What are supplements?
The Food and Drug Administration (FDA) characterizes all herbal, vitamin and mineral supplements (including diet pills) as "dietary supplements." Dietary supplements come in all shapes and sizes—pills, gel capsules, liquid and powder—and they can include any number of ingredients. Most often, supplements will be vitamins, minerals, amino acids, herbs or plants (also referred to as botanicals), or a mixture of these substances.

The tricky thing about dietary supplements is that they are not approved by the FDA before they go on the market. The FDA gives these supplements time on the shelves and stores, to see if consumers have any problems when they take them. Essentially, you are a "guinea pig" in a test lab when you buy and use these supplements. Of course, some supplements have been tested, so check out the label to make sure.

Beware of "miracle supplements." Any drugs advertised as producing "quick results" or "miracle cures" are probably not going to have the effect they say. Ask your doctor if you feel skeptical about any type of supplement that you might want to try.

Good Vitamins and Minerals
Vitamins and minerals basically support your body in every area. They help you grow, help you get better when you're sick, help you think, and even help you sleep. Vitamins are organic, which means they come from plants and animals. Minerals are inorganic (remember learning this in bio class?) and they come from the soil and water.

There are some vitamins that you might need to take in addition to the food you eat. This is especially true if you have certain dietary restrictions, or if you are a vegetarian. However, the best way to get all of the vitamins you need is to follow the food guide pyramid. If you know that you skip vegetables for pizza or load up on carbs and forget the blueberries from time to time, then your best bet is a one-a-day multi-vitamin. As a teen, you don't need anything fancy, and you don't need to go to a natural health food store to get the most premium vitamins out there. Ask your doctor if you are unsure, and he or she will recommend a good multi-vitamin brand for you.

Folic Acid
Make sure your daily vitamin has folic acid in it because folic acid is almost impossible to get from food alone. Folic acid is important for your body in so many ways. It is one of the B vitamins, and helps make red blood cells and proteins, including DNA (the basic building block of your entire body!) and this means that it’s very helpful for growing teens. Folic acid is also important for your future. Later in life if you decide to have a baby, this nutrient may help protect the baby from birth defects. The easiest way to get folic acid is to take a multi-vitamin or folic acid tablet or eat a bowl of folic acid-fortified cereal every day.

Calcium
Calcium is a very important mineral for a growing body. A calcium-rich diet, which includes 3 to 4 servings (1,300 mg) of calcium each day, will ensure that your bones get enough calcium deposits and can grow properly. As a woman, you are going to be reminded again and again to eat calcium for the rest of your life. So you need to start now. Dairy products such as milk, yogurt and cheese are great sources of calcium. But you can also get calcium from green leafy vegetables and calcium-fortified soy products.

Iron
Iron is another important mineral for teenage girls. First of all, your body needs iron in order to make hemoglobin, which carries the oxygen throughout your body in your bloodstream. Once you begin menstruation, you begin to lose red blood cells that contain iron. If you are an athlete or regular exerciser, you are also losing iron through excessive sweat. It is a fact that many teenage girls are at risk for iron deficiency. Iron deficiency causes fatigue, irritability, headaches, lack of energy and even tingling sensations in the hands and feet. Get this—a recent study showed that mild iron deficiencies could possibly lead to lower test scores in math for teenage girls. Although that's not a proven fact, it is something to think about since we know iron deficiency will make you tired and irritable. Iron can be found in fish, red meats, whole grains, dried beans and peas, leafy green vegetables and dried fruits.

Zinc
Zinc is another essential growth mineral, although you don't need as much of it as you need calcium or iron. It helps out with wound healing, your sense of taste and smell, and your body's sexual maturation. Zinc is also vital in regulating your metabolism. Some studies also show that zinc lozenges help to reduce cold symptoms. Zinc is definitely essential, but keep consumption under control. Don't overdo it, because high doses of zinc can induce diarrhea, heartburn, nausea, vomiting and abdominal pain.

Special Diets
If you are on a special diet due to personal choice, weight loss (as prescribed by a doctor), allergies or disease, a multi-vitamin is a very good idea. Your doctor will be able to tell you the exact vitamins you should be taking. If you are a vegan or a vegetarian, you should take additional B-12. If you are lactose intolerant, you should get extra calcium. And if you avoid the sun at all costs, you should add some vitamin D to your diet.

Vitamin OD
OD isn’t a new vitamin—it’s vitamin overload. That's right, there is definitely too much of a good thing. If you take too many fat-soluble vitamins (that means they stay in your body longer than water-soluble vitamins like C), such as vitamins A, D, E, and K you can experience serious side effects, including liver damage, headaches and blurred vision. Certain oral acne medications contain a lot of vitamin A. So, talk to your dermatologist before you fill your prescription, and make sure not to take additional vitamin A if you already have a steady source.

Herbal Supplements
The most well-known herbal supplements out there are Echinacea, ginkgo and St. John's wort … but there are countless others. Just like diet pills, herbal supplements are not generally tested by the FDA before they are put into stores. Herbal medicines are all natural, but that doesn't mean they’re risk-free. There is not much proof out there that herbal supplements work, so be sure to consult your doctor about his or her opinion on your body and herbal supplements. Some may have dangerous side effects, and may react poorly with other medications you are taking or render them ineffective. Any changes that you seek through herbal remedies may also be attained through healthy nutrition and regular exercise.