Thyroid vs. Adrenal Fatigue: How to Tell the Difference (& Why It Matters for Your Weight)

Feeling exhausted but your doctor says your thyroid is 'normal'? You might be dealing with adrenal fatigue instead—or both at the same time.

If you're a woman over 35 struggling with stubborn weight gain and crushing fatigue, you've probably wondered about your thyroid. But what if I told you that your symptoms might actually be pointing to your adrenals instead? Or worse yet, both systems could be struggling simultaneously.

Understanding the difference between thyroid dysfunction and adrenal fatigue is crucial for getting the right treatment and finally addressing that weight that just won't budge. Let me break down the key differences so you can advocate for proper testing and get the answers you deserve.

The Thyroid Story: When Your Metabolic Engine Slows Down

Your thyroid is like your body's metabolic thermostat. When it's not functioning optimally, everything slows down—including your ability to lose weight. Here's what thyroid dysfunction typically looks like:

Energy Patterns That Never Quit Unlike the ups and downs of adrenal issues, thyroid-related fatigue is consistent and relentless. You wake up tired, stay tired all day, and rest doesn't help. It's an all-encompassing exhaustion that makes even simple tasks feel overwhelming. Some of my clients describe this as like never getting out of 1st gear…ALL.THE.TIME.

The Temperature Connection Are you always reaching for a sweater while everyone else is comfortable? Thyroid dysfunction often manifests as feeling cold all the time, especially in your hands and feet. Many women notice their body temperature runs consistently low.

Weight Gain That Defies Logic This is the big one that brings most women to my practice. Despite eating less and exercising more, the scale keeps creeping up. Thyroid dysfunction makes weight loss incredibly difficult because your metabolism has essentially downshifted into a lower gear.

The Physical Signs You Can't Ignore Look for thinning hair (especially the outer third of your eyebrows) or hair that beraks easily, dry skin that no amount of moisturizer seems to help, and brittle nails. Chronic constipation and persistent bloating are also common red flags.

Mental and Emotional Symptoms Brain fog, memory issues, and feelings of anxiety or depression can all stem from thyroid dysfunction. Many women describe feeling like they're "thinking through molasses."

Menstrual Changes Heavier periods, irregular cycles, or cycles that seem to drag on forever can all indicate thyroid issues.

The Adrenal Story: When Stress Hijacks Your Hormones

Your adrenals are your stress-response system, and in our always-on world, they're often working overtime. When they become fatigued, the symptoms look quite different from thyroid issues:

The "Tired But Wired" Phenomenon This is the hallmark of adrenal fatigue. You're exhausted but your mind races when you try to sleep. You might get a second wind late at night, making it hard to wind down. The infamous 3pm energy crash is another telltale sign.

Temperature Regulation Issues Instead of feeling cold, you might experience night sweats or feeling overheated. Your body's temperature regulation system becomes erratic.

While renovating our house last year, this was the adrenal flag I had experienced. I’ve never had hot flushes through perimenopause, but when my stress levels went crazy for periods of the renovation, this was my bodys way of letting me know I needed some help.

Stress-Driven Weight Gain Adrenal-related weight gain typically settles around your midsection as visceral fat. You might also notice intense cravings for salty or sweet foods, especially during stressful periods. Have you noticed this craving for sweet or salty when your really stressed?

Stress-Related Physical Changes Hair loss can be common for many women during particularly stressful periods. Skin issues like adult acne or unexplained rashes, and digestive upset that worsens during stress are all common signs.

Mental and Emotional Rollercoaster Worsening Anxiety, feeling overwhelmed by normal daily tasks, mood swings, and irritability are classic adrenal fatigue symptoms. These are all classic signs of our fight or flight response.

Menstrual Disruption Shorter cycles, severe PMS symptoms, or missed periods can all result from chronic stress and adrenal dysfunction.

The Complicated Truth: When Both Systems Are Struggling

Here's where things get really tricky—you can absolutely have both thyroid dysfunction and adrenal fatigue simultaneously. In fact, chronic stress can actually suppress thyroid function, creating a domino effect that impacts both systems.

Common symptoms that overlap include fatigue, weight gain, mood changes, and sleep disruption. This is why so many women feel confused and frustrated when trying to pinpoint what's wrong.

The reality is that these systems don't operate in isolation. Your hormones are all interconnected, and when one system struggles, it often affects the others. This is particularly true during perimenopause when declining estrogen adds another layer of complexity.

Getting the Answers You Deserve

If these symptoms sound familiar, it's time to consider getting some testing done to help determine is it thyroid or adrenal dysfunction (or both!)

For Thyroid Assessment:

  • Complete thyroid panel including TSH, Free T3, Free T4, Reverse T3, and thyroid antibodies (TPO and TgAb)

For Adrenal Assessment:

  • Cortisol awakening response test (saliva test taken at multiple points throughout the day) GPs tend to order a Fasting blood test on waking.

  • DHEA levels

Additional Supporting Tests:

  • Vitamin D, Vitamin B12, Iron studies

Remember, your symptoms are real and valid. You know your body better than anyone, and persistent fatigue and unexplained weight gain are not things you should just have to "live with" as you age.

Moving Forward

Understanding whether you're dealing with thyroid dysfunction, adrenal fatigue, or both is the first step toward getting your energy back and addressing that stubborn weight gain. The right testing can provide the roadmap for targeted treatment that actually addresses the root cause of your symptoms.

Don't let any Health Professional dismiss your concerns or tell you that feeling exhausted and gaining weight is just a normal part of aging. You deserve to feel vibrant and healthy at every stage of life.

If you're ready to dig deeper into what might be driving your symptoms, I'd love to help you connect the dots. Book a consultation to discuss your individual situation and create a personalized plan for getting your hormones—and your life—back on track.