New research has revealed that an odd claim made by cigarette companies decades ago, suggesting that smokers might be less likely to develop Parkinson’s disease, has been proven accurate. Although smoking is widely known to cause numerous health issues, recent studies have indicated a correlation between smoking and a reduced risk of this neurodegenerative disorder.
Historically, tobacco advertisements touted various unfounded health benefits. Before federal regulations enforced clear warning labels, companies made outlandish claims, such as a 1937 Philip Morris advertisement stating that their cigarettes could relieve nasal and throat irritation caused by other brands. Another 1946 ad suggested that most doctors preferred Camels, claiming they were good for one’s “T-zone,” a marketing phrase that remains baffling today.
Despite these misleading advertisements, a scientific claim from 1959 has held up: regular smokers showed a reduced likelihood of developing Parkinson’s disease. Researchers faced challenges in identifying the cause, as cigarettes produce more than 7,000 chemicals, according to the American Lung Association. While previous research dismissed nicotine as a possible contributor, recent investigations have pointed to low-dose carbon monoxide as a potential factor.
Carbon monoxide, a colorless gas typically associated with toxicity, might offer surprising benefits at low doses. A study published in JAMA Neurology involving over 500,000 Chinese adults highlighted a link between higher exhaled carbon monoxide levels and reduced risks of Parkinson’s. Clara Bueno Lopez from Oxford University, the study’s lead author, noted that laboratory and animal studies had hinted at the protective effects of low carbon monoxide but lacked large-scale human data.
In 2024, additional research in the journal npj Parkinson’s Disease reinforced the connection, demonstrating that smokers had higher concentrations of carbon monoxide bound to hemoglobin, which could shield against oxidative stress and inflammation. Furthermore, the study indicated that non-smokers with high exhaled carbon monoxide also exhibited lower Parkinson’s risk, suggesting that the beneficial effects are attributed to carbon monoxide rather than smoking itself.
Lopez emphasized that while carbon monoxide might play a protective role against Parkinson’s, smoking is still responsible for approximately 85% of lung cancer cases, making it an inadequate preventive measure for Parkinson’s. However, this discovery has spurred interest in exploring carbon monoxide’s potential benefits in a clinical context.
In June 2026, a biotechnology company based in San Diego plans to begin a Phase 2a clinical trial for an oral drug called HBI-002, which utilizes low-dose carbon monoxide as a treatment for Parkinson’s disease. The company’s press release acknowledged the health hazards of smoking while recognizing the intriguing statistical anomaly related to carbon monoxide’s protective properties.
This ongoing research could provide significant insights and potential relief for the 1.1 million individuals affected by Parkinson’s disease in the United States alone.
