A normal amount of hair loss for a person on any given day can be up to 75 to 100 strands of hair. At the same time that that's happening though, follicles that have not been growing will enter a stage of regrowth. So day in and day out you really shouldn't notice any changes in the thickness of your hair.
You should be concerned that you might be losing too much hair if you're noticing balding patches on your scalp. If you have itching, burning flaky skin on your scalp. If you're not feeling well in addition to having those symptoms and if it's happening suddenly then it might be time to see a provider to get to the bottom of why you're losing so much hair.
There are several things that can cause a person to lose more hair than normal on a day to day basis. And that can range anywhere from hormonal to endocrine problems such as thyroid disease, polycystic ovarian syndrome, pregnancy and androgenic alopecia which is just male or female pattern baldness. There's a lot of medications that can cause hair loss. I think people commonly will associate chemo therapy with hair loss from a medication stand point. But there's actually medications that people take on a daily basis that can be causing their hair loss like blood pressure medications. Medications that control your cholesterol, blood thinners and then some antidepressants as well. Significant stress can cause hair loss especially if it's a sudden shock emotional or physical. You can lose more hair during that phase of time. Significant weight loss, especially rapid weight loss can cause hair loss. Nutritional deficiencies, extreme hair styles like wearing really tight braids or wearing a tight bun every single day can cause you to lose hair more frequently. And then of course just getting older can cause hair loss as well.
There are people who are at an increased risk for hair loss. Those people would include individuals who have family members that have also suffered from hair loss. People with a significant amount of stress in their life are at an increased risk for hair loss. People who are suffering from nutritional deficiencies or eating disorders are at an increased risk for hair loss. And people that have comorbid conditions such as autoimmune disorders, diabetes, they're also at an increased risk for hair loss.
There are certain things you can do to address hair loss. There are medications available to help with hair loss. Over the counter people commonly will try remedies such as Rogaine. Depending on the type of hair loss that you have, your doctor might prescribe a medication. There's also lifestyle modifications such as healthy diet, exercise, sleep, reducing stress, ensuring that you're not suffering from a nutritional deficiency. And then of course if you do identify a medication as the cause then talk to your doctor about maybe finding something with a similar efficacy that doesn't have the side effect of hair loss.