When there is a family history having a genetic predisposition or susceptibility to thinning hair and hair loss, it is commonly known as male or female pattern hair loss. In pattern hair loss, the enzyme 5-Alpha-Reductase (5AR) is primarily responsible for the conversion of the circulating hormone Testosterone into the hormone Di – Hydro – Testosterone (DHT), which starts the process of your losing your hair.
If you are a male and any of the following family members have or had thinning hair or hair loss, you also may experience male pattern hair loss: your father, grandfather, uncle or brother. If you are a female, and any of the following family members have or had thinning hair or hair loss, you also may experience female pattern hair loss: your father, grandfather, uncle or brother or your mother, grandmother, aunt or sister.
Side Effects from various Prescription Drugs
Many people are not aware that various kinds of prescription drugs and medications may either cause or contribute to thinning hair and hairloss. This includes various acne treatments, anti-depressants, birth control pills, chemotherapy, drugs which help lower cholesterol, high blood pressure, treating ulcers, arthritis and blood thinners. See list of medications that cause hair loss.
Various kinds of health and medical conditions such as hyperthyroidism and lupus can cause thinning hair. Some women experience sudden hair loss at the conclusion of pregnancy or two to three months after discontinuing the use of birth control pills.
Stress and Trauma
It is commonly thought that extended periods of high stress can cause or contribute to hair loss, as stress may increase a constriction of the blood supply to the scalp. Sometimes after surgery, some individuals may experience either temporary or long term hair loss.
Poor or Improper Diet and Nutrition
Poor diet and nutrition may also contribute to losing one’s hair (but not as pattern hair loss). This may include diets high in animal fat (too much red meat / acidity), too much protein, too much fast food or quick weight loss diets.
Environmental Toxins and Pollutants
Various elements such as chlorine (swimming pools), metals, minerals and water pollution may also contribute in some way to losing one’s hair. Repeated and extensive use of very hot curling irons or straightening irons with metal plates (as opposed to ceramic plates), use of harsh chemicals used in hair coloring or hair styling products, such as lye or amonia, may also contribute to hair loss, particularly in women.
Medications That Cause Hair Loss
allopurinol, arsenic, apirin, l-asparaginase, bismuth, bleomycin, boric acid, bromocriptine, carbamazepine, carbon monoxide, chlorambucil, chloramphenicol, cimetidine, colchicine, clofibrate, clomiphene citrate, coumarin anticoagulant, cyclophosphamide, cyproterone acetate, dactinomycin, danazol, diethyl carbamazepine, dipyridamole, doxorubicin, ethionamide, etoposide, etretinate, fenifibrate, gentamycin sulphate, guanethidine, heparin (telogen effluvium after 6-16 weeks ), hydroxychloroquine, ibuprofen, idoxuridine, indandione, indomethacin, interferon, iodine, isophosphamide, levamisole, levodopa, lithium, mepacrine, mercury, mesalazine, methisazone, methotrexate, methyl CCNU, methysurgide, metoprolol, mitomycin, mitrexantrone, morphine, nadolol, nafoxidine, nicotinic acid, nicotinyl alcohol, nitrofurantoin sodium, norethisterone, estrogens, oral contraceptives, para aminosalicylate, phenindione, phenprocoumon, potassium thiocyanate, procainamide, propanolol, selenium sulphide, sodium aurothiomalate, sodium valproate, spironolactone, sulphasalazine, tamoxifen, thalium acetate, thiamphenicol, terfenadine, trimethadione, troxidone, vasopressin, vincristine, vindesine, vitamin A, warfarin
Resource: Hair Loss News