When
you swallow a racemic lipoic acid tablet - the kind
you get in nearly all "lipoic acid" supplements
- both the S(-)- and the R(+)-Lipoic Acid
are taken up into your blood
24 and then transported to your cells.
25 Already at this point, another advantage
of R(+)-Lipoic Acid becomes clear: the R(+)-Lipoic
Acid is dramatically more bioavailable than
the S(-)-form.The peak concentration of
plasma lipoic acid obtained from R(+)-Lipoic Acid
is twice as great as from an equal amount
of the S(-)-form
26
and the total R(+)-Lipoic Acid delivered
into the plasma over the course of time is 60 to 85%
greater than the total amount of the S(-)-form which
ultimately reaches the plasma as well.
27
28
More
importantly, studies show that R(+)-Lipoic Acid
is taken up into the tissues to a greater degree than
the S(-)-form. In one study
29
scientists gave lab animals the R(+)-, the S(-)-,
or the racemate form of lipoic acid - providing it
by injection, so as to bypass the differences
in absorption in the digestive system, and thus start
the animals off on a level playing field. As expected,
lipoic acid levels were the same in all three groups
within the first hour as the injected lipoic acid
made its way through the circulation. But three hours
later, the animals which had received R(+)-Lipoic
Acid had two to seven times more lipoic acid in the
lenses of their eyes than animals given the same amount
of the S(-)-form, and three times as much as
the animals given the racemate form!
Impressive
as these results are, an even more important difference
emerges only after the different forms of
lipoic acid have been taken into your cells.
