Exploring Hormonal Changes: Does Thyroid Production Decrease During Perimenopause?

Did you know that perimenopause can affect your thyroid function? 🙋♀️

One of the key factors at play is progesterone. During perimenopause, progesterone production takes a nosedive—sometimes dropping to near-zero levels—several years before menopause. But here’s the twist: the decline in progesterone levels can disrupt your thyroid’s function! 🧠⚡️

Progesterone deficiency can impact the thyroid’s ability to do its job properly. When progesterone is low, it can throw off the production and effectiveness of thyroid hormones. The key takeaway? Your thyroid and hormones work together like a synchronized dance—they depend on each other for smooth performance. If you’re in perimenopause, it’s essential to keep an eye on this dynamic relationship. 🌗✨

Research indicates that under active thyroid (hypothyroidism) becomes more common with age—especially among women. That’s not a coincidence.

Why does this happen?

One reason is progesterone deficiency. It’s completely normal for women to experience a major drop in progesterone levels—often to near-zero—at least 6–8 years before entering menopause. This hormonal shift can disrupt thyroid function, because progesterone supports thyroid hormone secretion.

Since the thyroid controls bone metabolism and repair, this hormonal interplay has significant implications for long-term health.

How to address this?

Start by testing your sex hormones and thyroid hormones. But don’t stop there—also listen to how you feel. If you’re experiencing persistent cold hands, fatigue, or difficulty losing weight, your body might not be effectively using thyroid hormones at the cellular level.

Support can include targeted supplementation and lifestyle changes. Hormone production naturally declines with age, and replenishing what your body needs can lead to a healthier, more vibrant life.

Hormone Supplement Cheat Sheet: Progesterone

Progesterone is one of the most important hormones in the body. You might consider supplementing if you're dealing with:

• Hormonal imbalances

• PMS symptoms

• Menstrual irregularities

• Perimenopause or menopause

• Fertility support

• Mood swings or anxiety

• Breast cancer or endometrial hyperplasia

• PCOS

• Hypothyroidism

• Fibrocystic breasts

• And more

Forms: Capsules, cream, or oil
Consideration: Be careful not to confuse progesterone with progestin—they are not the same.
Safety: Natural progesterone has no known toxic side effects. One potential effect is changes in cycle timing.

Why it's important to address low progesterone:

• Can cause mood swings, anxiety, and depression

• Can lead to irregular cycles

• Increases risk of osteoporosis

• Supports thyroid hormone secretion

• Essential for hormone balance during menopause

• Affects metabolism and weight management

• Calms the nervous system and improves sleep

• Protects brain function

• Counteracts estrogen, reducing risk of certain cancers

• Can help prevent migraines

• Supports cardiovascular health

• Prevents endometrial hyperplasia

Fast Facts: Progesterone

• Affects uterus, vagina, cervix, breasts, testes, and brain

• Produced from cholesterol, with pregnenolone as a precursor

• Requires healthy thyroid, vitamin A, and cholesterol to be synthesized

• Declines with age

• Protective to cells and brain

• Regulates breast tissue growth

• Cell growth is lower in the luteal phase than in the follicular phase

On Taking Progesterone

Will supplementing stop your body’s own production?
No. There's no evidence that natural progesterone supplementation shuts down your own production. In fact, progesterone may stimulate its own synthesis.

When should women take progesterone?

• If cycling: Typically taken two weeks on, two weeks off

• If in menopause: Often taken daily for protective benefits

How it’s made

Bioidentical progesterone is usually derived from a plant-based oil called diosgenin, found in soy or yams. It’s chemically modified to match the progesterone your body makes. There's no soy or yam left after this process—just bioidentical hormone.

⚠️ Look out for added ingredients.
Some formulations include titanium dioxide or peanut oil.
Titanium dioxide has been associated with metabolic concerns.
Raena does not use peanut oil in our hormone solutions. Peanut oil, which is high in omega-6, has been linked in studies to fatty liver and dyslipidemia (Nature, 2018), and it's a common allergen.