By Dr. Stephen Lewis, D.C.

Persistent fatigue is a symptom, not a diagnosis. It may be related to sleep, stress, medicines, nutrition, thyroid function, blood sugar, anemia, infection, mental health, or another medical condition. Because the possibilities overlap, the most useful next step is usually a careful history and appropriate evaluation—not guessing from one symptom or taking random supplements.

Feeling tired after a demanding week or a short night of sleep is common. Fatigue that lasts for weeks, repeatedly interferes with daily life, or does not improve with rest deserves attention. The National Library of Medicine notes that fatigue has many possible causes and should be evaluated when adequate sleep, nutrition, and a lower-stress environment do not help.

Too little sleep is an obvious cause of tiredness, but spending enough hours in bed does not always mean sleep is restorative. Insomnia, frequent waking, pain, shift work, and sleep disorders can affect daytime energy. Loud snoring, gasping during sleep, morning headaches, or significant daytime sleepiness are reasons to discuss sleep apnea with a healthcare professional; the National Heart, Lung, and Blood Institute lists these among common sleep-apnea symptoms.

Both underactive and overactive thyroid conditions can be associated with fatigue. Symptoms such as feeling cold, dry skin, constipation, changes in weight, or a fast heartbeat can have many causes, so symptoms alone cannot diagnose a thyroid disorder. The American Thyroid Association describes TSH as the usual initial blood test for thyroid function and explains when additional thyroid measurements may be useful.

If thyroid questions are central to your concerns, review the markers included in the Thyroid Hormones Extensive Lab Panel. A panel should be selected because its tests fit the question being evaluated—not because fatigue automatically means a thyroid problem.

Iron-deficiency anemia and vitamin B12 deficiency can cause tiredness or weakness. The NIH Office of Dietary Supplements provides detailed guidance on iron and vitamin B12, including risk factors and the importance of appropriate assessment. More is not always better: iron in particular should not be started solely because of fatigue, since excessive iron can be harmful.

Fatigue may occur with diabetes, but it is not specific to diabetes. Increased thirst, frequent urination, blurred vision, slow-healing sores, or recurrent infections are additional reasons to seek medical evaluation. The National Institute of Diabetes and Digestive and Kidney Diseases explains common diabetes symptoms and why testing should be discussed with a primary healthcare professional.

Emotional stress, depression, persistent pain, infection, and many other health conditions can affect energy. Prescription and nonprescription medicines—including some antihistamines, sleep medicines, and other medications—may also contribute. Do not stop or change a medicine without speaking with the healthcare professional who manages it.

Fatigue can result from more than one factor, and many possible causes produce similar symptoms. Laboratory testing can provide useful objective information, but it does not necessarily reveal a single explanation. Results are most useful when interpreted alongside symptoms, health history, medicines, sleep, nutrition, and other relevant information.

Our Laboratory Testing overview explains the Green Wisdom Health process, what is included with eligible LabCorp panels, and how Core and Specialty Lab Panels differ.

Call 911 or seek emergency help when fatigue occurs with chest pain, shortness of breath, a fast or irregular heartbeat, feeling as though you may pass out, severe abdominal, pelvic, or back pain, unusual bleeding, or a severe headache. Seek immediate help for thoughts of self-harm or suicide; in the United States, call or text 988. These warning signs follow current Mayo Clinic fatigue guidance.

Arrange a medical appointment for unexplained fatigue that persists, worsens, disrupts daily activities, or is accompanied by fever, unintentional weight loss, night sweats, weakness, or other concerning symptoms.

If you are medically stable but still unsure which Green Wisdom Health resource fits your concerns, complete the secure Health Survey. It gives our team context for the conversation; it is not a diagnosis and does not replace urgent or primary medical care.

• Looking Beyond Normal Lab Results
• Supporting Hormones in a High Stress World
• Early Warning Signs of a Thyroid Problem

1. National Library of Medicine. Fatigue. MedlinePlus Medical Encyclopedia. Reviewed May 19, 2025.
2. Mayo Clinic Staff. Fatigue: When to see a doctor. Updated February 20, 2026.
3. American Thyroid Association. Thyroid Function Tests.
4. National Heart, Lung, and Blood Institute. Sleep Apnea Symptoms. Updated January 9, 2025.
5. NIH Office of Dietary Supplements. Iron Fact Sheet for Consumers and Vitamin B12 Fact Sheet for Consumers.
6. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Diabetes.

You might notice more hair than usual in the shower, thinning around your temples, or your ponytail feeling smaller than it used to. Sometimes it seems to happen suddenly, while other times it shows up gradually over time.

A lot of people assume hair loss is purely genetic. And while genetics can definitely play a role, we often see other factors involved as well. Things like hormone changes, thyroid function, iron levels, and nutrition can all influence how healthy your hair follicles are.

What you might not know….. Hair loss is often a signal that the body might need support somewhere else.

Hair loss can feel discouraging, but it can also provide helpful clues about what may be happening in the body.

Instead of focusing only on the hair itself, functional medicine looks at the bigger picture. Hormone balance, thyroid health, nutrient levels, stress, and metabolism all influence the environment where hair follicles grow.

When those systems are supported, many people begin to see gradual improvements in hair growth over time.

If you’ve been noticing hair thinning or increased shedding, taking a closer look at what’s happening inside the body can often be an important first step.

Listen to our podcast to learn what you can do to save your hair!

One of the most common things we hear new patients tell us is, “My blood work was normal, but I still don’t feel like myself.”

They might be dealing with fatigue, brain fog, digestive issues, joint discomfort, or low energy. Yet when standard tests come back within the normal range, it can feel confusing and frustrating.

This is what makes functional testing different. We focus on understanding how the body is functioning before disease develops. Instead of waiting until a clear diagnosis appears, the goal is to look for early imbalances that may be placing stress on the body.

Sometimes these changes show up in lab markers long before a condition develops.

By looking a little deeper at those patterns, we can often identify opportunities to support the body earlier and help prevent larger issues down the road.

Listen to this podcast episode to understand the difference between normal and optimal lab work!

Have you ever felt like stress just hits you harder than it used to?

Maybe your sleep is lighter. Your patience is shorter. PMS feels more intense. Or you feel wired but exhausted at the same time.

Many men and women assume this is just part of modern life.

But there is real biochemistry behind why stress can feel more disruptive in a woman’s body.

In our latest podcast, you’ll find out:

• How cortisol and progesterone share hormonal building blocks
• Why chronic stress can lower progesterone over time
• How this shift impacts mood, sleep, cycles, and resilience
• Why stress tolerance often changes in perimenopause
• What you can do to rebuild your stress buffering capacity

If stress has been affecting your energy, mood, or cycle more than it used to, this podcast will help you understand why and what you can do about it.