Hormones Across the Lifespan: Integrating Thyroid, Adrenal and Sex Hormone Findings

Patients often arrive with the phrase “hormone imbalance”, sometimes self diagnosed, sometimes given by a practitioner. It is rarely a helpful description. Hormones are not separate dials to be balanced individually; the thyroid, adrenal and reproductive systems influence one another, and all are shaped by life stage, energy availability, illness, stress and medicines. Integrating hormonal findings means understanding these interactions, so that results can be interpreted correctly and specific, treatable problems identified.

Key interactions

Life stages

Puberty and adolescence

Irregular cycles are normal for several years after menarche, which is why PCOS is diagnosed cautiously in adolescents. Energy deficiency from restrictive eating or intense sport can delay puberty or cause amenorrhoea.

Reproductive years

Thyroid function, PCOS, prolactin and energy availability are common considerations in menstrual irregularity. Hormonal contraception alters many test results.

Pregnancy and postpartum

Thyroid hormone requirements rise in pregnancy. Postpartum thyroiditis affects a notable proportion of women within a year of delivery, often causing a phase of hyperthyroidism followed by hypothyroidism, and can be mistaken for postnatal depression or exhaustion.

Perimenopause and menopause

Fluctuating oestrogen and falling progesterone coincide with the peak age of thyroid disease in women, and symptoms overlap considerably.

Men across life

Testosterone declines gradually with age, but more with obesity, diabetes, illness, opioids and sleep apnoea.

Older age

TSH rises with age in healthy people; multiple medicines and illnesses increasingly affect hormone results.

Relative energy deficiency

Relative energy deficiency in sport, described in an International Olympic Committee consensus, occurs when energy intake is insufficient for the demands of training and normal physiology. It affects athletes of all sexes and many non athletes who restrict food and exercise heavily. Consequences include menstrual disturbance or low testosterone, low T3, reduced bone density and stress fractures, impaired immunity, mood changes and reduced performance. It is often missed because individual results appear to show separate problems rather than a single cause.

Functional hypothalamic amenorrhoea

A closely related condition, functional hypothalamic amenorrhoea, results from suppression of the reproductive axis by stress, weight loss, low energy intake or excessive exercise. It causes low oestrogen and absent periods, with bone health consequences. It is diagnosed after excluding other causes and treated primarily by restoring energy availability and addressing stress, rather than by hormone treatment alone.

Reading hormonal findings together

1. Start with the history: life stage, cycles, pregnancies, weight change, eating, exercise, stress, sleep, illness and medicines, including hormonal contraception and steroids.
2. Choose tests to answer specific questions, timed correctly.
3. Consider binding proteins when interpreting total hormone levels.
4. Look for a unifying explanation: low energy availability, illness, obesity, a medicine or pregnancy may explain several abnormal results.
5. Recognise adaptive changes, such as low T3 with calorie restriction, rather than treating them as primary disease.
6. Refer when findings suggest pituitary, adrenal or other endocrine disease.

Beyond “hormone imbalance”

Replacing the vague label with specific diagnoses improves care. Possible diagnoses behind symptoms described as hormone imbalance include hypothyroidism or hyperthyroidism, postpartum thyroiditis, PCOS, functional hypothalamic amenorrhoea, relative energy deficiency, perimenopause, hyperprolactinaemia, male hypogonadism, glucocorticoid related effects, and conditions unrelated to hormones, such as iron deficiency, depression and sleep disorders.

An illustrative case

A 26 year old runner training for a marathon has had no periods for 8 months, feels cold and tired, has had a stress fracture and has been told her thyroid is “slow” because her free T3 is low. She has lost 6 kg while training and eats little carbohydrate.

Integrated review shows a normal TSH and free T4 with a low T3, low oestradiol, low LH and FSH, normal prolactin and normal thyroid antibodies. Pregnancy is excluded. The unifying explanation is relative energy deficiency with functional hypothalamic amenorrhoea, not thyroid disease. Thyroid hormone is not indicated. Her plan, coordinated with her doctor and a sports dietitian, increases energy and carbohydrate intake, reduces training volume temporarily, addresses bone health with calcium, vitamin D and a bone density scan, and screens sensitively for disordered eating. Over 6 months her weight recovers, her periods return and her T3 normalises.

A connected system

Hormonal systems are interconnected and shaped by life stage and energy balance. Reading findings together, looking for unifying explanations and replacing vague labels with specific diagnoses allows practitioners to treat causes rather than chase individual numbers.