d-Alpha-Tocopherol Grades Explained: 1000, 1100, 1300 and 1490 IU/g — How to Choose and How to Compare Prices
Natural d-alpha-tocopherol is sold by IU strength rather than by percentage, and that single convention causes more purchasing confusion than any other aspect of the vitamin E trade. A buyer comparing a 1000 IU/g offer against a 1490 IU/g offer is not comparing two similar products at different prices. They are comparing two different concentrations, and the cheaper-looking option is frequently the more expensive one.
This guide explains what the IU numbers represent, how to select a grade for your application, and how to run a fair price comparison.
What Does IU/g Actually Mean?
IU (International Unit) is a measure of biological vitamin E activity, not of mass. For natural d-alpha-tocopherol (CAS 59-02-9, also written RRR-alpha-tocopherol), the pharmacopoeial conversion factor is:
1 mg d-alpha-tocopherol = 1.49 IU
Work that backwards and the grade names become self-explanatory. A product declared at 1490 IU/g contains approximately 1000 mg of d-alpha-tocopherol per gram — in other words, it is essentially 100% d-alpha-tocopherol. Every grade below that is the same molecule diluted, usually in a refined vegetable oil carrier.
| Grade | Approx. d-alpha content | What the balance is |
|---|---|---|
| 1490 IU/g | ~100% | Essentially neat d-alpha-tocopherol |
| 1300 IU/g | ~87% | Carrier oil |
| 1100 IU/g | ~74% | Carrier oil |
| 1000 IU/g | ~67% | Carrier oil |
Note that the conversion factor is specific to the free tocopherol form. The esters carry different factors: d-alpha-tocopheryl acetate (CAS 58-95-7) converts at 1 mg = 1.36 IU, and d-alpha-tocopheryl succinate (CAS 4345-03-3) at 1 mg = 1.21 IU. Never apply the 1.49 factor across forms.
How to Choose a Grade by Application
Softgel capsules and high-potency supplements. Choose 1490 IU/g. When the finished dose is 400 IU or 1000 IU per capsule, fill volume is the binding constraint, and any carrier oil you buy is volume you cannot use for active. The highest concentration almost always wins here.
Food and beverage fortification. 1000 to 1100 IU/g is usually sufficient and easier to disperse. At fortification levels the active is diluted heavily in any case, so a pre-diluted grade reduces the risk of dosing errors on the plant floor.
Cosmetics and personal care. 1000 to 1300 IU/g is common. Formulators often prefer a grade whose viscosity and colour are consistent batch to batch over one that is maximally concentrated, because colour carry-through into a white cream is a real formulation constraint.
Feed and premix. Consider whether a powder form serves you better than an oil. A spray-dried or microencapsulated powder handles far more reliably in a dry premix line than any liquid grade, regardless of IU.
Further processing into esters or powders. Choose 1490 IU/g. If the material is an intermediate, carrier oil is simply a contaminant you will have to remove or account for downstream.
The Price Comparison Mistake
The most common purchasing error is comparing offers on price per kilogram. Because grades differ in concentration, kilograms are not the comparable unit — IU are. The correct calculation is:
Cost per million IU = price per kg ÷ (IU per gram × 1000) × 1,000,000
Worked through with illustrative figures:
| Offer | Price/kg | IU per kg | Cost per million IU |
|---|---|---|---|
| A: 1490 IU/g | $60 | 1,490,000 | $40.27 |
| B: 1000 IU/g | $45 | 1,000,000 | $45.00 |
Offer B looks 25% cheaper per kilogram and is in fact about 12% more expensive per unit of activity. The gap widens once freight, duty and warehousing are added, because those are charged on gross weight and the lower grade ships roughly 50% more mass to deliver the same activity.
Run this calculation before every comparison. Ask each supplier to quote the guaranteed minimum IU/g rather than a typical value, since a "1000 IU/g nominal" material that tests at 980 changes the arithmetic.
Diluting In-House
Buying the concentrate and diluting on site is straightforward and often economical. Blend 1490 IU/g into a refined, low-peroxide carrier oil under nitrogen, at ambient or gently warmed temperature, and confirm homogeneity before drawing a retention sample. Two cautions: the carrier oil's own peroxide value becomes your starting point for shelf life, so specify it; and any in-house blending step usually needs to be captured in your HACCP plan before it goes into a food-contact product.
What to Request From a Supplier
Ask for these before you commit to a grade:
- Certificate of analysis stating assay in both IU/g and percentage
- Specific rotation, confirming the natural RRR configuration rather than a synthetic racemate
- Heavy metals and residual solvent results
- PAH results, specifically benzo(a)pyrene and PAH4, if the material is destined for the EU
- Peroxide value at release, plus the carrier oil identity for any diluted grade
- Non-GMO identity preserved documentation where the source is soy
- Stability data supporting the stated shelf life under nitrogen
Full IU Range, One Manufacturer
Worldbestve produces d-alpha-tocopherol across 1000–1490 IU/g, with guaranteed minimums on every COA. FSSC 22000 / ISO 22000 certified. MOQ from 10 kg — enough for bench work and a pilot run.
Request a Quote →Frequently Asked Questions
Is 1490 IU/g the same as 100% vitamin E?
It is approximately 100% d-alpha-tocopherol. It is not 100% "vitamin E" in the wider sense, since vitamin E as a family also includes beta, gamma and delta tocopherols and the four tocotrienols.
Can I substitute a synthetic grade at the same IU?
Not on a like-for-like basis. Synthetic dl-alpha-tocopherol is a mixture of eight stereoisomers and carries a different conversion factor and a different label declaration. If your label claims natural vitamin E, the material must be the RRR form.
Why do two suppliers quote different IU for the same percentage?
Usually because one is quoting typical assay and the other guaranteed minimum. Always compare guaranteed minimum values.
Does a higher IU grade have a shorter shelf life?
Not inherently. Shelf life is governed by packaging, nitrogen blanketing and storage temperature far more than by concentration. A diluted grade can actually be more vulnerable if the carrier oil itself oxidises.
What is the smallest quantity available for trials?
Zhejiang Worldbestve Biotechnology Co., Ltd. supplies from 10 kg for formulation trials, which is generally enough to complete bench work and a pilot run.
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