Hyalgan vs. Synvisc: Differences and Similarities

Medically Reviewed by David Zelman, MD on November 02, 2022
4 min read

Could a simple shot relieve your aching joints? Hyalgan and Synvisc, or hyaluronic acid, are two injectable drugs that treat knee, hip, or ankle pain from osteoarthritis (OA). These treatments may also help you put off knee replacement surgery.

Many other brands of this type of injection are available too. This treatment is also called viscosupplementation.

Originally, the hyaluronic acid used for these treatments was made from rooster’s combs. Today, most products contain other, genetically modified natural material. These new materials may reduce the potential side effects of these injections compared to older treatments.

Hyaluronic acid is a natural, gel-like substance in your joints. It cushions and lubricates your joints as you move them. If you develop OA, cartilage in your joint breaks down and wears away. OA causes you to lose hyaluronic acid too, so it’s difficult and painful to walk, or bend or move your joint.

In viscosupplementation, your doctor injects hyaluronic acid directly into your knee to reduce pain and improve movement. These drugs replace or add to the natural gel in your joint.

Both Hyalgan and Synvisc offer temporary pain relief for OA. They don’t repair cartilage or reverse bone damage from arthritis. But you can use them to help you move more easily with less pain. They may make daily activities or exercise more comfortable for you.

Hyaluronic acid injections may also help you delay knee replacement surgery if you aren’t ready for it yet. They may also be a pain-relief option if other treatments, like acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), steroid shots, physical therapy, losing weight, heat and ice treatments, or using a cane to walk haven’t worked.

You can take Hyalgan and Synvisc if you choose to continue to use these treatments.

At your doctor’s office, you’ll get a series of Hyalgan or Synvisc injections, usually one each week for 3 to 5 weeks. Most people need more than one injection to feel any relief.

Your doctor may need to take out some fluid from your affected joint first, then they’ll give you the injection.

You may start to feel pain relief within a few days to several weeks after starting the injections.

After each shot, don’t put too much pressure on your joint for about 48 hours. Skip strenuous activities like tennis, running, lifting heavy objects, or even standing up for too long.

Hyalgan and Synvisc treatments work differently for everyone. Not everyone has the same level of pain relief, and the effects don’t last the same amount of time for everyone. Maximum pain relief usually lasts for 2 to 3 months after treatment. Some people have pain relief for as long as 6 months.

At first, you may notice mild pain, redness, warmth, or swelling at the site of your injection. It may be a little hard to move your joint at first too. These symptoms should go away quickly. It’s OK to ice your joint to ease any discomfort.

Other possible side effects are:

  • Bruising
  • Rash
  • Itch
  • Fluid buildup in the joint
  • Infections or bleeding, although these are rare

Let your doctor know if you bleed after your injection, notice signs of an infection, or if your pain or swelling gets worse. We don’t know its effects during pregnancy or breastfeeding, so tell your doctor if you’re pregnant or nursing before you start treatment.

Both Hyalgan and Synvisc are both hyaluronic acid injections. But there are some differences to consider. Usually, you take Hyalgan in five weekly injections, while you take Synvisc in three weekly injections. Some forms of Synvisc only require a single injection.

While Hyalgan and Synvisc both contain the same active ingredient, they may have slightly different outcomes in the long term. In one study of over 50,000 people with knee osteoarthritis, people who took Hyalgan were less likely to need a total knee replacement later compared to people who took Synvisc. They also had a longer delay before they needed to have knee replacement surgery compared to people treated with Synvisc.

Other research shows that either treatment is equally effective at relieving joint pain and may be more effective early in your disease.