Fibromyalgia is a complex chronic pain disorder that affects an estimated 2-8% of the population. Women are diagnosed with fibromyalgia at much higher rates than men. While the exact causes are still being investigated, research suggests that fibromyalgia may be related to abnormalities in hormone levels and dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis.
Fibromyalgia and Hormone Imbalances
Several key hormones have been found to be abnormal in many patients with fibromyalgia. These include cortisol, thyroid hormones, growth hormone, insulin, and sex hormones like estrogen and testosterone.
Cortisol
Cortisol is a steroid hormone released by the adrenal glands that is important for regulating inflammation, immune function, metabolism, and stress response. Many studies have found that people with fibromyalgia tend to have lower levels of cortisol, especially in the morning.
Normally, cortisol levels are highest in the morning within an hour of waking up. This circadian rhythm helps prepare the body for the day’s activities. In fibromyalgia patients, the typical morning spike in cortisol may be blunted or completely absent.
Low cortisol can contribute to increased pain, fatigue, and sensitivity that are hallmarks of fibromyalgia. Cortisol helps regulate inflammatory cytokines that are often elevated in fibromyalgia. The loss of cortisol’s anti-inflammatory effects may allow cytokines to increase pain sensitivity and feelings of exhaustion.
Thyroid Hormones
The thyroid gland secretes hormones like thyroxine (T4) and triiodothyronine (T3) that regulate metabolism. Many studies have found that thyroid problems like hypothyroidism are more common in people with fibromyalgia than the general population.
Low thyroid hormone levels slow down metabolism and can worsen symptoms of fatigue, muscular pain, mental fogginess, and depression that occur in fibromyalgia. Some research suggests that low T3 levels in particular correlate with increased tenderness and pain in fibromyalgia patients.
Growth Hormone
Growth hormone (GH) is produced by the pituitary gland and has important metabolic functions. It promotes tissue growth and repair, increases muscle mass, and impacts exercise capacity. Several studies have observed reduced GH levels in some fibromyalgia patients compared to healthy controls.
Deficiencies in GH are associated with decreased aerobic capacity, muscle strength, and overall function. Restoring normal GH levels may help improve exercise tolerance and reduce fatigue in some people with fibromyalgia.
Insulin
Insulin is made by the pancreas and regulates glucose metabolism. Insulin resistance or prediabetes is more prevalent among people with fibromyalgia compared to the general public.
Chronically high insulin levels promote inflammation and have been linked to increased pain sensitivity. Improving insulin sensitivity through diet, exercise, and medication may help relieve fibromyalgia symptoms.
Estrogen
Estrogen is responsible for development of female sex characteristics and impacts many tissues in the body. Dramatic drops in estrogen levels are thought to trigger fibromyalgia symptoms in some women after events like childbirth, miscarriage, or menopause.
Low estrogen can contribute to pain sensitivity, sleep disturbances, and cognitive dysfunction experienced in fibromyalgia. Hormone replacement therapy may help alleviate fibromyalgia symptoms for some women with low estrogen.
Testosterone
Testosterone is an androgen hormone that controls development of male traits and has roles in muscle growth, bone density, mood, cognition, and pain modulation. Men with fibromyalgia tend to have lower free testosterone levels compared to healthy men.
Declining testosterone is linked to increased pain, fatigue, depression, and loss of muscle mass in men with fibromyalgia. Testosterone therapy under medical supervision may provide some symptom relief for men with low testosterone and fibromyalgia.
Fibromyalgia and HPA Axis Dysfunction
Many of the hormone abnormalities seen in fibromyalgia are related to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis refers to the complex interactions between the hypothalamus, pituitary gland, and adrenal glands that modulate hormone release and the body’s stress response system.
The hypothalamus produces corticotropin releasing hormone (CRH) which triggers the pituitary gland to secrete adrenocorticotropic hormone (ACTH). ACTH then stimulates the adrenal glands to produce cortisol and other hormones.
Negative feedback loops regulate this cascade, with cortisol signaling back to decrease further CRH and ACTH release. This system helps maintain homeostasis through hormone regulation and adaptation to physical and emotional stressors.
In fibromyalgia, dysregulation at multiple points in the HPA axis leads to hormone imbalances:
- The hypothalamus may overproduce CRH, causing excessive stimulation of the pituitary and adrenal glands.
- The pituitary gland can become less sensitive to cortisol, failing to reduce ACTH output in response to circulating cortisol levels.
- The adrenal glands may respond sluggishly to ACTH, resulting in inadequate cortisol secretion.
Through these mechanisms, the HPA axis loses its ability to appropriately regulate the body’s stress response and key hormone levels. Restoring normal HPA axis function remains an important target for fibromyalgia treatment.
Assessing Hormone Levels
Abnormal hormone levels do not occur in every fibromyalgia patient. But for those with chronic severe symptoms, getting tested may identify underlying imbalances that could be addressed.
Some of the main lab tests used to assess hormone status in fibromyalgia include:
| Hormone | Test |
|---|---|
| Cortisol | 8 AM fasting cortisol, 24-hour urine free cortisol |
| Thyroid | TSH, Free T4, Free T3 |
| Growth Hormone | IGF-1 |
| Insulin | Fasting glucose, Hemoglobin A1c, fasting insulin |
| Estrogen | Estradiol |
| Testosterone | Total and free testosterone |
These labs should be ordered by a doctor who can interpret the results and recommend treatment if any hormone abnormalities are found.
Treatment of Hormonal Imbalances
Fixing the underlying hormone disturbances in fibromyalgia may require a combination of approaches such as:
Medications
If thyroid levels are low, thyroid hormone replacement pills may be prescribed. Cortisol or testosterone deficiencies can be treated with hydrocortisone or testosterone supplements under medical supervision.
Lifestyle Changes
Stress management through yoga, meditation, therapy, and other relaxation techniques may help rebalance the HPA axis. Regular exercise can improve insulin sensitivity. A healthy diet and sleep hygiene supports normal hormone cycles.
Alternative Therapies
Mind-body practices like acupuncture, massage, and hypnosis may aid hormonal regulation. Some patients have success using herbal supplements or homeopathy to correct hormone imbalances.
The Bottom Line
Fibromyalgia patients often have underlying issues with cortisol, thyroid hormones, growth hormone, insulin, estrogen, testosterone, and HPA axis function. Laboratory testing can identify deficiencies suitable for treatment with medications, lifestyle changes, or alternative therapies. While fixing hormonal abnormalities may not cure fibromyalgia, it can greatly improve symptoms and quality of life for many patients.
References
- Tanriverdi F, Karaca Z, Unluhizarci K, Kelestimur F. The hypothalamo-pituitary-adrenal axis in chronic fatigue syndrome and fibromyalgia syndrome. Stress. 2007;10(1):13-25. doi:10.1080/10253890601130823
- Cuatrecasas G, Gonzalez MJ, Alegre C, et al. High prevalence of growth hormone deficiency in severe fibromyalgia syndromes. J Clin Endocrinol Metab. 2010;95(9):4331-4337. doi:10.1210/jc.2010-0110
- Riedel W, Layka H, Neeck G. Secretory pattern of GH, TSH, thyroid hormones, ACTH, cortisol, FSH, and LH in patients with fibromyalgia syndrome following systemic injection of the relevant hypothalamic-releasing hormones. Z Rheumatol. 1998;57 Suppl 2:81-87.
- Loevinger BL, Muller D, Alonso C, Coe CL. Metabolic syndrome in women with chronic pain. Metabolism. 2007;56(1):87-93. doi:10.1016/j.metabol.2006.08.003
- Alpsoy S, Aktas G, Uzun H. Serum estradiol levels are related to symptoms of fibromyalgia syndrome in female patients. Rheumatology International. 2021;41(2):289-294. doi:10.1007/s00296-020-04704-5
- Jones KD, Burckhardt CS, Clark SR, Bennett RM, Potempa KM. A randomized controlled trial of muscle strengthening versus flexibility training in fibromyalgia. J Rheumatol. 2002;29(5):1041-1048.
- Zimmer P, Bloch W. Impact of Resistance Training on Endocrine Function in Fibromyalgia – an Overview. Sports medicine – open. 2021;7(1):60. Published 2021 Aug 28. doi:10.1186/s40798-021-00349-5