Usually inositol is taken by the "gram".

My husband uses it fairly often in spurts... I think 1/2 to one scoop. (that comes with the powder). He does say that he reaches some "point" where he doesn't like it and then stops (after weeks/months usually). He has a severe head injury from the age of 2, where he fell out a 2nd story window. So at times he has difficulties, one of which is being able to express himself. (I think he has a right head injury). At times he has huge anxieties, mostly when he has to do something "new", or packing for our summer trip. He will get just as anxious coming home as well...it is the "change" that sets him off. So I bought the inositol in a tub in powder form, with that little scoop.

The doses for OCD treatments I've read go really high...like 10+ grams a day.

If you purchased capsules, they are usually 500mg each, so you could start at 500mg a day and very slowly increase as you think you need. It is rather slow onset and slow acting (not like RX drugs are), so give each dosage time to work.

The inositol used for PCOS is another form, called d-chiro-inositol, and that is available only by two brand makers, that I know of, at the doses of 300mg to 600mg a day. This form will help with insulin use, (didn't work for me) and also PCOS infertility. It seems to lower androgens in females with elevated androgen levels. And can be rather expensive compared to the myo- or regular inositol.

If you are looking for anxiety relief only...then try PharmaGaba.
This I have used several times. (mostly when our kitten Houdini disappeared)... and it is a newer form of GABA which does cross the blood brain barrier and get into the brain. It was not habit forming for me and I found it very useful at certain times where I'd get overwrought. My anxieties it turned out seemed to be generated by my levothyroxine becoming too strong for me.
Seems my hypothyroid situation changed, and I was actually suffering from HYPERthyroid symptoms. So last Nov. I discontinued it and my most recent tests were in late Feb and were totally normal. So I don't feel that terrible anxiety and heart pounding anymore. I am also on a beta blocker for my blood pressure and that really helps too, for me.
http://www.iherb.com/Natural-Factors...w&gclsrc=aw.ds

PharmGaba did not cause any habituation for me either. It is not very strong...like Valium or Xanax, but it does what it needs to more gently. I had no withdrawal effects stopping it.