How your Thyroid Affects PMS, Perimenopause, and Menopause – the Hormonal Connection

The overlooked role of the thyroid in female hormones

If you’ve been feeling off, exhausted despite a full night’s sleep, struggling with weight gain that won’t budge, or dealing with worsening PMS symptoms, it might not just be your hormones to blame. Your thyroid, the small but mighty gland in your neck, plays a huge role in regulating metabolism, energy, and hormone balance.

Think of your thyroid as the engine that keeps your body running smoothly. When it’s underactive or out of sync, it can throw everything from your menstrual cycle to your mood and metabolism into chaos. Despite its importance, thyroid function is often overlooked when it comes to women’s health, particularly during PMS, perimenopause, and menopause. Research confirms that thyroid dysfunction is more common in women and frequently misdiagnosed due to overlapping symptoms with hormonal changes.

The thyroid’s role in PMS & hormonal symptoms

If you experience intense mood swings, bloating, or brain fog before your period, your thyroid might be amplifying your PMS symptoms. Women with hypothyroidism, an underactive thyroid, are more likely to experience oestrogen dominance, a condition where oestrogen levels outweigh progesterone. This imbalance can lead to heavier periods, extreme fatigue, and worsened PMS symptoms.

Low thyroid function has also been linked to increased inflammation, which can contribute to painful cramps, breast tenderness, and even migraines around your cycle. One study found that women with thyroid imbalances reported more severe premenstrual symptoms, including cravings, irritability, and difficulty concentrating. When the thyroid is sluggish, the liver also struggles to metabolise hormones efficiently, leaving oestrogen levels unchecked and exacerbating symptoms.

The thyroid & perimenopause: why symptoms may be more severe

Perimenopause, the years leading up to menopause, is marked by fluctuating hormone levels that can make thyroid dysfunction even more apparent. As oestrogen and progesterone levels shift unpredictably, the thyroid often struggles to keep up.

For women with hypothyroidism, this can mean worsening fatigue, brain fog, and stubborn weight gain. Research suggests that as progesterone levels decline, thyroid hormone production can slow down, leading to sluggish digestion, mood swings, and difficulty managing stress. On the other hand, hyperthyroidism, an overactive thyroid, can cause intense anxiety, racing heartbeats, and even unintentional weight loss, making perimenopause feel even more overwhelming.

There’s also a strong connection between blood sugar imbalances and thyroid function during perimenopause. When thyroid hormone levels drop, insulin resistance can increase, leading to intense cravings, energy crashes, and difficulty maintaining a stable weight. Research suggests that women with low thyroid function are at greater risk of developing insulin resistance, which can further complicate hormonal balance.

Thyroid & menopause: how it impacts weight, energy & metabolism

As menopause arrives and oestrogen levels drop, the thyroid often slows down as well, leading to a sluggish metabolism and increased fat storage. Many symptoms commonly attributed to menopause, such as low energy, dry skin, brittle nails, and mood swings, are also hallmark signs of thyroid dysfunction.

One of the biggest concerns for women in menopause is unexplained weight gain, particularly around the abdomen. Thyroid hormones, particularly T3, regulate fat metabolism, and when levels drop, the body stores more fat instead of burning it for energy. One study found that postmenopausal women with lower thyroid function had significantly higher body fat percentages compared to those with optimal thyroid levels.

Because thyroid dysfunction mimics many menopausal symptoms, it’s important to get proper testing to differentiate between normal hormonal shifts and underlying thyroid issues.

Thyroid, weight gain & fat storage: what’s really going on?

If you’re gaining weight despite eating well and exercising, your thyroid could be the missing piece of the puzzle. Low thyroid function slows metabolism and causes the body to store fat more easily, particularly around the midsection.

Thyroid hormones also influence insulin sensitivity, which affects how your body processes carbohydrates. If your thyroid is underactive, your cells struggle to absorb glucose efficiently, leading to higher blood sugar levels, increased cravings, and fat accumulation. One study found that women with hypothyroidism had higher rates of insulin resistance, making weight loss even more difficult.

Another overlooked factor is muscle loss. Since muscle helps keep metabolism high, losing muscle mass due to low thyroid function means fewer calories burned at rest, making it even harder to shed excess weight. Women with Hashimoto’s thyroiditis, an autoimmune thyroid disorder, often experience significant metabolic slowdowns, further complicating weight management.

Strategies to support thyroid health during PMS, perimenopause & menopause

Nutrition for thyroid function

The right foods can make a huge difference in supporting thyroid health. Protein and healthy fats are essential for hormone balance, while key minerals like iodine, selenium, and zinc support thyroid hormone production. Magnesium and B vitamins play a role in stress regulation and thyroid function, and fibre-rich foods help the liver metabolise excess hormones efficiently.

Lifestyle habits that protect thyroid function

Managing stress is crucial, as chronic stress raises cortisol, which directly suppresses thyroid function. Prioritising quality sleep is just as important, as sleep deprivation throws off hormone balance and metabolism. Regular movement, particularly strength training, can help preserve muscle mass and support metabolic health.

Supplements that support thyroid health

When it comes to supplementation, selenium and ashwagandha are two of the most powerful thyroid-supporting nutrients. Vitamin D is also essential, as deficiencies have been linked to impaired thyroid function. Addressing these areas holistically can significantly improve symptoms and restore balance.

When to get your thyroid tested & what to look for

Many women go undiagnosed with thyroid imbalances because symptoms often overlap with PMS, perimenopause, and menopause. Comprehensive thyroid testing can help uncover underlying issues.

It’s important to request TSH, Free T3, Free T4, Reverse T3, and Thyroid Antibodies. Many doctors only test TSH, but optimal thyroid function goes beyond a “normal” TSH range.