Studies have shown that 30% of fibromyalgia patients is found with GH deficiency. This subset of fibromyalgia patients is observed to have subnormal levels of serum IGF-1 in their blood which suggest that they are also lacking in GH. GH deficiency is known to produce fibromyalgia-like symptoms such as muscle pain, weakness and fatigue in children. A 1999 study suggest that the lack of GH and IGF-1 can contribute to fibromyalgia pain. It is believed that the deficiencies can hinder with cell repair and renewal in affected fibromyalgia patients and hence result in more severe chronic pain. Studies investigating the effect of GH treatment in fibromyalgia patients showed positive effects including reduction of pain, reduction of tender points and improvement in quality of life in fibromyalgia subjects
The reason behind the low levels of GH seems to be due to a hypothalamic-pituitary-GH axis dysfunction leading to impaired GH secretion. Though the exact cause of impaired GH secretion is uncertain, clinical studies have narrowed down to two possibilities: presence of increased levels of somatostatin tone which reduces GHRH activity and GH resistance or insensitivity of GH receptors.
Currently, there are two types of treatments targeting growth hormone in fibromyalgia patients.