Testosterone, thyroid, and hormonal health, grounded in endocrinology research and clinical guidelines.
21 articles
Testosterone reference ranges vary by laboratory, assay method, and the population used to establish them. Here is why ranges differ and how to interpret your result in context.
Thyroid dysfunction affects SHBG, testosterone conversion, and androgen receptor sensitivity. Here is what the research shows about the thyroid-testosterone relationship in men.
Adult growth hormone deficiency is distinct from childhood GHD and produces reduced muscle mass, increased fat, and fatigue. Here is what the diagnostic criteria and treatment evidence show.
Testosterone pellets are implanted under the skin and release testosterone over 3-6 months. Here is what the evidence shows about their efficacy compared to injections and gels.
Low testosterone in men under 35 has different causes than age-related decline and often points to a treatable underlying condition. Here is what distinguishes it and how it is evaluated.
Low testosterone is associated with depression, reduced motivation, and cognitive fog. Here is what controlled trials show about the relationship between testosterone and psychological wellbeing in men.
Vitamin D deficiency is associated with lower testosterone in observational studies, and Leydig cells express vitamin D receptors. Here is what intervention trials show about whether supplementing raises testosterone.
Human chorionic gonadotropin (HCG) mimics LH and preserves testicular function during testosterone replacement therapy. Here is what the evidence shows about its use alongside TRT.
A standard hormone panel includes testosterone, SHBG, LH, FSH, estradiol, and prolactin. Here is what each value means, what affects it, and how to interpret the numbers together.
A University of Chicago study found that one week of sleep restriction reduced testosterone in young men by 10-15%. Here is what the research shows about sleep and hormone production.
Lifestyle changes including sleep, weight loss, resistance training, and vitamin D can raise testosterone. Here is what the evidence supports and by how much.
Men produce and need estrogen, and both too much and too little cause problems. Here is what normal estradiol levels look like in men, what affects them, and when levels require attention.
Injections and topical gels both deliver testosterone effectively but differ in pharmacokinetics, convenience, and cost. Here is what the evidence shows about each.
Chronic stress elevates cortisol, which suppresses testosterone through multiple pathways. Here is what the research shows about the cortisol-testosterone relationship and what affects it.
Testosterone replacement therapy suppresses sperm production in most men by reducing FSH. Here is what the data shows about the extent of suppression, reversibility, and alternatives.
Low testosterone affects energy, mood, body composition, and sexual function. These nine symptoms are frequently attributed to aging or stress when low T may be the underlying cause.
Clomiphene stimulates the brain to produce more LH and FSH, raising testosterone without suppressing fertility. Here is what the evidence shows about its effectiveness and limitations.
Testosterone replacement therapy carries documented side effects including erythrocytosis, testicular atrophy, and fertility suppression. Here is what the trial data shows about each.
Sex hormone-binding globulin binds most testosterone in the blood, making it unavailable to cells. High SHBG can produce low-testosterone symptoms even when total testosterone looks normal.
Normal testosterone ranges vary significantly by decade. Here is what the reference ranges mean, what affects them, and when low levels are worth discussing with a doctor.
Hypogonadism means the testes produce insufficient testosterone. Whether the problem originates in the testes or the brain determines treatment options. Here is how to tell them apart.