What No One Told You About Your Hormones in Your 40s
Hormones are your body’s internal messengers. They guide everything from energy and mood to metabolism, sleep, and appetite. When they’re working well, you may not think twice about them. But once you hit your 40s, hormonal shifts can begin to affect how you feel on a daily basis.
If you’ve been noticing more fatigue, stubborn weight gain, cravings, or poor sleep, it might be time to look at what your hormones are doing and how to support them.
What Do Hormones Actually Do?
Hormones are produced by glands in the endocrine system and travel through your bloodstream to organs and tissues. Their job is to send messages that help regulate your body’s key functions, including:
Blood sugar and metabolism
Sleep and wake cycles
Appetite and cravings
Mood and focus
Menstrual cycles and fertility
Stress response
And importantly, hormones don’t work in isolation. When one becomes imbalanced, others are often affected especially during times of stress or aging.
The HPOAT Axis: Your Hormone Communication System
At the center of hormone regulation is a communication network called the HPOAT axis, short for Hypothalamus-Pituitary-Ovarian-Adrenal-Thyroid axis. This system begins in the brain and sends signals to other hormone-producing glands in the body.
When things are working well, the HPOAT axis helps regulate:
Your stress response (via cortisol and adrenal function)
Your metabolism (via thyroid and insulin)
Your reproductive hormones (estrogen, progesterone, and more)
Stress, inflammation, poor sleep, and blood sugar swings can all interfere with this messaging system, especially after 40.
Cortisol: The Stress Hormone
Cortisol is often labeled the “stress hormone,” but it's more than that. It helps regulate energy, inflammation, blood sugar, and your sleep-wake rhythm.
Cortisol naturally peaks in the morning to help you wake up and should gradually decline by bedtime. But if you’re under chronic stress, that rhythm can get disrupted.
Signs of high cortisol:
Trouble falling or staying asleep
Anxiety, irritability, or feeling “wired”
Cravings for sugar, salt, or fat
Weight gain, especially around the middle
Signs of low cortisol (often from long-term stress):
Constant fatigue or burnout
Brain fog
Sugar or salt cravings
Poor recovery from workouts
Supporting cortisol levels often starts with stress reduction, blood sugar balance, and sleep hygiene.
Insulin: The Blood Sugar Hormone
Insulin helps move glucose (sugar) from your blood into your cells for energy. But after 40, especially in perimenopause, many people become more insulin-resistant. This means your body isn’t responding as effectively, so more insulin is required to keep blood sugar in check.
That can lead to:
Fat storage, especially in the abdomen
Energy crashes
Difficulty losing weight
Cravings for sweets or refined carbs
Insulin and cortisol are closely linked. When one is dysregulated, it is common for the other to experience dysregulation too.
Leptin & Ghrelin: Hunger and Fullness Signals
Ghrelin: Your Hunger Hormone
Ghrelin rises before meals to let you know it’s time to eat. But stress and sleep deprivation can cause ghrelin to rise too much, leading to increased hunger and overeating.
Leptin: Your Satiety Hormone
Leptin is produced by fat cells and tells your brain you’re full. But in cases of chronic inflammation or excess body fat, your brain may stop responding to leptin’s signal which is called leptin resistance.
Together, these hormones influence:
Hunger and fullness
Cravings
Weight regulation
They’re especially sensitive to stress, sleep, and nutrition patterns which often change in midlife.
Estrogen & Progesterone: The Reproductive Hormones
In your 40s, your body begins a gradual transition toward menopause. This phase—called perimenopause—involves major shifts in the reproductive hormones estrogen and progesterone. And those changes don’t just affect your cycle. They influence your brain, metabolism, sleep, gut, and stress response.
Even if your periods are still regular, the communication between your brain and ovaries may already be changing. This breakdown in signaling is one of the earliest signs of perimenopause.
How Low Progesterone Shows Up
Progesterone has a calming effect on the brain and nervous system. It supports restful sleep, reduces anxiety, and helps balance the stimulating effects of estrogen.
When progesterone starts to decline, you may notice:
Difficulty falling asleep or staying asleep
More irritability or anxious thoughts
Heavier or longer periods
Shorter menstrual cycles
Increased PMS symptoms
The Stress-Hormone Connection: The “Pregnenolone Steal”
One key reason hormone balance becomes more difficult in midlife is because of something called the pregnenolone steal.
Pregnenolone is the building block your body uses to make both cortisol (your stress hormone) and progesterone. When stress levels are high, whether from emotional strain, blood sugar swings, inflammation, or poor sleep, your body may shift production away from progesterone and toward cortisol.
This means progesterone starts to decline faster and earlier, even while estrogen continues to fluctuate.
What Low or Fluctuating Estrogen Can Do
Estrogen helps regulate metabolism, supports serotonin (a brain chemical that stabilizes mood), enhances insulin sensitivity, and keeps bones and skin healthy.
When estrogen levels start to fall—or swing up and down—you may experience:
Hot flashes and night sweats
Mood swings or increased anxiety/depression
Vaginal dryness or discomfort
Decreased libido
Increased insulin resistance
Reduced serotonin
Decreased melatonin
Estrogen also helps regulate body temperature, supports melatonin production (which affects sleep), and influences gut health through its impact on the microbiome.
While hormone replacement therapy (HRT) can be helpful, all people in perimenopause benefit from prioritizing the foundations of health: nutrition, movement, and stress management to reduce symptoms related to hormonal changes.
Thyroid Hormones: Your Metabolic Thermostat
Your thyroid helps regulate metabolism, energy, body temperature, and digestion. As estrogen and progesterone decline, thyroid function can also become sluggish, especially in women.
Signs of low thyroid:
Fatigue or depression
Cold hands and feet
Slower digestion or constipation
Weight gain
Dry skin and thinning hair
Stress and nutrients (like iodine, selenium, zinc, and iron) can impact thyroid function.
How to Support Hormones After 40
You don’t need a perfect or overly complicated routine. The magic happens when you build consistency with basic, strategic habits that support hormone signaling and body functions so you feel like yourself again. Let’s focus on evidenced-based habits that have the power to really move the needle when it comes to your health and how you feel!
1. Prioritize Sleep
Aim for 7–9 hours each night. Sleep directly impacts cortisol, insulin, ghrelin, and leptin. Poor sleep increases cravings, decreases energy, and makes it harder to recover from stress.
2. Eat Balanced Meals
Build meals with protein, fiber, and healthy fats. This stabilizes blood sugar, supports cortisol, and keeps you full longer—reducing insulin spikes and crashes. Check out our Protein + Fiber First cookbook for more easy recipe ideas!
3. Move Your Body
Walking, strength training, and light cardio support insulin sensitivity and improve cortisol regulation. You don’t need to overdo it, consistency matters more than intensity.
4. Manage Stress
Even 5–10 minutes of intentional stress relief can make a difference. Try breathwork, journaling, walking, or puzzles
5. Support Your Daily Rhythm
Get natural light in the morning, limit screen exposure at night, and maintain a regular sleep-wake schedule to help your body regulate cortisol and melatonin.
6. Focus on Key Nutrients
Magnesium, B vitamins, vitamin D, omega-3s, protein, and antioxidants all play vital roles in hormone production and balance.
Final Thoughts
Hormonal changes after 40 are normal, but they’re not something you have to “just live with.” The more you understand how your body is shifting, the better equipped you are to make choices that support your energy, mood, sleep, and metabolism.
If you’re ready to work with your body instead of against it, the next step is choosing small changes that support balance, starting with your meals, your mindset, and your rest.
Want more personalized support for midlife hormone health and weight loss? Check out our options for 1:1 Dietitian Nutrition Coaching here or go ahead and schedule a call with a dietitian today!
References:
Delamater L, Santoro N. Management of the Perimenopause (https://pubmed.ncbi.nlm.nih.gov/29952797/). Clin Obstet Gynecol. 2018;61(3):419-432.
North American Menopause Society. Menopause 101: A Primer for the Perimenopausal (https://www.menopause.org/for-women/menopauseflashes/menopause-symptoms-and-treatments/menopause-101-a-primer-for-the-perimenopausal).
The American College of Obstetricians and Gynecologists. The Menopause Years (https://www.acog.org/womens-health/faqs/the-menopause-years).
Thurston RC, Joffe H. Vasomotor symptoms and menopause: findings from the Study of Women's Health across the Nation. Obstet Gynecol Clin North Am. 2011 Sep;38(3):489-501. doi: 10.1016/j.ogc.2011.05.006. PMID: 21961716; PMCID: PMC3185243.
Santoro N. Perimenopause: From Research to Practice (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4834516/). J Womens Health (Larchmt). 2016;25(4):332-339.
