On page 133  of LR4YT, it says to take 500 mg of b-12.    1000 mcg = 1mg.  I would have to take 500 of Dr. Ds 1000mcg capsules to meet that dosage.  Is this a typo?  

Typo.

B-12 dosages are given in mcg.

Wow!  That is pretty major.  Has this been discussed before?  

Then that means that only 1/2 dose is necessary.

I called the order line yesterday and the lady that answered said that she was positive that 1000 mcg= 100 mg which meant that I would need to take 5 capsules.  That conversion did not sound right so I looked it up and got the different figures cited above.

when in doubt about a dosage, look it up in the encyclopedia and directly at DPN by clicking on the supplement facts

The abbreviation mcg represents micrograms.
A microgram is equivalent to a millionth of a gram
or a thousandth of a milligram

The abbreviation mg to represents milligrams.
A milligram is a thousandth of a gram
or a thousand micrograms.

A microgram can also abbreviated µg instead of mcg, where µ is the lower case greek letter mu.