Hormones: the body’s messaging network (and how to keep it in sync)

Hormones are chemical messengers made by endocrine glands (and many other tissues) that travel through the bloodstream to coordinate what your cells do, when to use or store energy, how you respond to stress, when you feel hungry or sleepy, and how you grow, repair, and reproduce. Unlike a “single switch” model, hormones work as an integrated network with feedback loops. When one signal runs too high or too low, the body often compensates by adjusting others, sometimes helpfully, sometimes creating a ripple effect of symptoms. This is why “hormone health” is rarely about one number in isolation.

Hormones 101

Hormones regulate:

• Energy balance and metabolism (insulin, glucagon, thyroid hormones)
  
• Stress response and recovery (cortisol and related HPA-axis hormones)
  
• Appetite and satiety (leptin, ghrelin)
  
• Sleep–wake and circadian rhythms (melatonin, cortisol)
  
• Reproductive function (estrogen, progesterone, testosterone, LH/FSH)
  
• Fluid and blood pressure (aldosterone, ADH)

A useful way to think about them is as a set of overlapping “dials” rather than separate “light switches.”

Examples of hormones, when regulated well, and when dysregulated

Insulin helps move glucose from blood into cells and supports energy storage. When insulin signalling is working well, blood sugar stays stable and you feel steady energy between meals. When insulin resistance develops, the body compensates by producing more insulin; over time this can contribute to higher glucose, cravings, energy crashes, and increased cardiometabolic risk (Saltiel & Kahn, 2001).

Cortisol is essential: it mobilises energy and helps you respond to challenges. It naturally follows a daily rhythm, higher in the morning, lower at night. Chronic stress, under-recovery, and disrupted sleep can shift this rhythm and influence other hormones (thyroid signalling, appetite hormones, sex hormones), because the stress system communicates broadly with the rest of the endocrine network (Chrousos, 2009).

Leptin and ghrelin help regulate appetite: leptin signals “enough,” ghrelin signals hunger. Short sleep and circadian disruption can tilt these signals toward increased appetite and reduced satiety, one reason sleep is foundational for hormone regulation (Spiegel et al., 2004).

Testosterone (in both genders) supports muscle protein synthesis, mood, and libido. Sleep restriction has been shown to reduce daytime testosterone levels in healthy young men, another example of how lifestyle inputs affect endocrine output (Leproult & Van Cauter, 2011).

Hormones act in networks: the knock-on effect

Due to hormones being linked by feedback loops, one disturbance can cascade. For example, consistent sleep debt may increase perceived stress and alter cortisol rhythms; that can influence appetite signalling (leptin/ghrelin), cravings, and food choices, which then affect insulin dynamics. Over time, the “problem” may look like weight changes, fatigue, low mood, poor recovery, irregular cycles, or reduced libido, symptoms that don’t map neatly to a single hormone.

Preventative hormone support: 5 top tips that actually move the needle

From a preventative health perspective, the highest-leverage habits are the least glamorous:

1. Protect sleep (regular schedule, morning light exposure, dim evenings, avoid late caffeine/alcohol if it disrupts sleep).

2. Prioritise muscle and metabolic health (strength training 2–4×/week, daily movement, adequate protein and fibre).

3. Stabilise blood sugar (balanced meals, reduce ultra-processed “spike and crash” patterns).

4. Manage stress + recovery (breathing, downshifts after work, realistic training load, rest days).

5. Address basics: iron status, vitamin D, omega-3 intake, hydration, because “foundational physiology” affects endocrine function.

If something doesn’t feel right: smart next steps

If symptoms persist (new fatigue, unexplained weight change, hair loss, cycle changes, palpitations, persistent low mood, heat/cold intolerance), don’t self-diagnose with random supplements. Start with:

• A GP-led review of symptoms, medications, menstrual history, sleep, and stress.
  
• Baseline bloods often include a full blood count (FBC), iron studies/ferritin, B12/folate, vitamin D, kidney/liver function, lipids, and glucose markers.
  
• Targeted hormone tests based on symptoms, commonly a thyroid panel (TSH, free T4, free T3, antibodies if indicated), and where relevant, sex hormones and sometimes prolactin. Interpreting results in context matters: timing, recent illness, sleep, training load, and cycle phase can all shift values.
  

Hormones aren’t the enemy nor are they magic. They’re responsive signals. When you support the network (sleep, nutrition, movement, stress regulation), the system is more likely to regulate itself. And when it doesn’t, a focused clinical work-up beats guesswork.

References:

Chrousos, G. P. (2009). Stress and disorders of the stress system. Nature Reviews Endocrinology, 5(7), 374–381.

Leproult, R., & Van Cauter, E. (2011). Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA, 305(21), 2173–2174.

Saltiel, A. R., & Kahn, C. R. (2001). Insulin signalling and the regulation of glucose and lipid metabolism. Nature, 414(6865), 799–806.

Spiegel, K., Leproult, R., & Van Cauter, E. (2004). Impact of sleep debt on metabolic and endocrine function. The Lancet, 354(9188), 1435–1439.