Ask Dr. Christiane Northrup

Intimate. Personal. Even embarrassing. This is no time to be shy. One of Oprah's favorite doctors, Dr. Christiane Northrup, answers all your questions!

Is there a Viagra® for women?

First up is Shirley from Illinois. "They have Viagra for men," she says. "Don't they have anything for women?"

The answer is no. "The reason they don't have Viagra for women is because for women, sex is multimodal and it involves your emotions and your feelings and all of that stuff," she says. "This is Viagra for women − turn yourself on to life. I want you to think of the things that bring you the most joy, that give you the most turn on. It might be funny movies. It might be romance novels."

Dr. Northrup also says all women should practice "self-cultivation," an alternative word for masturbation. "You can learn how to rewire yourself for maximum pleasure by connecting all the erogenous zones in your body down to your clitoris, and you practice," she says. "I'd prescribe three 30-minute sessions a week minimum, and once you're good at it, you can invite someone else in."

If you're still having trouble getting turned on, Dr. Northrup says to talk to your doctor and look into getting your testosterone and estrogen levels checked. If you have dryness, Dr. Northrup says a lubrication gel or estrogen cream can help. "Sunlight will often turn a woman on, by the way, because it increases testosterone levels," she says. "Not a lot, just a little bit, and it increases serotonin in your brain."

Do long winters make you feel SAD — literally?

One woman wants to know how to keep seasonal affective disorder from getting the best of her. "I'm from Utah & the winters last way too long," Carol says. "And the older I've gotten—I'm 45—it's become harder for me. I need the sunshine. And I am such a different person in the summer. I'm happier. My kids can see it. My husband can see it. And I'm just wondering, is there anything women can do?"

SAD affects people in climates that are gray for a good part of the year. "Seasonal affective disorder is the PMS of the annual calendar," Dr. Northrup says. "What it is, is you're not getting enough serotonin. So the reason you're getting depressed is absolutely real. It's not enough serotonin. Natural light is a nutrient, and it hits our retinas and it increases our serotonin in our blood so everybody in Chicago, everyone in the whole northern areas needs some natural light."

If you can't get enough natural light outside, there are other things you can do, the doctor says. "You need to get a good light box that has enough of the regular bright sunlight wavelengths. And those are widely available," she says. "Even, believe it or not, a lightbulb that's full spectrum lighting. Those fluorescent bulbs, and you just keep it out of the corner of your eye, where you can see it, reading at night, that will turn you right around."