Most people get about a month of pain relief from a lidocaine trigger point injection, though the timeline varies. The initial numbing from the lidocaine itself wears off within hours, but the therapeutic benefit, which comes from releasing the knotted muscle, typically kicks in between 24 and 72 hours after the procedure and can persist for several weeks.
What the Relief Timeline Looks Like
There are two distinct phases of relief after a lidocaine trigger point injection, and it helps to understand both so you’re not caught off guard.
The first phase is the local anesthetic effect. Lidocaine numbs the area quickly, and some people feel immediate relief right on the table. This numbness fades within a few hours. What follows can be confusing: many people experience soreness at the injection site that lasts about two to three days. This is normal. The needle physically disrupts the tight muscle knot, and that mechanical trauma causes temporary inflammation in the tissue.
The second phase is the actual therapeutic relief. Once the post-injection soreness fades, typically between 24 and 72 hours after the procedure, the deeper pain relief sets in. For most people, this lasts roughly a month. Some people get longer relief, others shorter. The variability depends on factors like how chronic the trigger point is, how many trigger points are involved, and whether the underlying cause of the muscle tension is still present.
How Many Injections You May Need
A single injection sometimes resolves a trigger point permanently, especially if it’s a newer one caused by a specific injury or strain. Chronic trigger points that have been building for months or years often require a series of injections.
Clinical guidelines vary on spacing. The American College of Occupational and Environmental Medicine recommends three to four weeks between injections. The American Society of Interventional Pain Physicians takes a more conservative approach: during an initial diagnostic phase, injections can be given as frequently as once a week, but once you move into ongoing treatment, they recommend spacing sessions at least two months apart. Their upper limit is six injections per year, and they look for at least 50% improvement lasting six weeks or more before continuing.
Medicare limits coverage to three sessions per 12-month period, which gives you a practical sense of how often most providers consider these injections appropriate for long-term management.
Does the Type of Anesthetic Matter?
You might wonder whether a longer-acting anesthetic like bupivacaine would give you more relief than lidocaine. The short answer: probably not in a meaningful way. A multicenter study comparing the two found no statistically significant difference in how long patients experienced strong pain relief. Lidocaine patients reported an average of about 12 to 16 hours of intense numbing relief, while bupivacaine patients reported a similar range depending on how relief was measured.
This makes sense when you consider that the lasting benefit of trigger point injections comes not from the anesthetic itself but from the mechanical disruption of the muscle knot. The needle breaks up the taut band of muscle fibers, interrupting the pain cycle. The lidocaine simply makes the process more comfortable.
Does Physical Therapy Extend the Relief?
It’s commonly recommended to stretch or do physical therapy after a trigger point injection, with the logic that the temporary pain relief gives you a window to work on the muscle. A randomized controlled trial tested this directly, comparing lidocaine injections alone, physical therapy alone, and the two combined. At both one month and three months, there was no significant difference in pain scores between the groups. The combination didn’t outperform either treatment on its own.
That said, the physical therapy group did show better range of motion in certain movements at both time points. So while adding physical therapy may not extend how long the pain relief lasts, it can help you regain mobility that the trigger point was restricting. If your trigger points are related to posture, repetitive strain, or muscle imbalances, addressing those root causes through exercise or ergonomic changes is still your best bet for preventing recurrence.
What About the Twitch Response?
During the injection, the provider aims the needle at the tightest part of the muscle knot. Sometimes this causes a visible twitch in the muscle, called a local twitch response. For years, many practitioners believed that eliciting this twitch was essential for a successful outcome. Multiple systematic reviews have found no consistent evidence that this is true. Studies show that pain and disability improvements don’t correlate with whether a twitch was triggered during the procedure. So if your provider doesn’t get a twitch, it doesn’t mean the injection won’t work.
What Affects How Long Your Relief Lasts
The month-long average is just that: an average. Several factors push the duration shorter or longer.
- Chronicity of the trigger point. A trigger point that’s been active for years with layers of compensatory muscle tension is harder to fully resolve and more likely to return quickly.
- Number of trigger points. If you have multiple active trigger points in the same muscle group, treating just one may provide incomplete relief because the others continue driving the pain cycle.
- Ongoing aggravating factors. Poor posture, repetitive work tasks, stress-related muscle clenching, or sleep positions that strain the affected muscle can reactivate a trigger point within weeks.
- Individual response. Some people respond dramatically to a single injection and never need another. Others find the relief fades after two or three weeks consistently.
If your relief consistently lasts less than six weeks, your provider will likely reassess whether trigger point injections are the right approach or whether something else is contributing to your pain.