How long does a knee gel injection last?

October 10, 2025 •

4 min read

For many patients with knee osteoarthritis, the effect of a knee gel injection typically lasts for about six months. The duration of pain relief from these hyaluronic acid injections, known as viscosupplementation, can vary based on several key factors, including the severity of arthritis and individual patient response.

Quick Summary

Knee gel injections provide temporary relief for knee osteoarthritis symptoms, often lasting up to six months. The longevity of the effects depends on factors such as the severity of arthritis and individual patient response to treatment.

Key Points

Typical Duration: Most patients experience pain relief from a knee gel injection for approximately six months.
Onset of Effect: The benefits of the injection are not immediate and usually begin to be felt 4 to 6 weeks after the treatment.
Influencing Factors: The longevity of the injection depends on the severity of your arthritis, your individual response, and your activity level.
Difference from Cortisone: Gel injections provide longer-lasting relief than cortisone shots, but take longer to become fully effective.
Repeatable Treatment: Viscosupplementation injections can be safely repeated as needed, typically every six months, without the joint damage risks associated with frequent steroid injections.
Brand and Protocol: The type of hyaluronic acid brand and the number of injections (single vs. a series) can influence the effectiveness and duration of the treatment.
Conservative Approach: Best results often come from combining gel injections with other conservative management techniques, like physical therapy and weight control.

Understanding Knee Gel Injections

Knee gel injections, also known as viscosupplementation, involve injecting a gel-like substance called hyaluronic acid (HA) directly into the knee joint. In a healthy joint, synovial fluid contains natural HA that acts as a lubricant and shock absorber, allowing for smooth, pain-free movement. However, in people with osteoarthritis, this natural HA diminishes, leading to increased friction, pain, and stiffness. Viscosupplementation works by supplementing the depleted synovial fluid, helping to restore the joint's natural lubrication and cushioning.

What to Expect from the Duration of a Knee Gel Injection

The duration of relief from a knee gel injection is not immediate and varies from person to person. While the injection is a quick, in-office procedure, it takes time for the hyaluronic acid to integrate into the joint fluid and take full effect.

Timeline for a Gel Injection

Relief is not instant: Unlike corticosteroid injections, which offer rapid relief, the benefits of a gel injection are delayed.
Onset of full effect: Patients can expect to start noticing significant pain relief and improved function around 4 to 6 weeks after the injection or the final shot in a series.
Peak effectiveness: The most effective period often occurs between weeks 5 and 13 post-injection.
Typical duration: The effect usually starts to wear off after about six months.
Extended relief: Some patients experience longer-lasting relief, with benefits extending up to a year.

Factors Influencing the Longevity of a Knee Gel Injection

Several variables can influence how long a knee gel injection lasts for an individual.

Severity of Osteoarthritis: Patients with mild to moderate arthritis often experience longer-lasting and more successful relief compared to those with advanced arthritis. In advanced cases, the joint damage may be too extensive for viscosupplementation to be effective.
Injection Protocol: Some treatments are delivered in a single dose, while others are a series of weekly injections over three to five weeks. Research suggests that a series of injections may provide more sustained relief.
Individual Patient Response: A person's unique physiology and how their body reacts to the treatment play a significant role. Not all patients experience pain relief from viscosupplementation.
Activity Level and Lifestyle: Maintaining a healthy lifestyle is crucial. High-impact activities can put excessive strain on the knee, potentially shortening the duration of relief.
Weight Management: A person's body weight significantly impacts the amount of stress placed on the knee joint. Maintaining a healthy weight can improve the longevity of the injection's effects.

Comparing Knee Gel Injections to Other Treatments

To understand where viscosupplementation fits into treatment plans, it helps to compare it to other common knee injections, such as corticosteroids.


Feature	Hyaluronic Acid (Gel) Injections (Viscosupplementation)	Corticosteroid Injections (Steroid Shots)
Mechanism	Supplements natural joint fluid, acting as a lubricant and shock absorber.	Reduces inflammation and swelling in the joint.
Onset of Relief	Delayed; typically takes 4-6 weeks to feel full effects.	Rapid; can begin providing relief within 1-3 days.
Duration of Relief	Longer-lasting; typically 6 months, but can extend to a year or more.	Shorter-lasting; relief typically declines after 2-3 months.
Frequency	Can be repeated every six months to a year, and repeated use is generally safe.	Should be limited to 2-3 times per year to prevent potential joint damage.
Appropriate For	Mild-to-moderate osteoarthritis and patients seeking long-term symptom management.	Patients with acute flare-ups of severe pain and swelling, or those needing immediate relief.
Impact on Joint	Shown to be associated with decreased progression of degeneration in studies.	May be associated with an increased progression of osteoarthritis with repeated use.

Different Gel Injection Brands and Protocols

There are various brands of hyaluronic acid injections available, which can be administered in a single dose or a series of multiple shots. The specific brand and protocol your doctor selects can influence the treatment's effectiveness and duration. Examples include:

Single-injection products: Some formulations, like Synvisc-One, are designed for a single injection.
Multi-injection series: Others, such as Hyalgan or Synvisc, involve a series of 3 to 5 weekly injections. Some evidence suggests that a series of injections may offer more sustained relief.
Variations in Composition: The source of HA (animal-derived vs. synthetic) and its molecular weight can also differ between brands. For instance, brands like Hyalgan may offer a longer delay before knee replacement surgery compared to Synvisc in some studies, although both are effective.

Conclusion: Maximizing the Benefits of Viscosupplementation

While a knee gel injection is not a permanent cure for osteoarthritis, it can provide significant, long-lasting temporary relief for many people, especially those with mild to moderate conditions. Maximizing the duration of this relief requires a multifaceted approach. Combining the injections with other conservative treatments, such as physical therapy to strengthen supporting muscles, maintaining a healthy weight, and avoiding high-impact activities, is key to managing chronic knee pain effectively. It is crucial to have a comprehensive discussion with your healthcare provider to determine the best injection type and protocol for your specific condition.

For more information on therapeutic options, consult with your orthopedic specialist or refer to trusted medical resources like the Hospital for Special Surgery for guidance.

What to Expect After the Procedure

After a knee gel injection, you will be able to leave the doctor's office immediately.

Initial Aftercare: It is recommended to avoid strenuous activities, like jogging or heavy lifting, for 24 to 48 hours to allow the gel to settle properly.
Manage Soreness: Some patients experience mild and temporary soreness, swelling, or discomfort at the injection site. Applying an ice pack for 10-15 minutes at a time can help alleviate these symptoms.
Monitor for Rare Reactions: In very rare cases, a reaction that looks like an infection (pseudoseptic reaction) can occur, causing redness and significant swelling. While typically not an infection, it requires discontinuation of further injections in a series.
When to Call a Doctor: You should contact your physician if you experience severe pain, excessive swelling, fever, or signs of infection.

Frequently Asked Questions

Relief is not immediate with a gel injection. While some patients may feel minor changes sooner, it typically takes 4 to 6 weeks to experience the full benefits of reduced pain and improved function.

Gel injections can typically be repeated every six months. Unlike corticosteroid injections, frequent use of hyaluronic acid does not carry the same risk of damaging the joint, though effectiveness may lessen as arthritis progresses.

Gel injections and cortisone shots have different purposes. Cortisone shots offer quicker, short-term pain relief (lasting a few months), whereas gel injections take longer to work but provide more sustained relief (up to 6 months or longer). Recent studies also suggest that frequent cortisone injections may accelerate cartilage degeneration, while hyaluronic acid may not have that effect.

Viscosupplementation is the medical term for a gel injection. It involves injecting hyaluronic acid into the knee joint to supplement the naturally occurring but diminished fluid in people with osteoarthritis. This helps to lubricate and cushion the joint.

Gel injections are generally most effective for patients with mild to moderate osteoarthritis. For individuals with severe arthritis and significant joint damage, the injections may be less effective, and other treatments might be necessary.

Following a gel injection, you should avoid strenuous activity and heavy use of the knee for 24 to 48 hours. You can use ice to reduce temporary soreness and swelling at the injection site.

While gel injections are not a permanent cure, repeated courses of the treatment have been shown in some studies to help delay the need for a total knee replacement. They do not, however, stop the progression of arthritis.