Hair loss can stem from hormonal imbalances, thyroid disorders, certain medications and nutritional deficiencies, according to specialists who appeared on CNN Sinais Vitais.
Endocrinologist Denise Iezzi, from the Centro de Diabetes e Obesidade at Hospital Sírio-Libanês, said patients should note whether hair loss persists and whether it coincides with other symptoms such as increased body hair, acne and menstrual irregularity. She said those signs are linked to elevated androgen levels, which can trigger hair shedding.
Thyroid dysfunction is also a significant factor. Iezzi confirmed that both hypothyroidism, where the gland functions more slowly than normal, and hyperthyroidism can disrupt the hair growth cycle and lead to loss.
Medications that can contribute
On the medication side, Iezzi named diphenylhydantoin, lithium and certain older beta-blockers as drugs that can cause hair loss, and urged patients to have this possibility checked even when it may not seem like an obvious culprit.
Weight-loss pens and the indirect effect
Weight-loss injection pens were also discussed. Iezzi said these drugs do not cause hair loss directly. The effect is indirect, she explained, arising from rapid weight loss when caloric and protein intake is not properly managed. Patients can develop deficiencies in vitamin D, iron, ferritin, vitamin B12 and folic acid, and it is those nutritional gaps rather than the medication itself that damage hair health.
Iezzi stressed the importance of blood tests to detect nutritional shortfalls and of maintaining regular medical supervision while using such drugs. Dermatologist Letícia Nanci, also of Hospital Sírio-Libanês, added that because the pens suppress appetite significantly, patients must prioritise a balanced diet rich in protein, vegetables and greens.
The specialists noted that many people use weight-loss pens with no professional oversight, or begin treatment under medical guidance but abandon it over time.