Your carrier liquid is not a minor detail. It determines how your e-liquid wicks, how it tastes, how it feels in the throat, and whether your filling equipment can handle it at room temperature. VG and PG are not interchangeable. They are fundamentally different formulation tools, and the choice between them affects everything from consumer experience to production economics.
Most experienced formulators already understand the basics. But the decision goes deeper than "VG for clouds, PG for flavor." Your carrier choice interacts with nicotine concentration, device compatibility, shelf stability, regulatory requirements, and production line design in ways that can make or break a product line.
VG: The Cloud Builder
Vegetable glycerin (USP/EP grade) is thick, slightly sweet, and produces dense vapor. It is derived from plant oils, typically palm, soy, or coconut, through hydrolysis of the triglyceride followed by distillation and purification to pharmaceutical grade.
What VG does well
Vapor density. Sub-ohm users want clouds. VG delivers them. Glycerin is the heavier, higher-boiling of the two carriers (about 290 degrees Celsius at atmospheric pressure, with decomposition), and it condenses into larger, denser aerosol droplets. This is the primary reason the sub-ohm segment gravitates toward high-VG formulations.
Smooth draw. Minimal throat irritation, even at higher nicotine concentrations. For products targeting consumers who find PG-heavy formulations harsh, VG-dominant carriers provide a gentler experience. This is particularly relevant for nicotine salt formulations at 30 to 50 mg/mL, where throat irritation would otherwise limit usability.
Mild sweetness. VG adds a subtle sweetness that fills out flavor profiles without requiring additional sweetener. This can be an advantage for dessert and bakery flavor categories. It can also be a problem for manufacturers working with delicate or savory profiles where unwanted sweetness muddles the intended taste.
Perceived quality. Consumer perception in the sub-ohm market associates thick liquid and large vapor clouds with premium products. Whether or not this perception is scientifically meaningful, it drives purchasing behavior.
What VG does not do well
Wicking. High-VG liquids (above 70% VG) struggle in small-coil pod systems and tight-draw devices. The high viscosity means liquid cannot wick fast enough to keep up with the coil's heating cycle, leading to dry hits, burnt flavor, and coil degradation. This is a hard constraint imposed by the physics of capillary action, and no amount of formulation adjustment fully overcomes it in devices with small wicking channels.
Flavor clarity. VG mutes flavor compared to PG. The mechanism is straightforward: glycerin's viscosity and inherent sweetness compete with added flavor compounds for the user's palate. If you are selling on flavor precision, particularly in tobacco or menthol categories where subtlety matters, high VG is working against you.
Production handling. VG is strongly hygroscopic. Leave containers open and it pulls water out of the air, diluting your nicotine concentration and shifting your carrier ratio at the same time. How fast that happens depends on your ambient humidity, the exposed surface area and the exposure time, so it is something to measure in your own plant rather than assume from a published figure. Sealed containers, inert gas headspace, and humidity control in the mixing room are not optional for high-VG production.
Cold-weather logistics. Glycerin viscosity climbs steeply as temperature falls, from a room-temperature figure already more than a thousand times that of water. Drop the ambient temperature and pumps, filling nozzles and gravity-fed lines that ran fine in summer start to struggle. If your facility is not temperature-controlled, or if you ship to distributors in cold climates, VG-heavy formulations create handling challenges that PG-heavy products avoid.
PG: The Flavor Carrier
Propylene glycol (USP/EP grade) is thin, nearly odorless, and the easier of the two carriers to work with as a nicotine solvent. It is produced industrially from propylene oxide and is one of the most widely used pharmaceutical excipients in the world.
What PG does well
Flavor fidelity. PG carries flavor compounds more accurately. Its low viscosity allows flavor molecules to volatilize more freely during heating, reaching the user's palate with greater clarity and intensity. This is why flavor houses quote dosing rates against a PG base: at the same flavor loading, a PG-heavy blend reads sharper and closer to the intended profile than a VG-heavy one.
Throat hit. Smokers switching to vaping want that familiar throat sensation. PG delivers it. The mild irritant properties of propylene glycol, combined with nicotine, produce a throat hit that approximates the sensation of inhaling cigarette smoke. For smoking cessation products and adult smoker conversion, this is a feature, not a bug.
Production efficiency. PG flows through standard filling equipment at room temperature. No heated nozzles. No viscosity headaches. Low viscosity also means less time and less energy to reach homogeneity, because the same agitator moves more liquid per revolution. For contract manufacturers running multiple product lines, PG-based nicotine dilutions simplify changeover and cleaning between batches.
Solvency and handling at strength. Freebase nicotine mixes with both carriers, but PG is the easier solvent to work with as concentration climbs. It wets and disperses the nicotine faster, and the resulting solution stays low enough in viscosity to sample, pump and assay accurately. That is why concentrated bases are more often built in PG than in VG.
Antimicrobial properties. PG has inherent antimicrobial activity, which provides an additional margin of safety for finished product shelf life. This does not replace proper microbial testing, which still runs under USP chapters 61 and 62, but it contributes to product stability over time.
What PG does not do well
Vapor volume. Thin, wispy clouds. Not what the sub-ohm market expects. For manufacturers targeting cloud-chasing consumers, PG-dominant formulations fail to deliver the visible vapor production that drives satisfaction and social media engagement in that segment.
Sensitivity. Some users report mild irritation from PG: dry mouth, sore throat, or skin reactions. How large that group is has never been well established and published estimates vary widely, but it is large enough that most brands keep a high-VG option in the range. There is no EU-wide limit on PG content in e-liquid as of February 2026. The European Commission's pending revision of the Tobacco Products Directive is the place to watch if that changes.
How This Affects Your Production Line
PG-based nicotine dilutions mix faster with flavoring concentrates. Homogeneity takes less time, less agitation, and less energy. VG-based blends often need gentle warming and a longer mix to distribute evenly, and some plants add ultrasonic or high-shear mixing to close the gap at the cost of extra equipment. The actual times belong in your own batch record rather than in an article: they depend on vessel geometry, agitator design, batch size and starting temperature, and they have to be qualified against your own homogeneity testing.
Your filling equipment matters too. High-VG formulations need wider flow paths and sometimes heated dispensing to hold fill volumes consistent, because viscosity fights you at every restriction in the line. PG flows through standard equipment without modification. If you are scaling production from hundreds to thousands of units per hour, that difference turns into real capital expenditure and throughput constraints. Size the flow path against your own liquid and your own filler rather than against a rule of thumb.
Cleaning and changeover between flavor profiles is also faster with PG-based formulations. VG's viscosity means residual product clings to mixing vessels, tubing, and nozzles more tenaciously, requiring longer flush cycles and more solvent.
Concentration Options
NicAlliance dilutions are not sold as a fixed catalogue of strengths. The nicotine concentration is specified at inquiry and the material is blended to it, which makes the choice of strength yours and worth making deliberately.
The tradeoff runs in one direction. A weaker base is safer to handle and more forgiving to dose, but it carries more carrier liquid into every batch, which eats into the VG/PG ratio you are trying to hit and leaves less room for flavor. A stronger base does the opposite: less carrier contributed, tighter control over the final ratio, fewer handling steps per batch, and a much smaller margin for error in the measurement itself.
Two practical consequences follow:
- Dose by weight rather than by volume as strength goes up. Off a strong base, a small volumetric error becomes a proportionally larger concentration error in the finished product. Gravimetric dosing removes the meniscus, the temperature correction and most of the operator variance in one move.
- Match the strength to the safety infrastructure you actually have. Lower-concentration dilutions exist precisely so that facilities without industrial nicotine handling infrastructure can produce e-liquid without ever holding concentrated nicotine on site.
Whichever strength you settle on, fix it in writing before the quote is issued. The specification, safety data sheet and certificate of analysis all have to correspond to the exact concentration and carrier system supplied, so the configuration has to be agreed before the documentation can mean anything.
What "Quality" Actually Means in Dilutions
A nicotine dilution is only as good as its two components: the nicotine and the carrier. Both must meet pharmaceutical-grade standards independently. Ask yourself: does your dilution supplier provide all of this?
- Nicotine purity at or above 99.5% (USP/EP grade) before dilution
- USP/EP pharmaceutical-grade carrier (both VG and PG must meet pharmacopoeial specifications)
- Nicotine concentration verified by assay on the batch you are actually receiving, against the specification agreed for that configuration
- Heavy metals testing on the finished dilution within pharmacopoeial limits
- Microbial testing compliant with USP chapters 61 and 62
- Full COA covering both the nicotine and the carrier, with batch-specific data
- Documented traceability from nicotine source through dilution process
If any of those are missing, you are taking a quality risk that will eventually show up in your finished product. The dilution step introduces an additional opportunity for contamination, concentration error, and documentation gaps. Your supplier's quality system needs to cover the entire process, not just the raw nicotine.
Common Formulation Ratios
Most commercial e-liquids blend both carriers. The ratio you choose depends on your target device, consumer preferences, and regulatory environment:
- 70/30 VG/PG. Balanced vapor and flavor. The default for sub-ohm devices. Provides satisfying cloud production with reasonable flavor clarity. Wicks adequately in devices with large wicking channels.
- 50/50 VG/PG. The pod system standard. Works across device types, from pods to sub-ohm tanks. The most versatile ratio, which is why many contract manufacturers default to it for new product development.
- 80/20+ VG/PG. Maximum clouds. Appeals to a niche but loyal audience. Requires devices designed for high-VG liquids. Not suitable for most pod systems. Production requires heated handling equipment.
- 60/40 PG/VG. Less common but used in some European markets and smoking cessation-oriented products where throat hit is prioritized over vapor volume.
Remember: your nicotine base carrier shifts the final ratio. A nicotine-in-PG base pushes your finished product toward PG. A nicotine-in-VG base pushes it toward VG. The size of the shift is arithmetic, not judgment: the base contributes a share of finished volume equal to your target strength divided by the base strength. At 3 to 6 mg/mL for sub-ohm off a 100 mg/mL base, that is 3 to 6% of the bottle and barely matters. At 20 to 50 mg/mL for pod systems off the same base, it is 20 to 50% of the bottle, which is enough to overwhelm whatever ratio you thought you were mixing. Factor that into your formulation math.
Shelf Stability Considerations
VG-based dilutions are often held to be the more stable of the two over extended storage, on the mechanistic argument that glycerin's far higher viscosity slows the diffusion of dissolved oxygen through the solution and therefore slows nicotine oxidation. However, VG's hygroscopic nature means improperly sealed VG dilutions absorb atmospheric moisture faster, which can dilute nicotine concentration below specification over time.
PG-based dilutions have lower viscosity, which means faster oxygen diffusion and potentially faster nicotine degradation if not stored under inert gas. The antimicrobial properties of PG partially compensate by reducing microbial-driven degradation.
For both carriers, proper storage conditions are the same: sealed containers with inert gas headspace, controlled ambient temperature, protection from light, and batch-level shelf life tracking. If your supplier cannot document storage conditions for the dilution from production through delivery, the COA from manufacturing is only half the story.
Which Should You Choose?
If you are making pod system liquids, lean PG or 50/50. The wicking properties and throat hit match the hardware. If you are targeting sub-ohm vapers, go VG-dominant for vapor production. If you are developing nicotine salt products at high concentrations (20 to 50 mg/mL) for pod devices, PG-based dilutions give you better solvency and easier handling.
Most manufacturers stock both VG-based and PG-based dilutions. That gives you the flexibility to serve multiple product lines without reformulating your nicotine base. The incremental cost of maintaining two SKUs is minimal compared to the flexibility it provides.
The carrier is the foundation. Get it right and everything downstream (flavor accuracy, throat feel, production speed, shelf stability) works better. Understanding the difference between nicotine salts and freebase nicotine is equally important for dialing in the right formulation, since the nicotine form and the carrier interact to determine the final product experience.
Frequently Asked Questions
What is the difference between VG and PG nicotine dilutions?
VG (vegetable glycerin) and PG (propylene glycol) nicotine dilutions use different carrier liquids to dilute pure nicotine to usable concentrations. VG is thick, slightly sweet, and produces dense vapor, making it preferred for sub-ohm devices. PG is thin, nearly tasteless, and carries flavor compounds more accurately, making it preferred for pod systems and products that prioritize flavor clarity and throat hit. The carrier also affects production handling: PG flows through standard equipment at room temperature, while VG often requires heated dispensing systems and longer mixing times.
Does the carrier liquid affect nicotine stability?
Yes. VG's higher viscosity limits oxygen diffusion, which can slow nicotine oxidation during storage. However, VG is more hygroscopic than PG, meaning improperly sealed VG dilutions absorb atmospheric moisture faster, diluting nicotine concentration over time. PG has inherent antimicrobial properties that contribute to shelf stability, but its lower viscosity allows faster oxygen diffusion. Both carriers require sealed containers with inert gas headspace, controlled temperature storage, and batch-level shelf life tracking to maintain nicotine concentration within specification.
How does the nicotine base carrier affect my final e-liquid ratio?
The carrier in your nicotine dilution contributes to the final VG/PG ratio of your finished product. For low-concentration finished products (3 to 6 mg/mL), the nicotine base represents a small fraction of total volume, so its carrier has minimal impact. For high-concentration products like nicotine salt pods at 20 to 50 mg/mL blended off a 100 mg/mL base, the nicotine base represents 20% to 50% of the finished volume, which shifts the final ratio substantially. Formulators must account for the nicotine base carrier when calculating the additional VG and PG needed to reach the target ratio.
What nicotine dilution concentration should I use for e-liquid manufacturing?
There is no single standard answer, and NicAlliance dilutions are blended to the concentration you specify rather than sold as fixed grades. The tradeoff is consistent in either direction: a weaker base is safer to handle and easier to dose accurately but contributes more carrier liquid to every batch, while a stronger base contributes less carrier and gives tighter control over the finished VG/PG ratio at the cost of a much smaller margin for measurement error. Dose gravimetrically rather than volumetrically as strength increases, match the concentration to the safety infrastructure your facility actually has, and fix the concentration and carrier system in writing so that the specification, SDS and COA correspond to the material supplied.