PG / VG / Nicotine


Analysis of refill liquids for electronic cigarettes

Jean-François Etter, Eva Zäther, Sofie Svensson
Published online: 23 May 2013

Conclusion: The nicotine content of electronic cigarette refill bottles is close to what is stated on the label. Impurities are detectable in several brands above the level set for nicotine products in the European Pharmacopoeia, but below the level where they would be likely to cause harm


Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks

Igor Burstyn
Published online: 9 Jan 2014

Conclusion: Current state of knowledge about chemistry of liquids and aerosols associated with electronic cigarettes indicates that there is no evidence that vaping produces inhalable exposures to contaminants of the aerosol that would warrant health concerns by the standards that are used to ensure safety of workplaces


Cardiovascular toxicity of nicotine: Implications for electronic cigarette use

Neal L. Benowitz MD, Andrea D. Burbank MD
Published online: 6 Aug 2016

Studies of nicotine medications and smokeless tobacco indicate that the risks of nicotine without tobacco combustion products (cigarette smoke) are low compared to cigarette smoking, but are still of concern in people with cardiovascular disease.

Electronic cigarettes deliver nicotine without combustion of tobacco and appear to pose low-cardiovascular risk, at least with short-term use, in healthy users.


A Review on the Safety of Inhalation of Propylene Glycol in E-cigarettes

Cotta K.I., Stephen C.D., Mohammad N.

Introduction: “An electronic cigarette, or e-cigarette, is an electrical device that simulates the act of cigarette smoking by producing an inhaled mist bearing the physical sensation, appearance, and often the flavour and nicotine content of inhaled tobacco smoke. The primary stated use of the e-cigarette is a safe alternative to tobacco smoking, or as a smoking cessation device, while it attempts to deliver the experience of smoking without, or with greatly reduced, adverse health effects. However, the FDA in a July 22, 2009 press conference adopted the position that it will presume that e-cigarettes are as hazardous as conventional cigarettes. An opposing view is held by the Tobacco Control Task Force of the American Association of Public Health Physicians who has indicated that e-cigarettes closely resemble Nicotine Replacement Therapy (NRT) products approved by the FDA. Tests performed by the FDA have shown that e-cigarettes have similar nicotine levels and trace contaminants as NRT products. The Ruyan e-cigarettes use micro-electronics to vaporize, very small quantities of nicotine dissolved in propylene glycol into a fine aerosol with each puff. Nicotine and Propylene Glycol are two small molecules with known safety profiles. Propylene glycol (PG) is generally recognized as safe by oral, dermal or inhalation routes and has been a common ingredient in all American made tobacco cigarettes for seven decades.

Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague-Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints

Blaine Phillips, Bjoern Titz, Ulrike Kogel, Danilal Sharma, Patrice Leroy, Yang Xiang, Grégory Vuillaume, Stefan Lebrun, Davide Sciuscio, Jenny Hoa, Catherine Nury, Emmanuel Guedj, Ashraf Elamin, Marco Esposito, Subash Krishnan, Walter K.Schlage, Emilija Veljkovic, Nikolai V. Ivanov, Patrick Vanscheeuwijck, Julia Hoeng
Published online: 5 Sep 2017

Conclusion… Standard toxicological endpoints were complemented with systems toxicological analyses using transcriptomics, proteomics, and lipidomics of lung tissue, liver tissue, and serum. Both standard and systems toxicology endpoints demonstrated very limited biological effects of PG/VG aerosol with no signs of toxicity Systems toxicology analyses detected biological effects of nicotine exposure, which included up-regulation of the xenobiotic-metabolizing enzymes Cyp1a1 and Fmo3 in the lung and metabolic effects, likely interlinked with a generalized stress response to nicotine present in the exposure aerosols.” 

Sympathomimetic Effects of Acute E‐Cigarette Use: Role of Nicotine and Non‐Nicotine Constituents

Roya S. Moheimani, May Bhetraratana, Kacey M. Peters, Benjamin K. Yang, Fen Yin, Jeffrey Gornbein, Jesus A. Araujo, Holly R. Middlekauff
Published online: 20 Sep 2017

The acute sympathomimetic effect of e‐cigarettes is attributable to the inhaled nicotine, not to non‐nicotine constituents in e‐cigarette aerosol

Oxidative stress, as estimated by plasma paraoxonase, did not increase following any of the 3 exposures.


Tobacco-Specific Nitrosamines (NNAL, NNN, NAT, and NAB) Exposures in the US Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013–2014)

Baoyun Xia, PhD, Benjamin C Blount, PhD, Tonya Guillot, MPH, Christina Brosius, MPH, Yao Li, BS, Dana M Van Bemmel, PhD MPH, Heather L Kimmel, PhD, Cindy M Chang, PhD MPH, Nicolette Borek, PhD, Kathryn C Edwards, PhD, Charlie Lawrence, PhD, Andrew Hyland, PhD, Maciej L Goniewicz, PhD PharmD, Brittany N Pine, BS, Yang Xia, PhD, John T Bernert, B Rey De Castro, ScD, John Lee, BS, Justin L Brown, MPH, Stephen Arnstein, MS, Diane Choi, BS, Erin L Wade, BS, Dorothy Hatsukami, PhD, Gladys Ervies, PhD, Angel Cobos, BS, Keegan Nicodemus, BS, Dana Freeman, BS, Stephen S Hecht, PhD, Kevin Conway, PhD, Lanqing Wang, PhD
Published online: 27 Jul 2020

Among established, every day, exclusive tobacco product users, the geometric mean urinary NNAL concentration was 

  • highest for smokeless tobacco users (993.3 ng/g creatinine), 
  • followed by all types of combustible tobacco product users (285.4 ng/g creatinine), 
  • poly tobacco users (278.6 ng/g creatinine), 
  • and e-cigarette product users (6.3 ng/g creatinine).