Hair loss is often treated as a cosmetic problem, but dermatologists say persistent shedding or thinning can sometimes point to deeper health concerns. Experts warn that ongoing hair fall may be linked to nutritional deficiencies, hormone-related conditions or even autoimmune disorders, making medical evaluation important when symptoms do not improve.
According to dermatologist Dr. Jushya Bhatia Sarin, a number of blood tests can help identify the underlying cause of unexplained or chronic hair loss. In a recent Instagram post, she said these tests are often used to assess iron levels, vitamin deficiencies, hormone imbalances and other internal factors that may affect hair growth.
One of the most important markers, she said, is serum ferritin, which reflects the body’s iron stores. Low ferritin is frequently associated with long-term hair shedding, particularly in patients with iron deficiency. When iron levels are insufficient, the normal hair growth cycle can be disrupted, causing more follicles to enter the shedding phase earlier than they should.
Another commonly recommended test is vitamin B12. Dr. Sarin noted that low B12 levels may contribute to diffuse thinning across the scalp rather than patchy hair loss in one specific area. In some cases, vitamin B12 deficiency may also be linked to skin pigmentation changes and premature greying.
Hormonal imbalance is another possible contributor. Dr. Sarin said she sometimes checks DHEAS (dehydroepiandrosterone sulfate), a hormone related to androgen production. Elevated levels may increase male hormone activity in women, which can worsen acne and contribute to thinning hair.
When the cause of hair loss is less obvious, dermatologists may also consider an ANA (anti-nuclear antibody) test. This screening is used to detect autoimmune conditions, which can sometimes affect the skin and hair follicles. In such cases, the immune system may mistakenly attack healthy tissues, potentially leading to hair loss or pigment-related changes.
Stress may also play a role. A serum cortisol test can help evaluate whether long-term stress-related hormonal changes are contributing to hair thinning. Persistently elevated cortisol levels have been associated with both acne flare-ups and increased hair shedding.
Nutrition remains another key factor. Dr. Sarin said dermatologists may also test serum albumin, a blood protein that helps assess overall protein status. Low protein intake or poor absorption can affect hair strength and quality, and may also be accompanied by brittle or weak nails.
Still, experts stress that not every person experiencing hair loss needs the same tests. The right evaluation depends on symptoms, medical history and the pattern of hair loss. Dermatologists advise anyone dealing with ongoing or unexplained shedding to seek professional assessment rather than relying on self-diagnosis or social media advice alone.