After bariatric surgery the most frequent nutritional deficiency symptom is hair loss*. This is not permanent and usually occurs 3 to 6 months after the operation.
Hair loss occurs due to the physiological stress of surgery, hormonal changes, and the rapid weight loss after bariatric surgery. Low levels of Folic Acid, Biotin, Zinc, Ferritin and also protein deficiencies are related to hair loss.
* Ledoux S. et al, What are the micronutrient deficiencies responsible for the most common nutritional symptoms after bariatric surgery, 2020.