Factors influencing hormone production

There are many factors that influence hormone levels:

1. Time of day (cortisol - diurnal variation)

2. Time of month (LH/FSH/estradiol in menstrual cycle)

3. Time of year (melatonin levels higher in winter)

4. Age (T3 lower in elderly subjects, sex steroid levels lower in pre pubertal children)

5. Sex (testosterone/estradiol levels in men and women)

6. Stress (cortisol, adrenaline increase during stress )

7. Diet (insulin , growth hormone, cortisol change in fasting/feeding states)

8. Illness (thyroid function tests in non thyroidal illness)

9. Drugs (amiodarone/contraceptive pill effect TFT results)