Your estrogen and progesterone should be operating at their optimum strength. Their levels naturally ebb and flow as they control your monthly menstrual cycle.

Testosterone also usually functions on full power at this age, managing your sex drive, as well as helping maintain energy levels and muscle and bone strength.

Energy level
Low testosterone and estrogen levels at the start of your period can introduce fatigue, but this tiredness is short-lived. After menstruation, rising hormones return the bounce to your step.

To give them a helping hand, Debbie Reid, a registered dietitian at BC Children's and Women's Health Centre, suggests eating regular well-balanced meals.

"If you're not fuelling up at least every four hours, your energy will sag," she says. Add protein to each meal, and don't forget energy-boosting carbohydrates.

Sex drive
Testosterone reaches its pinnacle at ovulation, around Day 14 of your cycle, boosting your confidence and sexual cravings. "Our sex drive peaks when we're most fertile," says Dr. Jennifer Blake, CEO of the Society of Obstetricians and Gynecologists of Canada.

For some women, however, taking birth control pills reduces their sex drive. The extra estrogen in the pill can suppress testosterone's randy response. "Some women are sensitive to hormone levels and may need a different pill or form of birth control," says Blake.

Menstrual cycle
"This is the most stable time for the menstrual cycle and hormones," says Blake. It's not normal to have excessive pain, heavy bleeding or irregularity. "Period problems are the earliest indicator that hormones are out of balance," says Lorna Vanderhaeghe, a women's health expert and author of A Smart Woman's Guide to Hormones (Fitzhenry & Whiteside, 2011).

"It's important to fix [period difficulties now] because they can lead to bigger problems later," she says. Ask your doctor for a thyroid blood test to help diagnose troublesome menstruation.

Body and weight
Your body boasts plenty of muscle-building testosterone, as well as cardiovascular-friendly estrogen. A study from the University of Adelaide in Australia discovered that estrogen and progesterone levels peak two weeks before menstruation.

Women who exercised during these 14 days burned 30 percent more fat than at any other time of the month.

Estrogen also helps maintain strong bones. The hormone wanes later in life, but you can prevent brittleness by adopting bone-supporting habits now.

Reid suggests getting 1,000 mg of calcium via food (two to three daily servings of milk, cheese, yogurt or a fortified soy beverage) and taking a daily vitamin D supplement (400 to 1,000 IU).

Some exercises can also increase bone strength. Dr. Julia Alleyne, medical director for Sport CARE at Women's College Hospital in Toronto, recommends doing high-impact activities, such as skipping rope, dancing or jogging, every day.

Skin
Testosterone abnormalities can trigger breakouts. "If you have acne along your jaw or down your neck, it's usually hormonal," says Dr. Gordon Searles, president of the Canadian Dermatology Association. Blood tests ordered by your physician or dermatologist can help find a fix.

This story was originally titled "The Truth About Hormones" in the March 2013 issue. Subscribe to Canadian Living today and never miss an issue!