Chronic low back pain is one of the most common reasons adults seek medical care, and it becomes more complicated when obesity is also present. Excess weight changes how the spine loads, raises levels of inflammatory molecules in the blood, and can make pain harder to manage. Researchers have begun asking whether glucagon-like peptide-1 receptor agonists, a class of peptides known mainly for their effects on blood sugar and body weight, might also influence pain in this population.
A prospective pilot cohort study posted to a preprint server followed 35 adults for 12 months after they began using a GLP-1 receptor agonist. The participants had a median age of 41 years, 86 percent were women, and all had both obesity and chronic low back pain. The research team collected pain questionnaires, disability scores, quality-of-life measures, and blood samples for inflammatory markers at multiple time points. A subset of 24 participants also underwent physical performance testing and a specialized pain-sensitivity protocol called quantitative sensory testing.
The study was a single-arm design with no placebo group, which means it cannot prove the peptide caused the improvements it recorded. The authors themselves call for randomized controlled trials before causality can be established. Still, the findings offer a detailed look at how several biological markers moved together over the course of a year, and that picture is worth examining.
Study design and participants
All 35 participants were beginning GLP-1 receptor agonist therapy as part of their routine care, not as an experimental assignment. Twenty-four received tirzepatide and 11 received semaglutide. Because tirzepatide also activates glucose-dependent insulinotropic polypeptide receptors in addition to GLP-1 receptors, the two subgroups were not pharmacologically identical, though the study reported them together.
Questionnaires were completed at baseline and then at 3, 6, 9, and 12 months. The primary pain outcome was the Brief Pain Inventory Short Form, which asks participants to rate pain on a numeric scale and describe how much it interferes with daily activities. Secondary measures included the Oswestry Disability Index, a Numerical Rating Scale for back pain specifically, and the Short Form-12, which captures physical and mental aspects of quality of life.
At baseline and again at 6 months, a subset of 24 participants gave blood samples for inflammatory biomarkers including C-reactive protein, tumor necrosis factor alpha, interleukin-6, and interleukin-10. Adipokines, specifically leptin and adiponectin, were also measured. These are signaling molecules released by fat tissue that can influence inflammation and pain pathways. Hemoglobin A1c, a marker of average blood sugar over roughly three months, was included as well.
Weight and metabolic changes
Over 12 months, participants lost a meaningful amount of body weight. Median body mass index dropped from 39.9 to 34.9 kilograms per square meter, representing a 12.5 percent reduction. This is a relevant figure because spinal loading is directly tied to body weight, and losing roughly one-eighth of starting body mass could reduce mechanical stress on the lumbar vertebrae and surrounding tissues.
Hemoglobin A1c decreased over the same period, suggesting improved blood sugar regulation. Leptin, a hormone produced by fat cells that tends to run high in obesity and has been linked to inflammatory signaling, also declined. Adiponectin, another adipokine that is generally considered anti-inflammatory and tends to be lower in people with obesity, moved in the opposite direction and increased, though that change did not reach statistical significance in this small sample.
Pain and disability scores
The primary outcome showed a notable shift. Median Brief Pain Inventory severity scores moved from 4.8 at baseline to 2.0 at 12 months. A drop of that size is generally considered clinically meaningful on this scale, meaning it likely reflects a real change in how participants experienced their pain rather than random variation in reporting.
Pain interference scores, which capture how much pain limits work, sleep, mood, and daily activities, also improved. The Oswestry Disability Index, a widely used measure of functional limitation from back problems, showed improvement as well. Numerical Rating Scale scores for back pain specifically followed the same direction. Short Form-12 physical component scores improved, though the mental component scores were not highlighted as a primary finding.
Inflammatory markers
C-reactive protein, a general marker of systemic inflammation that is often elevated in obesity, decreased over the six-month window during which blood samples were collected. This finding is consistent with the weight loss itself, since adipose tissue is a source of pro-inflammatory signaling molecules and reducing its volume tends to lower circulating inflammatory markers.
Tumor necrosis factor alpha and interleukin-6, both of which are associated with pain sensitization in some research contexts, were measured but the abstract does not describe their individual trajectories in detail. Interleukin-10, an anti-inflammatory cytokine, was also tracked. The overall pattern in the blood data is consistent with a shift toward a less inflammatory internal environment, though how much of that shift is attributable to weight loss versus a direct action of the peptide on immune pathways cannot be separated in a single-arm study.
Sensory testing and physical performance
One of the more scientifically interesting components of this study was the inclusion of quantitative sensory testing, a standardized method for assessing how the nervous system processes experimental pain stimuli such as heat or pressure. If GLP-1 receptor agonists directly altered central pain processing, researchers would expect to see changes in sensory thresholds independent of weight loss.
The study found that experimental pain sensitivity was unchanged after six months. This does not rule out a central mechanism entirely, but it does suggest that whatever improvements occurred in clinical pain scores were not accompanied by measurable shifts in how the nervous system responded to controlled stimuli. Physical performance testing also improved, but that change did not reach statistical significance, likely because the sample of 24 participants who completed those assessments was small.
Limitations and next steps
The authors are transparent about the constraints of this work. Thirty-five participants followed in a single arm with no control group cannot establish that the peptide caused the improvements. People who begin any new health intervention often experience some improvement due to increased attention, lifestyle changes, or placebo effects. The absence of a comparison group makes it impossible to separate those influences from the biological effects of the peptide.
The mix of two pharmacologically distinct compounds in one sample is another limitation. Tirzepatide and semaglutide act on overlapping but not identical receptor targets, and grouping them may obscure differences between the two. The follow-up period of 12 months, while longer than many pilot studies, does not capture what happens if participants regain weight after stopping.
The researchers conclude that randomized controlled trials are the appropriate next step. Those trials would need a placebo arm, standardized dosing, and ideally a mechanism to separate the effects of weight loss from any direct action of the peptide on pain pathways. The current study provides a detailed set of outcomes to power such a trial and suggests which biomarkers are most likely to show movement.
