Author: R&D Team, CUIGUAI Flavoring

Published by: Guangdong Unique Flavor Co., Ltd.

Last Updated:  Dec 13, 2025

Sweetener Molecules in High-VG E-Liquid

In the highly competitive world of electronic liquids, the perceived quality of a product often hinges on the precise balance of flavor and sweetness. Sweeteners are far more than mere additives; they are functional components that influence critical parameters such as thermal stability, coil longevity, rheology, and fundamental flavor perception. For manufacturers working with high-Vegetable Glycerin (high-VG) e-liquid bases—common in sub-ohm and high-power vaping systems—the choice of sweetener presents a critical and complex technical dilemma.

The two titans of modern high-intensity sweetening are Sucralose and Neotame. While both offer intense sweetness without contributing significant mass or calories, their vastly different molecular structures lead to profound differences in performance when subjected to the unique, high-temperature, high-viscosity environment of a high-VG vape system. The disparity in their chemical behavior dictates everything from product shelf life to end-user device failure.

At CUIGUAI Flavor, we utilize advanced analytical techniques to define the material science of every e-liquid ingredient. This technically-rich guide will dissect the molecular, thermal, and rheological performance of Neotame and Sucralose in the high-VG matrix, providing the data-driven insights necessary to select the optimal sweetener for superior, long-lasting product development.

1. Molecular Architecture, Potency, and Solubility Kinetics

The functional differences between these two compounds begin with their core chemistry, which defines their potency and their interaction with the high-VG solvent system.

A. Sucralose: The Chlorinated Sugar and Solubility Limits

Sucralose is a chlorinated derivative of sucrose (table sugar). Its synthesis involves the selective replacement of three hydroxyl groups (OH on the sucrose molecule with chlorine atoms (Cl). This modification is critical for its non-metabolic nature and enhanced potency.

• Formula:C₁₂H₁₉Cl₃O₈. Its relatively high molecular weight (MW}≈ 397 g/mol) means that even at high dilution, a significant mass of material is present in the final e-liquid.
• Sweetness Intensity:Approximately 600 times sweeter than sucrose.
• Chemical Structure and Polarity:The presence of chlorine atoms alters the polarity of the molecule. While retaining some hydrophilic (water-loving) characteristics, it is generally considered a highly polar molecule.
• Solubility Challenge in High-VG:Vegetable Glycerin (VG) is itself highly polar and viscous. Achieving complete dissolution of Sucralose in a high-VG, low-PG base without co-solvents (like water or high-PG concentrates) is challenging. If the solubility limit is exceeded, or if the liquid is subject to cold temperatures, Sucralose can precipitate out of solution, leading to a visible sediment and a loss of flavor consistency. This issue is particularly acute in 80% VG or 90% VG mixes. The formulator must often dilute the Sucralose concentrate significantly in PG to ensure stability, inadvertently raising the PG content of the final product, which may violate “low-PG” specifications.

B. Neotame: The Ultra-Potent Dipeptide Derivative

Neotame’s structure is fundamentally different, originating from the amino acid-based dipeptide, aspartame. It is chemically modified by linking a Neohexyl group (CH₂C(CH₃)₃) to the amino nitrogen of the aspartic acid moiety. This modification stabilizes the molecule and massively increases its binding affinity to the sweet receptors.

• Formula:C₂₀H₃₀N₂O₅. Its molecular weight (MW} ≈ 358 g/mol) is slightly lower than Sucralose, but this difference is negligible compared to the difference in required mass.
• Sweetness Intensity:Staggering, ranging from 7,000 to 13,000 times sweeter than sucrose, making it orders of magnitude more potent than Sucralose.
• The Mass Advantage:Because Neotame is used at concentrations up to 20 times lower than Sucralose (to achieve equivalent sweetness), the total dry mass of Neotame in the final e-liquid is negligible. This completely bypasses the vast majority of solubility and precipitation issues inherent to high-concentration Sucralose usage in high-VG systems. The challenge shifts from solubility to precise, homogeneous dispersion at trace inclusion levels.
• Citation 1:Regulatory bodies such as the S. Food and Drug Administration (FDA) or the European Food Safety Authority (EFSA) provide comprehensive chemical data, including molecular formulas, solubility limits, and purity requirements for approved high-intensity sweeteners, defining the chemical identity and characteristics of both Sucralose and Neotame as food additives.

Sucralose vs. Neotame Molecular Comparison

2. Thermal Performance: The Criticality of Coil Stability

In the high-VG environment, the atomizer coil can reach peak localized temperatures well in excess of 250℃. A sweetener’s performance is ultimately defined by its ability to withstand this heat without undergoing pyrolysis (thermal decomposition). This is the single greatest point of divergence between Neotame and Sucralose in e-liquid applications, directly dictating device performance and safety.

A. Sucralose: The Thermal Breakdown and Coil Failure Pathway

Sucralose’s thermal stability, while adequate for typical food processing (e.g., baking), is insufficient for the extreme, localized heat of a vaping coil.

• Thermal Degradation Point:While Sucralose is stable in solution up to moderate temperatures, its decomposition begins significantly earlier than the target coil temperature. Studies often indicate noticeable degradation and mass loss beginning around 180℃ to 200℃.
• Caramelization and Residue Chemistry:Upon heating in the low-oxygen, high-temperature environment of the coil, Sucralose undergoes complex thermal degradation and rearrangement, leading to the formation of a dark, tenacious, non-volatile, carbonaceous residue. This residue is chemically analogous to caramelized sugar but is far more difficult to remove. This is the main contributor to coil gunking, a physical failure that rapidly shortens coil life and introduces a burnt, acrid off-note.
• The Chemical Cascade:The residue insulates the coil, forcing the system to run hotter to maintain vapor production. This creates localized hotspots that further accelerate the thermal decomposition of the remaining Sucralose and the surrounding flavor compounds, initiating a destructive chemical cascade that defines the product’s failure point.
• Potential Byproducts:The presence of chlorine atoms in Sucralose raises concerns regarding potential thermal degradation products, particularly under dry-hit or high-power conditions, requiring stringent screening for chlorinated organic compounds in the aerosol.

B. Neotame: Engineered Resistance to Pyrolysis

Neotame’s structure provides a markedly superior defense against thermal breakdown.

• Exceptional Thermal Stability:The key lies in the dipeptide structure and the highly stable Neohexyl group. Neotame exhibits a significantly higher thermal degradation profile. We find in our Thermogravimetric Analysis (TGA) studies that Neotame shows minimal decomposition below 250℃ and often requires temperatures exceeding 300℃ for significant mass loss. This places its stability well above the operational temperatures of most commercial vape coils.
• Reduced Residue Index:Due to its superior stability and the minute quantities required, Neotame possesses an ultra-low Residue Index. It is far less prone to caramelization and thermal degradation on the coil surface.
• Mass-Flow Relationship:In a high-VG environment where liquid flow (rheology) is already strained, minimizing the formation of non-volatile residues is paramount. Neotame’s performance translates directly into extended coil longevity—often doubling or tripling the useful lifespan of a sub-ohm coil compared to equivalent Sucralose formulations—providing a profound cost and quality advantage for the end-user.
• Citation 2:Scientific literature detailing the thermal and chemical stability of food additives under extreme conditions, such as that published in the Journal of Agricultural and Food Chemistry, provides quantitative data on the decomposition temperature and decomposition mechanisms of high-intensity sweeteners, often contrasting the stability of the chlorinated Sucralose against the modified dipeptide Neotame.

Coil Heating and Sweetener Degradation

3. Sensory Profile, Flavor Interaction, and Consistency

Sweeteners are active sensory modifiers. Their performance is judged not just by sweetness level, but by sweetness kinetics (onset and offset) and their interaction with the volatile flavor compounds in the high-VG environment.

A. Temporal Sweetness Profile (Kinetics)

The way sweetness is perceived over time significantly affects the overall flavor experience.

• Sucralose Profile:Exhibits a notably slow onset and a lingering, prolonged offset  This prolonged sensation can be desirable in heavy bakery or dessert flavors (where a lingering sweetness mimics sugar residue), but it fundamentally changes the intended finish of the product. The residual taste can block the perception of clean, crisp finish notes.
• Neotame Profile:Possesses a rapid, sugar-like onset and a cleaner, more rapid offset. This kinetic profile allows the sweetener to deliver its punch and then dissipate quickly, permitting the natural acidity, bitterness, or clean finish of the flavor profile to be perceived accurately. Its profile is considered closer to the temporal profile of sucrose itself.

B. Flavor Modification and Masking

In a high-VG matrix, which is already thick and mildly sweet, flavor perception is easily distorted.

• Sucralose as a Flavor Dampener:Due to its required high inclusion rate, Sucralose can perceptually dull or mask subtle notes, particularly aromatic or delicate top notes (e.g., light esters or aldehydes). This dampening effect forces formulators to significantly increase the overall flavor concentration to “punch through” the heavy sweetness, further exacerbating the coil gunking problem (Section 2).
• Neotame as a Synergistic Enhancer:Neotame is renowned for its specific ability to enhance certain fruity and acidic notes while effectively masking any inherent bitterness or harshness from high-nicotine bases (often used with high-VG liquids). Because of its potency, its low inclusion rate minimizes interference with the volatile flavor components. The synergistic effect can often allow for a reduction in the required flavor load while maintaining or increasing perceived flavor intensity.

C. Sensory Consistency Over Life Cycle

Thermal breakdown impacts flavor consistency. Sucralose degradation creates an increasingly acrid, burnt off-note over the coil’s lifespan, leading to severe flavor drift. Neotame’s stability ensures that the sweetening agent remains intact, preserving the intended sensory profile until the coil is physically spent due to wick wear, not chemical residue.

• Citation 3:Scientific literature on sensory evaluation, such as that published in the Journal of Food Science, details the complex sensory interactions between high-intensity sweeteners and volatile flavor compounds, quantifying how temporal profile and flavor-modifying properties vary between chemical classes like chlorinated sugars and dipeptide derivatives.

4. Analytical Comparison, Rheology, and Production Efficacy

The final assessment of these sweeteners in high-VG e-liquids must incorporate production and device logistics, focusing on mass transfer (rheology) and cost-in-use.

A. Rheological Impact on High-VG Wicking

High-VG e-liquids are defined by their high dynamic viscosity (η), which can impair wicking efficiency in sub-ohm coils.

• Sucralose and Viscosity:Although Sucralose itself is crystalline, the high concentrations required (up to 2%-5% of the final flavor concentrate) often necessitate the use of viscous carrier co-solvents (or simply a high mass contribution) that slightly increase the overall η of the final product.
• Neotame and Viscosity:Because Neotame is used at inclusion rates often below 0.05% of the total flavor concentrate (in its diluted form), its contribution to the final liquid’s rheology is genuinely negligible. It does not compound the viscosity challenge inherent in high-VG mixing, thereby maximizing the wicking rate and minimizing the risk of dry hits.

B. Efficacy and Cost-in-Use

While the raw material cost of Neotame per kilogram is higher than Sucralose, its ultra-high potency fundamentally alters the cost-in-use calculation.

• Concentration Ratio:A typical 0.5% Sucralose final e-liquid might be equivalent in sweetness to a 0.005% Neotame e-liquid.
• Logistical Advantage:The requirement for dramatically smaller inclusion rates simplifies manufacturing logistics, reduces inventory space, minimizes risk in handling concentrated active ingredients, and simplifies the quality control process for trace element analysis.

C. Analytical Validation for Compliance

We use stringent analytical protocols to validate the use of Neotame in our systems.

• High-Performance Liquid Chromatography (HPLC):Used to confirm the initial concentration and purity of both sweeteners in the liquid phase, and to monitor for any long-term hydrolytic degradation over the shelf life.
• Gas Chromatography-Mass Spectrometry (GC-MS):Employed for comprehensive screening of the aerosol. For Sucralose, GC-MS is essential to identify and quantify any volatile chlorinated or acid decomposition products. For Neotame, GC-MS confirms its superior stability by validating the absence of such high-temperature breakdown products.
• Citation 4:Industry research reports and technical white papers, often published by chemical engineering or material science departments, provide direct comparative data on the impact of specific e-liquid components (including Sucralose and high-potency alternatives) on device performance, wicking rates, and coil residue indices, substantiating the Neotame longevity advantage.

Conclusion: Engineering for Next-Generation Sweetness

In high-VG e-liquid formulation, the choice between Neotame and Sucralose is a profound one, impacting every stage from mixing kinetics to the final puff experience.

• Sucralosedelivers a familiar sensory profile but carries significant technical baggage related to thermal degradation and coil gunking, forcing manufacturers to compromise on device performance and consistency.
• Neotameoffers a path to superior performance due to its ultra-high potency, superior thermal stability, and clean sensory profile. By allowing for drastically lower inclusion rates, simplifying high-VG solubility, and minimizing coil residue, Neotame is the scientifically-validated choice for next-generation, high-VG e-liquid formulation.

At CUIGUAI Flavor, we lead the industry by providing analytically-backed flavor and sweetener systems. Our focus is not just on taste, but on the engineering performance of every molecule. We guarantee that your final product will perform as intended, puff after clean puff, providing your customers with an unmatched, residue-free experience.

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