1) My problem is this: whenever I have to study late at night, or do anything late at night, I usually have trouble (a lot of trouble) concentrating on whatever it is that I have to do. I'm not going to try anything like No-Doz, but when I drink coffee or anything with caffeine, it just knocks me out even faster. I can't believe it — it's like caffeine's some kind of sleeping potion for me. Some of my friends say eating while you work can help you stay up. I tried that, too. Didn't work. Any suggestions? Or am I just better off sleeping and leaving the work 'till the next day?

2) I am a junior in college. I am pre-med which means I study all the time. However, I can really only focus when I study at night. When I study during the day, it seems that I cannot recall as much information as opposed to studying late at night. How come I can't stay focused during the day? What should I do to help me concentrate during the day?

I have dandruff that responds well to over-the-counter shampoo. Ergo, I have been using the stuff almost exclusively for ten years. No brand in particular, sometimes zinc pyrithione (the blue stuff!), sometimes coal tar (the smelly brown stuff!). Anytime I switch to non-dandruff shampoo for like three to four days straight, I get my dandruff back. I worry that I might be addicted to dandruff shampoo. Should I worry?

Ever since high school, I've had very oily hair and skin, but it became worse in college. Now I'm in my mid-twenties and have to shampoo my hair about 10 times each day to get it clean. Then by evening it's already oily again. This isn't my scalp trying to moisturize itself after being over cleaned, because I've tried not washing it completely and it's even oilier the next day.

Are there any special shampoos or medications that help reduce oily skin? I've tried some facial products from my dermatologist, but they haven't reduced the oil production. This is an embarrassing problem and limits the overnight activities I can do, like camping or staying with friends.

I find that I'm most alert late at night, and at school I'll stay up till three or four in the morning. Since I've had morning classes in the past, I've tried to form a habit of going to bed earlier — around midnight or one — but realistically, I don't think this is ever going to happen. I was thinking of trying, when I go back to school this fall, to go to bed around three or four and sleep for four hours, and then also take a four-hour nap during the day. Is this a good solution, or will I be more tired than if I sleep eight hours straight at night? Thanks!

I was wondering what causes fingernails to turn yellow if you leave nail polish on for a long time. Is it bad? And what can you do about it?

The last time I was at the hair cutting salon, the person who washed my hair asked me if I washed my hair everyday. I said I did, and she said she could tell. I'm not sure what she meant by this, but please tell me how she could determine this, and what is the best overall practice for washing hair in terms of frequency. I'm interested in the health of my hair as well as the health of my scalp. Thanks for you help!

How do I know if my hair is oily or dry? Does it make a difference if I'm a guy with short hair?

Do you have any suggestions for trying to stay healthy and sane while working the graveyard shift?

Thanks very much.

What are the reasons for getting white hair in teenagers?