If your clothes fit differently this year while your habits have stayed much the same, your body is responding to one of the larger hormonal transitions of adult life. That response has a clear physiology, and it deserves understanding more than blame.
During perimenopause, ovulation becomes less predictable, progesterone declines, and estrogen swings up and down before it gradually falls. As estrogen drops, the body tends to store more fat around the abdomen and less around the hips and thighs. Cells also respond less readily to insulin, and muscle becomes harder to maintain. Together, these shifts explain why so many people notice a change in body shape during their 40s and early 50s, most often around the waist.
Some change in body composition during this season is normal and expected. A body in transition is adapting. The aim of care here is support: helping your metabolism, heart, brain, bones, and joints move through the change well, since those systems shape how you feel and function for decades to come. The number on the scale is one small data point among many.
Why Does Body Composition Shift in Perimenopause?
The clearest picture comes from the Study of Women's Health Across the Nation (SWAN), which followed women for roughly 18 years, from well before their final period to a decade after. Researchers found that about two years before the final menstrual period, the rate of fat gain doubled and lean mass began to decline. Those changes continued until about two years after the final period, then leveled off.
Two parts of this finding matter for how you think about your own body. First, the shift has a window. Body composition changes most quickly across a few years of the transition, then settles into a new, steadier pattern. Second, the scale misses much of it. The SWAN researchers noted that total weight does not capture the gain in fat and loss of lean tissue happening underneath, which may be one reason BMI becomes a weaker predictor of health risk in older women.
So the more useful questions during this season are about composition and function: how well you're preserving muscle, where fat is being stored, and how your blood sugar, blood pressure, lipids, and bones are responding.
Several hormonal and physiological changes drive the shift at once:
Estrogen declines. Estradiol favors fat storage in the hips, thighs, and breasts. As it falls, storage moves toward the abdomen, including visceral fat around the organs.
Ovulation becomes irregular and progesterone falls. This often produces a period of relative estrogen excess early in perimenopause, before overall estrogen declines.
Insulin sensitivity drops. Estrogen helps cells respond to insulin, so its decline makes blood sugar harder to regulate.
Muscle becomes harder to maintain. Lean mass is metabolically active tissue, and losing it lowers the body's capacity to use glucose.
Sleep and stress physiology change. Night sweats, early waking, and a more reactive stress response raise cortisol and appetite signals, which compound everything above.
Estrogen, Progesterone, and the Role of Ovulation
Hormones always act in relationship to one another, and perimenopause is easiest to understand as a change in those relationships.
Estrogen is a family of hormones. Estradiol (E2) is the most potent and dominant form during the reproductive years, made mainly by the ovaries. It supports bone density, blood vessel flexibility, healthy cholesterol patterns, insulin sensitivity, and the brain's serotonin, dopamine, and norepinephrine systems. Estrone (E1) is weaker and is made largely in fat tissue; it becomes the predominant estrogen after menopause. Estriol (E3) is the weakest of the three, formed mostly as a metabolite of the other two and produced in large amounts by the placenta during pregnancy.
Progesterone is estrogen's counterbalance. It rises after ovulation, calms the nervous system, supports sleep, and keeps estrogen's growth-promoting effects on the uterine lining and breast tissue in check. Progesterone depends on ovulation: without an egg released, the body makes very little of it. For more on this, read The Quiet Power of Ovulation.
In early perimenopause, ovulation becomes irregular while estrogen can still run high or swing widely. The result is often a period of relative estrogen excess, even when estrogen itself isn't unusually high. This is why the early years of the transition can bring heavier or closer-together periods, breast tenderness, migraines, worsening allergies, sleep disruption, anxiety, irritability, and weight gain. Later, as estrogen declines as well, symptoms shift toward hot flashes, vaginal dryness, and the metabolic changes described above.
Several everyday factors can deepen the imbalance:
Chronic stress, which can disrupt ovulation and lower progesterone further
Alcohol, which slows the liver's clearance of estrogen and increases conversion of testosterone to estrogen
Xenoestrogens, estrogen-like compounds in some plastics, pesticides, and personal care products, which are fat-soluble and can be stored in adipose tissue
A sluggish gut, since the gut microbiome helps regulate how much estrogen is cleared or recirculated
Where hormone therapy fits
For many people, bioidentical hormone support is a thoughtful part of care. Oral micronized progesterone is chemically identical to the progesterone the body makes and often helps with sleep, mood, and cycle symptoms. It tends to behave differently in the body than synthetic progestins, which is one reason many clinicians prefer it when progesterone is the goal.
For symptomatic people under 60 or within 10 years of menopause, The Menopause Society's 2022 position statement concludes that the benefits of hormone therapy generally outweigh the risks for those without contraindications, and that therapy helps prevent bone loss. The right choice depends on your history, symptoms, and values, and is best made together with your care team.
Insulin, SHBG, and the Metabolic Thread
Of all the changes in perimenopause, the shift in insulin sensitivity ties the most symptoms together.
Estrogen helps muscle, liver, and fat cells respond to insulin. As estrogen falls, the same meal can produce a higher, longer blood sugar rise, and the pancreas releases more insulin to bring it down. Insulin is a storage hormone, so higher levels favor fat storage, especially around the abdomen. Visceral fat is also biologically active: it releases inflammatory signals that make cells even less responsive to insulin. A gentle loop forms, and it tends to build quietly over years.
This loop has another effect that often goes unrecognized. Higher insulin lowers sex hormone–binding globulin (SHBG), the protein that holds testosterone in reserve. With less SHBG, more testosterone circulates in its free, active form. Total testosterone actually declines slowly with age, but as estrogen falls and free testosterone rises, the balance between the two shifts toward androgens. That shift reinforces abdominal fat storage.
The same androgen shift can show up on the skin and scalp: adult acne along the jaw, thinning at the part or hairline, or new hair on the chin and upper lip. These changes share the same metabolic roots as midlife weight changes and deserve their own discussion.
Stress and sleep amplify all of this. Cortisol raises blood sugar, and even a few nights of short or broken sleep reduce insulin sensitivity and increase hunger signals. The carbohydrate cravings many people notice in perimenopause make sense in this light: a body that is under-slept, stressed, and less insulin-sensitive is asking for fast fuel.
Why Supporting Your Physiology Matters Now
The reason to pay attention to metabolic health in perimenopause has little to do with appearance. Estrogen has quietly supported many systems for decades, and the transition is a natural moment to give those systems more direct support.
Heart and blood vessels. Estrogen helps keep blood vessels flexible and supports a favorable cholesterol pattern. After menopause, LDL cholesterol and blood pressure tend to rise, and cardiovascular risk rises, narrowing the gap with men. Insulin resistance and visceral fat add to that risk, which makes this transition an ideal time to look closely at lipids, blood pressure, and blood sugar.
Brain and cognition. The brain is rich in estrogen receptors, and estrogen helps neurons use glucose for fuel. The brain fog, word-finding pauses, and mood shifts many people notice in perimenopause reflect this recalibration and usually ease with time. Over the longer arc, stable blood sugar, good sleep, and regular movement are some of the most protective things you can offer your brain.
Bones, muscles, and joints. Bone loss speeds up across the transition, and muscle becomes harder to build and keep. Joint pain, stiffness, and frozen shoulder are also common and often dismissed as ordinary aging. A 2024 review in Climacteric named this cluster the musculoskeletal syndrome of menopause, estimating that more than 70% of women experience musculoskeletal symptoms through the transition. Muscle matters metabolically as well as structurally: it is the body's largest site of glucose disposal, so preserving it supports blood sugar, bones, balance, and independence all at once.
Cells and tissues. At the cellular level, persistently high blood sugar and insulin promote inflammation, oxidative stress, and glycation, a process in which sugar binds to proteins and stiffens tissues such as blood vessels, skin, and connective tissue. Supporting insulin sensitivity helps keep that cellular environment calmer, which benefits nearly every organ system.
What Helps: Simple Supports With a Large Return
The most effective supports in this season are usually simple and sustainable. Restrictive dieting tends to backfire during perimenopause, since under-eating accelerates muscle loss and raises stress hormones. These approaches work with your physiology instead:
Protein at every meal, starting with breakfast. Protein preserves muscle, steadies blood sugar, and quiets cravings later in the day. Plant-forward and vegetarian eaters can get there with lentils, tofu, tempeh, edamame, Greek yogurt, eggs, and seeds.
Strength training. Two or three sessions a week of challenging resistance work is one of the most direct ways to protect muscle, bone, and insulin sensitivity. Heavier weights than you might expect are often appropriate, built up gradually.
A short walk after meals. Ten to fifteen minutes of easy movement after eating helps muscles take up glucose and blunts the blood sugar rise.
Fiber and plants. Vegetables, legumes, whole grains, and ground flax feed the gut bacteria that help clear estrogen. Soy foods and flax also offer phytoestrogens, gentle plant compounds that can ease some symptoms of the transition.
Protecting sleep. Sleep is metabolic medicine. A cool, dark room, a consistent wake time, and addressing night sweats directly all support blood sugar and appetite regulation.
Rethinking alcohol. Many people find they tolerate alcohol less well in perimenopause. Reducing it often improves sleep, hot flashes, and estrogen clearance.
Regulating the nervous system. Slow breathing, time outdoors, and practices that engage the vagus nerve shift the body out of a chronic stress state, which lowers cortisol and helps blood sugar settle.
Acupuncture. Acupuncture can support sleep, hot flashes, stress physiology, and musculoskeletal pain, making it a useful companion through the transition.
Supplements to Consider
Supplements work best layered onto the foundations above, chosen for your specific physiology. Some are broadly supportive; others make the most sense once testing confirms what's driving your symptoms.
Broadly supportive
Creatine monohydrate. Well studied for building and preserving muscle, and increasingly studied for bone and cognitive support in midlife women. It pairs especially well with strength training.
Magnesium glycinate. A gentle, well-absorbed form of magnesium that supports sleep, nervous system regulation, muscle relaxation, and insulin sensitivity.
Methylated B vitamins. B vitamins support energy production and methylation, one of the pathways the liver uses to clear estrogen. Some people, particularly those sensitive to methylfolate, feel wired or anxious on higher doses, so starting low is wise.
Psyllium husk. If you're not reaching your daily fiber goals through food, psyllium helps steady blood sugar, supports regularity, and aids estrogen clearance through the gut. Increase it gradually with plenty of water, and take it at least two hours apart from medications, since it can slow their absorption.
Targeted support
Myo-inositol. Supports insulin signaling and has been studied most closely in PCOS. It can be helpful when blood sugar regulation, cycle irregularity, or androgen symptoms are part of the picture.
DIM and calcium-D-glucarate. DIM supports healthier estrogen metabolism in the liver, and calcium-D-glucarate helps prevent estrogen from being reabsorbed in the gut. These are best used when testing confirms a pattern of estrogen excess or less favorable estrogen metabolism. Anyone with a history of hormone-sensitive cancer, or taking tamoxifen, should use them only with guidance from their oncology team.
Berberine. A plant compound with strong evidence for improving insulin sensitivity and blood sugar. It is most appropriate when insulin resistance has been confirmed with testing, such as fasting insulin, fasting glucose, and hemoglobin A1c. Berberine can cause low blood sugar when used without a clear need or combined with diabetes medications, and it interacts with a number of other medications, so it belongs in a supervised plan.
Supplement quality varies widely, and more is rarely better. A short, well-chosen list that fits your labs and symptoms usually does more than a long one.
None of this requires perfection. A few consistent habits, repeated over months, carry far more weight than an ambitious plan that lasts two weeks.
Labs Worth Pursuing
Standard screening often catches metabolic changes late, once blood sugar or cholesterol has already crossed a diagnostic threshold. A broader look can show where your body is heading while there is still plenty of room to respond. Useful markers to discuss with your care team include:
Fasting insulin and fasting glucose, which together can reveal insulin resistance years before blood sugar rises
Hemoglobin A1c, a picture of average blood sugar over about three months
A lipid panel, ideally with apolipoprotein B (ApoB) for a clearer view of cardiovascular risk
SHBG, total and free testosterone, and DHEA-S, to understand the androgen balance
Estradiol, progesterone, and FSH, interpreted in light of where you are in your cycle, since values swing widely in perimenopause
A thyroid panel with antibodies, since thyroid changes often surface in midlife and mimic perimenopause
Ferritin and vitamin D, which influence energy, mood, muscle, and bone
High-sensitivity CRP, a marker of systemic inflammation
Hormone levels in perimenopause change from week to week, so a single test is a snapshot. Your symptoms, cycle pattern, and history often tell as much of the story as the numbers.
Specialty Testing
When standard labs leave questions open, a few specialty tools can fill in the picture, especially for guiding targeted supplements and hormone decisions.
DUTCH test. A dried urine test collected at home over a day. Beyond hormone levels, it shows how your body is processing estrogen, including which metabolic pathways are favored and how well methylation is working, along with progesterone and androgen metabolites and your daily cortisol rhythm. This makes it especially useful before starting estrogen-metabolism supports like DIM and calcium-D-glucarate. Timing matters: if you're still cycling, the test is usually collected in the second half of the cycle, which can take some planning when cycles are irregular.
Mira hormone monitor and app. An at-home device that reads urine test wands for FSH, LH, E3G (an estrogen metabolite), and PdG (a progesterone metabolite), with results tracked in an app. Because perimenopausal hormones shift from week to week, following these patterns over time can reveal whether and when you're ovulating, how your estrogen-to-progesterone balance is changing, and how you're responding to hormone therapy. It tracks trends; only a clinician can confirm your menopause stage.
Continuous glucose monitor (CGM). A small sensor worn on the back of the arm that tracks blood sugar around the clock. A CGM shows how your body responds to specific meals, sleep, stress, and exercise, which often makes blood sugar patterns feel concrete and workable. It's available by prescription through conventional care, or without a prescription through Stelo by Dexcom, which is cleared for adults 18 and older who don't use insulin. Even a two-week trial can be illuminating, and the data are most useful reviewed alongside your fasting insulin and A1c.
An East Asian Medicine Perspective
Classical Chinese medicine offers a lovely name for the years after menopause: the second spring. The transition is understood as a redirection of vital resources. Energy once devoted to monthly cycles and reproduction turns inward, toward the self, longevity, and wisdom.
Through this lens, perimenopause reflects a gradual shift in the Kidney, the Organ Network associated with constitutional reserves, the reproductive cycle, bones, and the long arc of aging. As Kidney Yin, the cooling and nourishing aspect, becomes less abundant, heat can rise, showing up as hot flashes, night sweats, restlessness, and disrupted sleep.
The tendency to hold weight around the middle often relates to the Spleen and Stomach, which govern digestion and the transformation of food into usable energy. When the Spleen is strained by stress, irregular meals, or poor sleep, the body tends to accumulate what Chinese medicine calls Dampness, a heaviness that settles in the abdomen and can feel like sluggishness, bloating, or foggy thinking. The Liver, which keeps Qi moving smoothly, is often involved as well, especially when irritability, tension, and stress-related symptoms are prominent.
Acupuncture treatment is tailored to each person's pattern and might include points such as Spleen-6, Stomach-36, and Kidney-3 to nourish reserves, support digestion, and calm the nervous system. This perspective pairs naturally with the physiology above: both see the transition as a whole-body reorganization that responds well to steady, attentive support.
Perimenopause Care in Minneapolis
Perimenopause is a transition your body is built to move through, and it tends to go more smoothly with thoughtful support. In my practice, that support starts with understanding your whole picture: your symptoms, history, labs, digestion, sleep, stress load, and what matters most to you.
I offer in-person acupuncture and bodywork at my office in the Loring Park neighborhood of Minneapolis, and virtual naturopathic visits that include lab review and a personalized plan. You can work with me on one side of the practice or both, and I'm glad to collaborate with your other providers.
If your body is changing and you'd like a clearer understanding of why, and a steady, realistic way to support it, schedule a visit here.
Frequently Asked Questions
Is weight gain in perimenopause normal?
Yes. Some change in body composition is an expected part of the transition. Research from the SWAN study shows fat gain accelerates and lean mass declines starting about two years before the final period, then levels off about two years after. The focus of care is supporting muscle, blood sugar, heart health, and bones through that window.
Why does perimenopause cause belly fat?
As estrogen declines, the body shifts fat storage from the hips and thighs toward the abdomen. Lower insulin sensitivity, a relative rise in androgens, disrupted sleep, and higher cortisol all reinforce that pattern.
When does perimenopause weight gain usually start?
For many people it begins in the early to mid 40s, as cycles start to change. The fastest shifts in body composition tend to happen in the few years surrounding the final menstrual period.
Can perimenopause affect blood sugar?
Yes. Estrogen supports insulin sensitivity, so its decline can make blood sugar harder to regulate. Fasting insulin, fasting glucose, and hemoglobin A1c can show these changes early.
Can acupuncture help with perimenopause symptoms?
Acupuncture can support sleep, hot flashes, stress physiology, digestion, and joint and muscle pain. It works well alongside nutrition, movement, and, when appropriate, hormone therapy.
What supplements help with perimenopause weight gain?
Creatine, magnesium glycinate, methylated B vitamins, and fiber such as psyllium are broadly supportive. Myo-inositol and berberine can help with insulin resistance, and DIM with calcium-D-glucarate can support estrogen metabolism, however these targeted options work best when testing confirms the pattern, and berberine in particular should be used with guidance and in coordination with other blood regular regulation therapies because it can lower blood sugar too far.
Can I track perimenopause hormones at home?
Yes. The Mira monitor tracks urinary FSH, LH, estrogen, and progesterone metabolites over time, and the DUTCH test is a home urine collection that also shows estrogen metabolism and cortisol rhythm. For blood sugar, a continuous glucose monitor is available by prescription or over the counter through Stelo.
About the Author
Dr. Clair Hamilton, ND, LAc, is a naturopathic doctor and licensed acupuncturist with ten years clinical experience in integrative medicine. From offers comprehensive care both in-person, through her office in Minneapolis's Loring Park neighborhood, as well as virtually, and helps people navigate perimenopause, metabolic health, digestive concerns, chronic pain, and nervous system regulation, blending naturopathic medicine, East Asian medicine, functional medicine, and manual therapy. Learn more about Dr. Hamilton.
Sources
Briden L. Metabolism Repair for Women: A Compassionate, Science-Based Guide to Balancing Insulin, Losing Weight, and Improving Health. 2024. (Published in Australia as The Metabolism Reset.)
Centre for Menstrual Cycle and Ovulation Research (CeMCOR), University of British Columbia. Research and resources on ovulation, progesterone, and perimenopause.
Greendale GA, et al. Changes in body composition and weight during the menopause transition. JCI Insight. 2019.
Study of Women's Health Across the Nation. Changes in body composition and weight during the menopause transition (study summary).
The North American Menopause Society. The 2022 hormone therapy position statement. Menopause. 2022.
Wright VJ, et al. The musculoskeletal syndrome of menopause. Climacteric. 2024.
A note on language: capitalized terms such as Kidney, Spleen, and Liver refer to the Chinese medicine understanding of each Organ Network, which includes the organ, its channels, and its physiologic, mental, emotional, and spiritual expressions. Lowercase terms refer to the anatomical organ as understood in Western medicine.
This article is for educational purposes and does not replace individualized medical care.