New Delhi: Hair loss despite “normal” blood tests is a common frustration for many women. Doctors say the answer lies not in routine reports, but in what’s happening inside the skull.For female pattern alopecia, patients are usually advised a series of tests – testosterone, free androgen index, thyroid function and nutritional functions such as vitamin levels. Yet, these are often generalized, leaving both patients and physicians without clear answers.A study published in an international journal of dermatology now provides an explanation. Researchers at Delhi’s Ram Manohar Lohia Hospital found that women with female pattern hair loss had significantly higher levels of a hormone marker called 3α-diol G – even when standard hormones such as testosterone remained within normal limits.Female pattern hair loss, which causes gradual thinning at the front and top of the scalp, affects a large number of women and often impacts self-confidence. But routine testing often fails to identify the cause.The study compared 44 women with hair loss with 30 women without hair loss. It found that levels of 3α-diol G – a marker of hormone activity within hair follicles – were almost double in affected women, and higher levels were associated with more severe thinning.Explaining the difference, Dr Kabir Sardana, Professor in the Department of Dermatology, RML Hospital, said that female pattern hair loss (FPHL) is a genetic, gradual thinning that often appears as a wide patch, while telogen effluvium (TE) is a temporary, rapid shedding usually caused by stress or illness. While FPHL leads to permanent miniaturization of hair follicles, TE is usually self-limiting.He said, “We have always believed that female pattern hair loss is not caused by androgens, but this is not true. It’s just that we’re not looking in the right place for the right test. We are already offering off-label anti-androgen medications that block these hormones, but they should be used with caution, especially in women who are planning pregnancy because they may affect conception.Unlike traditional tests, 3α-Diol G reflects hormone action at the skin level – where hair loss actually begins. This helps explain why many women continue to lose hair even after blood reports come back normal.The researchers also found that only a small number of patients showed abnormalities in routine hormone tests, pointing to limitations in current diagnostic approaches that rely on systemic measurements.Experts say the findings could shift attention away from hormone levels in the blood to hormone activity in the scalp, potentially improving diagnosis and treatment. However, larger studies are needed before this approach can become part of routine care.In simple terms, the study underscores a key message, the researchers said, that it is not just the amount of the hormone in the blood, but what it is doing to the hair follicle that causes hair loss.