Hormone & Metabolism Tests Explained

Estrogen levels do far more than govern fertility — this key hormone shapes everything from your bones and heart to your skin, mood, and sleep. Unlike most blood markers, estrogen has no single “normal” number: in women it rises and falls dramatically across the menstrual cycle, then drops at menopause. This guide explains what’s typical…

Insulin resistance is one of the most important — and most overlooked — signals in metabolic health, often building silently for years before it ever shows up on a standard blood test. It happens when your cells stop responding properly to insulin, the hormone that moves sugar out of your blood and into your cells….

Understanding your testosterone levels by age helps you tell the difference between a normal part of getting older and a real problem worth checking. Testosterone is the main male sex hormone — it drives sex drive, muscle and bone strength, energy, and mood — and it naturally peaks in early adulthood before drifting down over…

Cortisol levels have become one of the most talked-about numbers in health — usually blamed for stress, stubborn belly fat, and poor sleep. But what does cortisol actually do, what are healthy cortisol levels, and how do you know if yours are too high or too low? Let’s separate the science from the hype and…

Quick answer HbA1c (called A1C in the US) shows your average blood sugar over about the past 3 months. US guidance (ADA 2026) calls below 5.7% normal, 5.7–6.4% prediabetes and 6.5% or more the diabetes range. UK guidance (NICE) works in mmol/mol: 42–47 mmol/mol means a high risk of type 2 diabetes, and 48 mmol/mol…

Quick answer TSH (thyroid-stimulating hormone) is your pituitary gland’s signal to your thyroid. Most adult labs treat roughly 0.4–4.5 mIU/L as normal. Many UK labs use about 0.27–4.2. A high TSH usually means the thyroid is underactive. A low TSH usually means it is overactive. The range printed on your own report is the one…