What Deficiency Causes Weak Nails and Hair?
                                
                                
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                                    4 min read                                
                            
                                According to the World Health Organization, iron deficiency is one of the most common nutritional deficiencies globally and a frequent cause of brittle nails. Many factors can influence the strength and appearance of your hair and nails, but nutritional shortfalls are a significant and often overlooked cause, leading many to wonder what deficiency causes weak nails and hair.