One observational study found 66 people with rheumatoid arthritis had less pantothenic acid in their blood than 29 healthy people. The more severe the arthritis, the lower the blood levels of pantothenic acid were. However, this result doesn't prove that pantothenic acid supplements can effectively reduce any of the symptoms of rheumatoid arthritis. To follow up on this finding, researchers then conducted a small placebo-controlled trial involving 18 subjects to see whether pantothenic acid would help. However, a study this small doesn't mean much on its own.
More research is needed.
No significant side effects have been reported for pantothenic acid or pantethine, used by themselves or with other medications. However, maximum safe dosages for young children, pregnant or nursing women, or people with serious liver or kidney disease have not been established. Gaddi A, et al. Controlled evaluation of pantethine, a natural hypolipidemic compound, in patients with different forms of hyperlipoproteinemia. Angelico M, et al.