Hypothyroidism, Oestrogen and Weight Gain

The thyroid gland, or simply the thyroid, is an endocrine gland in the neck.

An underactive thyroid gland (hypothyroidism) is where your thyroid gland doesn't produce enough hormones. According to the American Association of Clinical Endocrinologists, about one in eight women will develop a thyroid problem in her lifetime.

The thyroid is a small, butterfly-shaped gland in the neck that influences metabolism and the function of the kidneys, heart, liver, brain and skin. It is important to make sure your thyroid is functioning normally and many women with thyroid conditions and/or medication such as thyroxine do use Serenity Cream as it is often associated with oestrogen dominance.

Understanding Thyroid Function

The thyroid gland produces two key hormones: thyroxine (T4) and triiodothyronine (T3). These hormones regulate your metabolic rate — the speed at which your body converts food into energy. Every cell in your body has receptors for thyroid hormones, which is why an underactive thyroid can affect virtually every system in the body, from your digestion and heart rate to your body temperature and mental clarity.

The thyroid is controlled by the pituitary gland, which releases thyroid-stimulating hormone (TSH) to signal the thyroid to produce more T4 and T3. In conventional medicine, a high TSH level is considered the primary marker of hypothyroidism — it means the pituitary is working harder to stimulate a sluggish thyroid. However, as many women discover during menopause, it is possible to have "normal" TSH levels and still experience all the symptoms of an underactive thyroid. This is where the connection with oestrogen becomes critically important.

How Oestrogen Blocks Thyroid Function

Unopposed oestrogen (oestrogen dominance) can interfere with thyroid hormone activity and is often an underlying cause of thyroid dysfunction.

Because oestrogen and thyroid hormone have opposing actions, probably at the thyroid hormone receptor level, unopposed oestrogen will prevent the thyroid hormone from "completing its mission", resulting in "hypothyroid symptoms" despite normal serum levels of thyroid hormone.

This mechanism works in several ways. Excess oestrogen increases the production of thyroid-binding globulin (TBG), a protein in the blood that binds to thyroid hormones and makes them inactive. More TBG means more of your thyroid hormones are "locked up" and unavailable to your cells, even though a standard blood test may show normal total thyroid hormone levels.

Additionally, oestrogen appears to compete with thyroid hormone at the receptor level. Just as a key cannot turn a lock if another key is already jammed in it, thyroid hormones cannot activate their receptors if oestrogen is blocking access. The result is functional hypothyroidism — the thyroid gland itself may be working adequately, but the hormones it produces cannot do their job.

Dr John Lee wrote extensively about this connection, noting that many women diagnosed with hypothyroidism actually had underlying oestrogen dominance. By restoring progesterone levels to counterbalance the excess oestrogen, thyroid function often improved — sometimes dramatically.

Hypothyroidism and Weight Gain

Thyroid problems can result in a number of symptoms, not the least of which is otherwise unexplained weight gain. Some of the extra weight gained in hypothyroid individuals is due to excess accumulation of salt and water, while some is extra fat due to a slowed metabolism.

When your thyroid is underactive — whether from primary thyroid dysfunction or from oestrogen blocking thyroid hormone activity — your basal metabolic rate drops. This means your body burns fewer calories at rest, making it easier to gain weight and harder to lose it, even with careful attention to diet and exercise. Many women find this particularly frustrating because they feel they are doing everything right but the scales will not budge.

The weight gain associated with thyroid dysfunction tends to be gradual and diffuse, though it often accumulates around the middle. It is frequently accompanied by water retention, which can add several pounds of "false weight" that fluctuates from day to day. For women going through menopause, this thyroid-related weight gain compounds the hormonal weight changes that are already occurring — creating a double challenge. For more on this topic, see our article on menopause and weight gain.

Why Menopause and Thyroid Symptoms Overlap

How can you tell whether your weight gain may be caused by hypothyroidism? Here are some other commonly observed hypothyroidism symptoms:


If this list looks familiar, that is because many of these symptoms are also classic signs of menopause. Fatigue, weight gain, mood swings, brain fog, hair thinning, dry skin, sleep problems — all are common to both menopause and hypothyroidism. This significant overlap is one reason why thyroid dysfunction is frequently missed in perimenopausal and menopausal women. Symptoms are attributed to "just menopause" when the thyroid may be contributing to or even causing many of them.

The connection runs deeper than coincidence. As progesterone declines during perimenopause, oestrogen becomes increasingly dominant. This oestrogen dominance then interferes with thyroid hormone function, creating a cascade: declining progesterone → oestrogen dominance → impaired thyroid function → worsening symptoms. It is a vicious cycle that can leave women feeling profoundly unwell while their standard blood tests appear normal.

The Role of Progesterone in Supporting Thyroid Health

Conversely, progesterone - like that found in Serenity Cream and 20-1 Cream - redirects the activity of oestrogen by increasing the sensitivity of oestrogen receptors. This inhibits many of oestrogen's undesirable side effects, including interference with thyroid hormone activity and subsequent weight gain.

Natural progesterone supports thyroid function in several important ways:


Many women report that after beginning transdermal progesterone cream, their thyroid-related symptoms — including fatigue, weight gain, brain fog and cold intolerance — improve noticeably. Some women on thyroid medication find that their required dose can be reduced (under their doctor's supervision) once hormonal balance is restored.

Testing and Diagnosis: What to Ask Your Doctor

If you suspect your thyroid may be involved in your menopause symptoms, it is worth asking your doctor for a comprehensive thyroid panel rather than relying on a TSH test alone. A thorough assessment should include:


It is also worth noting that "normal" TSH ranges on standard blood tests are broad, and many functional medicine practitioners consider the upper end of the conventional range to be too high. A TSH above 2.5 mIU/L, while technically "normal," may indicate early thyroid dysfunction in some women.

Because oestrogen dominance can cause hypothyroid symptoms even when thyroid hormone levels appear normal, it can also be helpful to have your hormone levels assessed — including progesterone and oestrogen. A healthcare professional experienced in bioidentical hormones can help you understand how these levels interact and whether hormonal supplementation might benefit your thyroid health.

Practical Steps for Supporting Thyroid Health During Menopause

In addition to addressing hormonal balance, there are several lifestyle factors that can support thyroid function:

Wellsprings Products for Hormonal and Thyroid Support

Wellsprings offers several products that can help address the interconnected issues of oestrogen dominance, thyroid dysfunction and menopause symptoms:


To find the right product for your needs, visit our cream comparison page or read our customer reviews. We always recommend discussing any thyroid concerns with your healthcare professional, particularly if you are currently taking thyroid medication. Adjustments to thyroid medication should only be made under medical supervision.

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