Researchers said Wednesday that even a low dose of omega-3 fatty acids can lower blood pressure. But is your supplement giving you those great perks?

Omega-3s are essential fatty acids. They're found in cold-water fish-like salmon, mackerel, halibut and sardines. Studies found omega-3 fatty acids may reduce the chances of dying from heart disease, joint tenderness, bad cholesterol, menstrual cramps, colon cancer and prostate cancer. They may also improve blood pressure, mood, acne and asthma. People who don't like fish can take a supplement, although some supplements can leave with unpleasant side effects. "There's unpleasant burping. People would almost have a fishy taste all the time and their skin might actually smell bad," Dr. David Becker said.

The Food and Drug Administration doesn't regulate supplements, so consumers don't know what they're really getting. Becker told NBC News that he has a simple test that can be done at home.

The test is not scientific. It's what he calls the "poor man's way" to test omega-3s.

Take a fish oil capsule, puncture it with a pin and drain it on a solid plate, not paper. Put it in the freezer for at least five hours. If the oil freezes or turns to slush, the doctor said it's probably junk.

"If, on the other, it's either liquid or it evaporates, you've got high-quality fish oil, and I'd recommend you stay with it," Becker said.

(And test whether it makes you weak or strong) www.betheonewhoknows.com