Why am I always tired even when I get enough sleep?

Persistent fatigue despite adequate sleep is rarely about sleep itself — it is usually a signal from your biology. The most common drivers include:

• Low thyroid function — even subclinical hypothyroidism can cause profound fatigue that standard TSH testing misses
• Cortisol dysregulation — a flattened or inverted cortisol curve leaves you exhausted in the morning and wired at night
• Insulin resistance — cells that cannot efficiently use glucose for energy produce fatigue as a primary symptom
• Chronic low-grade inflammation — persistent immune activation is metabolically expensive and directly suppresses energy production
• Nutrient deficiencies — iron, ferritin, B12, vitamin D, and magnesium are all critical for cellular energy and are frequently missed on standard panels

Standard blood panels often miss these because they use broad "normal" ranges rather than optimal functional ranges. A result can fall within the reference range and still be far from where your body functions best.

A functional medicine evaluation looks at your full biomarker picture — not just whether a number falls inside a wide reference band — to identify what is actually depleting your energy. If you have been told your labs are normal but still feel exhausted, that is exactly the situation functional medicine is designed to address.