As an endocrinologist, I often see patients who are frustrated, confused, and discouraged. They come in saying the same thing: “I’ve been gaining weight, and I don’t know why. I’m constantly tired, even when I sleep well. Could it be my hormones?” The short answer is yes, hormonal imbalances are a common, and often overlooked, reason behind persistent weight gain and chronic fatigue.
Hormones regulate virtually every function in the body, including metabolism, energy production, appetite, and sleep. When even one hormone falls out of balance, it can disrupt your entire system. One of the most common conditions I check for is hypothyroidism. When the thyroid gland underproduces thyroid hormones, the body slows down. Metabolism decreases, weight increases, and energy levels plummet. Many patients with hypothyroidism also experience constipation, cold intolerance, dry skin, and brain fog—but not always. In some cases, the only symptoms are weight gain and fatigue.
Cortisol is another hormone that plays a powerful role. It’s produced by the adrenal glands in response to stress. In small, balanced amounts, cortisol helps regulate blood sugar, inflammation, and energy. But chronic stress can keep cortisol elevated, or eventually suppress its production altogether. Either scenario leads to significant disruption in energy regulation. Patients with cortisol imbalances often report difficulty losing weight, especially around the midsection, poor sleep, and feeling “tired but wired.”
Insulin, the hormone responsible for controlling blood sugar, is frequently at the root of unexplained weight gain. If your body becomes resistant to insulin, it starts to store more glucose as fat rather than using it for energy. This leads to fatigue after meals, constant hunger or cravings, and a gradual increase in abdominal fat. Many people don’t realize they’re in a state of insulin resistance until it evolves into prediabetes or type 2 diabetes. By then, the fatigue and weight changes are usually quite pronounced.
Sex hormones also play a significant role in energy and body composition. In women, changes in estrogen and progesterone levels, especially during perimenopause or due to conditions like polycystic ovary syndrome (PCOS), can lead to irregular periods, mood changes, and stubborn weight gain. Progesterone has a calming effect on the brain, so when it’s low, women often feel more anxious and exhausted. Estrogen dominance, where estrogen levels outweigh progesterone, is also linked to fatigue, bloating, and increased fat storage.
In men, a drop in testosterone can cause a decrease in muscle mass, increased fat accumulation (particularly around the belly), low motivation, and ongoing fatigue. Unfortunately, many men attribute these symptoms to aging and never get evaluated, despite the fact that testosterone deficiency is treatable.
Other hormone-related conditions can also contribute. For instance, vitamin D deficiency, which we often test for due to its impact on the endocrine system, can cause muscle weakness, mood shifts, and low energy. Poor sleep quality, often influenced by melatonin and cortisol imbalances, only compounds the problem.
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The important message I share with patients is this: if you’re gaining weight without explanation and feeling fatigued despite getting adequate rest, it’s not just in your head—and it’s not necessarily a lifestyle issue. It could very well be hormonal. Through a combination of lab testing, symptom evaluation, and a detailed medical history, we can identify the root cause and develop a personalized treatment plan.
Weight gain and fatigue aren’t always about eating less and moving more. When hormones are out of balance, your body is essentially fighting itself. Getting the right diagnosis is the first step toward restoring balance, regaining energy, and feeling like yourself again. If you’ve been struggling with these symptoms, don’t ignore them. Your body is trying to tell you something—and we’re here to help listen.
About the author: Dr. Sharwari Sudhir Dabhade, Consultant Internal Medicine, Diabetology & Endocrinology, MBBS, MD Internal Medicine, Fellowship Diabetes and Clinical Endocrinology (New Delhi), PGDip Clinical Endocrinology (Cardiff, UK).
Disclaimer: The views and opinions expressed in this article are those of the author only and do not necessarily represent the official policy or position of Healthcare Radius.