My girlfriend's finger nails are breaking very easily. why could this be? thank you! :)

Brittle Nails: This condition affects up to 20 % of the population. It can result from nail polish remover, excessively strong soap use, eating disorders such as anorexia or bullemia, hypothyroidism, etc. According to one study the use of the b-complex vitamin biotin increased nail thickness by 25 %.

Uncertain: Crumbling or brittle nails can occur due to lengthy contact with nail polish, detergents, chemicals, water. Other possible causes: fungal infections, lichen planus,nail psoriasis, & thryoid problems. Wearing gloves when hands have excessive water exposure or use of topical moisturizer can help. In some case - a medical workup is indicated.