Alpha-tocopherol forms and their activity in the body
What it found
The natural and synthetic forms of alpha-tocopherol are handled differently by the body, and the natural form is more potent.
In people and animals, researchers often rely on indirect markers rather than clear health outcomes.
What they found
Animal and lab studies
Cows prefer natural form
Cows preferentially move RRR-alpha-tocopherol into their milk and blood. This shows notable differences between animal species in how they handle the 2R forms.
Tissue distribution varies
The mix of stereoisomer forms differs from tissue to tissue. In some cases, such as in rats, higher levels of the synthetic 2R forms than the RRR form were found.
Studies in people and animals
Natural vs synthetic form
In human and animal studies using deuterium-labeled forms, the natural RRR form was about twice as potent as the synthetic all-rac form. This differs from the accepted ratio of 1.36 to 1.
2S forms have little activity
The 2S forms of alpha-tocopherol have very little importance for vitamin E activity because the body takes up only limited amounts of them.
Factors affecting handling
How the body handles the different stereoisomer forms is influenced by age, dietary levels, and time after dosage.
Other findings
Lab method for separation
A relatively simple analytical method separates the alpha-tocopherol stereoisomers into five peaks. This lets researchers measure the relative amounts of each form.
What the authors conclude
“More focus should be given on the bioactivity of the individual 2R-forms rather than just the comparison between RRR- and all-rac-alpha-tocopheryl acetate.”
Also in their conclusions
- They say more focus should be given to the bioactivity of the individual 2R forms rather than just comparing RRR- and all-rac-alpha-tocopheryl acetate.
- They note that the analytical method presented allows quantification of total tocopherol content and composition.
How it was done
It has been hard to measure the true vitamin E activity of different alpha-tocopherol forms because clinical signs are difficult to measure in larger animals and people. So researchers looked at how the body handles these forms and what markers can be used.
The authors reviewed studies in rats, poultry, cows, other animals and people that measured how much of each alpha-tocopherol form reaches fluids and tissues. They also described a lab method that separates the eight stereoisomers into five peaks using normal phase and chiral HPLC.
What it can’t tell you
- We summarised it from the abstract only.
- For people and larger animals, only indirect markers of vitamin E activity have been measured, not clear health outcomes.
- The review cannot show how the different forms affect long-term health in people because most human data come from short-term markers.
- Animal results may not apply to people because species handle these forms differently.
Who paid
- Authors work at
- University of Aarhus, Denmark
The paper
- Title
- Alpha-tocopherol stereoisomers
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Abstract only
- Cite
- Jensen SK, Lauridsen C (2007). Alpha-tocopherol stereoisomers. Vitamins and hormones. doi:10.1016/S0083-6729(07)76010-7PubMed 17628178DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error