Stellate Ganglion Block (SGB) for Long COVID
The stellate ganglion block (or SGB) is one of the more dramatic interventions discussed in Long COVID circles: an injection into the neck that some patients describe as transformative. It also sits in an unusual evidence zone. There is a plausible biological rationale, a long history of use in other conditions, and striking patient reports. But for Long COVID itself, the evidence is still mostly uncontrolled, and the best controlled trial so far, for post-COVID parosmia, was negative.
Here is an honest look at what SGB is, why people are interested in it, and what we actually know. If you've had a SGB, please consider adding a review to our database here.
What It Is
The stellate ganglion is a cluster of sympathetic nerves near the lower front of the neck, close to the first rib. The sympathetic nervous system is the “fight or flight” branch of the autonomic nervous system, helping regulate heart rate, blood pressure, sweating, blood vessel tone, and related automatic functions.
An SGB is an injection of local anesthetic near that nerve cluster, usually guided by ultrasound or fluoroscopy. The goal is to temporarily block sympathetic signaling. Some clinicians describe the hoped-for effect as a “reset” of an overactive sympathetic system, though that mechanism is still a hypothesis, especially in Long COVID.
A Brief History
SGB is not new. Pain specialists and anesthesiologists have used it for decades for conditions such as complex regional pain syndrome, sympathetically mediated pain, circulation problems in the arm, Raynaud’s syndrome, and some headache or facial pain disorders.
More recently, SGB has drawn attention for non-pain conditions, including hot flashes and post-traumatic stress disorder. The PTSD literature includes sham-controlled randomized trials, with mixed but notable findings, and that work helped raise the question of whether dampening sympathetic overactivity might help other conditions involving autonomic dysregulation.
When Long COVID emerged with prominent symptoms like racing heart, orthostatic intolerance, sweating and temperature problems, poor sleep, and a sense of being stuck in fight-or-flight, SGB became a natural intervention to try. Early case reports and case series, including reports of improved smell and taste, added to the excitement.
Why People Are Looking at It for Long COVID
The rationale is autonomic. Many people with Long COVID have symptoms that point to dysautonomia: tachycardia on standing, blood pressure instability, temperature dysregulation, sweating changes, poor sleep, GI motility problems, exercise intolerance, and hyperadrenergic “wired but exhausted” states.
SGB directly targets sympathetic signaling in the neck and upper chest. The hypothesis is that temporarily quieting that pathway could reduce autonomic overactivation and improve downstream symptoms. Some researchers also speculate about effects on blood flow, inflammation, and neuroimmune signaling.
Getting It: Who Performs It, and How
SGB is a medical procedure, typically performed by anesthesiologists, pain-management physicians, and some interventional specialists in a clinic or outpatient setting. It is usually done with imaging guidance.
For Long COVID, SGB remains experimental/off-label. There is no established Long COVID indication, and availability depends on whether a clinician is willing to offer it for this use. Insurance coverage is inconsistent, and patients may pay out of pocket. Some protocols use one side only; others use sequential right- and left-sided blocks, which adds cost and procedural exposure.
Because this is an injection into the neck near major nerves, blood vessels, the airway, and the lung apex, the experience and technique of the clinician matter.
Reported Benefits
Patient reports are the main reason SGB gets attention. Some people describe rapid improvement in smell, brain fog, fatigue, sleep, dysautonomia, and the sensation of being trapped in fight-or-flight.
Uncontrolled studies have also reported improvement. A 2026 systematic review found that seven included Long COVID studies all reported symptomatic improvement, with response rates ranging from about 56% to 100%. The strongest reported signals were for symptoms such as cough, dyspnea, headache, joint pain, pain intensity or interference, pins-and-needles sensations, and subjective overall relief.
The caveat is essential: these studies did not have control groups. They cannot separate the effect of SGB from placebo response, expectation, selection bias, natural recovery, or the ordinary ups and downs of Long COVID.
Risks and Side Effects
SGB is generally considered safe in experienced hands, but it is not in the same risk category as trying a low-risk oral medication.
Common temporary effects of a successful block include droopy eyelid, red or watery eye, nasal stuffiness, hoarse voice, warmth or tingling, difficulty swallowing, and a lump-in-the-throat sensation. These usually resolve within hours.
Rarer but more serious complications include bleeding, infection, vascular puncture, nerve injury, pneumothorax, thyroid or esophageal injury, spread of anesthetic to nearby nerves affecting breathing or swallowing, seizure from intravascular anesthetic injection, and other local-anesthetic complications. These are uncommon, but real.
What the Research Actually Says
The evidence gap is still large.
For broad Long COVID symptoms, the published evidence remains mostly uncontrolled. A 2026 systematic review found promising reports across seven studies, but all lacked control groups and used heterogeneous protocols, outcomes, and follow-up periods. The authors called for larger randomized trials with placebo or sham comparison.
The first randomized placebo-controlled trial touching a post-COVID symptom was published in 2025 and tested SGB for COVID-induced parosmia, or distorted smell. It enrolled 57 participants and compared SGB with saline placebo. At three months, response rates were similar: 43% with SGB and 38% with placebo. The trial found no meaningful advantage over placebo and concluded that SGB should not be recommended for COVID-induced parosmia.
That result does not prove SGB cannot help any Long COVID subgroup. But it is a strong warning against assuming that dramatic patient stories translate into treatment effects.
More trials are now underway or being planned. STAR-CO, a randomized controlled trial in Quebec, is recruiting adults with Long COVID. CeASE, a Toronto randomized placebo-controlled trial of cervicothoracic sympathetic block for post-COVID autonomic dysfunction, is listed as not yet recruiting. RECOVER-TLC also lists stellate ganglion nerve block as a planned Long COVID trial, not yet enrolling. Stanford has a small sham-controlled POTS trial, though that is not specifically a Long COVID trial.
If you'd like to find someone who can perform a stellate ganglion block, search our database here.