We conducted a market survey to compare label statements of commercial disposable e-cigarette products for nicotine concentration and e-liquid volume with analytically verified levels of the same parameters. The findings indicate large discrepancies between labeled nicotine content and e-liquid volume vs. actual measured amounts for many of the product samples evaluated in this study.
The American E-liquid Manufacturing Standards Association (AEMSA) was formed to develop standards to assure the quality and safety of e-liquid products for electronic cigarettes . AEMSA guidelines state that nicotine concentrations should be within ± 10% of the concentration stated on the product label. Measured levels of nicotine and e-liquid volumes of many of the products surveyed deviated from their label statements by greater than ± 10%. In many cases, calculated total nicotine content was less than half of the expected total nicotine, indicating the consumer is getting far less than what they expected. These products could potentially be regarded as misbranded by the FDA .
Differences in labeled nicotine amount and measured nicotine concentrations tend to cluster by manufacturer. For example, the nicotine concentrations of MNGO Stick and Posh samples were among the lowest relative to their respective label declarations while Kangvape and Breeze Smoke products were among the highest. Eleven of 39 samples (28%) had measured total nicotine content amounts that were less than half of their expected total nicotine content amount (based on label declarations). MNGO Stick, Puff XXL, and RARE FLOW were among the samples that had the lowest measured total nicotine content relative to their respective expected total nicotine content.
Comparison of our findings with those in the published literature is complicated by the fact that our study was on e-liquids contained within closed system disposable e-cigarette devices while most published studies are on e-liquid refill products. Nevertheless, market surveys that compared label vs. measured nicotine content of e-liquid refill products frequently observe marked discrepancies between label vs. measured nicotine content consistent with our findings.
Davis and co-workers reported that 35 of 54 nicotine containing commercial e-liquid samples deviated from their product label declarations by more than ± 10%. Deviations of labeled vs. measured nicotine concentration ranged from -12.9% to + 89.7% . Farsalinos and co-workers reported that 12 of 21 refill e-liquid samples had nicotine levels within ± 10% of their label statements. Overall, deviations of actual nicotine content vs. label statements ranged from − 21% to 22.1% . Kim and co-workers compared labeled vs. measured nicotine content of e-liquids purchased in the United States (n = 32), South Korea (n = 29) and Poland (n = 30). Most of the products with inaccurate labels were those purchased in United States. Of these, 14 had discrepancies between label vs. actual nicotine content of greater than ± 10%. Overall, deviations of labeled vs. measured nicotine concentrations ranged from – 92.4% to + 103.7% . Peace and co-workers measured nicotine concentrations in 27 e-liquid formulations. They reported variances between labeled vs actual nicotine concentration that ranged from -55% to + 31%. Additionally, 18 of 27 products deviated from the labeled nicotine concentration by more than 10% . Lisko and coworkers compared labeled vs. measured nicotine concentration in a sample of 36 commercial e-cigarette cartridges. The investigators reported three fourths of the products contained lower nicotine levels than what was stated on the product labels . Bębenek and coworkers compared labeled vs. measured nicotine and other aspects of e-liquids purchased from seven European countries. Commercially available e-cigarettes sold in Europe are only available in nicotine concentrations of 20 mg/mL or less. Only one liquid had a quantified nicotine concentration more than 10% higher than the labeled amount. Twenty-one liquids had a quantified nicotine concentration less than 10% of the labeled amount. One e-liquid with a labeled nicotine concentration of 6 mg/mL had no traces of nicotine .
In general, Good Manufacturing Practices (GMPs) assure proper design, monitoring, and control of manufacturing processes and facilities in order to protect public health.Footnote 3 In the US, FDA has the authority to establish Good Manufacturing Practices or Tobacco Product Manufacturing Practices (TPMPs) for tobacco products, however, it has not yet done so. Rather than inspect for TPMP compliance, FDA inspects tobacco establishments biennially from the date of registration to ensure that they are compliant with provisions of the Food, Drug, and Cosmetic Act and that products are not adulterated or misbranded.Footnote 4 Additional provisions FDA utilizes but are not limited to include registration and product listing; ingredient listing; requirements for packaging, labeling, and advertising; and marketing authorization for certain tobacco products.Footnote 5 Once FDA establishes TPMPs for tobacco products, its investigators will also inspect for compliance with those requirements. Perhaps the issues identified in this publication would be addressed by the establishment of TPMPs.
A few limitations should be considered when interpreting the findings from this study. Because of the large number of e-cigarette brands currently available, the samples selected for this survey may not be representative of the overall market. Some of the products did not label e-liquid volumes. Therefore, comparisons of label information vs. actual e-liquid volumes could not be made for these samples. The labels on some products did not indicate whether the nicotine percent stated on the label was expressed as mg/g or mg/mL of e-liquid. In such cases, it we assumed the percentage was expressed as mg/g. We corrected for density to compare percentages expressed as mg/mL. This had the effect of conservatively increasing apparent nicotine concentration for products that expressed nicotine percent as mg/g. E-liquid volumes were not measured for all samples, resulting in a smaller sample size (N = 39 vs. 51) for the e-liquid volume and total nicotine content assessments. Although the actual amount of losses from the e-liquid extraction method is unknown, we conservatively assumed losses of 10%. However, the relative ranking of the samples remains unchanged regardless of the actual amount of e-liquid losses. The technology and regulatory oversight of these products is evolving rapidly. Therefore, this survey could be outdated in a relatively short time as manufacturers modify their products to optimize consumer acceptance and meet regulatory compliance.
A strength of this survey is that we measured e-liquid volumes in closed system, disposable e-cigarette products. Relatively few published studies have compared e-liquid volumes vs. label declarations in closed system disposable products.
Researchers have commented that variations in product characteristics such as nicotine content could impact health, safety, and dependence potential of e-cigarettes [10, 12]. As noted above, some products contained substantially less total nicotine than the expected amount based on product label. Not only is the consumer getting less than what they expect, such products may be less effective as alternatives to tobacco burning cigarettes. Results of a recently published randomized placebo-controlled trial concluded that “ENDS with nicotine delivery approaching that of a cigarette are more effective in enabling ambivalent cigarette smokers to quit smoking” . Moreover, misleading labeling could erode public confidence in the benefit of ENDS as a less harmful alternative to conventional cigarettes. Label discrepancies may be caused by poor manufacturing quality control, losses during storage, or questionable business practices.
In order to optimize the harm reduction potential of ENDS, it is imperative that these products are manufactured using quality control practices, the highest-grade materials, and have product labeling that is clear, accurate, and conforms to applicable quality and regulatory standards.