Are Scented Candles Bad For You?

Many people wonder if their favorite scented candle is secretly harming their health. The short answer is that for most people, using scented candles occasionally in a well-ventilated room is not bad for you. However, some types of candles and certain ingredients do release compounds that can be problematic, especially with daily, long-term use in small, unventilated spaces. This article breaks down what the actual science says so you can make an informed choice.

What Do Scented Candles Release Into the Air?

When you burn a scented candle, it does not just release a pleasant smell. The flame breaks down the wax and the fragrance oils. This process creates a mix of chemicals in the air.

The main things released are tiny particles called particulate matter (PM) and gases like volatile organic compounds (VOCs). The amount depends heavily on the wax type, the fragrance, and how cleanly the candle burns. A 2014 study published in Environmental Health Perspectives found that burning candles can produce levels of particulate matter comparable to diesel engines, but only in very specific, poorly ventilated conditions. This sounds scary, but the key is the comparison to real-world exposure.

Research from the German Environmental Agency has shown that paraffin-based candles can release more VOCs like toluene and benzene than soy or beeswax candles. However, the levels are typically very low. The agency concluded that for a healthy person, the risk from occasional candle use is negligible. The bigger concern is for daily, all-day burning in a small bathroom or bedroom with the door closed.

Are Scented Candles Bad For You? The Real Health Concerns

The primary health concern with scented candles is not poisoning or cancer from a single use. The real issue is long-term, repeated exposure to the fine particulate matter. These tiny particles are small enough to get deep into your lungs.

For someone with asthma, COPD, or other respiratory conditions, even a small increase in indoor particulate matter can trigger symptoms. A 2015 review in International Journal of Environmental Research and Public Health noted that indoor air pollution from sources like candles is a known trigger for asthma attacks. If you have a respiratory condition, you should be more careful about any burning product.

Another concern is the synthetic fragrance oils. Many are made from phthalates, which are used to make the scent last longer. Phthalates are endocrine disruptors, meaning they can interfere with your hormones. The CDC has acknowledged that phthalate exposure is widespread from many consumer products. While the amount from candles alone is low, it adds to your total daily exposure from plastics, personal care products, and food packaging.

Paraffin Wax vs. Soy Wax vs. Beeswax: What the Research Says

Not all candle waxes are the same. The type of wax is the biggest factor in what gets released into your air. Here is a clear comparison based on available evidence.

The key takeaway is that paraffin wax is the most likely to produce unwanted chemicals. Soy and beeswax are better choices if you burn candles frequently. Beeswax is the clear winner for air quality, though it is more expensive.

Do Scented Candles Cause Cancer?

This is the most common fear, and it is worth addressing directly. The American Cancer Society states that there is no conclusive evidence linking occasional candle use to cancer in humans. The concern comes from the fact that some candle emissions are classified as carcinogens by the International Agency for Research on Cancer (IARC). But the dose matters.

IARC classifies things based on hazard, not risk. A hazard is something that can cause cancer under certain conditions. Risk is the likelihood that it will cause cancer at the level you are actually exposed to. The amount of benzene or formaldehyde from a candle is far lower than what you get from traffic exhaust, secondhand smoke, or even cooking on a gas stove.

One study from South Korea in 2017 did find that burning candles increased indoor formaldehyde levels. But the levels were still below the safety limits set by the World Health Organization. So while the hazard exists, the real-world risk for a person burning a candle a few times a week is very low. The risk would only become meaningful if you burned multiple candles for hours every day in a sealed room.

What About Lead Wicks and “Soot-Free” Claims?

Lead wicks were a real problem in the past. They were used to keep the wick standing straight. Burning a lead wick releases lead particles into the air, which is toxic, especially for children. The good news is that the U.S. Consumer Product Safety Commission banned lead wicks in 2003.

If you have very old candles from before 2003, throw them away. Any candle bought in the last 20 years uses cotton or paper wicks. Some wicks have a metal core, but those are usually zinc or tin, which are not considered a health concern at the levels released.

You may also see candles labeled “soot-free.” This is mostly marketing. All burning candles produce some soot. The amount depends on the wax, the wick length, and whether the flame is steady. A flickering flame creates more soot. To reduce soot, always trim your wick to ¼ inch before lighting. A clean, steady flame produces far less particulate matter.

How to Burn Candles More Safely

If you enjoy candles and do not want to give them up, there are practical steps you can take to reduce your exposure. You do not need to choose between your health and your cozy evening.

• Ventilate the room. Open a window slightly while the candle is burning. This is the single most effective thing you can do. It dilutes the particles and gases.
• Trim the wick. Keep it trimmed to ¼ inch. A long wick produces a larger, dirtier flame and more soot.
• Choose cleaner wax. Beeswax or soy wax are better than paraffin. Read the label. If the wax type is not listed, assume it is paraffin.
• Avoid candles with “fragrance” only on the label. Look for candles that list specific essential oils or natural fragrances. “Fragrance” can hide phthalates.
• Do not burn for more than 4 hours at a time. The flame gets larger and less stable the longer a candle burns. Extinguish it and let it cool before relighting.
• Use an air purifier. A HEPA air purifier in the room where you burn candles can capture the fine particles before they settle in your lungs.

These steps are simple and effective. They do not eliminate the risk entirely, but they reduce it to a point where most researchers consider it negligible for healthy adults.

Common Misconceptions About Scented Candles

There is a lot of misinformation online. Some sources claim that all candles are toxic bombs. Others say they are perfectly safe with no caveats. Neither is accurate.

Misconception: “Essential oil candles are always safe.” This is not true. Essential oils are complex mixtures of chemicals. When burned, they can change into different compounds. Some essential oils, like citrus oils, can release limonene, which reacts with ozone in the air to form formaldehyde. The levels are low, but the point is that “natural” does not automatically mean “safe to burn.”

Misconception: “Soy candles are completely non-toxic.” Soy wax is a better choice than paraffin, but it is not zero-emission. All burning produces carbon monoxide and carbon dioxide. The fragrance oils in soy candles can still contain phthalates. The base wax is cleaner, but the overall product depends on the fragrance too.

Misconception: “Candles are worse than air fresheners.” This depends on the product. Plug-in air fresheners and aerosol sprays often contain more VOCs than candles because they are designed to release fragrance continuously without burning. A 2015 study from the University of Washington found that many scented products, including plug-ins, emit hazardous VOCs. Candles are not necessarily the worst offender.