E216; Propylparaben

(in 37,187 products)

Banned by Gov or classified as a carcinogen by IARC

1. Antimicrobial Preservative - Actively kills and inhibits the growth of unwanted microorganisms which may be harmful.

2. Flavor / Flavoring / Flavor Enhancer - Provides or enhances a particular taste or smell.

3. Preservative - Prevents and inhibits the growth of unwanted microorganisms which may be harmful

Propylparaben occurs as a natural substance found in many plants and some insects. It is also produced synthetically for use in cosmetics, pharmaceuticals, and foods. It is a preservative typically found in many water-based cosmetics, such as creams, lotions, shampoos, and bath products. As a food additive, it was previously assigned the E-number E216. It is no longer approved as a food additive by the EU. [1]

European Commission rules require manufacturers to reduce the concentration of propylparaben in cosmetics products and to avoid using this preservative in products designed for application on the nappy area of children under the age of three. [1]

“Propylparaben is a stable, nonvolatile preservative that is active at low concentrations and used to prevent decay of gum binders in cosmetic creams, lotions, and powders.” [2] It is also often used in food processing, where “Both Methylparaben and Propylparaben preservatives are included among optional ingredients permitted in artificially sweetened fruit jellies and jams.” [2] “The popular use of paraben preservatives in cosmetics and toiletries arises from their low toxicity, broad spectrum of activity, worldwide regulatory acceptance, biodegradability, and low cost.” and its ease of application, where “methylparaben and propylparaben can be added to the base’s [the product's] water and oil phases, respectively.” [2] This also highlights propylparaben’s solubility in oil, increasing its potential to bioaccumulate. Propylparaben can also be used prophylactically to prevent alveolitis sicca dolorosa (ASD). [2]

Propylparaben and methylparaben are the most commonly used parabens found in 99% of leave-on products and 77% of rinse-off products. [3] Canadian sewage samples also found traces of parabens, indicative of human systemic absorption. [3] A Norwegian study also found paraben and paraben esters present in 60% of the blood samples taken from the general population. [4] There is also a "significant association between blood paraben concentration and self-reported use of personal care products". [4] Propylparaben has proven to have high retention rates in the human body and in marine animals, which may lead to eventual toxicity. [3][4]

In a study consisting of 160 breast tissue samples, paraben was detected in 99% of all samples, methylparaben in 95%, ethylparaben in 92%, n-propylparaben in 75% and isobutylparaben in 85%. [4] "Mixtures of different parabens together in lower concentrations can stimulate human breast cancer cell proliferation". [5] There has also been sufficient data to show that methylparaben "affects breast cancer tumor-initiating cells", and has an effect on NANOG, a protein that regulates pluripotency (stem cell-ness, the ability of the cell to differentiate into other more specialized cells). [5]

In vitro studies on the Vero cell line (kidney epithelial cells extracted from an African green monkey), showed adverse effects of propylparaben over a course of 24h. [6] Propylparaben was observed to have affected “cell-proliferation rates rather than in cell viability.” where the mechanism of action targeted the “cell-cycle arrest at the G0/G1 phase”. [6] “It has been unequivocally demonstrated in various in vivo and in vitro screening tests that parabens have endocrine-disrupting activity that may represent a potential risk to human health.” [6]

In another study, the cytotoxic effects of propylparaben were investigated in human placental BeWo cells. [7] “Propylparaben significantly reduced cell viability in a dose-dependent manner. It induced cell cycle arrest at the sub-G1 phase by reducing the expression levels of cyclin D1, whereas the cell population at the G0/G1 and S-phases was decreased. Furthermore, propylparaben induced apoptosis by enhancing the activity of caspase-3.” [7]

Fortunately, propylparaben undergoes photocatalytic degradation in water via hydroxyl radicals. [8] It follows pseudo-first-order kinetics where increasing concentrations of titanium dioxide will also increase the rate of photocatalytic degradation while increasing concentrations of propylparaben will decrease it. [8] Namely, lower starting concentrations of propylparaben will increase the rate of its photocatalytic degradation in water. This is in agreement with a separate environmental study where much lower concentrations of propylparaben were found in cetaceans and sea otters in comparison to methylparaben. [9]

1. PubChem: https://pubchem.ncbi.nlm.nih.gov/compound/7175

2. Final report on the safety assessment of methylparaben, ethyl paraben, propyl paraben, and butylparaben. (J. Am. Coll. Toxicol. 1984. 5(3) 147-209)

3. Paraben esters: review of recent studies of endocrine toxicity, absorption, esterase and human exposure, and discussion of potential human health risks. (J Appl Toxicol. 2008 Jul;28(5):561-78. DOI: 10.1002/jat.1358.)

4. Measurement of paraben concentrations in human breast tissue at serial locations across the breast from axilla to sternum. (J Appl Toxicol. 2012 Mar;32(3):219-32. DOI: 10.1002/jat.1786. Epub 2012 Jan 12.)

5. Methylparaben stimulates tumor initiating cells in ER+ breast cancer models. (J Appl Toxicol. 2017 Apr;37(4):417-425. DOI: 10.1002/jat.3374. Epub 2016 Sep 1.)

6. Oxidative DNA damage contributes to the toxic activity of propylparaben in mammalian cells. (Mutat. Res. Genet. Toxicol. Environ. Mutagen., 702(1), 86–91. doi:10.1016/j.mrgentox.2010.07.012)

7. Propylparaben induces apoptotic cell death in human placental BeWo cells via cell cycle arrest and enhanced caspase-3 activity. (Mol. Cell. Toxicol. doi:10.1007/s13273-019-00062-9)

8. Advanced Oxidation Kinetics and Mechanism of Preservative Propylparaben Degradation in Aqueous Suspension of TiO2 and Risk Assessment of Its Degradation Products. (Environ. Sci. Technol., 47(6), 2704–2712. doi:10.1021/es304898r)

9. Elevated Accumulation of Parabens and their Metabolites in Marine Mammals from the United States Coastal Waters (Environ. Sci. Technol., 2015, 49 (20), pp 12071–12079 DOI: 10.1021/acs.est.5b03601)

1. US California Assembly Bill 418, Food Product Safety, https://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=202320240AB418 - Propylparaben

2. South Korea - Ministry of Food and Drug Safety - Prohibited/Restricted Chemicals

- Ref: 1135, 1178, 1197, 1256

3. EU Scientific Committee on Consumer Safety

- https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_132.pdf

4. Japan’s List of Designated Food Additives under Article 10 of the Food Sanitation Act

- Propyl p-Hydroxybenzoate

5. EU CosIng Annex V, PRESERVATIVES ALLOWED IN COSMETIC PRODUCTS [2017]

- Ref: V/12

6. Association of Southeast Asian Nations Annex VI, Allowed Preservatives

- Salts of benzoic acid other than that listed under reference number 1 and esters of benzoic acid, Propyl 4- hydroxybenzoate and its salts, Propylparaben, sodium propylparaben, potassium propylparaben

7. US FDA Generally Recognized As Safe (GRAS) Food Substances (21 CFR 184) [2017]

- § 184.1670 - Propylparaben