17: What Else You’re Missing: Thyroid, Nutrients & Reading Your Body’s Patterns Part 2

Hey, it’s Megan. Grab your coffee and let’s have a convo.

You’re exhausted. Your hair is thinning. You can’t lose weight no matter what you do. Your digestion is a mess. You’re cold all the time.

You go to the doctor and they run your TSH. It comes back 3.1. “Normal,” they say. “Nothing to worry about.”

But you feel terrible.

Sound familiar?

I’m Megan Pfiffner and this is Mornings with Megan. Last episode, we talked about metabolic health and cardiovascular risk – the silent crisis that catches up with women during perimenopause. Today, we’re filling in the rest of the picture.

Because your metabolic markers don’t exist in isolation. Your thyroid function, your nutrient status, your inflammatory markers – they all work together to create a complete picture of your health. And when you know how to look for patterns across these markers, you can support your body before you hit the diagnosis zone.

Why Thyroid Matters in Perimenopause

Let’s start with thyroid, because this is where things get really frustrating for a lot of women in perimenopause.

A lot of perimenopause symptoms and thyroid symptoms crossover:

• Fatigue? Could be perimenopause, could be thyroid.
• Changes in body weight? Could be perimenopause, could be thyroid.
• GI issues? Could be perimenopause, could be thyroid.
• Sleep problems? Could be perimenopause, could be thyroid.
• Mood changes? Could be perimenopause, could be thyroid.
• Brain fog? You see where I’m going here.

And here’s what makes this even more complicated: Your thyroid function can change during perimenopause. Estrogen affects thyroid hormone binding proteins, thyroid hormone conversion, and even thyroid receptor sensitivity. So when estrogen starts fluctuating, your thyroid can struggle to keep up – even if you’ve never had thyroid issues before.

This is why it’s critical to get thyroid function ruled out if you’re experiencing symptoms. Not just so you can get treatment if you need it – so you can stop wondering if your thyroid is the problem when it’s actually your hormones, or vice versa.

The Problem with “Just TSH”

Most doctors will run TSH – thyroid stimulating hormone. And if this comes back normal, they consider thyroid ruled out.

But TSH is just one piece of the puzzle. It tells you what your brain is asking your thyroid to do. It doesn’t tell you if your thyroid is actually doing it, or if your cells are able to use the thyroid hormone once it’s made.

TSH can look “normal” at 3.0 or 3.5, but many women feel terrible at this level. Most functional practitioners want to see TSH between 1.0 and 2.0 for optimal function. But even that doesn’t tell the whole story.

What a Complete Thyroid Panel Looks Like

TSH – What your brain is asking your thyroid to do

Free T4 – The inactive form of thyroid hormone your thyroid produces. This is the storage form.

Free T3 – The active form of thyroid hormone that your cells actually use. Your body has to convert T4 to T3, and that conversion can be impaired by stress, nutrient deficiencies, inflammation, and – you guessed it – fluctuating hormones.

Thyroid Peroxidase Antibodies (TPO) – Checks for autoimmune thyroid disease. The majority of hypothyroidism in the United States is actually Hashimoto’s – an autoimmune condition where your immune system attacks your thyroid.

Thyroid Globulin Antibodies (TG) – Another marker for autoimmune thyroid disease.

If your TSH is over 2.5, or if you have symptoms that could be thyroid-related, request the full panel. Not just TSH.

And if your antibodies come back positive, that changes everything about how you need to support your body – even if your TSH is still “normal.”

Nutrient Deficiencies: The Foundation Everything Else Sits On

Now let’s talk about nutrients, because these are the foundation that everything else sits on.

You can’t make energy without iron – it’s a critical component of the electron transport chain in your mitochondria where energy is actually produced.

You can’t regulate your immune system without vitamin D.

You can’t convert T4 to T3 without selenium.

You can’t make neurotransmitters without B vitamins – they’re essential cofactors for producing serotonin, dopamine, and GABA.

And yet, nutrient testing is often an afterthought – if it happens at all.

Vitamin D: More Than Bone Health

Vitamin D isn’t just about bone health – though that matters too, especially in perimenopause when bone density starts to decline, or rather, when we start to notice the decline.

Vitamin D is critical for:

• Hormone production and regulation
• Immune function
• Mood regulation
• Insulin sensitivity
• Inflammation control

Most people are deficient or insufficient in vitamin D, especially if you live in a northern climate, work indoors, or have darker skin.

Target: 50-80 ng/mL for optimal function. Many conventional ranges say 30 is sufficient, but for hormonal and immune health, you want to be higher than that.

And here’s something important: You need to test vitamin D to know where you are. You can’t guess. Taking too much without testing can cause problems, and taking too little won’t get you where you need to be.

Iron: Beyond the Standard CBC

Iron deficiency is incredibly common in women, especially in perimenopause when cycles can get heavier and more frequent.

Symptoms of iron deficiency:

• Fatigue and exhaustion that sleep doesn’t fix
• Weakness
• Shortness of breath
• Cold hands and feet
• Poor immunity – getting sick more often
• Hair loss
• Restless legs
• Difficulty concentrating

Your CBC might show hemoglobin and hematocrit are normal – and that doesn’t mean your iron stores are adequate. You need a complete iron panel.

Serum Iron – The amount of iron in your blood right now Optimal: 85-130 μg/dL

TIBC (Total Iron Binding Capacity) – How much transferrin – the protein that carries iron – you have available Optimal: 250-350 μg/dL

Transferrin Saturation – What percentage of your transferrin is carrying iron Optimal: 24-35%

Ferritin – Your iron storage protein. This is the most sensitive marker for iron deficiency. Optimal: 45-79 ng/mL

Many conventional ranges say 15-20 is normal, but you may feel terrible at that level.

At minimum, get serum iron and ferritin tested. If those show issues, then get the full panel.

B Vitamins: Energy, Brain, and Detoxification

B vitamins are involved in energy production, neurotransmitter synthesis, hormone metabolism, and a process called methylation that’s critical for detoxification and cellular function.

Vitamin B12 is especially important if you’re vegetarian or vegan, if you have digestive issues, or if you’re over 50 – stomach acid declines with age, making B12 absorption much harder.

Low B12 can cause fatigue, brain fog, memory problems, mood issues, and nerve problems – think tingling and numbness.

Folate works with B12 for methylation and cell regeneration. It’s particularly important for cardiovascular health and detoxification pathways.

If you’re taking a multivitamin or even still taking your prenatal with folic acid – the synthetic form – make sure you’re actually absorbing it. Some people have genetic variations that make it hard to convert folic acid to the active form your body can use: methylfolate.

Other Valuable Nutrient Markers

Magnesium – Involved in over 300 enzymatic reactions in your body (still counting – the research is ongoing). Critical for blood sugar regulation, blood pressure, muscle and nerve function, sleep, and stress response.

Unfortunately, serum magnesium doesn’t tell you much because your body keeps blood levels stable by pulling from bones and tissues if it gets too low. RBC (red blood cell) magnesium is a better test if you can get it.

Omega-3 Index – Measures EPA and DHA levels. These are anti-inflammatory fats that support cardiovascular health, brain function, and hormone production. Target: above 8% for optimal cardiovascular protection.

Your Baseline: Metabolic Panel and CBC

The basic metabolic panel and complete blood count might seem boring, but they give you critical information about how your body is functioning.

Your metabolic panel checks:

• Kidney function – Are your kidneys filtering waste properly?
• Liver function – Is your liver processing hormones, cholesterol, and toxins efficiently?
• Electrolyte balance – Sodium, potassium, chloride, CO2 – all critical for cellular function
• Glucose – Your baseline blood sugar

This is your foundation. If your kidneys or liver aren’t functioning well, everything else becomes harder. Your body can’t detoxify properly. It can’t process hormones efficiently. It can’t regulate blood sugar effectively.

The CBC screens for:

• Anemia – Low red blood cells, hemoglobin, or hematocrit
• Immune function – White blood cell counts and differential
• Platelet function – Important for clotting

If your hemoglobin or hematocrit are out of range, you need that complete iron panel. If your white blood cells are too high or too low, you need to investigate why.

These aren’t sexy numbers, but they matter. This should be part of your annual physical.

Symptom Clusters: Your Starting Point

Now let’s get practical. I’m going to walk through four common symptom clusters and the basic labs that can help you figure out what’s going on.

These are starting points – the low-hanging fruit you can get with standard lab work before moving into advanced or functional testing. But they give you valuable information and often uncover issues that can be addressed.

“I’m Exhausted No Matter How Much Sleep I Get”

This is probably the most common complaint I hear, and it can have multiple causes.

Start by checking these markers:

• Complete iron panel – Low iron is one of the most common causes of persistent fatigue, especially through that electron transport chain component in your mitochondria
• Ferritin specifically – You can have a normal CBC but depleted iron stores
• Full thyroid panel – Not just TSH. Low T3 can cause fatigue even if TSH looks okay
• Vitamin D – Low vitamin D contributes to fatigue and poor energy
• Vitamin B12 – Essential for energy production
• Fasting insulin and HbA1C – Blood sugar dysregulation causes energy crashes throughout the day

If all of these come back optimal and you’re still exhausted, then we look at stress hormones, sleep quality, gut health, and other factors. But we start with these basics because they’re often part of the cause.

“My Hair Is Falling Out”

Hair loss in perimenopause is incredibly common and incredibly distressing.

Start by checking these markers:

• Ferritin – This is often the issue. Many women with hair loss have low ferritin
• Full thyroid panel – Both hypothyroidism AND hyperthyroidism can cause hair loss
• Vitamin D – Supports hair follicle cycling
• Zinc – Important for hair health, though it isn’t on a standard panel

Hair loss can be related to hormonal shifts in perimenopause – particularly changes in the ratio of estrogen to androgens. But rule out nutrients and thyroid first with basic testing.

“I Can’t Lose Weight No Matter What I Do”

This is where metabolic health and thyroid overlap.

Start by checking these markers:

• Fasting insulin – This is the first place to look. Insulin resistance makes weight loss incredibly difficult
• HbA1C – Are you dealing with chronic blood sugar elevation?
• TG:HDL ratio – Another indicator of insulin resistance if you can’t get fasting insulin. This can be calculated from your lipid panel
• Full thyroid panel – Hypothyroidism or poor T4 to T3 conversion slows metabolism
• Ferritin – Low iron impairs thyroid hormone conversion
• Vitamin D – Low vitamin D is associated with difficulty losing weight
• hs-CRP – Inflammation makes weight loss much harder

If you’re doing everything right but can’t lose weight, something metabolic is going on. These basic labs can help you figure out a lot before moving into more complex testing.

“I Can’t Think Straight / Brain Fog”

Brain fog is one of the most frustrating symptoms because it affects everything – your work, your relationships, your confidence.

Start by checking these markers:

• Fasting insulin and HbA1C – Blood sugar dysregulation is a huge cause of brain fog
• Full thyroid panel – Low T3 particularly affects cognitive function
• Vitamin B12 – Essential for brain function and memory, and remember it’s a cofactor in neurotransmitter production
• Ferritin – Low iron affects oxygen delivery to the brain
• Vitamin D – Supports cognitive function and mood

Brain fog can also be related to sleep quality, stress, hormonal fluctuations, and other factors. But these basic labs give you a foundation to start from.

These four symptom clusters cover what I hear most often from women in perimenopause. And in many cases, basic lab work reveals issues – nutrient deficiencies, thyroid dysfunction, metabolic problems – that can be addressed. This is your starting point. If these labs don’t reveal the issue, then you move into more advanced testing: hormone panels, gut testing, organic acids, neurotransmitter testing, and more specialized functional labs.

You’d be surprised how often these basics uncover exactly what’s causing your symptoms.

What to Do With This Information

So what do you actually do with all of this?

First, request the labs. Use the lab guide – it has all of this organized for you to bring to your doctor. Download it at meganpfiffnernutrition.com or find the link in the show notes.

Second, get your results. You’re legally entitled to your lab results. Request a copy – either a printout or access to your patient portal to download yourself.

Third, look for patterns across your symptoms and your lab results. Compare your results to the optimal ranges we covered – not just normal ranges.

Fourth – and this is where many women get stuck – work with someone who can help you interpret the results and create a support plan.

Your conventional doctor might not have time for this level of investigation. That’s not a criticism – it’s just reality. They have 10 minutes per patient and they’re trained to diagnose and prescribe medication, because that is how our medical system is set up.

That’s where practitioners like me come in. We can spend 30 minutes or even an hour looking at your labs, understanding your symptoms, identifying patterns, and creating a nutrition and lifestyle plan to support your body.

We’re not replacing your doctor. We’re filling in the gaps.

If your labs show something that needs medical attention – like thyroid antibodies, severely low nutrients, or metabolic markers that indicate the need for medication – we’ll tell you to follow up with your doctor. But for the in-between zone, where things aren’t disease but they’re not optimal, we can help you support your body before it becomes disease.

The goal isn’t to diagnose. As a nutritionist, I can’t diagnose and I wouldn’t want to. The goal is to gather information, look for patterns, and listen to what your body needs. Then create a plan that supports the systems that need a little extra help before you hit the diagnosis zone.

The Reality Check: About Medication

I want to be really honest with you about something.

I’m not promising that perfect labs and perfect nutrition mean you’ll never need medication. Most of us will need some medication in our lifetime. It’s very hard to be medication-free living as long as we do with our modern lifestyle. Genetics play a role. Environmental exposures play a role. Stress and life circumstances play a role.

Maybe if you moved to the woods, had no exposures, lived in perfect harmony with nature, got perfect sleep every night, and had zero stress. But even then, genetics might still get you.

What I AM promising is this: when you catch problems early and support your body proactively, if you do need medication eventually, you’re starting from a much stronger foundation. You’ll need lower doses. You’ll have fewer side effects. You’ll feel better overall. And in many cases, you can prevent or delay the need for medication by addressing nutrient deficiencies, reducing inflammation, and supporting metabolic health early.

Prevention is always easier than treatment.

Lab Prep Reminders

Quick reminder on getting accurate labs:

• Go in the morning and fasted – Nothing but water for 12 hours before. This matters for glucose, insulin, lipids, and some other markers.
• Skip your workout that morning – Exercise can temporarily spike glucose, lipids, and inflammatory markers.
• Stop biotin at least two weeks before – It’s in many hair, skin, and nail supplements and can interfere with thyroid testing.
• Stay normally hydrated – Not thirsty, not chugging water. Just comfortable.
• Tell your provider if something was off – Didn’t fast? Took supplements? Had a cold? These things can all affect your results.

Closing: Your Body Is Always Talking to You

Your body is always talking to you. Your energy levels, your sleep, your mood, your digestion, your weight, your hair, your cycles – these are all information. Your labs give you the data to understand what your body is trying to tell you.

But data without interpretation is just numbers on a page. And interpretation without action is just intellectual curiosity.

The magic happens when you gather the information, identify the patterns, and create a plan to support your body.

A year from now, you’ll either wish you’d started today, or you’ll be glad you did. You’ll either still be wondering why you feel terrible despite normal labs, or you’ll understand your body’s patterns and have a clear plan to support your health.

The difference? One decision right now.

If you want help interpreting your labs and creating a personalized support plan, we offer a lab review session – 30 minutes where we talk through your results together and translate your numbers into clear action steps. Find more information at meganpfiffnernutrition.com or look for the link in the show notes.

Download the free lab guide – “Not Just In Your Head: The Lab Guide for Women Who Know Something’s Up.” It has everything we’ve covered in these two episodes, organized for you to bring to your doctor.

You deserve answers. You deserve to understand your body. You deserve to feel good.

I’m Megan, and until next time – you’ve got this.

If this was helpful, share it with one person who might need to hear it today. Our bodies didn’t come with a user manual and this perimenopause thing can feel confusing and lonely – but you’re not alone, you’re not crazy, and you’re definitely not broken. Maybe someone in your life needs that reminder too. Let’s spread the word and be kind to each other and ourselves.

Legal note: I’m a nutritionist, but I’m not your nutritionist. This podcast is for information and education only. No client relationship was formed. Always seek medical advice when necessary.