This household item may spark joy, but it has serious health harms
Key Takeaways
Burning scented candles can be a harmful source of indoor exposure to pollutants, including VOCs and PM.
Scented candles increase the risk of respiratory issues, headaches, and other health conditions.
Patients should be advised to purchase scented candles made of natural materials and to air out rooms after a scented candle is burned.
An estimated 77% of Americans use scented candles and other scented products in their homes, including trash bags, toilet paper, and baby products.[][] In the US, an estimated $2 billion a year is spent on scented candles, with demand only rising.[]
Despite their increasing popularity and seemingly innocuous nature, scented candles do pose health risks as a form of indoor pollution that releases volatile organic compounds (VOCs), particulate matter (PM), and phthalates.
In-home air pollution
The evaporation of fragrance from the heated wax bowl releases VOCs, including acetone, toluene, and benzene. This happens even with candles labeled “organic” or “green.” Synthetic fragrances used to make candle scents also contain phthalates, which can be absorbed through the skin or inhaled.[]
Particulate matter is also released from the burning of scented candles, with these small particles lodging in the alveoli, where they are difficult to expel. Once in the alveoli, PM can lead to cardiovascular and respiratory issues.[]
More generally, scented candles and other fragranced products are linked to headaches, migraines, shortness of breath, coughing, allergic rhinitis, and dermatitis. VOC exposure is related to irritation of the eyes, nose, and throat, as well as dyspnea, nausea, and damage of the central nervous system.[]
What the research says
Data show that 24.8% of scented-candle users reported health-related problems, with 15.2% reporting headache, 8.9% shortness of breath, and 7.8% cough. The risk of headache, sneezing, and wheezing was higher with usage lasting 60 minutes or more.[]
“The most common complaints from those who had been exposed to scented candles were vertigo, headaches, mucosa irritation, respiratory issues, watery eyes, sneezing, stuffy nose, chest tightness, and a dry or irritated throat,” wrote authors of an editorial in Annals of Medicine and Surgery.[] “Formaldehyde and aromatic hydrocarbons like toluene and benzopyrene may be released in large quantities from commonly available scented candles, especially the less expensive ones made from paraffin wax.”[]
The authors point to an intriguing case study involving an older woman who was diagnosed with exogenous lipoid pneumonia after inhaling vaporized paraffin from burning candles.[] It should be noted, however, that the woman lived and worked in a shrine all her life, where candle usage is much higher than average.
Although dependent on the specific type, how someone is exposed, and the length of that exposure, phthalates can be especially dangerous, and they have been associated with the following unexpected health detriments.
Dysfunction in fetal development
Decreased sperm concentration and motility
Preterm birth, early puberty, and issues with female fertility
Insulin resistance[]
Phthalates alter the endocrine and metabolic axis by interfering with the protein sex hormone binding globulin (SHBG), thus resulting in decreased SHBG levels. Additionally, insulin resistance may be due to oxidative stress and mitochondrial dysfunction caused by phthalates.
Because candle wax is still colored using toluene derivatives and benzidine-based dyes—both of which are associated with the development of urothelial cancer—“[f]requent consumption of scented candles for quite a long time and their use in inadequately ventilated rooms may increase the chance of developing urothelial cancer,” state authors in the Annals of Medicine & Surgery.[]
What this means for you
Clinicians may want to advise their patients on the safer use of scented candles. For patients less inclined to omit candles from their life, it’s important to prioritize candles made of natural materials (eg, beeswax, soy wax, essential oils). Less-expensive scented candles made with paraffin or artificial materials should be avoided, as they can increase the risk of illness. Phthalates found in scented candles can disrupt reproduction, hormone levels, and metabolism.