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Euflexxa and Synvisc: Which One Is Best?

Lisa, an active middle-aged woman, had always enjoyed an active lifestyle, whether it was hiking in the mountains or playing tennis with her friends. However, as time went by, she experienced knee pain that limited her mobility for her favorite activities. Seeking a solution, Lisa decided to explore the option of viscosupplementation, an increasingly popular treatment for knee osteoarthritis.

Knee osteoarthritis is a common and debilitating joint condition affecting millions worldwide. It pertains to the progressive deterioration of cartilage within the knee joint, resulting in pain, stiffness, and diminished mobility. This condition often necessitates the exploration of treatment options to alleviate discomfort and improve joint function.

Viscosupplementation involves injecting gel-like substances, known as hyaluronic acid, into the knee joint to alleviate pain, reduce inflammation, and increase joint lubrication. Among the options available, Euflexxa and Synvisc are two of the most well-known and widely used brands. Each boasts its unique benefits, leaving Lisa with the question: Which one is best for her?

In this article, we compare Euflexxa and Synvisc, examining their effectiveness, safety profiles, duration of relief, and patient experiences.

Understanding Euflexxa and Synvisc


Synvisc is a medical product used in the treatment of knee osteoarthritis. It belongs to a class of therapies known as hyaluronic acid injections or viscosupplements. These injections alleviate the symptoms of knee osteoarthritis by providing lubrication and cushioning to the affected joint.

Synvisc primarily comprises hyaluronic acid, a naturally occurring substance in the synovial fluid that lubricates the joints. Hyaluronic acid absorbs shock, reduces friction, and provides joint cushioning.

Synvisc comes from the comb of roosters. The comb is a fleshy, crown-like structure on the rooster’s head, containing a high concentration of hyaluronic acid. The production process involves extracting and purifying hyaluronic acid from the rooster combs. The resulting hyaluronic acid is sterilized and formulated into Synvisc for medical use.


Euflexxa is another hyaluronic acid injection used to treat knee osteoarthritis. Like Synviscs, it falls under the category of viscosupplements and aims to improve joint function and alleviate pain for individuals with this condition.

However, Euflexxa ‘s hyaluronic acid is not derived from animal sources but undergoes a controlled biotechnological process. This process includes fermenting genetically modified bacteria to produce hyaluronic acid. The resulting hyaluronic acid undergoes careful purification and formulation into Euflexxa. The biofermentation process enables precise control over the composition and quality of the hyaluronic acid used in the product.

What is Euflexxa derived from?

Euflexxa is derived from a natural, avian-derived source called avian rooster combs. It is a highly purified form of hyaluronic acid, a substance found in the body’s synovial fluid, used to treat knee pain due to osteoarthritis.

Which is better SYNVISC or EUFLEXXA?


In the FLEXX trial, Euflexxa (IA-BioHA) has proven its effectiveness as a knee osteoarthritis treatment. This well-designed study involved randomized, double-anonymized comparisons between Euflexxa and a saline control group. The results were remarkable, showing that Euflexxa provided significant pain relief and improved joint function over a span of 26 weeks. Subjects treated with Euflexxa reported a median pain reduction of 53%, while the control group experienced a 38% reduction.

Secondary assessments conducted during the trial, such as the Osteoarthritis Research Society International responder index and health-related quality of life enhancements, further supported the benefits of Euflexxa. Notably, the therapy exhibited excellent tolerance, with minimal adverse events reported by participants. These trial findings confirm that Euflexxa is a promising and safe option for individuals facing knee osteoarthritis, as it offers both pain relief and an improved quality of life.

On the other hand, Synvisc has been the subject of many comparative studies, evaluating its efficacy against various control groups, including intra-articular saline, intra-articular steroids, NSAIDs, and standard care. Notably, two randomized, placebo-controlled trials comparing Synvisc to intra-articular saline revealed statistically significant improvements with Synvisc in crucial outcomes such as weight-bearing pain and activity-related pain at both 12 and 26 weeks.

Moreover, in a multicenter trial conducted in an evaluator-blinded fashion, Synvisc showed longer-lasting efficacy in pain relief and overall condition compared to intra-articular steroid treatments at the 26-week mark. Experts have also compared Synvisc to continuous NSAID use in two multicenter trials. While one study reported equivalent efficacy between the two treatments, the other suggested Synvisc offered superior efficacy.


When considering Euflexxa and Synvisc as treatments for knee osteoarthritis, prioritizing safety is crucial. Both are generally well-tolerated, but awareness of the potential side effects of both injections is essential.

Common Side Effects:

  • Mild pain, swelling, redness, and warmth at the injection site

Rare or Severe Side Effects:

  • Mild skin irritation, infection, and joint effusion 

Other Uncommon Effects 

  • Extremely rare, may include temporary increased joint pain, stiffness, or warmth

Duration of Results 

Though individual responses vary, Euflexxa and Synvisc offer lasting pain relief and improved joint function.

Euflexxa: Typically provides relief for several months, often up to six months or more. The duration depends on factors like the severity of osteoarthritis and individual response.

Synvisc: Synvisc offers substantial relief from one to six months or more. Duration varies among patients based on their specific condition and response.

It’s vital to note that periodic injections may be necessary to maintain relief.


Cost is a significant consideration for many patients when comparing Euflexxa and Synvisc:

Euflexxa: The cost varies based on the number of injections needed and insurance coverage. Typically, a whole series includes three injections over several weeks. The cost of one injection usually ranges between $477 to $1,321. Patients should check insurance coverage and consider associated healthcare provider fees.

Synvisc: Cost factors include the number of injections and insurance. A complete Synvisc treatment involves three injections over weeks. The average cost of 1 Syringe, 6ml of 48mg/6ml, can be around $1,600.

Many clinics import the injections from countries outside of the U.S. to reduce the overall cost. 

Patients should collaborate with healthcare providers and insurers for informed decisions. Exploring financial help and payment options can help manage treatment costs effectively.

Which is Better?

When comparing Synvisc and Euflexxa, it’s essential to consider that both are hyaluronic viscosupplements used to treat knee osteoarthritis. Healthcare specialists administer injections into the knee joint, such as rheumatologists or orthopedic surgeons. Both treatments work by supplementing the naturally occurring hyaluronic acid that lubricates the joints.

While a few direct head-to-head studies are comparing Synvisc and Euflexxa, several sources provide insights into the effectiveness and characteristics of these treatments.

Synvisc (Hylan G-F 20) is an injectable fluid composed of Hylan A and Hylan B polymers derived from rooster combs, making it an avian-derived hyaluronic acid (AV-HA). Some studies comparing Synvisc to intra-articular saline have shown statistically significant improvements in pain relief and overall condition, as well as enhanced outcomes such as weight-bearing and activity-related pain.

On the other hand, Euflexxa (IA-BioHA) has shown effectiveness in pain relief and joint function improvement in the FLEXX trial. The study showed a significant reduction in pain and improved joint function over 26 weeks, with patients reporting a median pain reduction of 53%.

It’s important to note that the choice between Synvisc and Euflexxa may depend on individual preferences, patient characteristics, and the recommendations of healthcare professionals. Factors such as treatment tolerance, cost, and insurance coverage may also influence the decision.

We need further research and consultation to determine which treatment may be more suitable for an individual’s specific needs and circumstances.

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