Usual oral doses are about 1 to 1.5 grams a day. Though oral administration is most common, it has also been given by injection into a joint, and by intramuscular or intravenous injection. There is no substantial evidence that this makes any difference. Outcomes used in trials vary enormously, as is the norm in arthritis trials, especially older ones. This inhibits pooling of data in meaningful ways.
Trials are often short, again as has been the case for older trials in arthritis.
Finally there is the control. Despite these problems, two systematic reviews have been able to come to conclusions about the evidence. This Cochrane review was notable because the authors found a number of unpublished studies. The mean age of patients was 61 years. Twelve of the trials could be included in the review.