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Why Is My Hair Falling Out? The Top Reasons For Hair Loss + Your Lab Test Checklist
Noticing more hair in your brush? Explore the top root causes of hair loss, from hormones to nutrition, plus a lab test checklist to help you regrow thick hair.
Written and medically reviewed by Dr. Courtney Ranieri, ND, a licensed naturopathic doctor registered with the College of Naturopaths of Ontario (Reg. #3726). Last reviewed July 2026.
First things first, hair loss can be totally normal. We are supposed to lose around 100 strands per day, which is not too noticeable given that roughly 120,000 hairs are growing on your scalp at any given time.
However, if hair loss is a concern for you, whether you've noticed more strands than normal, thinning on the scalp, or hair getting thicker on other areas of the body, it might be time to take a deeper look. Female hair loss is a common but important symptom of many deeper health concerns.
As a Naturopathic Doctor, my goal is to help you uncover the root cause of your hair loss so we can optimize your hair from the inside out.
Tip #1: Take a look into your hormones, get tested
Hormonal imbalances are one of the top causes of hair loss.
- Estrogen: optimal levels are necessary to grow thick hair, since estrogen keeps the follicle in its growing phase. Low estrogen (in peri- and post-menopause, or conditions like PCOS and endometriosis) may lead to thin hair, stalled growth and female-pattern hair loss.
- Thyroid hormones: hair loss is one of the first signs of low thyroid function. When the body doesn't produce enough T3 and T4, hair growth stops at the root. Testing TSH, free T4 and T3 is important.
- Testosterone: an important hormone in women too. High levels can contribute to female-pattern hair loss and are an indicator of PCOS; low levels are common as we age.
Tip #2: Focus on nutrition
Nutritional deficiencies can contribute to hair loss.
- Protein: a top nutrient for healthy hair, since 80 to 85% of hair is made of the protein keratin. Getting adequate protein is imperative for thick, healthy hair.
- Iron: iron deficiency is a common cause of female hair loss, and many women are deficient without knowing. Include iron-rich foods like beef, poultry, beans, lentils and dark leafy greens.
- Vitamin B12: low B12 can cause anemia and hair loss, and is especially common in vegans and vegetarians. I test B12 levels and offer B12 injections in practice.
Tip #3: Optimize a hair-healthy lifestyle
- Stress pushes hair follicles into a resting phase called telogen effluvium, causing hair to fall out and depleting vitamins and minerals needed for growth.
- Digestion: conditions like celiac disease, Crohn's, colitis and food sensitivities can impair absorption of nutrients that support healthy hair.
- Autoimmune conditions like lupus, alopecia areata and Hashimoto's are common causes of female hair loss. Testing for antibodies (anti-TPO, ANA) can help.
Natural Treatments
As a Naturopathic Doctor, treatments are tailored to each patient. Our plan focuses on optimal hair-health nutrition, comprehensive lab testing to determine the root cause, regulating hormones, targeted botanicals and supplements, addressing deficiencies, and improving stress and sleep.
About the author
Dr. Courtney Ranieri, ND is a board-licensed naturopathic doctor and the founder of Somewhere Health. She earned her Doctor of Naturopathic Medicine at the Canadian College of Naturopathic Medicine in Toronto and holds an Honours Bachelor of Science from the University of Western Ontario. Her clinical focus spans hormonal health, fertility, digestion, and women's health, with advanced training in pelvic floor therapy and integrative fertility care.
