Every fact on this site, with its evidence grade, its caveats, and a link to the source.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
The industry / Review of other studies
According to an industry report cited in this review, about 75% of scented candles are fragranced with artificial scents because they cost less than natural fragrance materials.
Weak evidence: Cited without an independently checkable primary source in this review; industry-report figure (ref. 48).
Source: Adamowicz 2019, Cancer Prevention Research Link to this fact
The industry / Other evidence
The US market for scented candles is estimated to be worth approximately $2 billion annually.
Weak evidence: Abstract-only/background figure; sourced from an industry-characterization paper (Ahn et al. 2015) not independently verified in this evidence base.
Source: Nazir et al. 2024, Annals of Medicine & Surgery Link to this fact
The industry / Other evidence
A study by Petry et al. (2014) concluded that, under normal conditions of use, scented candles do not pose known health risks to consumers.
Weak evidence.
Caveats
Petry et al. 2014 is not yet a evidence base primary; its funding/COI has not been independently verified here, though several co-authors and the paper's risk-assessment framing are consistent with fragrance-industry-connected toxicology work. It is one study among several in this same Viewpoint reaching the opposite conclusion (Adamowicz 2019, Derudi 2014, Chandrasekaran 2021).
Source: Singh 2023, Environmental Science & Technology Link to this fact
Information, not medical advice. See also: myths we won’t tell you.