SGB, or stellate ganglion block, is an injection of local anesthetic into a cluster of nerves on the side of the neck. These nerves, called the stellate ganglion, are part of the sympathetic nervous system, the body’s “fight or flight” wiring. By temporarily numbing this nerve bundle, SGB can calm an overactive stress response and reduce symptoms of chronic pain, PTSD, anxiety, and several other conditions. The procedure takes only minutes, is performed under ultrasound guidance, and has been used in pain medicine for decades.
How the Injection Works
The stellate ganglion sits near the base of the neck, in front of the sixth or seventh cervical vertebra. It acts as a relay station for sympathetic nerve signals traveling to the head, neck, arms, and upper chest. When the body is stuck in a heightened state of stress or pain, this nerve cluster can become overactive, continuously pumping out norepinephrine (the chemical that drives the fight-or-flight response) and amplifying pain signals.
Injecting a local anesthetic directly onto the ganglion interrupts that cycle. The block reduces norepinephrine release, quiets abnormal pain signaling from nerve roots, and appears to lower neuroinflammation in both the spinal cord and brain. Think of it as hitting a reset button on the sympathetic nervous system. The nerves aren’t destroyed; they’re temporarily switched off, which can allow the system to recalibrate to a calmer baseline.
Conditions Treated With SGB
SGB was originally developed for excessive sweating (hyperhidrosis) and has been a standard treatment for complex regional pain syndrome (CRPS) and other chronic pain conditions for years. Its uses have expanded considerably:
- PTSD and anxiety. This is the application that has drawn the most public attention. A landmark multi-center randomized controlled trial in 2019 demonstrated efficacy using two injections spaced two weeks apart for PTSD symptoms. In a study of 114 patients with generalized anxiety disorder, bilateral two-level blocks reduced anxiety scores by an average of 52% at three months, with nearly 87% of patients showing lasting improvement.
- Chronic pain syndromes. CRPS, nerve pain in the head and upper body, and certain types of facial pain are among the most established indications.
- Hot flashes and night sweats. Women in perimenopause and breast cancer survivors who cannot take hormone therapy have used SGB for vasodilatory symptoms like hot flashes.
- Heart rhythm problems. SGB has been used to improve outcomes in drug-resistant ventricular arrhythmias.
- Long COVID symptoms. Early case series have explored SGB for persistent loss of taste and smell after COVID-19. In one series of six patients, five out of six (83%) reported significant improvements, with some patients recovering 80% or more of their sense of taste or smell within weeks.
What Happens During the Procedure
You’ll lie on your back with your head turned slightly. The doctor uses an ultrasound probe on the side of your neck to visualize the vertebrae, blood vessels, and the ganglion itself in real time. This imaging is critical for accuracy and safety, since the injection site sits near the carotid artery, jugular vein, and esophagus.
Once the target is identified (typically near the sixth or seventh cervical vertebra), a thin needle is advanced under continuous ultrasound guidance. A small volume of local anesthetic is injected around the nerve cluster. The entire injection takes just a few minutes. Some protocols call for one injection on the right side, others for bilateral injections (right side first, then left side at a follow-up visit), depending on the condition being treated.
Within minutes, you’ll likely notice a drooping eyelid, a constricted pupil, and warmth in the arm on the treated side. These are signs of Horner’s syndrome, a temporary and expected effect that confirms the block is working. Hoarseness and mild difficulty swallowing can also occur as nearby nerves are temporarily affected. These effects typically resolve within hours.
What Recovery Looks Like
There’s no general anesthesia involved, so you stay awake throughout. Most people go home the same day. Pain relief and symptom improvement can begin within hours, though the full effect sometimes takes a day or two to settle in.
How long the benefits last varies. For pain conditions, some people experience relief lasting days to weeks from a single injection, with relief generally lasting longer after each subsequent treatment. For PTSD and anxiety, a common protocol involves two injections spaced about two weeks apart, and studies have tracked symptom improvement lasting at least three months. Many patients need a series of injections. Sometimes two are enough; in other cases, ten or more may be needed over time.
PTSD Results: What the Evidence Shows
The evidence for SGB and PTSD is promising but still evolving, and it’s worth understanding the full picture. Uncontrolled case series (where everyone gets the treatment and there’s no comparison group) have reported rapid clinical improvement in 70% to 75% of PTSD patients. Those are compelling numbers, but they don’t account for the placebo effect.
In a randomized controlled trial, where SGB was compared to a sham injection of saline, the results were more modest. After one round of treatment, PTSD symptom improvement ranged from about 5% to 15%, and after a second round, 12% to 21%, which was not significantly better than saline. The gap between real-world reports and controlled trial results suggests that some of the benefit seen in clinical practice may come from placebo response, patient selection, or differences in technique and dosing.
That said, newer studies using bilateral, two-level protocols (injecting at two vertebral levels on both sides of the neck) have shown stronger and more durable results, particularly for anxiety. The field is refining which protocols work best for which conditions.
Risks and Side Effects
SGB is considered relatively safe. Severe complications occur at a rate of roughly 1.7 per 1,000 blocks. The most common side effects are temporary and related to the anesthetic spreading to nearby structures:
- Hoarseness is the most frequently reported side effect, caused by the anesthetic reaching the recurrent laryngeal nerve.
- Light-headedness occurs in a smaller number of patients.
- Difficulty swallowing can happen as throat muscles are temporarily affected.
- Hematoma (bruising or blood collection at the injection site) is the most common local complication.
Rare but serious complications include pneumothorax (a punctured lung), seizures if anesthetic enters a blood vessel, and infection. The widespread adoption of ultrasound guidance has significantly reduced these risks compared to the older landmark-based technique, where doctors relied on feeling for bone structures rather than seeing them on a screen.
Cost and Insurance Coverage
A pair of SGB injections costs approximately $2,000. Insurance coverage depends heavily on the indication. Blocks performed for established pain conditions like CRPS are more likely to be covered. Coverage for PTSD, anxiety, or hot flashes is inconsistent, since these are considered newer or off-label uses by many insurers. It’s worth calling your plan before scheduling to ask whether the specific diagnosis code your doctor will use is covered.
SGB is offered at pain management clinics, some military and VA medical centers (which have been early adopters for PTSD treatment), and a growing number of private practices specializing in interventional psychiatry. Availability has expanded considerably over the past few years, though it remains more accessible in urban areas and near academic medical centers.