acute graft-versus-host disease in children 2 months and older [11]. It's a narrow approval for a serious transplant complication. It doesn't extend to joints, and it isn't a Wharton's jelly product.
Injections of biologics also carry real, if uncommon, risks. A multicenter case series described 14 patients with complications such as infection or severe inflammation after injections that included cord blood, BMAC, placental tissue, and unspecified "stem cell" products [12]. Product handling and the setting matter. Our questions to ask first can help, and our guide Is Stem Cell Therapy FDA Approved? explains the difference between approved, in a trial, and neither.
What we still don't know
Which source works better for joints. There's no definitive head-to-head trial in people.
The right dose and schedule. Trials use very different cell counts and timing [5][7].
How long any effect lasts. Most trials follow people for a year or less.
Whether cells rebuild cartilage. Imaging results are mixed and hard to interpret.
How much lab quality varies. Two products with the same label can be processed very differently.
How much is placebo. The BMAC saline-controlled trial shows why placebo groups matter [8].
Frequently asked questions
Are Wharton's jelly stem cells better than bone marrow stem cells? Not proven. Lab studies show differences: cord cells tend to multiply faster, while bone marrow cells lean toward bone formation [3][4]. No large trial has compared them directly in people.
Does age affect bone marrow stem cells? Research suggests yes. MSC numbers and markers of cell health in bone marrow decline with age [2]. Wharton's jelly comes from newborn tissue, so donor age differs.
Is Wharton's jelly FDA approved for knees? No. The FDA says regenerative medicine therapies have not been approved for orthopedic conditions such as osteoarthritis or knee pain [10]. The same is true for bone marrow products.
What's the difference between BMAC and bone marrow MSCs? BMAC is marrow concentrated the same day; it contains many cell types and relatively few MSCs. Culture-expanded MSCs are grown in a lab to a set dose and in the U.S. are generally studied in clinical trials.
Will my body reject donor cells? Researchers describe MSCs as "immune evasive, not immune privileged." Some studies found immune responses to donor MSCs, though what that means for results is unclear [9].
Where can I find current clinical trials? ClinicalTrials.gov lists studies of both umbilical cord and bone marrow MSCs [13]. A listing alone does not mean a product is approved.
Still have questions?
Comparing studies like these is confusing, and that's normal. If you'd like help reading a study, decoding a product description, or figuring out what to ask next, email hello@vivonyx.com or use our Ask page. We'll give you a straight answer, including "the research doesn't know yet" when that's the truth.
Related reading
Educational disclaimer: This article is for general educational purposes only and is not medical advice, diagnosis, or treatment. It does not describe or suggest the treatment, cure, or prevention of any disease or condition. Regulatory status can change; check the cited FDA pages for current information. Talk with a qualified, licensed healthcare professional before making any medical decision.
References
Dominici M, Le Blanc K, Mueller I, et al. Minimal criteria for defining multipotent mesenchymal stromal cells. The International Society for Cellular Therapy position statement. Cytotherapy. 2006;8(4):315-317. PMID: 16923606. https://pubmed.ncbi.nlm.nih.gov/16923606/
Stolzing A, Jones E, McGonagle D, Scutt A. Age-related changes in human bone marrow-derived mesenchymal stem cells: consequences for cell therapies. Mech Ageing Dev. 2008;129(3):163-173. PMID: 18241911. https://pubmed.ncbi.nlm.nih.gov/18241911/
Baksh D, Yao R, Tuan RS. Comparison of proliferative and multilineage differentiation potential of human mesenchymal stem cells derived from umbilical cord and bone marrow. Stem Cells. 2007;25(6):1384-1392. PMID: 17332507. https://pubmed.ncbi.nlm.nih.gov/17332507/
Hsieh JY, Fu YS, Chang SJ, et al. Functional module analysis reveals differential osteogenic and stemness potentials in human mesenchymal stem cells from bone marrow and Wharton's jelly of umbilical cord. Stem Cells Dev. 2010;19(12):1895-1910. PMID: 20367285. https://pubmed.ncbi.nlm.nih.gov/20367285/
Matas J, Orrego M, Amenabar D, et al. Umbilical cord-derived mesenchymal stromal cells (MSCs) for knee osteoarthritis: repeated MSC dosing is superior to a single MSC dose and to hyaluronic acid in a controlled randomized phase I/II trial. Stem Cells Transl Med. 2019;8(3):215-224. PMID: 30592390. https://pubmed.ncbi.nlm.nih.gov/30592390/
Aratikatla A, Maffulli N, Gupta M, et al. Wharton's jelly and osteoarthritis of the knee. Br Med Bull. 2024;149(1):13-31. PMID: 38061765. https://pubmed.ncbi.nlm.nih.gov/38061765/
Lamo-Espinosa JM, Mora G, Blanco JF, et al. Intra-articular injection of two different doses of autologous bone marrow mesenchymal stem cells versus hyaluronic acid in the treatment of knee osteoarthritis: multicenter randomized controlled clinical trial (phase I/II). J Transl Med. 2016;14(1):246. PMID: 27565858. https://pubmed.ncbi.nlm.nih.gov/27565858/
Shapiro SA, Kazmerchak SE, Heckman MG, Zubair AC, O'Connor MI. A prospective, single-blind, placebo-controlled trial of bone marrow aspirate concentrate for knee osteoarthritis. Am J Sports Med. 2017;45(1):82-90. PMID: 27566242. https://pubmed.ncbi.nlm.nih.gov/27566242/
Ankrum JA, Ong JF, Karp JM. Mesenchymal stem cells: immune evasive, not immune privileged. Nat Biotechnol. 2014;32(3):252-260. PMID: 24561556. https://pubmed.ncbi.nlm.nih.gov/24561556/
U.S. Food and Drug Administration. Important Patient and Consumer Information About Regenerative Medicine Therapies. https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/important-patient-and-consumer-information-about-regenerative-medicine-therapies
U.S. Food and Drug Administration. FDA Approves First Mesenchymal Stromal Cell Therapy to Treat Steroid-refractory Acute Graft-versus-host Disease (Dec 18, 2024). https://www.fda.gov/news-events/press-announcements/fda-approves-first-mesenchymal-stromal-cell-therapy-treat-steroid-refractory-acute-graft-versus-host
Eliasberg CD, Nemirov DA, Mandelbaum BR, et al. Complications following biologic therapeutic injections: a multicenter case series. Arthroscopy. 2021;37(8):2600-2605. PMID: 33872744. https://pubmed.ncbi.nlm.nih.gov/33872744/
ClinicalTrials.gov (U.S. National Library of Medicine). Search: mesenchymal stromal cells, knee osteoarthritis. https://clinicaltrials.gov/search?cond=Knee%20Osteoarthritis&term=mesenchymal