How Do I Know If My Symptoms Are From Perimenopause or Thyroid Dysfunction?
Navigating symptoms like fatigue, weight changes, brain fog, and mood swings can be confusing for many women in midlife because these symptoms commonly overlap between perimenopause and thyroid dysfunction. Understanding the differences and the connection between these two conditions is key to finding the right treatment and support.
What Is Perimenopause?
Perimenopause is the transitional phase before menopause when hormone levels, especially estrogen and progesterone, fluctuate unpredictably. This phase can start as early as the mid-30s, but more commonly begins in the 40s and lasts up to 10 years. Of note, many women in their late 30’s/early 40’s with peri-menopausal symptoms report that they are often being dismissed by their healthcare providers. Symptoms include irregular periods, hot flashes, night sweats, sleep disturbances, mood changes, decreased libido, weight gain (often around the abdomen), and bone density changes. Perimenopause is diagnosed primarily based on menstrual cycle changes and symptom patterns. As a provider, it’s helpful to know, “Is this a symptom of recent onset or have you always had this?”.
What Is Thyroid Dysfunction?
The thyroid gland regulates metabolism, energy, and growth hormones. Thyroid dysfunction can manifest as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid). Symptoms vary but often include fatigue, weight changes, mood swings, brain fog, temperature sensitivity, hair thinning, irregular periods, and muscle weakness. Thyroid conditions are common in women over 40 and may co-occur or be confused with menopausal symptoms.
Why the Confusion?
Both perimenopause and thyroid disorders share many symptoms such as fatigue, mood changes, weight gain, sleep problems, and irregular periods, making self-diagnosis challenging. Additionally, fluctuating estrogen levels in perimenopause can suppress thyroid function, complicating symptoms and test results.
How to Tell the Difference
Symptom Patterns and Timing: Perimenopause symptoms often revolve around menstrual irregularities and vasomotor symptoms (hot flashes, night sweats) while thyroid issues may present more consistently with sensitivity to cold, dry skin, and constipation (hypothyroidism) or sweating and anxiety (hyperthyroidism).
Lab Testing: Thyroid dysfunction requires comprehensive blood tests including TSH, Free T4, Free T3, reverse T3, and thyroid antibodies to check for autoimmune thyroiditis. It’s important to have this testing annually. Perimenopause diagnosis relies on clinical symptoms and menstrual history, as no definitive blood test exists for perimenopause, though hormone panels can help understand estrogen and progesterone levels.
Functional Testing: Advanced functional lab testing can assess adrenal function, estrogen metabolism, and thyroid hormone conversion, and gut health imbalances, uncovering underlying imbalances that contribute to symptoms. Often, routine lab tests can be reviewed through a functional medicine lens to identify lab results that were considered to be in a normal range by standard lab ranges, but are suboptimal from a functional medicine framework.
Professional Evaluation: Consulting healthcare providers skilled in both hormone therapies and thyroid management is vital. They can interpret overlapping symptoms and labs to create an individualized treatment plan.
What if It's Both?
It’s common for perimenopause and thyroid dysfunction to coexist. I often joke with patients that they’re allowed to have more than one issue. Bioidentical hormone therapy or herbal medicine can relieve peri-menopausal symptoms, while thyroid hormone replacement or nutrition/lifestyle interventions address thyroid health.
When to Get Tested
If you are a woman aged 40 to 60 experiencing symptoms like fatigue, mood swings, weight fluctuations, brain fog, and menstrual irregularities, it’s important to request comprehensive thyroid testing along with a thorough hormone evaluation. Early diagnosis leads to better symptom control and quality of life. Sadly, many people suffer from these symptoms for months and years before seeking help. Often, they regret waiting so long.
Conclusion
Differentiating between perimenopause and thyroid dysfunction can be challenging due to significant symptom overlap, but timely lab testing, symptom tracking, and professional evaluation can clarify the cause. Proper diagnosis enables targeted treatments—whether bioidentical hormone therapy, thyroid management, or both—empowering women to reclaim their health during midlife transitions.