What blood tests should i do to figure out what causes my hair loss (like iron, I don't know the others)?

You should start by seeing a doctor before considering the tests you need. Your doctor who examines you, usually recommends the tests.  Blood tests do not always diagnose a hair loss condition.

This is a common question and unfortunately there is no set of blood tests for everyone!!! It depends on the history of your hair loss, your medical history and what pattern of hair loss you have!Here are a few general principles I'd give any female with hair loss:1. First and foremost, blood tests are often normal in most people with hair loss. So blood tests are only a part of the story. Most people with androgentic alopecia, alopecia areata, traction alopecia and scarring alopecia have normal blood work. Too many individuals are "surprised" when their blood test results come back normal. Don't be!!!2. Hemoglobin, ferritin (iron test) and TSH (thyroid) are essential for ANY female regardless of the cause of hair loss. 3.  Consider also 25 hydroxy-vitamin D and B12 (especially if vegetarian vegan)4. Zinc testing is only needed if an individual has a dietary problem or bowel problem5. Any female with irregular menstrual periods needs more detailed evaluation, including evaluation by an endocrinologist or gynecologist. Tests such as DHEAS, free testosterone, total testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, androstenedione may be appropriate. Check with your doctor. 6. Any female with hair loss and increased hair on the face or acne should have tests for DHEAS and free and total testosterone7.  Any female with hair loss accompanied by sensitivity to the sun, ulcers in the mouth, joint pains, chronic fatigue should have a blood test for anti- nuclear antibody (ANA).  Many, many other tests are also possible depending on the individual's medical history.  These are good starting points.