OBJECTIVES: To assess and analyse, using an epidemiological approach, persons suffering from hair loss. METHODS: A sample of the population, representative of the population over the age of 15, was established by CSA Santé. Hence, 4506 individuals were interviewed by phone and selected according to the quotas method. RESULTS: Hair loss affects nearly 20% of the population with a greater prevalence in men compared with women (25.2% vs 15.2%, p<0.001). Hair loss was more frequently seen in patients over 35 years old (14.8% of patients under 35 against respectively 23.3% and 21.7% of subjects over 35 years old). In addition, subjects suffering from hair loss considered more frequently having sensitive scalp than subjects who did not suffer from hair loss (58.7% vs 40.6%, p<0.001). For patients with hair loss, this problem was long-standing (34.7%), reactional (14.4%), occasional (29.2%) or chronic (17.3%). Scalp sensitivity was not correlated with the type of hair loss except for reactional hair loss for which sensitive subjects were significantly more numerous than non sensitive subjects. (19.5% vs 7.2%, p=0.015). Subjects who were more frequently prone to hair loss were those with greasy scalps then came those with dry scalp and those with normal scalps (respectively 31.0% vs 25.2% vs 14.9%, p<0.001). Finally, subjects with hair loss were more numerous to report skin sensitivity than others (62.9% vs 55.1%; p=0.045). CONCLUSIONS: This study therefore shows that nearly 1/5 of the population is affected by hair loss with a greater prevalence of men and oily scalps. Hair loss appears to be linked with scalp sensitivity, which backs up the approach of current hair loss treatments. However, it appears that hair loss is also correlated with overall skin sensitivity. Treating the skin may hence help treat hair loss. These results support our wish to continue research on the matter.