Only plants and other photosynthetic organisms make vitamin E. Animals, including us, can’t build it and have to eat it.1Physiologia Plantarum. Progress in the dissection and manipulation of plant vitamin E biosynthesis A vitamin E supplement therefore starts one of two ways: as plant material, or as chemicals assembled in a factory to copy the plant molecule. The copy isn’t a perfect match, which is why two bottles with the same milligrams can do different amounts of good.
Why Plants Make Vitamin E in the First Place
“Vitamin E” is the name for a family of eight related compounds, the tocopherols and tocotrienols, which have very different strengths as a vitamin.2Physiologia Plantarum. Progress in the dissection and manipulation of plant vitamin E biosynthesis Photosynthetic organisms make them, from green plants to algae and some light-using bacteria.3PubMed Central. Metabolic Origins and Transport of Vitamin E Biosynthetic Precursors Alpha-tocopherol is the member most people mean by vitamin E, and the one supplements are built around.
Most of the plant machinery traces back to ancient bacteria that became the green, light-capturing structures in plant cells. Vegetable oils, nuts and seeds are the richest food sources.
Inside a plant, vitamin E sits where it’s needed. Leaves hold it in the membranes that capture sunlight. Seeds store it in their oils to keep those fats from going rancid, and that seed oil is why sunflower, wheat germ and soybean oils matter commercially.
Bright light produces reactive forms of oxygen that can damage cell membranes.4Plant, Cell & Environment. The antioxidant effects of thylakoid Vitamin E (α‐tocopherol) Vitamin E protects the light-harvesting machinery from wearing out and keeps membrane fats from being damaged by light.5PubMed Central. Vitamin E Protects against Photoinhibition and Photooxidative Stress in Arabidopsis thaliana These light-capturing membranes are packed with fats that are especially easy for reactive oxygen to attack, so the protection has to sit right inside them. Vitamin E is fat-soluble, so it can lodge within the membrane itself instead of floating in the watery part of the cell.
Plants also make more of it when strong light stresses them, so it works as a defense that responds to conditions. The same protective chemistry that guards a leaf is what makes vitamin E an antioxidant in our bodies.
How a Plant Builds a Vitamin E Molecule
The plant joins a small ring-shaped piece to a long fatty tail.6PubMed Central. Metabolic Origins and Transport of Vitamin E Biosynthetic Precursors The type of tail decides the result: one kind makes tocopherols, another makes tocotrienols.7PubMed Central. Vitamin E Biosynthesis and Its Regulation in Plants A saturated, flexible tail leads to tocopherols. A tail with three extra double bonds leads to tocotrienols. Those double bonds put kinks in the chain, which changes how the molecule sits in a membrane.
Further steps then close the ring and add small chemical groups that can turn other forms into alpha-tocopherol.8Nature Research Intelligence. Tocopherol Biosynthesis in Photosynthetic Organisms How much of each form a seed ends up with depends on how far those final steps run. Tocopherols dominate in most seed oils, while tocotrienols are common in palm oil, rice bran and barley.
The other forms still matter. Gamma-tocopherol and the tocotrienols are strong antioxidants in their own right, and some may neutralize certain harmful molecules better than alpha-tocopherol does. The body keeps far less of them, though, as a later section explains.
Scientists can tune the recipe. Adding one barley gene for tocotrienol-making raised total vitamin E in corn seeds by up to six times.9PubMed. Metabolic redesign of vitamin E biosynthesis in plants for tocotrienol production and increased antioxidant content These are research plants, not grocery items.
How Natural Vitamin E Is Taken From Plants
When vegetable oils are refined, a byproduct is collected that is an important source of natural vitamin E.10ACS Sustainable Chemistry & Engineering. Selection of Imidazolium-Based Ionic Liquids for Vitamin E Extraction from Deodorizer Distillate The steaming that removes off-flavors from the oil carries vitamin E away with it. The vapors are condensed into a dark, sludgy material. That sludge contains free fatty acids, sterols and vitamin E. It once counted as waste but is now sold as a raw material. The vitamin E is a small share of the mix, so it has to be concentrated before it can go into a capsule.
Solvents pull the vitamin E out of this leftover, and how well that works depends heavily on the solvent chosen.11ACS Sustainable Chemistry & Engineering. Selection of Imidazolium-Based Ionic Liquids for Vitamin E Extraction from Deodorizer Distillate Newer approaches use solvent systems designed to grab vitamin E while leaving other oily compounds behind.12ACS Sustainable Chemistry & Engineering. Enhanced Vitamin E Extraction Selectivity from Deodorizer Distillate by a Biphasic System: A COSMO-RS and Experimental Study
Natural doesn’t always mean unchanged. The extract is a mix of alpha, beta, gamma and delta tocopherols, and the non-alpha forms are less potent.13Google Patents. Process for converting a mixed tocopherol concentrate to essentially all alpha-tocopherol Manufacturers can chemically convert these mixed tocopherols into alpha-tocopherol.14Google Patents. Process for converting a mixed tocopherol concentrate to essentially all alpha-tocopherol The result is still the natural-shaped molecule, so it can be sold as d-alpha.
“Mixed tocopherols” on a label means the product keeps several family members rather than only alpha. It usually comes straight from oil distillate, and it is often used as a natural preservative in foods and pet food.
Plant extraction is limited by how much raw material exists and by the costs of growing crops.15PubMed. Evolution of Vitamin E Production: From Chemical Synthesis and Plant Extraction to Microbial Cell Factories Natural vitamin E therefore remains a smaller, pricier share of the market.
How Synthetic Vitamin E Is Made in a Factory
Factories react a copy of the ring head with isophytol, a copy of the oily tail, using an acid catalyst.16Google Patents. Process for the synthesis of vitamin E The catalyst is often a metal salt such as zinc chloride.17ChemAnalyst. How Is Vitamin E Made? From Plants to Supplements The two building blocks are mixed in a solvent with the catalyst and heated, and the ring and tail join and then close into the finished molecule. The catalyst speeds the joining without becoming part of the product, but it has to be removed and the product purified afterward. What comes out is an oily liquid with the same chemical formula as plant alpha-tocopherol, often converted to the acetate form for sale. So the factory copies the plant’s head-plus-tail design without any plant. The product is labeled dl-alpha-tocopherol, or all-rac on technical documents.18Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet From here on, this is the synthetic vitamin E, and the plant-derived d-alpha-tocopherol is the natural vitamin E.
The catch is a mirror-image problem. The alpha-tocopherol molecule has three spots that can twist two ways, giving eight possible shapes.19Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry Plants make only one, called RRR, sold as d-alpha.20Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry Synthetic vitamin E contains all eight shapes in equal amounts.21Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry Only the four with the right twist at the key spot count toward vitamin E needs.22Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry The body’s transport proteins fit one shape best, so only some of a mixed batch is used well.
That doesn’t make synthetic unsafe. It has the same chemical formula and is not a foreign substance; the issue is potency, not toxicity. It is widely used in fortified foods and animal feed.
The chemistry has also gotten cleaner. Older synthesis created byproducts and wastewater, and newer catalysts reach yields above 94%.23Catalysis Today. Rare earth triflate catalysts in the synthesis of Vitamin E and its derivatives One maker reports its process uses up to 60% less non-renewable energy than competitors, though that is a company claim.24Cosmetics Business. DSM’s vitamin E has the lowest carbon footprint in the industry
Does Your Body Treat Natural and Synthetic Vitamin E Differently
The gut absorbs all forms of vitamin E fairly indiscriminately.25PubMed Central. Alpha-Tocopherol Transfer Protein (α-TTP): Insights from Alpha-Tocopherol Transfer Protein Knockout Mice The sorting happens afterward. After absorption, vitamin E travels to the liver, where a transfer protein binds alpha-tocopherol of the plant shape more tightly than the other shapes and loads it into particles that carry it through the blood.26PubMed Central. Alpha-Tocopherol Transfer Protein (α-TTP): Insights from Alpha-Tocopherol Transfer Protein Knockout Mice It favors alpha over beta, gamma and delta forms.27PubMed Central. Alpha-Tocopherol Transfer Protein (α-TTP): Insights from Alpha-Tocopherol Transfer Protein Knockout Mice Vitamin E the protein doesn’t pick up is broken down and cleared faster, so the unused shapes in synthetic vitamin E mostly pass through.
The official figure says natural is about 1.36 times as potent as synthetic.28PubMed. Relative bioavailabilities of natural and synthetic vitamin E formulations containing mixed tocopherols in human subjects But a study tracking both forms in the same people found natural gave roughly twice the blood and tissue levels.29PubMed. Human plasma and tissue alpha-tocopherol concentrations in response to supplementation with deuterated natural and synthetic vitamin E In another study the gap was about 1.3 to 1 in non-smokers and nearly disappeared in smokers.30PubMed. Vitamin E bioavailability in humans Natural is clearly more efficient, but how much depends on the person.
For buying, neither form is useless. You need a higher milligram dose of synthetic to match natural, so compare by vitamin E activity on the label, not raw milligrams. Price per effective dose may still favor synthetic.
A “natural” front label still needs checking. D-alpha means the natural shape and dl-alpha means synthetic, and a front label may mix in synthetic, so read the ingredient list.
How to Read a Vitamin E Label
First check whether the bottle says d- or dl-, then use these conversions:
- 1 mg of vitamin E equals 1 mg of natural d-alpha-tocopherol.31Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet
- 1 mg of vitamin E equals 2 mg of synthetic dl-alpha-tocopherol.32Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet
- 1 IU (international unit) of natural form equals 0.67 mg of vitamin E.33Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet
- 1 IU of synthetic form equals 0.45 mg of vitamin E.34Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet
U.S. Supplement Facts labels now list vitamin E in mg of alpha-tocopherol, counting only the right-shaped forms.35Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry
For an older bottle, find the form first, because the factor differs. Then multiply the number by 0.67 for natural or 0.45 for synthetic. A 400 IU capsule works out to about 268 mg of vitamin E if natural and about 180 mg if synthetic. Adults need 15 mg a day, which either one far exceeds.
Why Supplements Use Acetate and Succinate Forms
Plain alpha-tocopherol reacts with air easily, so makers attach an acetate or succinate group to stabilize it.36Elchemy. Natural vs Synthetic Vitamin E: Which One Is Better? After you swallow it, gut enzymes remove that group.37Elchemy. Natural vs Synthetic Vitamin E: Which One Is Better? Only the unwrapped form is absorbed by the intestine.38PubMed Central. Vitamin E Bioavailability: Mechanisms of Intestinal Absorption in the Spotlight
Enzymes from the pancreas and the gut lining do the cutting. What’s left is the same alpha-tocopherol that plants make, or its synthetic mirror-image mix. That is why a bottle listing d-alpha-tocopheryl acetate still counts as natural vitamin E for potency.
Both natural and synthetic can come as acetate. Acetate is also common in skin creams, where the skin doesn’t unwrap it well. For capsules, take them with a meal containing fat, which helps release and absorption.
Newer formats include powders and tiny-droplet emulsions that protect vitamin E from heat and storage loss. They are used in drink mixes and gummies, with benefits shown mainly in lab tests.
New Ways of Making Vitamin E
Yeast engineered with plant genes can produce tocotrienols, reaching 320 mg per liter in fermentation.39PubMed Central. Fermentative production of Vitamin E tocotrienols in Saccharomyces cerevisiae under cold-shock-triggered temperature control Yeast doesn’t normally make tocopherols or tocotrienols, so engineers add plant genes that supply the missing steps. It already makes the building blocks for the tail, so the added genes only have to join and finish them.
Algae are different. The alga Euglena already makes vitamin E that is over 97% alpha-tocopherol,40PubMed Central. Microbial Cell Factories for Green Production of Vitamins so the work is in growing it well and extracting the vitamin. Compounds made by microbes can also serve as a starting material for the isophytol tail used in synthesis.41PubMed Central. Revolution of vitamin E production by starting from microbial fermented farnesene to isophytol Future vitamin E may be natural in shape without needing oil crops.
For shoppers, this could eventually mean cheaper natural-shape vitamin E and less dependence on oil refining supply. These methods are mostly research-stage or early commercial.