Are there any over-the-counter herbal or vitamin/mineral type substances that show any efficacy in treatment for fibromyalgia?

Homeopathy: I agree with dr. Baker's excellent answer -- and also want to mention that homeopathy can provide much benefit for people with fibromyalgia. You'll need a well-trained, experienced classical homeopath to take your case and treat you, though, because any one of hundreds of possible homeopathic remedies might be the one you need. Dr. Iris bell has done several studies. http://tinyurl.com/7ekkqhz.

Yes: ? OTC substances might benefit fibromyalgia (FM). Cannabis indica prepared cold & ingested has effective analgesic & sleep enhancing qualities absent "the high". Topical cannabis lotions relieve regional pain. Vitamin D needs evaluation in invalids w. minimal sun exposure. Probiotics might help intestinal dysfunctions. Ribose, magnesium & vitamin C are candidates for orthomolecular FM therapy.