Hydrogenated, Fully Hydrogenated, Interesterified and Non-Hydrogenated Oils

Ingredient lists use several words for oils that have been changed to make them more solid: "hydrogenated," "fully hydrogenated," "interesterified," and, on the other side, "non-hydrogenated." These words describe how the oil was processed, and they tell you something about the kinds of fat in the food. Here is what each term means and what US rules say.

Why food makers change oils at all

Most vegetable oils, such as soybean, canola, and sunflower oil, are liquid at room temperature. Many foods, such as cookies, frostings, and margarine, need a fat that is solid or semi-solid instead. Food makers have three main ways to get a firmer fat: use a fat that is naturally solid (such as palm oil or coconut oil), harden a liquid oil by hydrogenation, or rearrange the oil's fats by interesterification.

Partially hydrogenated oil: the one that is gone

Hydrogenation adds hydrogen to the unsaturated fats in a liquid oil, which makes the oil more solid. When the process is stopped partway, the result is partially hydrogenated oil (PHO). Partial hydrogenation creates artificial trans fat, which raises LDL ("bad") cholesterol.

In June 2015, the FDA issued a final determination that PHOs are no longer "generally recognized as safe" (GRAS) for use in human food. Companies had until June 18, 2018 to stop adding them, with some later dates for foods already made and for a few specific uses, ending January 1, 2021. In that determination, the FDA defined PHOs as fats and oils that have been hydrogenated "but not to complete or near complete saturation," with an iodine value (a lab measure of how unsaturated a fat is) above 4.

So "partially hydrogenated soybean oil" is an ingredient US food makers can no longer add, though it may linger on old or imported packaging. Our guide to trans fat and partially hydrogenated oils covers the full history.

Fully hydrogenated oil: a different product

If hydrogenation is carried all the way, almost all of the unsaturated fat becomes saturated fat. The result is a hard, waxy fat called fully hydrogenated oil. The FDA's 2015 order defined fully hydrogenated oils as those hydrogenated to complete or near complete saturation, with an iodine value of 4 or less, and said they were outside the scope of the PHO order. The FDA explained that these oils generally contain trans fat at levels similar to ordinary refined oils that were never hydrogenated, which is typically below 2 percent.

So "fully hydrogenated" does not mean "trans fat," but it does mean mostly saturated fat. The USDA's FoodData Central lists an industrial hydrogenated palm kernel filling fat at about 88 g of saturated fat per 100 g.

How "hydrogenated" appears on a US label

The FDA's ingredient labeling rule, 21 CFR 101.4(b)(14), says that if a fat or oil is completely hydrogenated, its name must include the term "hydrogenated," and if it is partially hydrogenated, the name must include "partially hydrogenated." That is why you see names like "hydrogenated palm oil," "hydrogenated soybean oil," "hydrogenated cottonseed oil," or "fully hydrogenated vegetable oil." Since PHOs can no longer be added to food, a current US label that just says "hydrogenated" usually refers to a fully hydrogenated fat.

Older terms such as "hydrogenated vegetable fat" are general names. The same rule says that when a blend is called a "vegetable oil shortening" or "blend of vegetable oils," the specific oils must follow in parentheses, so check there for the actual source.

Interesterified oil: rearranged fats

Fats in food are mostly triglycerides, which are three fatty acids attached to a backbone called glycerol. Interesterification moves those fatty acids around, within and between triglyceride molecules, using either a chemical catalyst or an enzyme. The fatty acids themselves are not changed into trans fats. What changes is how the fat melts and sets.

A common approach, described in a 2016 review in the journal Advances in Nutrition, is to take a high-melting fat, such as a fully hydrogenated oil or a palm oil fraction, and a liquid oil, and interesterify them together. The product has a texture closer to the old PHOs, without the trans fat. The same review noted that many food technologists turned to interesterified fats after the FDA's 2015 PHO determination.

What the research says

The review's authors also found that the long-term health effects of eating interesterified fats are less well understood than those of other fats. Some studies that fed relatively high amounts of interesterified fats rich in stearic or palmitic acid reported effects on blood lipids, blood sugar, and other markers, and the authors listed several open research questions. In plain terms: interesterified fat avoids the trans fat problem, but scientists have not finished studying it, and it is often high in saturated fat.

On a label you may see "interesterified soybean oil" or "interesterified vegetable oil." You can look up both on our interesterified soybean oil and interesterified vegetable oil pages.

Non-hydrogenated oil: what it does and doesn't tell you

"Non-hydrogenated" simply means the oil has not been through hydrogenation. Most bottled cooking oils, like canola, sunflower, and soybean oil, are non-hydrogenated, so the phrase "non-hydrogenated canola oil" or "non-hydrogenated sunflower oil" describes how most of those oils are sold anyway.

The phrase is useful because it tells you the oil is not a hydrogenated fat. It is not a health claim on its own, for two reasons:

• Refined oils can still contain small amounts of trans fat. The FDA noted in 2015 that refined oils that were never hydrogenated generally contain trans fat as an unavoidable result of high-temperature processing, typically below 2 percent.
• Saturated fat depends on the oil, not on the word. "Non-hydrogenated palm oil" and "non-hydrogenated coconut oil" are still high in saturated fat because those oils are naturally rich in it. USDA FoodData Central lists palm oil at about 49 g and coconut oil at about 83 g of saturated fat per 100 g, compared with about 7 g for canola oil and about 16 g for soybean oil.

Quick comparison

• Partially hydrogenated oil: source of artificial trans fat; no longer GRAS in the US since the 2018 compliance date.
• Fully hydrogenated oil: very low trans fat; mostly saturated fat; must be labeled "hydrogenated."
• Interesterified oil: fatty acids rearranged to change texture; no trans fat created by the process; long-term effects less studied.
• Non-hydrogenated oil: not hydrogenated; its fat profile is that of the original oil.

How to read the label

The ingredients list shows the process; the Nutrition Facts panel shows the result. Two lines matter most:

• Saturated fat. The FDA Daily Value is 20 g per day, and the Dietary Guidelines for Americans 2025–2030 keep the long-standing advice to limit saturated fat to less than 10% of daily calories. Use the 5/20 rule from our %DV guide: 5% DV or less per serving is low, 20% or more is high.
• Trans fat. Under 21 CFR 101.9(c)(2)(ii), a serving with less than 0.5 g of trans fat may be labeled as 0 g. Since PHOs are no longer allowed, most current products will show 0 g.

How to use this on myfoodfact.com

• See products that use these fats on our hydrogenated soybean oil, fully hydrogenated vegetable oil, hydrogenated cottonseed oil, and non-hydrogenated vegetable oil pages.
• For older products, check our partially hydrogenated soybean oil page.
• Learn about palm-based fats in our guide to palm oil and its label names, and about liquid oils in seed oils: separating evidence from hype.
• Browse our low saturated fat list.

The bottom line

"Partially hydrogenated" was the source of artificial trans fat and has been phased out of US food. "Fully hydrogenated" and "interesterified" fats make solid fats without that trans fat, but are usually high in saturated fat, and research on interesterified fats is still developing. "Non-hydrogenated" tells you how the oil was processed, not how much saturated fat it has. For any of them, the saturated fat line on the Nutrition Facts panel is the most useful number to compare.

This guide is for general information and is not medical advice. If you have high cholesterol or heart disease, follow the guidance of your health care team.