REF-1464 · Maloney et al., 2020 · Tobacco Control · Paper · PubMed · Free full text

Does IQOS or a vape add CO like a cigarette?

In 18 smokers new to both, 10 puffs raised exhaled CO only with the cigarette; nicotine rose with all (IQOS 12.7, JUUL 9.8, cigarette 20.4 ng/mL). No exercise; heart rate unreported.

Main caveat: No exercise; markers and ratings only.
limited evidenceMeasured on non-athletes and recreational people

Maloney and colleagues (Virginia Commonwealth University) compared JUUL, IQOS and own-brand cigarettes in smokers with no experience of either device.

Eighteen community volunteers smoking at least 10 cigarettes a day did three sessions in Latin-square order, each after 12 h of verified abstinence: a directed bout of 10 puffs 30 s apart, then 25 min of rest, then 90 min of ad libitum use. Plasma nicotine rose in all three conditions and was significantly higher with cigarettes after both bouts.

Exhaled CO rose only with cigarettes, reaching 16.6 ppm after ad libitum use against 4.7 and 4.3 ppm with JUUL and IQOS. Craving and urges fell in all three after the directed bout, and with the cigarette and IQOS, not JUUL, after the ad libitum bout. Heart rate and blood pressure were monitored and not reported.

Our reading: the clearest acute side-by-side the base has: a device with no CO rise, with nicotine well below the cigarette but well above baseline. It says nothing about exercise. The IQOS kits were bought on eBay in 2017, and devices have changed since.

Protocol

Participants: n = 18 (13 men, 5 women), aged 18-55 by inclusion, at least 10 cigarettes a day, screening exhaled CO at least 15 ppm, no JUUL or IQOS experience.
Abstinence: 12 h before each session, verified by exhaled CO ≤10 ppm and plasma nicotine <5.0 ng/mL.
Products: JUUL (tobacco or mint), IQOS (tobacco or menthol), own-brand cigarette (mean machine-smoked nicotine yield 0.94 mg); flavours matched to own brand.
Use: one directed bout (10 puffs, 30 s interpuff) and, after 25 min rest, a 90-min ad libitum bout.
Measures: plasma nicotine, exhaled CO, subjective scales; heart rate and blood pressure monitored but not reported.
Funding and interests (as printed): National Institute on Drug Abuse (P50DA036105, U54DA036105) and the FDA Center for Tobacco Products. Eissenberg "is a paid consultant in litigation against the tobacco and electronic cigarette industry and is named on a patent for a device that measures the puffing behavior of ECIG users."

Key Results

Mean (SD)Own cigaretteJUULIQOS
Plasma nicotine before directed bout (ng/mL)2.1 (0.2)2.2 (0.7)2.1 (0.2)
After 10 puffs20.4 (11.4)9.8 (4.9)12.7 (6.2)
Before ad libitum, after 25 min rest8.8 (3.6)4.3 (1.8)5.4 (1.7)
After 90 min ad libitum21.0 (10.2)11.5 (9.3)11.3 (8.0)
Exhaled CO before directed bout (ppm)5.2 (2.4)5.5 (2.4)5.3 (2.0)
After 10 puffs8.7 (2.5)5.1 (2.3)4.9 (1.8)
Before ad libitum8.8 (2.8)5.3 (2.4)4.6 (1.8)
After 90 min ad libitum16.6 (7.0)4.7 (1.9)4.3 (1.4)
Share of the cigarette's nicotine after 10 puffs: IQOS about 62%, JUUL about 48% (our arithmetic); after ad libitum use about 54% and 55%. These are comparisons of concentration, not of a pre-race dose.
Craving and urges: reduced for all products after the directed bout; after ad libitum use reduced for own brand and IQOS; lower with own brand than JUUL after ad libitum use.

Mechanisms

Measured: nicotine delivered and exhaled CO in one sitting.
Authors' interpretation: cigarettes delivered more nicotine and suppressed abstinence more effectively than either device; JUUL's lower delivery may reflect short puffs by novices; independent work with experienced users is needed.
Inference: no CO rise means this part of the smoke cost (REF-1456, REF-1459) would not be expected. Nicotine's own effects are not removed, and this study reports none of them (REF-1471, REF-1462).

Practical Application

Does IQOS or a vape add CO like a cigarette? In 18 smokers new to both, 10 puffs raised exhaled CO only with the cigarette; nicotine rose with all (IQOS 12.7, JUUL 9.8, cigarette 20.4 ng/mL). No exercise; heart rate unreported.
Race morning: plasma nicotine fell by more than half in the 25 min after the directed bout (for example 20.4 to 8.8 ng/mL; our arithmetic, an early fall in forearm venous blood and not a half-life, which REF-1461 cites as 1-2 h). Not from this paper; the base's own practice: any race-morning timing is practice, and no nicotine product is presented as a performance aid (REF-1461).
Comparing with a cigarette: "no CO rise" is supported here; "no cost to the session" is not tested.
What it does not show: heart rate or blood pressure (recorded, not reported); airway effects; performance; experienced users, who may reach higher nicotine; current devices.

Limitations

No exercise; markers and ratings only.
Device novices, so nicotine delivery and satisfaction may understate experienced use.
Small (18, analyses on 17), volunteers aged about 37 who smoke, not athletes.
Heart rate and blood pressure not reported although monitored.
Old devices and purchases (IQOS kits via eBay in 2017), flavours varied.
Source read is the author manuscript; values below 2 ng/mL were replaced with 2, which likely explains the very small baseline SDs (our reading).
Interests: public funding (NIDA, FDA); one author is a paid consultant in litigation against the tobacco and e-cigarette industry and holds a patent on a puff-measuring device.
How this entry was checked and changed
Why this level

a controlled crossover of at least 15 would reach the rubric's B+, held one step down because the outcomes are plasma nicotine, exhaled CO and subjective ratings, with no exercise

Full text (checked 2026-10-30)
Community volunteers aged 18–55 who smoked ≥10 cigarettes daily and with expired air carbon monoxide (CO) ≥15 ppm at screening (full text)
Three, ~4-hour, Latin-square ordered sessions each preceded by 12 hours of nicotine/tobacco abstinence (verified with CO ≤10 ppm and baseline plasma nicotine concentration <5.0 ng/mL) (full text)
One 10-puff "directed" bout (30 second interpuff interval) and, after 25 minutes rest, a 90-minute ad libitum bout; heart rate and blood pressure data not reported (full text)
Mean age 36.8 (9.3) years; smoking a mean of 16.4 (5.1) cigarettes/day for 11.7 (8.9) years; 0.94 (0.17) mg machine-smoked nicotine yield (full text)
Mean CO increased significantly for OB only after the directed bout and after the ad libitum bout; no significant increases in CO were observed for JUUL or IQOS (full text)
Table: CO Pre-Directed, Post-Directed, Pre-Ad Lib, Post-Ad Lib: own brand 5.2, 8.7, 8.8, 16.6; JUUL 5.5, 5.1, 5.3, 4.7; IQOS 5.3, 4.9, 4.6, 4.3 (full text)
Four, sealed IQOS kits and HeatSticks were purchased via eBay in September, 2017 (full text)
Eissenberg is a paid consultant in litigation against the tobacco and electronic cigarette industry (full text)