Puffing Topography, Mouth Level Exposure, Average Daily Consumption and Machine Emissions of Three Variants of glo™ Heated Tobacco Products Among UK Smokers

Study day	Study stage
Study day	1	2	3	4	5	6	7	8	9	10	11	12	13
Visit 1: product/consumption diary allocation
Home placement 1
Visit 2: puffing topography & product allocation
Home placement 2
Visit 3: puffing topography & product allocation
Home placement 3
Visit 4: puffing topography measurements

Image of glo™ attached to the SA7 topography device.

Table 2.

Comparison of puffing topography data among the three consumable variants.^a

Parameter	Variant 1 comparison				Variant 2 comparison
Parameter	Base	Variant	Difference (variant - base)	Statistical equivalence^b	Base	Variant	Difference (variant - base)	Statistical equivalence^b
Puff number	15.9 ± 8.4	16.4 ± 8.5	0.53	–	15.9 ± 8.4	14.8 ± 8.3	−1.05	Equivalent (90% CI: 0.86, 0.98)
Puff volume (mL)	58.9 ± 31.7	63.4 ± 31.9	4.45	Equivalent (90% CI: 1.01, 1.12)	58.9 ± 31.7	58.8 ± 22.9	−0.15	–
Puff duration (s)	2.0 ± 0.9	2.0 ± 0.9	0.08	–	2.0 ± 0.9	1.8 ± 0.7	−0.21	Equivalent (90% CI: 0.86, 0.93)
Puff interval (s)	10.0 ± 4.8	9.7 ± 5.0	−0.37	–	10.0 ± 4.8	10.0 ± 5.6	−0.03	–
Effort (mm WGs)	500 ± 329	526 ± 314	26.2	Equivalent (90% CI: 0.99, 1.15)	500 ± 329	437 ± 279	−63.4	Not equivalent (90% CI: 0.80, 0.94)

a Data are mean ± SD of n = 70 participants.

b Equivalence between the variant and base consumable was evaluated using a ratio-based paired, two-one-sided t-test (TOST) with a predefined equivalence margin of 0.80–1.25 and 90% confidence intervals for the mean ratio presented.

– Indicates that the difference between the variant and base consumable was smaller than the predefined analytical threshold (see Supplementary Figure S1); such differences were classified as not measurable, and equivalence testing was not applied.

Table 3.

Comparison of ADC and MLE among the three consumable variants.^a

Parameter	Variant 1 comparison				Variant 2 comparison
Parameter	Base	Variant	Difference (variant - base)	Statistical equivalence^b	Base	Variant	Difference (variant - base)	Statistical equivalence^b
ADC study product (sticks/day)^c	4.5 ± 3.8	4.6 ± 3.8	0.10	–	4.5 ± 3.8	4.6 ± 4.0	0.07	–
Total ADC (sticks/day)^d	12.6 ± 6.0	12.7 ± 6.0	0.03	–	12.6 ± 6.0	12.0 ± 5.5	−0.69	–
MLE to NFDPM (mg/stick)	4.71 ± 1.86	5.30 ± 2.52	0.59	–	4.71 ± 1.86	4.59 ± 3.14	−0.12	–
MLE to nicotine (mg/stick)	0.30 ± 0.12	0.30 ± 0.14	0.007	–	0.30 ± 0.12	0.41 ± 0.28	0.112	Not equivalent (90% CI: 1.05, 1.34)
MLE to NFDPM (mg/day)	22.2 ± 21.5	27.2 ± 33.1	5.00	Equivalent (90% CI: 0.93, 1.23)	22.2 ± 21.5	22.4 ± 28.7	0.21	–
MLE to nicotine (mg/day)	1.40 ± 1.36	1.56 ± 1.91	0,159	–	1.40 ± 1.36	2.00 ± 2.57	0.597	Not equivalent (90% CI: 1.03, 1.48)

ADC: average daily consumption; MLE: mouth level exposure; NFDPM: nicotine-free dry particulate matter.

a Data are mean ± SD of n = 72 participants for ADC and n = 70 participants for MLE.

b Equivalence between the variant consumable and base consumable was evaluated using a ratio-based, paired two-one-sided test (TOST) with a predefined equivalence margin of 0.80–1.25 and 90% confidence intervals for the mean ratio presented.

– Indicates that the difference between the variant and the base consumable was smaller than the predefined analytical threshold (see Supplementary Figure S1); such differences were classified as not measurable and equivalence testing was not applied. For ADC and parameters derived from ADC (MLE per day), equivalence testing was carried out only for participants that used the study product during home placement (Variant 1: n = 68, Variant 2: n = 66).

c ADC of study product.

d Total ADC of study and non-study products, calculated using the sum of the number of study products plus the number of any non-study products consumed per day (n = 70 participants reported using their own cigarette brand during home placement of the base product; n = 68 participants reported using their own cigarette brand during home placement of Variant 1, and n = 69 participants reported using their own cigarette brand during home placement of Variant 2).

Table 4.

Comparison of ADC and MLE for the base product among three different studies.^a

Country	MLE to NFDPM (mg/stick)	MLE to nicotine (mg/stick)	ADC study product (sticks/day)^b	Total ADC (sticks/day)^c	Reference
Japan
Smokers (n = 52)	5.2 ± 3.4	0.3 ± 0.2	10.3 ± 5.5	12.1 ± 5.5	(23)
HTP users (n = 52)	5.0 ± 3.1	0.3 ± 0.1	8.6 ± 4.6	11.2 ± 6.2
Italy
Smokers (n = 52)	4.7 ± 2.9	0.3 ± 0.2	7.0 ± 5.5	11.6 ± 5.7	(24)
UK
Smokers (n = 70)	4.7 ± 1.9	0.3 ± 0.1	4.5 ± 3.8	12.6 ± 6.0	This study

ADC: average daily consumption; MLE: mouth level exposure.

a Data are mean ± SD.

b ADC of study product.

c Sum of number of study products and number of non-study products consumed per day during home use placement.

Table 5.

Percentage reduction in nine toxicants relative to cigarette smoke.^a

TobReg toxicant	Base product	Variant 1	Variant 2
CO	99.76	99.55	99.90
Formaldehyde	93.92	95.60	96.32
Acetaldehyde	94.96	94.16	96.37
Acrolein	98.59	98.92	98.66
1,3-Butadiene	99.99	99.99	99.99
Benzene	99.95	99.90	99.95
Benzo[a]pyrene	97.72	98.00	98.92
NNN	90.61	93.74	93.72
NNK	97.65	98.17	98.24
Overall reduction	97.02	97.56	97.93

CO: carbon monoxide; NNN: N-nitrosonornicotine; NNK: 4-[methyl(nitroso)amino]-1-(3-pyridinyl)-1-butanone.

a Percent reduction (%) relative to 3R4F reference cigarette. Machine-smoked using a modified Health Canada Intense puffing regime (volume, 55 ± 0.5 mL; duration, 2.0 ± 0.1 s; interval, 30 ± 1 s; bell-shaped profile; and 0% blocking of perforations). Eight puffs taken per consumable.

Table 6.

Comparison of other aerosol constituents among the study products.^a

Smoke constituent	Base product	Variant 1	Variant 2
Nicotine (mg/stick)	0.46 ± 0.04	0.38 ± 0.03	0.55 ± 0.03
NFDPM (mg/stick)	13.50 ± 1.20	11.00 ± 0.50	11.10 ± 0.40
Water (mg/stick)	12.10 ± 1.00	15.74 ± 0.44	12.80 ± 0.40
Glycerol (mg/stick)	3.02 ± 0.25	1.94 ± 0.35	2.74 ± 0.19

NFDPM: nicotine-free dry particulate matter.

a Machine-smoked using a modified Health Canada Intense puffing regime (volume, 55 ± 0.5 mL; duration, 2.0 ± 0.1 s; interval, 30 ± 1 s; bell-shaped profile; and 0% blocking of perforations). Eight puffs taken per consumable.

Articles in this issue

DOI: https://doi.org/10.2478/cttr-2026-0006 | Journal eISSN: 2719-9509 (formerly 1612-9237)

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Language: English, French, German

Page range: 77 - 89

Submitted on: Nov 26, 2025

Accepted on: Apr 29, 2026

Published on: Jun 20, 2026

Published by: Beiträge zur Tabakforschung GmbH

In partnership with: Paradigm Publishing Services

Keywords:

Average daily consumption,

ADC,

puffing topography,

tobacco heating product,

THP,

heated tobacco product,

HTP,

glo™,

mouth level exposure,

MLE,

use behaviour

Related subjects:

Life sciences,

Life sciences, other

© 2026 Adam Gray, Lauren Edward, Krishna Prasad, published by Beiträge zur Tabakforschung GmbH
This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License.

Volume 35 (2026): Issue 2 (April 2026)

Puffing Topography, Mouth Level Exposure, Average Daily Consumption and Machine Emissions of Three Variants of glo™ Heated Tobacco Products Among UK Smokers

Figures & Tables

Figure 1.

Table 1.

Figure 2.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6.

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