In a pouch, which nicotine the manufacturer bought barely matters — the pH of the wet pouch in your mouth decides how much nicotine is available to be absorbed, and an alkaline pH adjuster overrides whichever raw material went in. The vape world’s “nic salts versus freebase” framing does not transfer, and a manufacturer’s own patent says why: a pH adjuster “converts the nicotine salt into nicotine base in situ”.
If you came to pouches from vaping, you arrived with a mental model. Nic salts are smoother and hit faster; freebase is harsher and needs lower concentrations. It is a real distinction in e-liquid and it is reasonable to expect it to carry over. It does not, and the reason is specific rather than hand-wavy: in an e-liquid the acid that forms the salt is the thing that sets the pH, so the name on the bottle tracks the chemistry. In a pouch there is a separate alkaline ingredient whose entire job is to set the pH wherever the maker wants it, regardless of what form the nicotine arrived in.
That claim is not mine. It is in the patents, in a regulator’s opinion, on the ingredient lists, and in a randomised trial that varied nothing but pH. Here it is.
The chemistry, in the smallest useful amount
Nicotine is a base with two ionisable nitrogens. The one that matters for absorption is the pyrrolidine ring, and its pKa is the hinge on which everything else swings.
Measured values, from a spectroscopic study: “For (S)-(−)-nicotine the two pKa values were found to be 2.96 and 8.07 at 20 °C, 2.85 and 7.89 at 25 °C, 2.84 and 7.83 at 30 °C and 2.74 and 7.57 at 40 °C.” The authors are at British American Tobacco’s Southampton R&D group, which I note because almost all of this literature has an industry fingerprint somewhere.
Above that pKa, nicotine is mostly uncharged — “free base”. Below it, mostly protonated — a “salt”. And the uncharged form is the one that gets through the lining of your mouth. CDC’s tobacco laboratory puts it plainly: “Compared with protonated nicotine, nicotine in its unprotonated state passes through epithelium much more readily and results in larger and more rapid increases in blood nicotine levels”, and “Nicotine absorption across oral mucosa is highly dependent upon product pH, which influences the proportion of total nicotine present in the unprotonated form.” That work was “supported by internal funds of the Centers for Disease Control and Prevention (CDC)” with “no conflicts of interest” — the cleanest source in this article.
Here is a detail I have not seen made anywhere else, and I think it is worth printing. Every published free-base percentage for pouches is computed with a pKa measured at or near room temperature. BfR uses 8.0. CDC uses 8.02. Two industry sources use about 7.8. But the measured pKa at 40 °C is 7.57, and your mouth is at 37 °C. Using a pKa a few tenths too high understates the free-base fraction. So when you read that pouches average 86% free base, the figure in a real mouth is probably a little higher than that.
What is actually in the pouch: a salt, plus something to undo it
BfR asked the manufacturers, and reported the answer: “According to the manufacturer, nicotine salts are used, which are mixed with microcrystalline cellulose, various other salts (including sodium carbonate and hydrogen carbonate), citric acid and flavourings.”
Then BfR measured what came out. Across 44 products: “The median pH for aqueous extracts was 8.8 for the pouches examined by the BfR, with only one product exhibiting an acidic pH”, and “The median proportion of free-base nicotine was 86%”.
Salt goes in. Eighty-six per cent free base comes out. That single pairing is the whole argument of this article, from a regulator, in one document.
The patent that says the quiet part out loud
US 9,161,908 B2 is titled, with no irony, “Pouch containing nicotine in free salt form”. Its own explanation of the trade-off is worth quoting in full, because it is the clearest statement of the engineering problem anywhere:
“Nicotine base is readily absorbed through mucosal membranes. Unfortunately, nicotine base is highly unstable and is difficult to contain using conventional packaging materials. Nicotine salts, on the other hand, are generally stable. Nicotine salts, however, are not readily absorbed through mucosal membranes.”
So the maker wants the salt’s stability and the base’s absorption. The patent’s solution: “This problem can be solved by incorporating a pH adjusting agent which converts the nicotine salt into nicotine base in situ.” And on the target: “Such a high local pH is important to ensure that the dissolved nicotine is unprotonated and hence can be effectively absorbed through the oral mucosa”, with the arithmetic spelled out — “The pKa of nicotine is about 7.8 which means, for example, that at a pH of about 8.8 approximately 90% of the nicotine is in the nonprotonated form.”
In other words: the industry buys a salt precisely because it is a salt, and then undoes it in your mouth. The raw material was never the delivery lever. It was a shelf-life decision.
Other families say the same thing from the other direction. A Philip Morris-held patent lists essentially every nicotine salt in the pharmacopoeia as interchangeable — ascorbate, benzoate, bitartrate, citrate, lactate, salicylate and a dozen more — and then states the real relationship: “Providing nicotine in the free base form allows facilitates obtaining a higher pH in the pouch composition, without using too much alkaline pH adjusting agent.” Form is a means to a pH target. The same corporate family’s US grant claims “free-base nicotine” as the raw material. Swedish Match’s tobacco-free pouch patent is blunter still: the nicotine source “may be nicotine base or a nicotine salt such as nicotine hydrochloride, nicotine dihydrochloride, nicotine monotartrate, nicotine bitartrate…” — “may be… or”. Optional. The pH adjuster is in the ingredient list either way.
Proof that pH is the variable: a trial that changed nothing else
This is the strongest piece of evidence in the whole subject and it deserves to be better known.
Wilhelm, Mishina, Viray, Paredes and Pickworth took one commercial smokeless tobacco product and chemically amended it to four different pH levels, holding the product, the tobacco and the nicotine content constant. Forty moist-snuff users used “a single 2 g portion of Copenhagen Original Long Cut amended to 4 pH levels: 5.0, 7.7, 8.2, and 8.6 (free-base nicotine 0.1, 32, 60, and 79%) for 30 minutes.”
The result: “Nicotine PK substantially depends on its free-base proportion, with more than 4-fold increases in mean plasma nicotine maximum concentration and area under the curve over 240 minutes (3.9 to 16.7 ng/mL; 385 to 1810 ng min/mL, respectively, both P < 0.001) from pH 5.0 to 8.6.” Their conclusion: “Research and regulation of smokeless tobacco products should consider both total nicotine content and product pH.”
The work was “supported by the Center for Tobacco Programs of the US Food and Drug Administration” — a regulator-funded study, not an industry one.
Four-fold, from pH alone, with the nicotine raw material untouched. Against that, the question of which salt the maker bought looks like what it is: a procurement detail.
The pouch-specific confirmation comes from an unlikely place. An Altria-funded modelling study — “solely funded by Altria Client Services LLC” — found that what separated three products’ absorption was the pouch’s own effect on saliva pH: “the pH of the artificial saliva increased over time in the presence of DRYFT and ZYN ONPs, eventually reaching a pH of around 7.5”, while “no significant change in the pH of the artificial saliva was observed by VELO”, and it attributed “the enhanced nicotine permeability from DRYFT as a result of increased buccal/saliva pH of 7.3 compared to the pH by VELO of 7.0”. The pouch is not just alkaline; it alkalises the fluid around it.
None of which is new. A 1997 review in Tobacco Control reached the conclusion a quarter of a century before pouches existed: “manipulating tobacco pH appears to be the primary means by which the speed of nicotine absorption is determined in moist-snuff products.”
You cannot find out from the label, and that is a finding
I read every brand-owner ingredient list I could reach. Not one names a nicotine salt.
ZYN’s own ingredients page lists “Nicotine”, “Flavourings”, “Cellulose”, “pH Adjusters – Adjusts the pH of the nicotine pouch.”, “Sweeteners” and “Water”. The pH adjuster is declared as a function with no compound named. VELO’s US FAQ is more specific — “Nicotine derived from the tobacco plant, maltitol, modified cellulose, sodium carbonates, acesulfame K, and artificial flavor” — and names sodium carbonates. But VELO’s Irish site, for the same brand, lists “Water, Plant-based materials, Flavourings, Sweeteners, Nicotine” with no pH agent at all. A Killa product page lists an “acidity regulator” without saying which direction it regulates in.
So: every list says “nicotine”, every list that mentions pH at all describes a function rather than a substance, and one brand publishes two different ingredient lists in two markets. The “salts or freebase?” question is literally unanswerable from any pack sold anywhere. That is not a gap in my research; it is the state of disclosure.
The one place the pH is published is the reference products the industry uses to calibrate its own testing. The CORESTA/CTRP data sheets list ingredients as “Fillers, pouch material, nicotine, pH adjuster, stabilizer, water and sweetener” for both, and give NP1 Dry at pH 8.25 and NP2 High Moisture at pH 9.10, at nicotine concentrations of 15.1 and 15.4 mg/g respectively. Two reference pouches with essentially the same nicotine concentration, deliberately set 0.85 pH units apart. On a pKa of 8.0 that is roughly 64% versus 93% free base — my arithmetic, not theirs. Same nicotine, very different available fraction, set by one ingredient.
Where the vape logic does transfer — and who is using it
I should not overstate the case. The direction of the trade-off is the same in both categories, and one manufacturer is now building the vape rationale into oral products.
First, what the e-liquid rationale actually is. CDC’s laboratory states it cleanly: “The nicotine salt e-liquids used in pod e-cigarettes such as JUUL™ are prepared using weak acids, such as benzoic acid, which serves to reduce the pH of the e-liquid, allowing the administration of higher doses of protonated nicotine with reduced throat irritation”, and measured that “90% of the nicotine present in JUUL™ samples is in protonated form as nicotine benzoate”. Worth noting in passing: that harshness rationale is not in the famous nicotine-salt patent everyone attributes it to. I read US 9,215,895 B2 and it contains no sentence using the word “pH” and none using “harsh”, “throat” or “irritation” — its own argument is about satisfaction and plasma uptake rate. The harshness story is real; its usual citation is wrong.
Second, the transfer. BAT’s Nicoventures has a published patent application for “ORAL PRODUCTS WITH LOW FREE-BASE NICOTINE CONTENT”, claiming oral products with “a pH of 8.6 or less” and “an amount of nicotine present in free-base form is 15% or less”, with embodiments descending to 4% free base and pH 7.0 to 7.5. Its stated purpose: “Pouches with low free-base nicotine content may, in some embodiments, be advantageous in providing low levels of harshness/irritation within the oral cavity and throat.” And it makes the design logic explicit: “In some embodiments, a target pH value is set prior to formulating a given pouched product based on the desired free-base nicotine of the composition”.
That is the vape trade-off, applied to pouches, by a manufacturer. It is also, so far, an assertion in a patent rather than a published result — I found no efficacy data behind it. But if low-free-base pouches reach the market, the honest framing will be that they are low-pH pouches, which is a real and meaningful difference. It just has nothing to do with which salt was in the hopper.
There is a precedent, incidentally, and it runs the same way. Swedish Match’s own account of snus production says the target pH “is about 8.5”, that “Sodium carbonate helps to stabilize the pH”, and that “Before the 1970s the pH of snus was typically higher, but with the introduction of new production technique, the target pH level was intentionally reduced as a result of research on ‘snus lesions.'” Manufacturers have been dialling this number up and down for fifty years for reasons that have nothing to do with the nicotine’s chemical form. (All the authors of that paper “are or have been employees of Swedish Match AB”.)
The two framings side by side
| E-liquid (“nic salt” vs freebase) | Nicotine pouch | |
|---|---|---|
| What sets the pH | The acid used to form the salt — so the name tracks the pH | A separate alkaline pH adjuster, independent of the raw material |
| Direction | Acid added to lower pH, reduce harshness, allow higher concentration | Alkali added to raise pH, increase free-base fraction, speed absorption |
| Typical outcome | ~90% protonated in one measured pod product | Median 86% free base across 44 products |
| Does the raw material tell you anything? | Yes, loosely — the salt name implies the acid | No. A pH adjuster “converts the nicotine salt into nicotine base in situ” |
| Is it on the label? | Often, as “nic salt” | Never. No brand-owner list names a nicotine salt |
| Is it regulated? | Varies by jurisdiction | No jurisdiction regulates pouch pH or free-base fraction anywhere |
That last row deserves a sentence of its own. Poland caps nicotine at 20 mg per gram; Finland at 16.6; Iceland at 20; Sweden caps contaminants but not nicotine. None of them says anything about pH or free-base fraction. A survey of pouch regulation worldwide, published in October 2025, found no jurisdiction regulating either parameter. Yet CDC’s own measurements across 37 pouch brands found free nicotine ranging from 7.7% to 99.2% of total. Two pouches with identical labelled nicotine can differ more than tenfold in the fraction available to absorb, and every regulation in the world caps only the number on the label. If you want the strength figures themselves, that is nicotine pouch strengths: the complete mg guide; what the labels do and do not mean is mg per pouch vs mg per gram.
Frequently asked questions
So are nicotine pouches “nic salts” or “freebase”?
Both, sequentially. A salt goes into the manufacturing process for stability; an alkaline pH adjuster converts a large majority of it to free base once saliva reaches it. BfR measured a median of 86% free base in the extracts of 44 products made, on the manufacturers’ own account, from salts.
Will a “nic salt” pouch be smoother than a freebase one?
There is no such product distinction to buy. Smoothness in a pouch tracks pH, and no brand publishes its pH. The only products designed around low free-base content exist in a BAT patent application rather than on shelves, and its harshness claim is an assertion with no published data behind it.
Does a higher pH mean more nicotine?
No — it means more of the nicotine is in the absorbable form. Content and availability are separate. In the FDA-funded trial, holding nicotine content constant and raising pH from 5.0 to 8.6 raised peak blood nicotine more than four-fold.
Can I tell a pouch’s pH from how much it stings?
Roughly, and that is the most useful rule of thumb in the category: the sting is largely the alkalinity, not the dose. A measured range across seven mint products ran from pH 7.43 to 8.98. But it is a sensation, not a measurement, and it varies between people.
Has anyone tested salt versus base in a pouch at the same pH?
Not that I can find, and I consider that the real hole in this literature. Studies vary pH; none varies the raw material at constant pH. The question the vape framing cares about has never actually been asked of a pouch.
Sources
- Clayton PM, Vas CA, Bui TTT, Drake AF, McAdam K, “Spectroscopic investigations into the acid–base properties of nicotine at different temperatures”, Analytical Methods (RSC), first published 9 November 2012. One author affiliation: British American Tobacco, Group R&D, Southampton. Article
- Lawler TS, Stanfill SB, Zhang L, Ashley DL, Watson CH, “Chemical characterization of domestic oral tobacco products: Total nicotine, pH, unprotonated nicotine and tobacco-specific N-nitrosamines”, Food and Chemical Toxicology 57:380–386, 2013. “All research was supported by internal funds of the Centers for Disease Control and Prevention (CDC)”; “The authors report no conflicts of interest.” PDF
- Bundesinstitut für Risikobewertung, “Health risk assessment of nicotine pouches”, Updated BfR Opinion no. 023/2022, 7 October 2022. PDF
- Wilhelm J, Mishina E, Viray L, Paredes A, Pickworth WB, “The pH of Smokeless Tobacco Determines Nicotine Buccal Absorption: Results of a Randomized Crossover Trial”, Clinical Pharmacology and Therapeutics 111(5):1066–1074, 2022, doi 10.1002/cpt.2493. “This work was supported by the Center for Tobacco Programs of the US Food and Drug Administration (Task Order HHSF22301003T under the contract HHSF223201310030I).” Abstract read from the Johns Hopkins institutional repository because the publisher blocks access. Record
- Tomar SL, Henningfield JE, “Review of the evidence that pH is a determinant of nicotine dosage from oral use of smokeless tobacco”, Tobacco Control 6:219–225, 1997, doi 10.1136/tc.6.3.219. Only the abstract was retrievable; the funding statement could not be read. Abstract
- US 9,161,908 B2, “Pouch containing nicotine in free salt form”, granted 20 October 2015. Full text
- WO 2020/244722 A1, “Nicotine pouch composition”, NCP Nextgen AS, published 10 December 2020, and US 11,096,412 B2, assigned to Philip Morris Products SA, granted 24 August 2021. WO text · US text
- EP 4 404 775 B1, “Method for moisturizing a pouched product for oral use”, Swedish Match North Europe AB, granted 10 September 2025, para. [0051] and [0091]. Full text
- EP 4 659 596 A1, “Oral products with low free-base nicotine content”, Nicoventures Trading Limited, published 10 December 2025. Full text
- Knopp MM et al., “Development of a model to predict nicotine pharmacokinetics from oral nicotine pouches”, Scientific Reports 16:25582, 2026. “This research, including the clinical study and all analyses described in this manuscript, was solely funded by Altria Client Services LLC.” Full text
- Platt SP et al., “Dissolution and physical characterization of oral nicotine pouch products”, Scientific Reports, 6 January 2026. Funded by Altria Client Services LLC, affiliate of the manufacturer of on!. Full text
- Rutqvist LE et al., “Swedish snus and the GothiaTek standard”, Harm Reduction Journal, 16 May 2011, doi 10.1186/1477-7517-8-11. Competing interests: “All authors are or have been employees of Swedish Match AB.” Full text
- Bravo Cardenas R, Watson C, Valentin-Blasini L, “Determination of Benzoic Acid and Benzyl Alcohol in E-Liquids (JUUL™ Pods)”, Contributions to Tobacco and Nicotine Research 30(4):212–220, 2021. CDC authors; conflicts of interest declared as “None”. PDF
- US 9,215,895 B2, “Nicotine salt formulations for aerosol devices and methods thereof”, granted 22 December 2015. Full text
- CORESTA / Cooperative Tobacco Reference Products data sheets, NP1 Dry and NP2 High Moisture nicotine pouches, reference values generated 25 September 2024. NP1 PDF · NP2 PDF
- Grilo G et al., “Global Regulatory Scenario of Nicotine Pouches”, Institute for Global Tobacco Control, Johns Hopkins Bloomberg School of Public Health, 6 October 2025. Supported by Bloomberg Philanthropies’ Bloomberg Initiative to Reduce Tobacco Use. PDF
- Brand-owner ingredient pages, read 1 October 2026: ZYN ingredients (published 27 August 2025); VELO US FAQ; VELO Ireland (24 October 2025); Killa Cold Mint.
What I could not establish: no study varies the nicotine raw material at constant pH in an oral pouch, so the question the vape framing poses has not been tested in this product class. Funding for the 1997 Tobacco Control review could not be retrieved. The ranges BfR reports for pH and free-base fraction come from the same institute, the same authors and the same sample set as its opinion, published three times over — they are one finding, not three. And the measured free-base percentages across this literature are all calculated from pH using a pKa above body temperature, so they are conservative. Last verified 1 October 2026.