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[Biochemistry](https://durgical.com/en/biochemistry/) · Molecule

# Vitamin E (α-tocopherol)

Vitamin E is the membrane antioxidant: it slows the oxidation of cell fats, especially in nerves and red blood cells.

Updated 2026-11-01

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## Key facts

- A fat-soluble antioxidant that breaks the chain of lipid peroxidation in membranes.
- Vitamin C regenerates it; selenium (glutathione peroxidase) works in the same defence.
- Deficiency: haemolytic anaemia, peripheral neuropathy, spinocerebellar ataxia and retinopathy.
- The liver's α-tocopherol transfer protein (TTPA gene) selects the α form; its failure causes ataxia with vitamin E deficiency.

## In detail

- Sources: vegetable oils, nuts, seeds, avocado, leafy greens.
- Mechanism: the hydroxyl of the chromanol ring donates a hydrogen to a lipid peroxyl radical; the tocopheroxyl radical left behind is stable and vitamin C returns it to the active form.
- Transport: absorbed with fat, it reaches the liver in chylomicrons, and α-TTP loads it into VLDL for delivery.
- Deficiency (rare, nearly always from fat malabsorption or in premature babies): fragile red cells (haemolysis), degeneration of the dorsal columns and peripheral axons.
- Excess (supplements): it can antagonise vitamin K and raise bleeding risk, especially with anticoagulants.
- Lab: serum α-tocopherol, best expressed relative to total lipids (cholesterol and triglycerides).

**Also called**
α-tocopherol, Tocopherols and tocotrienols

**Formula**
C₂₉H₅₀O₂

**PubChem**
[CID 14985](https://pubchem.ncbi.nlm.nih.gov/compound/14985)

## Structure

- A chromanol ring (carrying the antioxidant OH) joined to a saturated 16-carbon phytyl tail that sits in the lipid bilayer.
- There are eight natural forms (α, β, γ, δ tocopherols and tocotrienols); the liver keeps the α form.

## Clinical notes

- Its neurological picture (ataxia, loss of proprioception, areflexia) resembles Friedreich ataxia and vitamin B12 deficiency.
- Premature babies are born with low stores and may develop haemolytic anaemia.
- Large trials did not show that vitamin E supplements prevent cardiovascular disease or cancer.

## Related

- [Selenium](https://durgical.com/en/biochemistry/topics/selenium/)
- [Vitamin C (ascorbic acid)](https://durgical.com/en/biochemistry/molecules/vitamin-c/)
- [Vitamin A (retinol)](https://durgical.com/en/biochemistry/molecules/vitamin-a/)

## Test yourself

Think of the answer, then tap the question to see it.

## How does vitamin E protect membranes?

It donates a hydrogen to lipid peroxyl radicals and stops the chain reaction that oxidises unsaturated fatty acids.

## Which vitamin regenerates oxidised vitamin E?

Vitamin C (ascorbate) reduces the tocopheroxyl radical and makes it active again.

## Which findings suggest vitamin E deficiency?

Haemolytic anaemia, ataxia, loss of deep sensation and peripheral neuropathy in someone with fat malabsorption.

## Which gene fails in ataxia with vitamin E deficiency?

TTPA, which encodes the liver protein that loads α-tocopherol into VLDL; without it the vitamin is lost in bile.

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Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [alpha-Tocopherol (CID 14985)](https://pubchem.ncbi.nlm.nih.gov/compound/14985) (PubChem, NCBI, 2026) · Public domain; [Vitamin E: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/002406.htm) (MedlinePlus, US National Library of Medicine, 2026); [Ataxia with vitamin E deficiency: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/ataxia-with-vitamin-e-deficiency/) (MedlinePlus, US National Library of Medicine, 2026); [TTPA gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/ttpa/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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