URBANA, Md. -- Americans spend billions of dollars each year on vitamins and supplements, but what works for one person might not work for another.

Now a company is selling vitamins it says are tailor-made for you, reported WRC-TV in Washington, D.C.

"We are able to program a supplement program, based on your genetics -- what your biochemistry needs," said Gary Sandman of Maryland-based Individualized Health Solutions.

Sandman is president of the company that makes signature supplements. Each one contains a combination of vitamins, minerals and amino acids.

Sandman said that the right combination balances a person's biochemistry and is the key to achieving optimal health.

"It's basically a wide range from just feeling more youthful, more energy, to skin issues to overall just feeling better," Sandman said.

So how do they determine your formula?

There's no doctor visit or blood test. There is an online assessment test with dozens of questions to answer. Sandman said the company has already tested more than 20,000 people to come up with the foundation for the individual formulas.

"From that, we are now able to deduct that if you have a cluster of certain symptoms, we can predict, with 99 percent certainty, what your biochemical imbalance is," Sandman said.

The online test asks for medical information, but the answers to the questions are multiple choice.

That's a red flag for registered dietitian Cindy Clark.

"You have to take a look at the person and their lifestyle, their medical condition and everything," Clark said.

Despite some initial skepticism, Vickie Kordell of Gaithersburg, Md., tried the custom-made supplements.

"I noticed an increase in energy, ability to stay on top of things a lot easier. Things didn't quite get me down as they used to," Kordell said.

Amanda Welborn, 14, has suffered with the skin condition psoriasis for years. She's used topical ointments, but she said her skin only started clearing up after taking her custom vitamins.

"It went away, and that's never happened before," Welborn said.

The medical experts do not agree on the value of taking any kind of supplements, and you should talk to your own doctor before you start taking them, the television station reported.

"A lot of vitamins and minerals can interact with medications, so you want to make sure you are taking what's best for you," Clark said.

Signature supplements cost anywhere from $40 to $80 for a one-month supply, depending on the ingredients in your formula.

The manufacturers don't make any claims about curing health problems or about preventing diseases. It's all about basic nutrition for optimal health, according to the company.

For more information about signature supplements, visit SignatureSupplements.com.