Hormones
The chemical messengers that coordinate metabolism, mood, and repair across the entire body.
Overview
What this system actually governs
Hormones are the body's slow signalling layer: molecules released in one tissue that change gene expression and enzyme activity in another. They set the context every other system operates in — how much energy is available, whether tissue is built or broken down, how sensitive you are to stress, and how well you sleep. Because they operate in feedback loops, a single hormone value in isolation is almost never interpretable.
Feedback loops, not dials
Thyroid, adrenal, and gonadal axes all run through hypothalamic–pituitary feedback. That means low output can reflect a gland problem, a signalling problem, a conversion problem, or an adaptive response to energy deficit, illness, or poor sleep. Thyroid is the clearest example: TSH, free T4, free T3, and reverse T3 tell four different stories, and iodine, selenium, iron, and cortisol all sit inside the conversion pathway. Testosterone and oestrogen behave similarly — sex hormone binding globulin, insulin, body composition, and sleep change the free fraction more than most people expect.
The levers that actually move hormones
Sleep timing and duration, energy availability, resistance training, body composition, and micronutrient sufficiency (iodine, selenium, zinc, magnesium, vitamin D) do most of the work. Endocrine-disrupting exposures, alcohol, and chronic under-recovery push the other way. Replacement therapy has a real place, but it works best after the upstream inputs are addressed, because otherwise a dose is compensating for a signal that could have been restored.
How to read this hub
Tier 1 entries explain each axis in plain terms and describe what a sensible panel looks like. Tier 2 entries cover receptor sensitivity, binding proteins, conversion enzymes, pulsatile secretion and why timing of blood draws matters, and the frontier debates around hormone optimisation in healthy adults.
- T2Iodine Decoded: How It Builds Thyroid Hormone, Where Else It Works, and Why the High-Dose Debate Still Matters24 min
- T2The Cortisol–Mitochondria Feedback Loop24 min
- T2The Menopause Protocol: A Full-Body Remodel, Not a Broken Switch15 min
- T2The Thyroid as Metabolic Thermostat: Reading the Panel Properly16 min
Foundational — Tier 1 primers
0 articlesPrimers for this hub are being prepared.
Deeper — Tier 2 investigations
6 articlesThe Menopause Protocol: A Full-Body Remodel, Not a Broken Switch
Menopause is a systemic remodel of energy, bone, brain, and vascular biology, not simply the end of ovulation — and the interventions that help most are timed, mechanistic, and unglamorous.
Iodine and the Thyroid Terrain
Iodine has one of the narrowest useful ranges of any nutrient. Too little and the thyroid cannot build hormone; too much and it shuts down.
Iodine Decoded: How It Builds Thyroid Hormone, Where Else It Works, and Why the High-Dose Debate Still Matters
Iodine is the only nutrient built physically into a hormone molecule. This guide maps requirement, deficiency disease, food sources, supplement forms, extrathyroidal roles, cofactors, and the high-dose debate — with the risks stated plainly.
Sun Exposure: Weighing Skin Cancer Risk Against Vitamin D and Beyond
The evidence supports avoiding sunburn, not avoiding sunlight — and the distinction has consequences for vitamin D status, nitric oxide, circadian timing, and all-cause mortality.
The Thyroid as Metabolic Thermostat: Reading the Panel Properly
Most thyroid complaints are evaluated with a single number. The tissue-level question — how much active hormone actually reaches the cell — requires more of the panel than TSH alone.
The Cortisol–Mitochondria Feedback Loop
How chronic glucocorticoid exposure alters mitochondrial morphology and respiratory capacity in the prefrontal cortex.
Frequently asked questions
- Why can I feel hypothyroid with normal TSH?
- TSH reflects pituitary signalling, not tissue-level thyroid activity. Adequate T4 with poor conversion to T3, high reverse T3 during illness or energy deficit, or low iron, selenium, or iodine can all produce symptoms with a normal TSH. A fuller panel plus symptom pattern is more informative.
- Do cortisol and "adrenal fatigue" explain chronic tiredness?
- Cortisol rhythm disruption is real and measurable; adrenal fatigue as a diagnosis is not a recognised entity. In practice a flattened cortisol curve usually accompanies disrupted sleep, energy deficit, or chronic stress load rather than a failing gland.
- Can lifestyle changes actually raise testosterone?
- Meaningfully, yes, when the starting point is poor: correcting sleep debt, reducing excess body fat, training with resistance, treating sleep apnoea, and restoring adequate energy and zinc intake all move it. Lifestyle will not replicate pharmacological levels, and it is not meant to.
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