Gel shots are injections of hyaluronic acid, a thick, gel-like substance that naturally exists in your knee joint fluid. When osteoarthritis breaks down that natural fluid, these injections aim to restore cushioning and lubrication. The medical term is viscosupplementation, and the treatment is FDA-approved specifically for knee osteoarthritis in people who haven’t gotten enough relief from painkillers or basic treatments like physical therapy.
How Gel Shots Work
Your knee joint contains synovial fluid, a slippery liquid that acts as both a lubricant and a shock absorber. Hyaluronic acid is the key ingredient that gives this fluid its thick, viscous quality. As osteoarthritis progresses, the concentration of hyaluronic acid in your joint drops, and the molecules that remain shift toward smaller, less effective sizes. The result is thinner fluid that doesn’t cushion or lubricate nearly as well.
A gel shot delivers a concentrated dose of hyaluronic acid directly into the joint space. The injected gel lubricates the joint capsule, reducing friction between cartilage surfaces that would otherwise grind against each other and break down further. It also absorbs pressure and vibration during movement, protecting the cartilage cells from mechanical damage. Higher molecular weight formulations tend to provide greater friction reduction because of their thicker consistency.
What the Treatment Looks Like
Depending on which product your doctor uses, you’ll receive either a single injection or a series of weekly injections spread over three to five weeks. Synvisc-One is a common single-shot option. Synvisc requires three weekly injections, Supartz FX involves one injection per week for three to five weeks, and Hyalgan typically runs as a five-week series. Each visit is a standard office appointment where the injection goes directly into the knee joint, often guided by ultrasound to ensure accurate placement.
Relief isn’t immediate. Unlike cortisone, which can reduce pain within days, gel shots build their effect gradually. Most people notice improvement several weeks after starting treatment. If the injections work well for you, the benefits can be repeated, though at least six months should pass between treatment series.
Who Benefits Most
Gel shots work best for people with early to moderate osteoarthritis. Clinical evidence consistently shows that patients in the earlier stages of cartilage wear get the most meaningful improvement in pain and function. As the disease advances toward bone-on-bone severity, the injections become less effective because there’s less intact cartilage left to protect.
Higher molecular weight formulations have shown more consistent results for people with moderate to severe symptoms, making them a reasonable option for patients looking to delay surgery. But if your knee has progressed to advanced osteoarthritis, gel shots are unlikely to provide significant relief, and your doctor will likely discuss surgical options instead.
Gel Shots vs. Cortisone Injections
These two injections serve different roles. Cortisone (a steroid) is an anti-inflammatory that works fast, typically providing noticeable pain relief within days to a few weeks. In head-to-head comparisons, cortisone is consistently better at short-term pain control, especially in the first month.
Gel shots take longer to kick in but tend to outperform cortisone at later time points. Studies show better results with hyaluronic acid at follow-up evaluations beyond the first month, though the effect is moderate by the six-month mark. The side effect profile is similar to saline injections, meaning gel shots don’t carry the same concerns about cartilage thinning that come with repeated steroid use. For people with mild to moderate osteoarthritis, gel shots offer better medium-term symptom control than cortisone.
In practice, many treatment plans use both: cortisone for flare-ups when you need quick relief, and gel shots as a longer-term management strategy.
Side Effects
Gel shots are generally well tolerated. The most common side effects are temporary pain and swelling at the injection site, which typically resolve within a few days. Some people experience warmth or stiffness in the knee for 24 to 48 hours after the injection. Icing the knee and avoiding strenuous activity for a day or two after each shot helps minimize these reactions.
Rare but possible complications include a condition called pseudosepsis, where the knee becomes significantly swollen and painful shortly after injection, mimicking an infection. True joint infections are extremely uncommon with proper sterile technique. Allergic reactions are also rare, though some products are derived from rooster combs (chicken-sourced hyaluronic acid), so people with poultry or egg allergies should let their doctor know. Fermentation-derived options like Euflexxa avoid this concern entirely.
Insurance and Cost
Medicare covers gel shots, but only after you’ve met specific requirements. You need a confirmed osteoarthritis diagnosis in the knee, and you must have tried and failed at least three months of conservative treatment. That includes both non-drug approaches (physical therapy, exercise, weight management, bracing) and medications (over-the-counter pain relievers, anti-inflammatory drugs). You also need to have tried or have a reason not to use cortisone injections first.
For repeat series, Medicare requires that your symptoms returned after a previous round that actually helped, and that at least six months have passed since your last series. Private insurers generally follow similar criteria, though the specifics vary by plan. Without insurance, a full treatment series can range from several hundred to over a thousand dollars depending on the product used and whether you need one injection or five.
What to Expect Realistically
Gel shots are not a cure for osteoarthritis, and they don’t regrow cartilage. They’re a symptom management tool that works well for a specific window of the disease. The best evidence supports their use in early to moderate stages, where they can meaningfully reduce pain and improve how well your knee functions day to day. For some people, that’s enough to stay active and push back the timeline for knee replacement surgery by months or years.
Not everyone responds to the treatment. If your first series doesn’t provide noticeable improvement, a second round is unlikely to change the outcome. But for those who do respond, repeated series every six to twelve months can be a sustainable part of managing knee osteoarthritis over the long term.