Dihydroxyacetone Heating and Toxin Formation: Study Analysis
Many consumers recognize dihydroxyacetone (DHA) primarily as the active color-forming compound formulated in topical sunless tanning sprays and lotions. However, chemical safety researchers have also investigated how the compound behaves under thermal stress. A 2018 laboratory study evaluated dihydroxyacetone levels in electronic cigarette aerosols, exploring how heating coils and wick temperatures influence chemical degradation and toxin formation.
Thermal Breakdown and the Aerosol Study Setup
The laboratory investigation was published in 2018 under the title "Dihydroxyacetone levels in electronic cigarettes: Wick temperature and toxin formation." in Aerosol Science and Technology: The Journal of the American Association for Aerosol Research. The researchers noted that earlier testing had identified DHA, known as the active ingredient in sunless tanners, within electronic cigarette emissions. Because heating chemical liquids can induce thermal decomposition, the researchers set out to quantify DHA in aerosol emissions and explore how device engineering alters these levels.
The study design analyzed aerosols collected from three commercial brands of e-cigarettes. To assess whether hardware geometry influenced chemical emissions, the researchers compared two devices with horizontal heating coil configurations against one device equipped with a sub-ohm resistance vertical heating coil. DHA levels were identified and measured using a combination of GS/MS and 1H NMR analytical techniques while the wicking properties and wick temperatures were recorded under varying power levels.
What the Laboratory Testing Found
The investigation confirmed that DHA was generated across all three tested e-cigarette devices. However, the volume detected varied substantially depending on the internal coil orientation and thermal behavior:
- DHA was present in the aerosol output of every tested device brand.
- The sub-ohm resistance vertical coil device produced substantially less DHA in its aerosol compared to the two devices built with horizontal heating coils.
- The temperature of the wet layer of the wick remained relatively stable for the vertical coil configuration when battery power output was increased, whereas the horizontal coil wicks showed different thermal behavior.
- The authors noted that their findings aligned with prior studies investigating wicking efficiency and aerosol toxin formation, concluding that wick temperature measurements offer a practical way to compare different hardware designs during operation.
Biological Concerns Identified in the Paper
The detection of aerosolized DHA prompted the authors to highlight significant biological concerns regarding non-topical exposure. Specifically, the paper noted that DHA has been shown to react with DNA in vitro. In laboratory cell cultures, this chemical reactivity raises questions about potential cellular harm if the molecule reaches vulnerable internal tissues.
Furthermore, the researchers emphasized existing regulatory boundaries established by federal health officials. The Food and Drug Administration (FDA) restricts the use of DHA strictly to external application only. The FDA explicitly states that DHA should not be inhaled, ingested, or allowed to come into contact with any areas containing mucous membranes due to unknown risk. For consumers reviewing non-UV cosmetic methods, these established boundaries are central to understanding product safety, as detailed in our guide on Safer Alternatives to Melanotan: Sunless Tanning Explained.
What This Single Study Does Not Prove
While the study provides valuable physical chemistry data regarding hardware design and chemical emissions, it is important to understand its methodological limits:
First, this was a benchtop aerosol and engineering study, not a clinical trial in living human participants. It does not measure human health outcomes, track respiratory symptoms over time, or determine specific disease rates among individuals exposed to heated aerosols.
Second, the demonstration that DHA reacts with DNA in vitro does not prove how the molecule behaves inside intact human respiratory systems, nor does it quantify clinical genetic risk in living users. Laboratory cell assays often expose isolated biological material to conditions that differ from human lung defense mechanisms.
Finally, the study evaluated only three specific e-cigarette hardware designs. It does not evaluate every combination of coil metal, wicking fabric, or liquid formulation on the market. Most importantly, because it investigated aerosolized liquids in heated electronic devices, it does not evaluate standard ambient topical sunless tanning creams applied directly to intact skin.
External Application Versus Inhalation Hazards
The core distinction emphasized by both the researchers and regulatory authorities is the difference between topical absorption and respiratory inhalation. On the surface of the skin, DHA produces cosmetic pigmentation through surface interactions, a process regulated under specific external-use standards outlined in DHA and Sunless Browning: FDA Safety Rules Explained.
However, when DHA is heated across an electrical filament, thermal stress and vaporization alter the physical delivery route entirely. As demonstrated in the Aerosol Science and Technology study, thermal degradation can introduce reactive chemicals into inhaled aerosols. Because the biological risks of inhaling these byproducts remain uncharacterized, federal regulators caution against inhaling DHA in any format. Anyone experiencing respiratory issues or evaluating cosmetic ingredients should seek professional guidance from a licensed physician or dermatologist.
Sources
PubMed: Dihydroxyacetone levels in electronic cigarettes: Wick temperature and toxin formation.
Published October 31, 2026. Sources are linked in the text. See our Medical Disclaimer.