Taking a Supplement? Ask These 6 Questions

The vitamin D pill you take because you don’t get enough sunlight. The calcium chew your grandma eats to protect her bone health. The protein powder your teen mixes into a shake before hitting the gym.

All of these—and so many more—fit into the enormously broad category of “supplements,” which includes vitamins, minerals, herbs, enzymes, probiotics, amino acids and animal byproducts.

Sometimes, supplements are helpful for our health. Other times, they can be useless or even cause health risks, says UNC Health sports medicine physician Justin Lee, MD.

“It really depends on the person and the product, if there’s a deficiency they’re trying to fix, and what other supplements or drugs they might be taking,” he says.

Ask yourself these questions if you’re already taking a supplement or wondering if you should start.

1. Am I experiencing symptoms?

Tell your doctor if you’re always tired, often getting sick or feeling unwell, or struggling to eat a balanced diet. They may order blood tests to check for vitamin deficiencies, anemia (low red blood cell count) and levels of substances in the body that can indicate certain health conditions (such as a thyroid condition).

Based on these tests, doctors may recommend supplements such as B12, which keeps blood and nerve cells healthy and helps prevent anemia, and vitamin D, which is important for bone health and hard to get naturally if you don’t spend much time in the sunshine, Dr. Lee says.

Another time when supplements are critical? Pregnancy. Prenatal vitamins help provide vital nutrients to mom and baby. Folic acid is especially important to reduce the risk of certain birth defects.

“Prenatal vitamins are absolutely essential for anyone who is pregnant, even if you’re eating a healthy diet,” Dr. Lee says.

2. Can I get what I need from food or sleep?

Supplements can be helpful, but “people in general should get the majority of their vitamins and minerals from food,” Dr. Lee says. “Our bodies are designed to digest food and use nutrients in their most natural form.”

A concentrated pill or powder is unlikely to be as effective as fruits, vegetables and lean proteins at improving our health, he says. For example, fish oil supplements are often marketed as being good for cardiovascular health, but the research supporting those claims is thin. On the contrary, there’s lots of evidence that what you eat can improve your heart and brain function. (Focus on vegetables, especially leafy greens, berries and other fruits, nuts, seeds, beans and whole grains.)

And don’t forget sleep. Most adults don’t get enough, and working to fix that is likely to do more for your energy than caffeine or other “energy-boosting” supplements on the market.

3. Do I know what’s in this supplement?

Some supplements contain a laundry list of ingredients, and there’s no way to know if what’s represented on the bottle is true, Dr. Lee says. Ask your doctor before taking something if you are unsure.

“Supplements are not regulated by the FDA the same way as medicines,” he says. “You don’t always know exactly what you’re getting.”

Dr. Lee looked at a label for a workout supplement to demonstrate the problem with many of these products: “It has beet root powder, which we know seems to help with performance and recovery, but there are so many other things in here too that it makes me cringe,” he says.

4. Does this supplement have known side effects or interactions?

Even without cringeworthy ingredients, it’s important to consider possible side effects and interactions depending on other drugs and supplements you take. St. John’s wort, which some people take for depression despite limited evidence, can make other medications less effective, and if taken simultaneously with a standard antidepressant can cause a life-threatening condition called serotonin syndrome. Excessive vitamin A and iron can damage the liver and other organs. In recent years, calcium supplements have been linked to an increased risk of heart disease. If you take a supplement containing caffeine and also drink several cups of coffee or an energy drink, you may experience dehydration, heart palpitations and anxiety.

5. Is the supplement marketed with dramatic claims?

There’s a huge supplement market for people who want to lose weight and build muscle, and for men hoping to increase their testosterone and sex drive. Beware of bold claims that a supplement can burn fat, build “mega” muscles or revive libido, Dr. Lee says.

As opposed to overinflated promises, the benefits of supplements are more likely to be modest but can be meaningful for the right person. For example, there is evidence that protein powders, which can be animal-based or vegan, can help increase muscle mass. And supplements with the amino acid creatine can help with short bursts of exercise and strength training, such as trying to increase the weight on a bench press.

“Creatine does give people a little extra boost with strength and speed performance, and if you use it right, it’s fairly safe,” Dr. Lee says, though people with kidney problems should use creatine with caution.

As for energy and sex drive, again, diet, exercise and sleep can go a long way. If you experience erectile dysfunction, talk to your doctor about medication and whether it might be a symptom of another health problem.

6. Have I talked to my doctor?

Make sure your doctor knows everything you’re taking, both medications and supplements. If your doctor recommends a supplement, follow up to discuss how well it’s working.

If you’re an athlete interested in improving your performance, talk to a sports medicine doctor about which supplements are useful and which to avoid. Dietitians can be a helpful resource for anyone with questions about supplements and adjusting their diet to get more of what they need through food.

Have questions about supplements? Talk to your doctor, or find one near you.