With spring and beach season quickly approaching, many people are starting to get back into shape. For most, that means diet and exercise. But some may look to dietary supplements for a quick weight loss fix.

Dr. Diane Calello, medical director at the New Jersey Poison Control Center at Rutgers Medical School in Newark, warned consumers to be careful.

Supplements sold on the market are not tested and regulated for safety and effectiveness the same way prescription medications are, she warned. Products may contain hidden ingredients that are addictive, illegal and have dangerous side effects.

There have been a lot of drugs over the years that have been banned because they cause stroke or heart attack.

Erectile dysfunction drugs are also a problem. She said they can also contain substances that cause a drop in blood pressure, racing heart rate and may not work.

Drugs that claim to increase a person's energy or focus may contain banned stimulants in them or high levels of caffeine that are nowhere on the label. That can cause cardiac and neurological toxicity, said Calello.

She warned to be a careful of "all natural" supplements. They are not always safe and effective. She said people can be lured into this feeling of natural and not a medication so it must be safe. But quite the opposite can be true.

Be careful buying any dietary supplements online. She said if a person buys from a well-known retailer, that's a lot easier to trace and probably does have a bit more oversight than an online retailer no one has ever heard of before.

If a person is going to start a supplement for any health concern, Calello strongly suggests talking to a doctor. The supplement may interact with other medications that a person is currently taking.

Do research and know the side effects of each supplement.

"You should take one at a time because if you take four or five supplements, start them all at once and then you experience a side effect, you won't know what it is," said Calello.

Be very conscious of any side effects such as heart palpitations, dizziness, chest pain, anything out of the ordinary. Stop the supplement, call the doctor or even the New Jersey Poison Control Center at 1-800-222-1222.

Calello said a person can overdose on a dietary supplement. Nobody knows what ingredients are actually in a supplement because the regulation is not as tight as it is with prescription medications. So a person could actually be taking a full dose or a double dose of a drug in the supplement.

Keep in mind that some weight loss supplements contain anabolic steroids, which are illegal, unsafe and banned from use in competitions, Calello said.

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