Why Is My Ferritin Low and What Does It Mean?
You went to your doctor feeling exhausted, with thinning hair and no energy, and your blood work came back normal. But did anyone check your ferritin?
Ferritin is one of the most commonly overlooked markers in standard lab panels, and low ferritin is one of the most common — and most treatable — causes of fatigue and hair loss we see in our practice.
What Is Ferritin?
Ferritin is a protein that stores iron in your body. Think of it as your iron reserve tank. When ferritin is low, your body is running on empty — even if your hemoglobin and standard iron levels look normal. You can have low ferritin without being technically anemic.
What Are the Symptoms of Low Ferritin?
- Persistent fatigue that does not improve with rest
- Hair thinning or increased shedding — often diffuse, all over the scalp
- Shortness of breath with mild exertion
- Poor exercise tolerance or slow recovery after workouts
- Brain fog and difficulty concentrating
- Cold hands and feet
- Restless legs, particularly at night
- Brittle nails
- Feeling wired but tired
What Is a Normal Ferritin Level — and What Is Optimal?
The conventional reference range for ferritin in women is typically 12 to 150 ng/mL. But most functional medicine practitioners consider optimal ferritin for women to be between 50 and 100 ng/mL, and for men between 50 and 150 ng/mL. A ferritin of 14 ng/mL may not trigger a flag on a standard lab report, but a patient with a level that low will often feel profoundly fatigued and may be experiencing significant hair loss.
What Causes Low Ferritin?
Insufficient Iron Intake
A diet low in iron-rich foods — particularly red meat, organ meats, legumes, and leafy greens — is a common cause. Plant-based iron is also less bioavailable than animal-based iron, so vegetarians and vegans are at higher risk.
Poor Iron Absorption
Conditions like low stomach acid, celiac disease, or small intestinal bacterial overgrowth (SIBO) can impair how well you absorb iron — another reason gut health and nutrient status are so interconnected.
Blood Loss
Heavy menstrual periods are one of the most common causes of low ferritin in women. Even
periods that seem manageable can, over time, deplete iron stores significantly.
Increased Demand
Pregnancy, intense athletic training, and chronic inflammation all increase iron requirements
or affect how the body stores iron.
How Is Low Ferritin Treated?
Treatment depends on the underlying cause. At BeautyEtc, we look at a full iron panel — serum iron, TIBC, transferrin saturation, and ferritin — alongside gut health markers before making recommendations.
When supplementation is appropriate, we typically recommend iron bisglycinate, which is well-absorbed and gentler on the digestive system than ferrous sulfate. Pairing iron with vitamin C improves absorption. It generally takes three to six months of consistent supplementation to meaningfully raise ferritin stores.
The Thyroid and Hormone Connection
Iron is required for the conversion of T4 to the active thyroid hormone T3. Low ferritin is associated with worsened thyroid symptoms even in patients whose TSH appears normal. Ferritin also drops more readily under conditions of chronic stress — another reason fatigue, hormone issues, and low iron stores tend to show up together.
Ready to get the full picture? At BeautyEtc Medical Aesthetics and Wellness in Medfield, MA, we combine advanced hormone and gut health testing with nearly 30 years of clinical experience. Book a consultation at beautyetcaesthetics.com or call
508-216-0112.
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