Tired, Foggy, or Gaining Weight? Let’s Talk About Your Thyroid in Perimenopause

If you’ve been feeling unusually tired, struggling to shift weight no matter what you do, or finding it hard to concentrate lately, your thyroid could be calling out for some love.

Many women notice thyroid changes as they move through perimenopause, but often it’s brushed off as “just hormones” or “getting older.” The truth is, your thyroid is affected by hormonal shifts — and understanding that connection can make a huge difference in how you feel.

Let’s unpack why your thyroid might start to struggle during perimenopause and what you can do to support it naturally through food and lifestyle.

What Your Thyroid Actually Does

Your thyroid is a small, butterfly-shaped gland that sits at the base of your neck. Despite its size, it plays a big role in your wellbeing. It controls how your body uses energy — your metabolism — and influences everything from body temperature and mood to digestion, hair health, and weight.

When your thyroid is working well, you feel energised, focused, and balanced. But when it starts to slow down (a condition known as hypothyroidism), things can feel a bit sluggish — both physically and mentally.

Why the Thyroid Can Struggle During Perimenopause

Perimenopause is a time of big hormonal shifts — especially in oestrogen and

progesterone — and these changes can have a knock-on effect on thyroid function. Here’s how:

1. Oestrogen affects thyroid hormone availability

Oestrogen increases the amount of a protein called thyroid-binding globulin (TBG),

which binds to thyroid hormones and makes them less available for your cells to use.

This means you might have “normal” thyroid hormone levels on paper but still feel

low in energy.

2. Progesterone supports thyroid function

During perimenopause, progesterone naturally declines. Lower progesterone can

lead to increased inflammation and stress on the thyroid.

3. Adrenal stress

When you’re constantly on the go or under pressure, your adrenal glands pump out

more cortisol. High cortisol can suppress thyroid function — another reason stress

management becomes so important in midlife.

4. Nutrient depletion

Years of stress, dieting, caffeine, and a busy lifestyle can deplete key nutrients your

thyroid relies on, like selenium, zinc, and iodine.

5. Autoimmune factors

Women are more likely than men to develop autoimmune thyroid conditions, such as

Hashimoto’s thyroiditis, particularly during hormonal transitions like

perimenopause.

Common Signs Your Thyroid Might Be Under Pressure

If your thyroid is struggling, you might notice:

● Feeling tired or sluggish (even after a good night’s sleep)

● Unexplained weight gain or difficulty losing weight

● Cold hands and feet

● Brain fog or trouble concentrating

● Thinning hair or dry skin

● Constipation or slower digestion

● Low mood or anxiety

● Irregular or heavy periods

If several of these sound familiar, it’s worth speaking with your GP or a qualified health

practitioner about thyroid testing.

Nutrition to Support a Healthy Thyroid

Your thyroid needs the right nutrients to make and activate thyroid hormones. Here are some foods and nutrients that really help:

Iodine

Essential for making thyroid hormones. You’ll find it in sea vegetables (like nori and kelp), fish, eggs, and dairy. A little goes a long way — too much iodine can actually stress the thyroid, so don’t overdo supplements unless advised.

Selenium

Helps convert inactive thyroid hormone (T4) into its active form (T3). Great sources include Brazil nuts (just 2–3 a day is enough), tuna, sardines, and eggs.

Zinc

Supports hormone production and immune health. Found in pumpkin seeds, seafood, beef,and lentils.

Iron

Low iron can interfere with thyroid hormone production. Include lean red meat, lentils,

spinach, and pumpkin seeds.

Protein

Your thyroid hormones travel through your blood attached to proteins, so regular protein intake helps keep them stable. Include eggs, poultry, fish, tofu, beans, and lentils in each meal.

Support your liver and gut

Your liver converts thyroid hormones into their active form, and your gut helps eliminate what your body no longer needs. Eat plenty of fibre (fruit, veg, whole grains, legumes) and cruciferous vegetables like broccoli and kale — cooked if you’re worried about goitrogens (compounds that can interfere with iodine uptake in very large amounts).

Lifestyle Tips for a Happy Thyroid

Nutrition is just one part of the picture. Your thyroid also loves:

● Restful sleep: Aim for 7–8 hours; your thyroid repairs itself while you sleep.

● Stress reduction: Gentle movement, meditation, or time in nature can lower cortisol

and take pressure off your thyroid.

● Balanced exercise: Over-exercising can suppress thyroid function. Mix strength

training, walking, and yoga rather than intense cardio every day.

● Limit toxins: Reduce exposure to chemicals in plastics and household products.

Use glass containers and natural cleaning products where possible.

● Stay hydrated: Your body needs water to transport hormones and nutrients

effectively.

The Bottom Line

Perimenopause can be a tricky time for your thyroid — but understanding the connection means you can take action early. If you’ve been feeling unlike yourself lately, don’t just push through it. Listen to your body, check in with your GP or a nutrition professional, and start supporting your thyroid through nourishing food, gentle movement, and proper rest.

Your thyroid thrives on balance — and so do you.