Excess Matters

Tag: endocrinology

  • The Power of Hormones by Max Nieuwdorp: Summary, Key Ideas & Review

    Book in one sentence: A practicing endocrinologist walks you through every major hormone in the human body, from insulin to oxytocin, and shows why they cannot be understood in isolation from each other.

    What Is The Power of Hormones About?

    Picture the standard medical model of your hormones: a tidy diagram of glands, each one producing its own molecule, each one working in its lane. The thyroid does thyroid things. The pancreas does pancreas things. The adrenals do adrenal things. Clean, separate, manageable.

    Max Nieuwdorp, a professor of internal medicine at Amsterdam University Medical Center, has spent twenty years watching that model fail his patients. His book is a correction. The endocrine system is not a list of glands. It is a communication network, and nothing in it operates alone. Estrogen affects cortisol. Cortisol suppresses the hormones that govern ovulation. Gut bacteria determine how sensitive your cells are to insulin. Stress disrupts thyroid conversion. That chain of influence is not theoretical. It is the reason a hard year can derail your menstrual cycle, a course of antibiotics can trigger months of metabolic disruption, and a sleep deficit can make weight loss feel physiologically impossible.

    The book covers everything: insulin, cortisol, thyroid, growth hormone, testosterone, estrogen, oxytocin, leptin, ghrelin, GLP-1. It moves through the human lifespan from conception to old age, organized as narrative history as much as science (the discovery of insulin, the cortisol story, how the contraceptive pill changed society). Nieuwdorp is not a wellness influencer extrapolating from mouse studies. He is a working clinician who has also published research on fecal microbiota transplantation and insulin sensitivity, and the distinction shows on every page.

    Why Insulin and Cortisol Matter More Than You Think for Weight

    For readers on a weight or eating journey, two chapters stand out: the ones on obesity and hunger, and the one on stress.

    Insulin: blessing and curse

    Nieuwdorp describes insulin as “both a blessing and a curse.” That is not a throwaway line. Insulin is essential to life (without it, glucose cannot enter cells and you die). But in chronic dysregulation, the same molecule becomes a driver of fat storage, systemic inflammation, and metabolic disease. Insulin resistance is the pivot: when cells stop responding to insulin’s signal, the pancreas compensates by producing more, and chronically elevated insulin promotes fat storage while blocking fat breakdown. The body cannot easily access its own stored energy.

    What makes the insulin chapter useful for this audience is that Nieuwdorp connects it to eating behavior, not just blood sugar numbers. The gut’s own satiety hormones (GLP-1, CCK) are released in response to food and normally help the body regulate intake. When insulin signaling is chronically disrupted, that whole feedback loop becomes less reliable. Hunger signals stop reflecting actual caloric need. The relationship between what you eat and how satisfied you feel gets decoupled.

    Cortisol and the cascade it triggers

    The stress chapter does something most popular health books skip: it shows the precise mechanism by which chronic stress becomes a weight and eating problem, not just a mood problem.

    Chronically elevated cortisol suppresses GnRH, which lowers FSH and LH, which shuts down ovarian production of estrogen and progesterone. It also impairs the conversion of inactive T4 to active T3 in peripheral tissues, compounding any subclinical thyroid dysfunction. It promotes leptin resistance, making the brain less able to detect that you have enough stored energy. It disrupts sleep architecture, reducing the deep sleep during which growth hormone is released and tissues repair.

    Nieuwdorp’s clinical example is not exotic: a high-achieving woman with twelve-hour workdays, five gym sessions per week, four to five hours of sleep, absent menstruation, and labs that read as normal. The treatment is not a hormone prescription. It is more food, less exercise intensity, and more sleep. The hormones are not malfunctioning; they are responding correctly to the load the system is under. Stress reduction, adequate calories, and sleep restoration are hormone therapies, whether or not anyone frames them that way.

    How Does Your Body Defend Its Weight Against You?

    The obesity chapter is where Nieuwdorp’s book earns its place on the shelf for anyone who has ever felt like their body was working against them during weight loss. Because it is, and he explains exactly how.

    Ghrelin is the primary hunger hormone, produced by the empty stomach. It drives hunger, stimulates dopamine release (creating food-seeking behavior), and enforces the hypothalamic weight set-point. In people with obesity, ghrelin stays elevated even when there is plenty of stored body fat, while the hypothalamus has become resistant to leptin (the satiety signal from fat tissue). The result: persistent hunger that does not reflect actual caloric need.

    When caloric restriction is sustained, the body mounts a three-part defense:

    1. Ghrelin rises (driving more hunger)
    2. Resting metabolic rate drops (burning fewer calories at rest)
    3. Spontaneous physical activity decreases (conserving energy without conscious awareness)

    That is not a failure of willpower. It is an adaptive physiological response executing a defense strategy. The set-point the hypothalamus is defending is not a number you chose. And it is not one you can override through discipline alone.

    “Ghrelin concentrations paradoxically decrease after gastric bypass surgery, despite the stomach being empty more of the time.”

    That one sentence reframes bariatric surgery entirely. Bariatric surgery works (and produces durable results) not primarily by restricting food intake, but by resetting the hormonal thermostat. GLP-1 receptor agonist medications work the same way: they mimic the gut’s own satiety hormones and shift what the hypothalamus is defending. Neither is “cheating.” Both are working at the level where the problem actually lives.

    What Makes This Book Different from Other Hormone Books

    A lot of hormone books on the market are written by functional medicine practitioners, coaches, or journalists. They tend to focus on a subset of hormones (usually estrogen, progesterone, and thyroid) and emphasize protocols: what to eat, what to supplement, what to test.

    Nieuwdorp is none of those things. He is a practicing endocrinologist with a research background, and this is a medically rigorous hormone book written for a general audience in a way that very few are. A few things set it apart:

    Historical narrative. Each hormone chapter is partly a history of how that hormone was discovered (the story of insulin’s discovery in 1921, the cortisol experiments, the early testosterone research). It grounds each concept in the actual scientific process and makes the mechanisms memorable.

    The full spectrum of hormones. Most hormone books skip oxytocin, growth hormone, ADH, parathyroid hormone, and the gut peptides. Nieuwdorp covers them all, which matters because the interactions are the whole point. You cannot understand why stress disrupts your period without understanding the hypothalamic-pituitary-adrenal axis and its relationship to GnRH. You cannot understand why your gut matters for metabolic health without understanding GLP-1 and its relationship to insulin sensitivity.

    Calibrated caution about self-treatment. Nieuwdorp writes: “It’s clear that you can’t replace or even simulate the body’s own functions by administering hormones. Playing around with hormone preparations yourself can also be dangerous, especially without medical supervision.” For a book that could easily have pitched the opposite message, this is worth noting. The endocrine system’s complexity is precisely why hormone intervention requires clinical oversight.

    What it does not offer is a protocol. Nieuwdorp is more interested in mechanism than prescription. Readers who want the “what to do” alongside the science will need companion books. The related books table below has suggestions.

    Is The Power of Hormones Worth Reading?

    Read this if you have been told your labs are normal while feeling anything but, you want the actual mechanistic explanation for why weight loss gets physiologically harder over time, you are using a GLP-1 medication and want to understand why it works, or you are someone who thinks in systems and wants the full picture before making any decision about your hormonal health.

    Skip it if you want a step-by-step protocol, a supplement list, or a dietary framework. Nieuwdorp is a scientist, not a health coach, and the book reflects that completely.

    One caveat: The density is real. Some chapters (the history sections especially) move slowly, and readers who want a quicker route to the weight-relevant material can focus on chapters 5 (obesity and hunger) and 6 (gut and metabolism) without losing much. The payoff for reading straight through is the cumulative sense of how deeply interconnected every hormone system is, and it requires patience to get there.

    Books Like The Power of Hormones

    BookAuthorBest For
    It’s Your HormonesGeoffrey RedmondReaders who want clinical depth on female sex hormones specifically
    The Hormone MythRobyn Stein DeLucaReaders skeptical of hormone-blame narratives; a useful counterweight
    Thinking, Fast and SlowDaniel KahnemanFor readers who like dense, evidence-heavy science books on how systems shape behavior
    The XX BrainLisa MosconiBrain imaging data on what estrogen loss does to cognition; extends Nieuwdorp’s perimenopause chapters
    Hormone IntelligenceAviva RommThe protocol-forward complement: where Nieuwdorp explains the mechanism, Romm prescribes the intervention

  • It’s Your Hormones by Geoffrey Redmond: Summary, Key Ideas & Review

    Book in one sentence: A practicing endocrinologist explains the medical mechanics behind women’s hormonal symptoms and names the specific treatments most doctors won’t offer.

    What Is It’s Your Hormones About?

    One of Geoffrey Redmond’s patients described her experience this way: “I cry every time I wash my hair because so much falls out.” Another said, “I don’t feel like I’m living in my body anymore.” A third had been told by her doctor: “I’ve got patients with cancer. Why are you worrying about your hair?”

    Redmond is an endocrinologist who spent more than twenty-five years running the Hormone Center of New York, a clinic dedicated exclusively to women’s hormonal conditions. He estimates he has seen nearly ten thousand patients. Most of them came after being dismissed elsewhere, often repeatedly. It’s Your Hormones is his attempt to translate what he learned in that clinic into something a woman can take into a doctor’s appointment and actually use.

    The book is 480 pages and not a gentle read. It reads like a medical reference because that is what it is. Redmond covers PCOS, PMS, acne, hair loss, facial hair, low libido, perimenopause, menopause, and hormone therapy, each with clinical detail that most popular hormone books skip entirely. The organizing concept is “hormonal vulnerability”: the idea that some women’s bodies react more strongly to ordinary hormonal fluctuations than average, producing real symptoms even when lab values look normal. That framing is the reason the book still matters, nearly two decades after publication.

    Why “Your Labs Are Normal” Is Often the Wrong Answer

    The printed normal range on a lab report is a statistical construct. It reflects the middle 95 percent of a tested population. It says nothing about how sensitive your particular brain, skin, or hair follicles are to the hormones in your blood.

    Redmond makes this point early and returns to it throughout the book. A woman with debilitating PMS mood symptoms may have estrogen and progesterone that land squarely in the normal range. She may also be told there is nothing to treat. What’s actually happening is that her brain chemistry responds more strongly to those fluctuations than most women’s does. The level is not the problem. Her sensitivity to the level is.

    This reframe shifts the target of treatment. Instead of waiting for a lab value to go out of range, the clinical question becomes: what reduces the impact of hormonal fluctuations on vulnerable tissues? That question opens the door to treatments that work even when the numbers look fine.

    The lab interpretation issue gets worse when testosterone is involved. Most women tested for testosterone only receive total testosterone, which is frequently “normal.” But the biologically active fraction is free testosterone, the portion not bound to sex hormone-binding globulin (SHBG). SHBG is lowered by insulin resistance, obesity, and hypothyroidism. A woman with adult acne, scalp thinning, easy weight gain, and borderline-irregular cycles may have normal total testosterone and meaningfully elevated free testosterone. Requesting free testosterone and SHBG alongside total testosterone is something Redmond recommends for any workup involving skin or hair symptoms.

    How PCOS Drives Weight Resistance

    Redmond’s chapter on polycystic ovary syndrome leads with a frank admission: the name is wrong. The ovarian cysts are the least important feature. He prefers to think of PCOS as a cluster of five partially independent features that appear in different combinations in different women.

    Those five features are:

    • Androgen effects: acne, facial hair, scalp hair loss
    • Menstrual irregularity: though notably, some women with PCOS have regular cycles, which causes missed diagnoses
    • Metabolic tendency: weight gain that centralizes around the abdomen and resists typical dieting efforts
    • Insulin resistance: metabolically the heaviest feature, carrying long-term risk for type 2 diabetes and cardiovascular disease
    • Depression: both biochemically driven and situational

    The weight piece is what matters most for people navigating food and body struggles. Insulin resistance suppresses SHBG, which raises free testosterone, which drives androgen symptoms. Everything feeds everything. A woman who is struggling to lose weight despite genuine effort, carrying extra weight in her midsection, dealing with adult acne, and feeling low may be dealing with PCOS even if her cycles are roughly regular. Redmond’s position is that the diagnostic label matters less than identifying which features are present. Women who meet two or three criteria without qualifying for the full diagnosis still carry the underlying hormonal and metabolic reality.

    The medical interventions Redmond covers for PCOS are the ones integrative and functional medicine books routinely skip: metformin for insulin resistance, spironolactone for androgen suppression, and oral contraceptives chosen specifically for low androgenicity. These are not alternatives to lifestyle change. They work alongside it. For women with significant insulin resistance, metformin can meaningfully shift the metabolic picture in a way that diet modification alone often cannot.

    Acne, Hair Loss, and Facial Hair Are One Problem

    If you are dealing with two or three of the following, adult acne (especially jawline or chin), scalp hair thinning, and unwanted facial or body hair, Redmond argues you are dealing with one problem, not three.

    All three share the same root mechanism. Testosterone is converted in the skin to its more potent form, DHT, by an enzyme called 5-alpha reductase. In women with androgen-sensitive tissue, DHT does several things at once: it stimulates oil glands (producing acne), stimulates facial follicles (producing unwanted hair), and simultaneously miniaturizes scalp follicles (producing hair loss). The same hormonal signal drives all of it.

    “By treating each of these separately, a clinician may help one while inadvertently worsening another. What is needed is a unified approach that addresses the androgen cause of all three.”

    The clinical implication is straightforward. A dermatologist who prescribes topical retinoids for acne, laser for chin hair, and minoxidil for hair loss is treating manifestations, not cause. Anti-androgen treatment addresses the common mechanism and often improves all three simultaneously.

    Spironolactone gets its own chapter. Redmond is direct about what it does: it blocks androgen receptors at the skin and hair follicle level, preventing testosterone and DHT from stimulating their targets. Typical starting doses are 50 to 100mg daily. Meaningful improvement in acne takes three to six months. Hair loss stabilization takes six to twelve months. It must not be taken during pregnancy. Many dermatologists don’t think to offer it. Redmond’s suggestion is to ask for it by name.

    Is It’s Your Hormones Worth Reading?

    Read this if you have adult acne, scalp hair loss, or facial hair that has not responded to dermatological treatments, you suspect PCOS and want a clinical explanation of what is actually happening metabolically, or you have been told repeatedly that your labs are normal while still feeling genuinely unwell. The PCOS chapter and the androgen chapters are the strongest sections, and the framing around free versus total testosterone alone is worth the price of the book for anyone who has been through inconclusive hormone testing.

    Skip it if you want a lifestyle or integrative medicine approach. Redmond is a conventional endocrinologist and writes from that frame entirely. There is no functional medicine content, no elimination diet protocol, no adaptogens. He acknowledges botanicals where he sees evidence for them, but this is a clinical book.

    One caveat: The book was published in 2006 and some treatment-specific guidance is dated. Certain delivery methods he describes as state-of-the-art have since been superseded. Treat it as a framework reference, not a current prescribing guide. The clinical reasoning is sound; some of the specifics need updating with a current provider.

    Books Like It’s Your Hormones

    BookAuthorBest For
    Hormone IntelligenceAviva Romm, MDIntegrative approach to the same conditions; functional medicine perspective
    The Hormone ShiftTasneem Bhatia, MDPerimenopause and menopause from an integrative MD
    Healthy HormonesCassandra BarnsGentler lifestyle-first entry point for hormone basics
    Women Food and HormonesSara Gottfried, MDPCOS, insulin resistance, hormonal weight patterns; overlapping territory with a functional medicine lens
    The Science of MenopauseKristi KayeCurrent, evidence-based menopause reference; updates some of Redmond’s older HT guidance