Does vitamin C prevent a cold? Will having wet hair make you sick? 5 myths doctors want to debunk.

Respiratory virus season is officially here in the U.S., making it a prime time to catch a cold. And because the average adult gets two or three colds a year, you could be dealing with an onslaught of sniffles and sneezes a few times in the near future.

With that, it's a good idea to do what you can (like washing your hands) to avoid germs and lower your risk of getting ill. But there are a lot of myths about what is involved with catching colds, including how to prevent and treat them. In fact, Dr. Thomas Russo, professor and chief of infectious disease at the University at Buffalo in New York, says it's something he gets asked about a lot.

So what are the biggest myths about colds, and what's actually legit? Infectious disease doctors break them down.

Myth #1: There’s one virus behind the common cold

There’s a reason you might catch a cold multiple times a season — even after it feels like you just got over one, Russo says: They can be caused by a slew of viruses.

The common cold is caused by more than 200 respiratory viruses, which is a lot for your immune system to try to defend against. According to the Centers for Disease Control and Prevention (CDC), rhinoviruses are the most common cause of colds in the U.S., but other causes include human coronaviruses, parainfluenza viruses, adenoviruses, enteroviruses and human metapneumovirus.

Worth noting: SARS-CoV-2 (the virus that causes COVID-19), the influenza virus and respiratory syncytial virus (RSV) can also cause cold-like symptoms, but they don’t actually cause colds, according to the CDC.

Myth #2: Going out with wet hair raises the risk of getting a cold

This is a biggie that keeps coming up, but it’s just not true, Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life. “Colds are caused by viruses, and the fact that you have a wet head or are feeling chilly doesn’t matter to the virus,” he says.

This has actually been studied before. Schaffner points to older research in which people were divided into two groups. Half were warm and comfortable, while the other half were damp and uncomfortable. All were exposed to a virus that causes the common cold. “It turned out that both groups got equal rates of infection,” he says.

Myth #3: Vitamin C can prevent a cold

Pharmacy and grocery store shelves are packed with vitamin C supplements that heavily imply or even clearly state that they’ll help prevent a cold. But the evidence just isn’t there.

One study of 29 clinical trials involving more than 11,000 people found that taking vitamin C regularly had no impact on how often people got a cold. The National Institutes of Health (NIH) also clearly states online that “vitamin C supplements do not reduce the risk of getting the common cold.”

That said, some data suggests that taking vitamin C may help once you get a cold. An analysis of clinical trials found that people who took at least a gram a day of vitamin C when they had a cold reduced the severity of their cold by 15% and had symptoms for slightly less time than people who took a placebo. Another study found that taking vitamin C within 24 hours of symptoms starting may help reduce how long the cold lasts.

Ultimately, Russo says that there’s “no data to support” using vitamin C to lower your risk of getting a cold.

Myth #4: You can only get a cold in the winter

It’s true that colds are more common in the winter. In fact, the CDC says that most people get colds between September and May. But you shouldn’t be shocked if you happen to get a cold in the summer too.

“Viruses are always around,” Russo says. However, he points out that some viruses are more abundant during certain periods of time than others.

“There are summer cold viruses,” Russo adds. While rhinoviruses are the most common cause of colds as a whole, summer colds are usually caused by enteroviruses.

Myth #5: Antibiotics will help treat a cold

Antibiotics have been so widely used to treat infections that it’s understandable to at least wonder if taking these medications will help clear up your cold. But antibiotics don’t treat everything.

“Antibiotics are directed against bacteria, not viruses,” Russo says. In other words, antibiotics will do nothing to treat your cold.

“Not only are you exposing yourself to potential side effects of taking the antibiotic, you’re contributing to making the bacteria in your body more resistant to the antibiotics,” Schaffner adds. “Please don’t do that.”

It is possible that your “cold” could be due to something else, like bronchitis, strep or pneumonia, though. If you find that your symptoms are getting worse, or that you have a sore throat and fever, Russo recommends contacting a doctor for an evaluation.