Using E-Cigarettes and Cigarettes Together Is Not as Harmless as It Seems!

New research shows that people using e-cigarettes and cigarettes together have almost the same toxicant exposure as people who smoke cigarettes alone. This is an important warning for millions who view e-cigarettes as a bridge to quitting.

People seeking to reduce or stop smoking often choose e-cigarettes as a transition tool. Strong evidence has emerged, however, that this approach may be less safe than assumed. Nicotine & Tobacco Research published a comprehensive study on April 15, 2025 showing that dual users of cigarettes and e-cigarettes have toxicant exposure similar to cigarette-only users. Their risk is also much higher than that of e-cigarette-only users.

Study Scope: Who Was Examined?

The findings come from a study at the American Cancer Society's Tobacco Control Research unit, led by Zheng (Ashley) Xue. The team analyzed data from 2679 US adults participating in “Population Assessment on Tobacco and Health (PATH)” , a nationally representative study, at wave 5.

• 1913 people used cigarettes only,

• 316 used e-cigarettes only,

• 450 were dual users (both cigarettes and e-cigarettes).

Participants were also divided into subgroups by daily or monthly frequency of use.

Key Findings: Toxicant Exposure

The study measured toxicant exposure from tobacco products using several biomarkers. Particularly notable were:

• NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol): a tobacco-derived compound with potent carcinogenic effects.

• Volatile organic compounds (VOCs): Hazardous substances linked to respiratory cancers.

🔬 Results:

• Dual users and cigarette-only smokers had similar NNAL levels: (levels could reach approximately 312.02 ng/mg creatinine ).

• Dual use meant much higher toxicant exposure than exclusive e-cigarette use overall.

• Exposure increased substantially with greater daily use (P < 0.001).

• No significant difference in heavy metal exposure was found between groups.

These findings again challenge the common perception that e-cigarettes are harmless.

Expert Warning: “Dual Use Is Not a Protective Strategy!”

Lead author Xue stated:

“The most common form of multiple tobacco use in the US is combining cigarettes and e-cigarettes. Many people choose this method to quit or reduce smoking. Our results show, however, that it is not a strategy that protects health, but instead perpetuates harm.”

A Clear Public Health Message: Policies and Regulation Are Essential!

American Cancer Society Cancer Action Network President Lisa A. Lacasseemphasizes that the findings matter for public health policy as well as individuals:

“We must continue advocating policies proven to reduce tobacco use. Strong laws and enforcement are essential to prevent anyone, especially young people, from starting tobacco use.”

Lacasse highlights the importance of:

• Ending sales of all flavored tobacco products,

• Substantially increasing tobacco taxes,

• Expanding smoke-free and vapor-free public policies,

• Increasing access to evidence-based cessation support.

She also emphasizes that the FDA should fully use its authority to remove thousands of illegal tobacco products that do not benefit public health.

Conclusion: Tobacco Is Harmful, and Dual Use May Be Even More Dangerous

This study clearly exposes a misconception that is becoming increasingly widespread:

Combining e-cigarettes and cigarettes does not protect health; it increases risk.For people seeking to stop smoking, adopting a complete cessation strategy and using evidence-based support services is vital.