The herb red yeast rice contains several (up to 10) compounds that lower cholesterol. It is thought that because they are present in a "group" they exert the cholesterol lowering in a more gentle fashion.

There is great variability with red yeast rice products. Some are better than others. I address that above.
And there have been reports of Chinese produced red yeast rice being contaminated intentionally with lovastatin to make those sources seem stronger. So I am using only American made red yeast rice.

In Dr. Cohen's book (which I just loaned my doctor so I don't have it here now), his quoted medical source says that with 500 patients who use this herb, no side effects were reported.

Just for the record, I am starting d-chiro inositol now. I just ordered it. It is really expensive, but the studies show vast improvements in metabolic syndrome with it. I've been watching it for years. I used metformin for a while, but after 6months it made me very ill... acidosis. I was very disappointed when that happened.