Their manufacturers claim they work for everything from sexual dysfunction to memory woes, depression and weight gain.
And now, more Americans than ever are giving supplements a try before turning to medications.
But which ones are right for you?
On "The Early Show on Saturday Morning," Dr. Daniel Amen provided some answers.
He's the author of the current best-seller, "Change Your Brain, Change Your Body."
A walk through the aisle of your local vitamin store can be overwhelming, so Amen offered some guidance, stressing that this isn't a matter of one-size-fits-all: Supplements' effectiveness varies by the person. And some aren't very good at all.
Supplements can be very helpful but, he points out, just because something is natural doesn't mean it is innocuous. Having a thoughtful approach is very important.
If you are not taking any supplements at the moment and you feel pretty healthy, should you still take supplements?
I recommend three things for my patients: A good multivitamin, because 91 percent of Americans do not have the minimum requirement of five servings of fruit and vegetables per day -- the minimum requirement to get the nutrition you need. I recommend all of my patients take Omega 3 fatty acid supplements because, when those levels are low , people are vulnerable to dementia, depression, even suicide. Taking Omega threes has been found to be good for your heart, skin, eyes, joints , hair and brain. And everyone should get their Vitamin D level checked.
In the last five years, there has been a lot of information that has suggested that two-thirds of Americans are low in Vitamin D. And when you are low in Vitamin D, you are hungry all the time and you are at risk for cancer, diabetes, multiple sclerosis and heart attack.
RHODIOLA for Energy
Rhodiola was actually used by cosmonauts on the space station to help them with focus and energy. You can find it in energy drinks. We did a study on RHODIOLA and found it boosted blood flow to the front part of your brain. It is better than caffeine, because it enhances overall brain function and caffeine does the opposite.
5-HTP for Weight Issues
5-HTP is a supplement that boosts Serotonin, a chemical in your brain. When Serotonin is low, people can get obsessive, they can get over-focused and have mood problems. Research suggests it can also help you lose weight. And the dosage should be somewhere between 200-250 mg per day.
It can also be helpful for people who tend to be anxious, who tend to be depressed. But not all anxious, and not all overweight people are the same. You have to know your type of brain. So, it is very important to not just go out and take 5 HTP, but talk to your naturopath, your doctor and find out if it is the right thing for you.
Huperzine A for Memory
Huperzine A is a Chinese moss extract that has been found in a number of studies to aid memory. One study even suggested it may help kids with learning issues.
I am not a big fan of caffeine, but I am a big fan of green tea. It has a little caffeine in it. It also has something called an ingredient that can help you focus and relax at the same time. So, it can boost your willpower, to help you stay on track with things. And there are a number of studies that say it enhances brain function and makes your DNA look younger.
Are these supplements also good for your heart?
What I always say is that whatever is good for your brain is good for your heart - it is all about good blood flow. It is very important to understand that your physical health affects your brain health. And when your brain works right, you can make the right decisions about your health.
What is the most common misperception about supplements?
Well, there is the big debate! Some claim supplements don't work and there is no science behind them. That is not true. It is just important that you target them to your specific brain and your specific needs.
Is there any supplement you should not take
Well, it depends on the individual, which is why I write in the book about what is good and bad for your brain, depending on your brain type -- and we help you determine that.