Semaglutide and Smoking in HIV

A 2026 cohort study found that 123 people with HIV reported smoking an average of 2.5 fewer cigarettes per day after starting semaglutide. Their average fell from 10.5 cigarettes per day, and 21% reported not smoking at the end of follow-up^[1]. The signal deserves attention. It is not proof that semaglutide is a smoking-cessation treatment. The study compared participants with themselves before and after treatment, with no placebo group to separate the medicine from motivation, clinical support or other changes over time.

What the HIV cohort measured

The researchers used the Centers for AIDS Research Network of Integrated Clinical Systems, known as CNICS. They included people who reported current cigarette smoking when they began semaglutide between April 2018 and November 2025 at 10 participating sites. Smoking intensity came from patient-reported assessments completed during routine clinical visits. A statistical model estimated the average within-person change while adjusting for age, sex, race or ethnicity and time^[1].

The group had a mean age of 51 years, 24% were female and 95% had viral suppression below 200 copies per milliliter. Most had a standard reason to receive semaglutide: 77% had a body mass index of at least 30 kg/m², 61% had diabetes and 93% had at least one standard indication reported by the authors^[1]. The setting matters. This was a selected clinical group receiving semaglutide for weight management or diabetes, not a cessation program designed for all people who smoke.

The adjusted estimate was 2.5 fewer cigarettes per day, with a 95% confidence interval from 1.3 to 3.7 fewer. The authors described this as a 24% reduction in total smoking intensity. They also reported that 21% said they were not smoking at the final follow-up assessment^[1]. The abstract does not state how long each participant was followed, how abstinence was verified or how many follow-up assessments each person completed. It therefore cannot establish a durable quit rate.

Why the result is not a treatment verdict

A prepost design asks whether a measured outcome changed after an event. It cannot supply the missing comparison. People starting a weight or diabetes medicine may change several health behaviors at once, while routine care can include counseling, medication changes and repeated contact with clinicians. Without a concurrent control group, those influences remain plausible explanations alongside a drug effect.

Self-reported cigarettes per day reflects behavior outside a laboratory, but it is vulnerable to incomplete recall and social-desirability bias. It is also an intensity measure, not proof of sustained abstinence. A person can smoke fewer cigarettes without quitting, and a report of no smoking at one follow-up does not establish continuous abstinence. The title uses the word "reduces," while the design supports the narrower statement that smoking decreased after initiation.

Nothing in this result changes semaglutide's approved use or turns it into a self-directed cessation medicine. Readers considering semaglutide in the United States still need a clinician to assess the approved indication, contraindications and current product information. Smoking treatment should likewise be discussed with a qualified professional rather than inferred from an observational signal.

What the randomized trial found

A separate 2026 phase 2a trial provides a useful check on causal interpretation. It randomized 24 of 45 enrolled adults to semaglutide or placebo, with 12 people in each group. Participants smoked at least five cigarettes per day, were not seeking treatment to quit and received nine weeks of study treatment. Twenty-one participants completed the primary outcome assessment^[2]. This was a small screening trial, but randomization gives it a control that the HIV cohort did not have.

The prespecified treatment-by-time tests did not find a significant effect on laboratory smoking resistance or the number of cigarettes smoked in the laboratory. Semaglutide also did not significantly reduce weekly cigarettes per day. It did reduce cigarette craving over the treatment weeks, and a supplementary change-score analysis found a greater reduction in laboratory smoking with semaglutide than placebo^[2]. The pattern is mixed. It supports further study, not a claim of established cessation efficacy.

The trial authors highlighted its limited sample, short treatment period and focus on people who were not trying to quit. They concluded that larger trials should test cessation, weight change after quitting and cardiometabolic outcomes^[2]. The HIV cohort and randomized trial answer different questions. One observed routine-care behavior in a specific population; the other tested short-term laboratory and weekly outcomes in a small randomized sample.

How earlier real-world evidence fits

A 2024 electronic-health-record study compared 5,967 new semaglutide users with people starting seven other diabetes medicine classes. Among patients with type 2 diabetes and tobacco use disorder, semaglutide use was associated with fewer medical encounters coded for tobacco use disorder during 12 months. The association was strongest against insulin and smaller, though still statistically significant, against other GLP-1 receptor agonists^[3].

That study did not measure current smoking, cigarettes per day or medication adherence. Its authors listed documentation bias, residual confounding and missing body-mass data among the limitations^[3]. A lower rate of diagnosis codes or cessation counseling is not automatically a lower rate of smoking. The new CNICS analysis adds direct patient-reported cigarette counts, while retaining the limits of nonrandomized evidence.

What we don't yet know

We do not yet know whether semaglutide produces lasting abstinence, whether any effect differs for people with HIV, or whether changes in craving, appetite, weight and smoking share one mechanism. The available reports also do not establish how semaglutide would compare with approved smoking-cessation treatments or whether combining therapies would help. Those questions require adequately powered randomized trials with verified abstinence and longer follow-up.

The careful reading is simple. Cigarette use fell after semaglutide initiation in this 123-person HIV cohort, and the estimate was large enough to merit attention. Causation remains unproven. A small randomized trial found lower craving but did not meet its main smoking endpoints. The evidence supports more research, not a new treatment recommendation.

Medical disclaimer: This article is for educational and journalistic purposes only and does not constitute medical advice. Peptides discussed may be classified as prescription medicines or research chemicals depending on your jurisdiction. Always consult a qualified healthcare professional before using any peptide product. PeptideMethods.com does not sell, distribute, or facilitate the sale of any peptide product.