Executive context
Innovation in nicotine pouches has largely focused on formulation variables, nicotine strength, pH, buffering systems, flavours, and moisture content. These factors shape nicotine delivery and user perception and are central to regulatory assessment. However, a growing body of clinical, observational, and design-science evidence indicates that oral tolerability and mucosal outcomes are also strongly influenced by the mechanical interface between the pouch and gingival tissue
This perspective was articulated clearly in a recent technical blog by Michael Fruhling, which argues that geometry, not chemistry alone, plays a decisive role in sustained-contact products. When applied to nicotine pouches, this insight has direct relevance for harm reduction, product standards, and regulatory evaluation
The pouch as a mechanical interface
Nicotine pouches are not passive containers. They function as sustained-contact interfaces, operating under compression against sensitive gum tissue in a wet, confined environment for extended periods.
Flat or uniform pouch surfaces tend to concentrate pressure at a single site. As materials hydrate, they soften and collapse, increasing local pressure while trapping saliva and heat. Over time, these conditions can contribute to sensations commonly reported by users, burning, stinging, and soreness and, in some cases, observable mucosal changes
From a mechanical standpoint, irritation is not solely a function of nicotine concentration or pH. It is also shaped by how load, moisture, and contact stability are managed at the pouch–tissue boundary.
Lessons from interface design in other sectors
As Michael Fruhling notes, this problem is not unique to nicotine products. In footwear, medical devices, seating, and wearables, interface geometry has been used to improve comfort and performance without changing core materials.
The Nike Free example illustrates the principle. Rather than relying on softer foams, designers studied barefoot mechanics and introduced geometric features, segmentation and flex grooves, that allowed pressure to distribute dynamically. The breakthrough was not material chemistry but how the interface behaved under load
The same design logic applies to nicotine pouches: geometry can influence how pressure is distributed, whether materials fully collapse, and how heat and saliva move at the contact zone.
Emerging evidence from nicotine pouch studies
Recent studies cited in the literature support this mechanical interpretation.
Clinical and observational work has documented oral changes, such as white lesions and local irritation, at habitual pouch placement sites, though severity varies and often appears lower than with traditional smokeless tobacco
Importantly, a European pilot study involving a pouch with a protective gum-facing interface layer reported substantial reductions in irritation and lesion severity over several weeks, without changes to nicotine chemistry.
These findings suggest that modest structural changes, including barrier layers or altered surface geometry, may meaningfully improve oral comfort, even when formulation remains constant. While the evidence base is still developing, it points to interface design as a legitimate variable in mitigating adverse oral effects.
Relevance for harm reduction
From a harm-reduction perspective, consistency of use matters. Products intended to displace smoking or higher-risk smokeless tobacco only deliver population-level benefit if adults can tolerate them comfortably over time.
Interface geometry offers a pathway to improve tolerability:
- without increasing nicotine delivery
- without altering pharmacokinetics
- without introducing new active substances
This does not replace formulation science; it complements it. Together, formulation and geometry shape real-world use patterns and persistence.
Implications for regulation and standards
Current regulatory frameworks emphasise chemistry, emissions, and toxicology. The emerging evidence suggests that mechanical interface design also influences outcomes relevant to public health.
For regulators and standards bodies, this raises a practical question: whether product assessment and post-market surveillance should more explicitly consider pouch construction, interface layers, and contact mechanics as part of oral-health evaluation, alongside traditional toxicological safeguards
Recognising interface geometry as a modifiable design parameter could support innovation aimed at improving tissue compatibility without increasing risk.
GINN perspective
The key message is not that geometry eliminates risk. Rather, it highlights that risk and tolerability are shaped by more than chemistry alone. As nicotine pouch regulation matures, incorporating a clearer understanding of mechanical interface effects may help align product standards with harm-reduction objectives and real-world use.
Interface geometry represents a technically credible, evidence-supported area for further study, one that deserves attention alongside formulation in both regulatory science and product evaluation.
