Libido or colloquially sex drive, is a person’s overall sexual drive or desire for sexual activity. Sex drive is determined by biological, psychological, and social factors. Biologically, levels of hormones such as testosterone are believed to affect sex drive; social factors, such as work and family, also have an impact; as do internal psychological factors, like personality and stress. Sex drive may be affected by medical conditions, medications, lifestyle and relationship issues. A person who has extremely frequent or a suddenly increased sex drive may be experiencing hypersexuality, or puberty in which the body builds up chemicals and causes a higher sex drive. However, there is no universally agreed measure of what is a healthy level for sex. Asexual people may lack any sexual desires.