Management of High Sex Hormone-Binding Globulin (SHBG) Levels

Introduction to SHBG and Testosterone

Obesity is a major confounder in testosterone levels and can increase SHBG, according to the American Diabetes Association 1

Weight loss through regular physical activity and dietary modifications is recommended as a first-line approach to normalize SHBG levels, as suggested by the American Diabetes Association 1
A balanced diet with adequate protein intake, moderate carbohydrate consumption, and healthy fats can help manage SHBG levels 1
A combination of resistance training and aerobic exercise, aiming for at least 150 minutes of moderate-intensity exercise per week, can help manage SHBG levels, while avoiding excessive endurance training which may increase SHBG 1

If natural approaches fail after 3-6 months, consider screening with morning serum testosterone level if symptoms of hypogonadism persist, as recommended by the American Diabetes Association 1
In individuals with total testosterone levels close to lower limits, determine free testosterone concentrations using reliable methods, according to the American Diabetes Association 1
Consider medical consultation for potential hormone optimization if symptoms persist despite lifestyle modifications, as suggested by the American Diabetes Association 1

Understanding the causes of low estrogen, progesterone, and testosterone levels is crucial, as it can lead to significant health consequences, including bone loss, sexual dysfunction, and reduced quality of life, as recommended by the British Journal of Sports Medicine 2
The Female Athlete Triad, characterized by low energy availability, menstrual dysfunction, and decreased bone mineral density, can lead to hormonal deficiencies in female athletes, according to the British Journal of Sports Medicine 2
Functional Hypothalamic Amenorrhea (FHA) results from energy deficiency, leading to suppressed gonadotropin pulsatility and hypogonadism, as reported by the British Journal of Sports Medicine 2
Premature Ovarian Insufficiency (POI) can occur, especially iatrogenic POI following chemotherapy or radiation therapy, with a strength of evidence rated as high, according to Blood Reviews 3
Aging is associated with a natural decline in hormone production, particularly testosterone in men, with a strength of evidence rated as high, as reported by the Annals of Internal Medicine 4

GnRH Analogs can suppress ovulation and corpus luteum formation, reducing progesterone and estrogen levels, and are used to treat cyclic attacks in porphyrias and other conditions, according to Hepatology 5
Combined Oral Contraceptives, particularly those containing ethinylestradiol, can suppress endogenous hormone production and increase SHBG, as reported by the British Journal of Sports Medicine and Blood Reviews 2, 3
Certain Progestins with Anti-Androgenic Effects can worsen hypoandrogenism in patients with iatrogenic POI, according to Blood Reviews 3
Hormone Replacement Therapy with 17β-estradiol (preferably transdermal) and cyclical or continuous progestin can be used for POI patients, according to Blood Reviews 3
Testosterone Therapy can be used for men with confirmed low testosterone levels (<300 ng/dL) and symptoms, as reported by the Annals of Internal Medicine 4

A comprehensive hormone panel, including SHBG levels, total and free testosterone, estradiol, FSH, and LH, as well as thyroid function tests, is essential for diagnosing hormonal deficiencies, according to the Endocrine Society 6
Thyroid function tests, including TSH and free T4, are first-line tests for thyroid dysfunction, as recommended by the Endocrine Society 7, 8
The following table summarizes the characteristics of various conditions:

Condition	Characteristics
Hypothyroidism	Fatigue, weight gain, cold intolerance, dry skin, constipation, menstrual irregularities
Hyperthyroidism	Weight loss, palpitations, heat intolerance, tremor
Cushing's syndrome	Central obesity, moon facies, buffalo hump, purple striae, hypertension, hyperglycemia
Adrenal insufficiency	Fatigue, weight loss, hypotension, hyperpigmentation

Monitor SHBG and free testosterone levels every 3-6 months, and track symptom improvement with targeted questioning, as recommended by the American Urological Association guidelines and the Endocrine Society 9, 10, 11
Use calculated free testosterone (cFT) rather than free androgen index (FAI) for monitoring, as FAI correlates poorly with actual free testosterone levels, with a strength of evidence rated as low, according to the Endocrine Society 11
Monitor hematocrit, especially if considering any testosterone-increasing therapy, due to the risk of polycythemia, which is higher with injectable testosterone (up to 44%) compared to transdermal forms (3-18%), as recommended by the American Urological Association guidelines 12

A step-wise approach to treatment is recommended, with first-line treatment addressing underlying causes and lifestyle modifications, second-line treatment using hCG or selective estrogen receptor modulators (SERMs) or aromatase inhibitors, and third-line treatment considering combination therapy (e.g., hCG + aromatase inhibitor), as recommended by the American Urological Association guidelines 10
Increasing Energy Availability is the primary treatment for female athlete triad and FHA, as recommended by the British Journal of Sports Medicine 2
Addressing modifiable cardiovascular risk factors, such as hypertension, dyslipidemia, and diabetes, is essential in individuals with elevated SHBG levels, as recommended by the American Urological Association 10
Weight management through regular physical activity and dietary modifications is recommended to normalize SHBG levels and increase free testosterone levels, as suggested by the American College of Physicians and the Obesity Society 11, 13