How Long Does Stem Cell Therapy Last?

What this means

"How long does it last?" is really two questions. The first is how long symptom relief lasts after an injection. The second is whether anything in the joint actually changes. The research answers the first question only partly, and so far it answers the second mostly with "not that we can measure."

Most of the evidence comes from knee osteoarthritis, the wear-related joint condition where cell injections have been studied most. The products studied include cells concentrated from your own bone marrow or fat, and donor cells grown from umbilical cord tissue. Each behaves differently, and results from one type do not automatically apply to another. Shoulder, hip, back and tendon data are thinner still, so durability claims for those areas rest on even less.

Florida patients should also know the regulatory picture. The FDA has not approved any stem cell product for orthopedic conditions such as osteoarthritis, back pain or tendon problems (FDA, 2021). Florida law allows physicians to offer certain non-FDA-approved stem cell therapies in limited settings, which is a different thing from FDA approval (Fla. Stat. § 459.0127, 2025).

Candidacy

There is no FDA-defined candidate for an investigational injection, and no test predicts who will get long-lasting relief. People who ask about stem cell therapy usually have joint or tendon pain that has not settled with exercise therapy, weight management and medication. People with an active infection, cancer, a bleeding problem, or advanced joint damage where surgery is the better fit are usually poor candidates. Whether it is reasonable for you is a physician's decision after an evaluation, not a decision made by a product or a price list.

Clinical evaluation

Before discussing any injection, Dr. Chantasi looks at:

• The pain source. Arthritis, a meniscus or tendon problem, or pain referred from the hip or spine can look alike.
• Imaging. X-rays show how far arthritis has progressed. Ultrasound or MRI is added when the picture is unclear.
• What has been tried. Exercise therapy, weight changes, medication and prior injections, and how long each one helped.
• Medical history. Blood thinners, diabetes, immune conditions and any prior joint infection.
• Your goals. What you want to get back to, and what result would make a procedure worth it to you.

Available options

For knee arthritis, the mainstream options come first: exercise and physical therapy, weight loss when relevant, oral or topical anti-inflammatory medication, and bracing. A corticosteroid injection can give short-term relief, though the effect fades over weeks, and a Cochrane review found no evidence that it remains six months later (Jüni et al., 2015). Hyaluronic acid injections and, for advanced arthritis, joint replacement are other conventional choices.

Beyond those, options include platelet-rich plasma (PRP), enrolling in a registered clinical trial, or, in Florida, a stem cell therapy offered under state law with written informed consent (Fla. Stat. § 458.3245, 2025). These are not FDA-approved for joint pain. How PrimeCell approaches each is described on the stem cell therapy page.

Benefits, limitations and risks

In trials, many people did report less pain over the following year. The catch is that people given a steroid injection or a saline placebo often improved by similar amounts (Mautner et al., 2023; Pers et al., 2025). That makes it hard to say how much of the relief, or its duration, comes from the cells themselves.

Short-term reactions include soreness and swelling at the injection site, and harvesting bone marrow or fat adds a second procedure site. The FDA has received reports of serious harms from unapproved regenerative products, including infections, blindness and tumor formation (FDA, 2021). Cost is another real limitation: these injections are usually self-pay, and a result that fades may lead to requests for repeat injections.

What the evidence shows

What it establishes: In a randomized phase 3 trial of 480 patients with knee arthritis, bone marrow concentrate, fat-derived stromal vascular fraction and umbilical cord tissue cells were no better than one another, or than a steroid injection, for pain at 12 months. MRI arthritis scores did not change in any group, and no procedure-related serious adverse events were reported (Mautner et al., 2023). In the ADIPOA2 trial, a single injection of the patient's own fat-derived cells did no better than saline placebo at 6 months, with no group differences through 12 months (Pers et al., 2025).

A small trial of 26 patients found that two umbilical cord cell injections, six months apart, gave lower pain scores at 12 months than hyaluronic acid. One injection did not, and MRI scores did not differ (Matas et al., 2019).

What it does not establish: that results last beyond a year or two, that cartilage regrows, or that repeat injections keep working. It also does not tell you how a product prepared differently, or used in another joint, would perform. Longer, larger placebo-controlled studies are still needed.

Recovery and next steps

After a joint injection, most people go home the same day and are told to take it easy for a few days and avoid strenuous activity for longer. Call the office for increasing redness, warmth, fever or severe pain. If you are weighing an injection, ask for the exact product name, its FDA status in writing, what result would count as success, and when you would reassess. Individual results vary.

Orlando considerations

Since July 1, 2025, Florida law has allowed physicians, including osteopathic physicians, to use certain stem cell therapies that are not FDA-approved in orthopedics, wound care and pain management, with sourcing, manufacturing and informed-consent requirements (Fla. Stat. §§ 458.3245, 459.0127, 2025). State law does not make these products FDA-approved, and it does not say how long any result will last. Florida law also requires the patient notice shown below.