The choice between thiamine nitrate and thiamine hydrochloride is decided by the matrix, not by potency. Both salts release the same thiamine cation, so what changes a specification is moisture uptake, the pH the salt creates in water, and the mass the counterion adds. leave this factory as one vitamin in two carriers.
1. Two Salts Deliver The Same Vitamin, And Five Identifiers Differ
Both grades are metabolised to thiamine pyrophosphate after absorption, so nutrition labelling does not separate them. What separates them is documentary and physical: CAS number, formula, molecular weight, thiamine fraction and assay convention. Those five lines decide whether two quotations are comparable, and thiamine nitrate and thiamine hydrochloride differ on all five.
| 532-43-4 | 67-03-8 | ||
| C12H17N5O4S | C12H17ClN4OS, hydrochloride | ||
| 327.36 | 337.27 | ||
| About 81% | About 79% | ||
| 98.0% minimum | 98.5% to 101.5%, dried basis |
2. Thiamine Content Per Kilogram Sets The Real Cost
Price per kilogram compares two products. PubChem gives the thiamine cation a molecular weight of 265.36 against 327.36 for thiamine nitrate and 337.27 for the hydrochloride, so a kilogram of salt carries about 811 grams of thiamine as the nitrate and about 787 grams as the hydrochloride.
Buying one kilogram of actual vitamin B1 therefore takes roughly 1.23 kg of thiamine nitrate or 1.27 kg of the hydrochloride. The United States enrichment standard reads the same arithmetic in reverse: 21 CFR 137.165 calculates thiamine against the hydrochloride reference form at molecular weight 337.28, so a declaration on that basis does not transfer to thiamine nitrate without conversion.
The nitrate side also carries mass that is not vitamin. One mole of nitrate accompanies each mole of thiamine, about 19% of the salt by weight. Most adult supplement matrices live with that. Infant nutrition, or any project tracking nitrosamine precursors, does not, so declare it rather than let a customer discover it.
3. In Dry Blends, Hygroscopicity Decides Whether The Blend Cakes
Dry does not mean stable for the hydrochloride. Our thiamine nitrate grade is specified as low hygroscopicity and our hydrochloride grade as hygroscopic, and that one difference drives the handling rules below, because moisture is what starts thiamine loss in a powder.
› Weigh the hydrochloride in a humidity-controlled room, not on an open bench
4. In Solution, The Hydrochloride Wins By Acidifying The Water
Dissolved, the ranking reverses, and the controlling variable is the pH the salt creates rather than the counterion. Voelker, Miller, Running, Taylor and Mauer measured both salts side by side in Food Research International in 2018.
In 27 mg/mL solutions held at 80 ℃ for five days, 32% of thiamine nitrate remained against 94% of the chloride hydrochloride. Solution pH across the tested concentrations ran 5.36 to 6.96 for the nitrate and 1.12 to 3.59 for the hydrochloride, degradation was first-order for both, and thiamine nitrate degraded faster at every concentration and temperature tested.
| Remaining after 5 days at 80 ℃ | 32% | 94% |
| 5.36 to 6.96 | 1.12 to 3.59 | |
| 21 to 25 kcal/mol | 21 to 32 kcal/mol | |
The last row matters more than it looks. The hydrochloride lost less vitamin, but its breakdown products were far more visible and far more odorous, which is a sensory failure long before it becomes an assay failure. In a clear beverage or a white tablet, that is the risk to design against.
The 2021 follow-up by Voelker, Taylor and Mauer in BMC Chemistry held pH fixed and found thiamine significantly more stable at pH 3 than at pH 6, which points to solution pH rather than the counterion as the variable to control. The useful question is not which salt is more stable in liquid, but what pH the finished product sits at.
5. Above 95 Degrees, The Dry-State Advantage Reverses
The dry-state rule has a temperature ceiling. Labuza and Kamman compared the salts at high temperature and controlled water activity in the Journal of Food Science in 1982 and found thiamine nitrate more stable below 95 ℃ and the hydrochloride more stable above it.
› Where the process can exceed 95 ℃, such as expander conditioning, test the hydrochloride
6. Fortification Levels Come From The Standard, Not A Rule Of Thumb
Addition levels for thiamine in grain products vary by an order of magnitude, and the number that matters is the one in the standard your customer sells against. In the United States, 21 CFR 137.165 requires 2.9 milligrams of thiamin per pound of enriched flour, about 6.4 mg per kilogram.
Two details in that section decide the purchase. The overage clause deems the requirement met where reasonable overages within good manufacturing practice hold the declared level through shelf life, which is why the amount added and the amount declared never match. The reference form, thiamine chloride hydrochloride at molecular weight 337.28, fixes how the 2.9 mg is calculated.
A level of 20 to 50 mg/kg, which circulates in supplier summaries, sits three to eight times above that requirement. It holds only against the standard the product is sold under, and it is not a figure to copy into a specification without that standard beside it.
7. Pin These Six Lines Before You Compare Two Quotes
Two offers at the same price per kilogram are rarely the same product. These six lines move the landed cost, and each has a failure mode a certificate of analysis alone will not reveal. Request them with the technical data sheet attached.
› CAS 532-43-4 for thiamine nitrate and CAS 67-03-8 for the hydrochloride, matched to grade
› Assay with the analytical method named and the basis stated, dried or as-is
› Heavy metals by ICP-MS with the reporting limit shown, not only a pass mark
The last line is the one most quotations leave out, and the hardest to add later, because it changes a mass balance the customer has already approved.
8. Claim Language For A Vitamin B1 Ingredient Stops At Structure And Function
A thiamine ingredient can carry a structure or function claim and cannot carry a disease claim, and intended use draws the line between them.
Three conditions apply. The claim must describe the role of the nutrient in normal structure or function, the manufacturer must hold substantiation that it is truthful and not misleading, and the label must carry the disclaimer that FDA has not evaluated the claim and that the product is not intended to diagnose, treat, cure or prevent any disease. Notification is due no later than 30 days after marketing, not before.
A nutrient deficiency disease claim is the narrow exception, allowed only where the label also states how widespread that deficiency is in the United States. That is why a page about thiamine nitrate should not reproduce treatment protocols or dosing schedules: instructions for treating a deficiency belong on a drug label, and publishing them moves the product across the line the disclaimer depends on.
9. Match The Form To The Matrix, Then Write The Specification
The table below compresses the evidence into a selection rule. Read the middle column as what to quote and the last as what to test before a production batch is committed.
| Weight gain and assay at 40 ℃, high humidity | |||
| Stays free-flowing in a hygroscopic blend | |||
| Syrup at pH 3 to 4 | Self-acidified solution, slower loss | Assay and colour over 12 weeks at 40 ℃ | |
| Feed premix below 95 ℃ | |||
| Feed processed above 95 ℃ |
Q: Which Form Of Vitamin B1 Is More Stable In A Dry Powder Blend?
A: Thiamine nitrate, up to about 95 ℃. It takes up less moisture than the hydrochloride, and moisture is what starts degradation in a powder. Above that temperature the ranking reverses, so a note calling the nitrate form universally more stable in dry heat is only right below the crossover. Confirm both on your own blend.
A: Because of the pH it creates, not the counterion. A hydrochloride solution sits around pH 1.1 to 3.6 at typical concentrations, and thiamine is far more stable at pH 3 than at pH 6. A mononitrate solution sits near pH 5.4 to 7, where loss runs faster. Control the finished product pH and the salt matters less.
A: About 811 grams in a kilogram of thiamine mononitrate and about 787 grams in a kilogram of thiamine chloride hydrochloride, calculated from molecular weights of 327.36 and 337.27 against a thiamine cation of 265.36. Buying one kilogram of thiamine therefore takes roughly 1.23 kg of the nitrate or 1.27 kg of the hydrochloride.
A: Yes, and the amount is calculable: one mole of nitrate per mole of thiamine, about 19% of the salt mass. For most adult supplement matrices that is not a constraint. For infant nutrition, or any project tracking nitrosamine precursors, declare it in the specification and confirm it with the customer's quality team before the formula is fixed.
A: Not without conversion. The salts carry different thiamine fractions, and the United States enrichment standard calculates thiamine against the hydrochloride reference form at molecular weight 337.28. A declaration written on that basis needs recalculation before a nitrate substitution, and the overage clause in the same section assumes the declared level holds through shelf life.
Q: What Claim Wording Is Acceptable For A Vitamin B1 Ingredient?
A: Structure or function wording about normal function, substantiated, with the disclaimer that FDA has not evaluated the claim and that the product is not intended to diagnose, treat, cure or prevent any disease. Disease claims and treatment protocols are reserved to drugs. Deficiency disease claims are allowed only where the label also states how widespread the deficiency is in the United States.
Xi'an Huilin Bio-tech Co., Ltd. supplies thiamine nitrate and thiamine hydrochloride as supplement and food grade raw materials, with specification sheets and certificates of analysis on request.
- Voelker AL, Miller J, Running CA, Taylor LS, Mauer LJ. Chemical stability and reaction kinetics of two thiamine salts (thiamine mononitrate and thiamine chloride hydrochloride) in solution. Food Research International. 2018;112:443-456. https://doi.org/10.1016/j.foodres.2018.06.056
- Voelker AL, Taylor LS, Mauer LJ. Effect of pH and concentration on the chemical stability and reaction kinetics of thiamine mononitrate and thiamine chloride hydrochloride in solution. BMC Chemistry. 2021;15:47. https://doi.org/10.1186/s13065-021-00773-y
- Labuza TP, Kamman JF. Comparison of stability of thiamin salts at high temperature and water activity. Journal of Food Science. 1982;47(2):664-665. https://doi.org/10.1111/j.1365-2621.1982.tb10146.x
- Macek TJ, Feller BA, Hanus EJ. Pharmaceutical studies with thiamine mononitrate. Journal of the American Pharmaceutical Association, Scientific Edition. 1950;39(7):365-369. https://doi.org/10.1002/jps.3030390702
- 21 CFR 137.165, Enriched flour. Electronic Code of Federal Regulations. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-137/subpart-B/section-137.165
- Structure/Function Claims. U.S. Food and Drug Administration. https://www.fda.gov/food/food-labeling-nutrition/structurefunction-claims
- Thiamine Hydrochloride Injection, USP, label information. DailyMed, U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=43926cec-e483-8cf1-4d8d-5145e554d45d
- PubChem records for thiamine, CID 1130, and thiamine mononitrate, CID 10762. National Library of Medicine. https://pubchem.ncbi.nlm.nih.gov/compound/10762