In this video, Mikhail Varshavski, DO, who goes by "Dr. Mike" on social media, reviews research on the common practice of burning candles.
Following is a partial transcript of the video (note that errors are possible):
Varshavski: Hi, I'm Dr. Mike Varshavski, a board-certified family medicine doctor. Welcome to the new series, "Truth or Scare," where I dive into the latest research and give you my take on the scariest, most viral health claims making news today. This episode's claim: that burning candles indoors can emit toxic chemicals that cause all sorts of serious health problems, and the type of candle could make it worse.
Sunwave Club: Burning a candle for 1 hour has the same negative effects as smoking a whole cigarette.
Varshavski: Let's get into it. Whenever you burn anything, you will have chemicals released into the air that can be harmful for you. This will change drastically based on what's being burned, where it's being burned, and how long you're exposed to it. One group of chemicals detected in those emissions are called volatile organic compounds, or VOCs for short. Some VOCs like benzene or formaldehyde are well-known carcinogens, meaning they can cause cancer.
Then you have particulate matter, a mix of solid and liquid particles small enough to get deep into your lungs and enter your bloodstream. These particles are a component of soot, that dark powdery residue you might see on the floor of a fireplace or inside of a glass candle jar. Inhaling them can increase your risk of lung and other cancers, and respiratory diseases like asthma and COPD [chronic obstructive pulmonary disease]. Soot is mainly caused by incomplete combustion. This happens when the wax doesn't fully burn because there isn't enough oxygen available. Visible smoke is the most obvious sign of this incomplete combustion. Candles tend to give off this smoke right after they are lit or when the flame is dying out. One older EPA [Environmental Protection Agency] study actually found that a few seconds of smoldering produced more particle emissions than several hours of normal candle burning did.
Third are phthalates or endocrine disruptors. They are chemicals that truly can impact hormone levels as well as aggravate allergy and asthma symptoms. Technically, phthalates are considered like semi-VOCs. Phthalates are actually specific to scented candles. They are used in synthetic fragrances, which give most scented candles their aromas. Burning a candle creates a very low level of exposure to all of these chemicals. This is the case for both scented and unscented candles, and candles really made from all different types of wax.
However, there is some evidence showing the type of candle wax might play a role in worse emissions. In addition to containing phthalates, scented candles are said to give off more soot. There is some evidence that paraffin wax, which is made from petroleum, produces more VOCs and more soot than natural waxes like beeswax and soy wax. But these differences are likely too small to make candles a true health hazard. Also, at least one study found that I looked at showed that all types of wax basically release the same mix of chemicals into the air. Those worried about allergies should be on alert when it comes to scented candles. In that case, you'd want to avoid all products with added fragrance, not just candles.
But if you use candles a typical amount, should you panic? While "typical candle usage" doesn't have a truly defined meaning, the National Candle Association does recommend 4 hours as a limit. They also say to follow a candle manufacturer's instructions on ideal burn time using a well-ventilated space and limiting how many candles are burning at the same time.
There has actually been some research done to address the concerns surrounding scented candles. In one 2014 study, researchers burned candles for 4 hours in indoor spaces, ranging from the size of a small bathroom to an average-size living room. They measured airborne emissions of VOCs, semi-VOCs, and particulate matter throughout the entire burn session. Even in the smallest space, the highest VOC levels were less than half of the limit for safe indoor air quality as recommended by the WHO [World Health Organization]. Compared to candle emissions, you're exposed to far more particulate matter and VOCs when you use a wood-burning stove or an indoor fireplace, and neither activity is considered unsafe when used in moderation. However, heavy exposure to combustion products is a valid concern for some groups of people like chimney sweeps or anyone who smokes cigarettes inside without proper filtration.
What's the takeaway here? Burning a candle does release potentially harmful substances into the air. Unless you're overdoing it or uniquely vulnerable, the quantities are too low to make you sick. With that said, less soot is always better. If you notice that your candles produce a lot of it, here are some "sootable" steps to take -- sorry, I had to do it -- to minimize your soot exposure. Trim the wick to one-fourth of an inch. Remove any debris from the pool of wax around the wick. Put out the candle before it starts smoldering. Avoid placing a candle near an open window, fan, or air conditioner. Air movement like that can interfere with oxygen supply. Never leave a candle unattended, especially around kids or doggos. And no matter how often you burn candles, you never need to do this.
Janine Bowring: You may need to do a full body detox if you've been using candles for a number of years to get those toxins out of your body.
Varshavski: On my Truth or Scare scale, where 0 is total BS and 10 is a true evidence-based claim, this claim gets a 3.
Watch the video above for more.
, is a board-certified family physician and social media influencer with more than 12 million subscribers.