Get Your Personalized Supplement StackSupplement Stack Quiz

Propyl Gallate

Also known as: Propyl 3,4,5-trihydroxybenzoate, E310, PG, Propyl gallate

Overview

Propyl gallate (PG) is a synthetic antioxidant primarily utilized as a preservative in various products, including food, cosmetics, and pharmaceuticals. It is a propyl ester of gallic acid, which occurs naturally in some plants, but PG itself is synthesized for industrial applications. Its main function is to prevent oxidation, particularly rancidity in fats and oils, thereby extending product shelf life. Research on PG largely focuses on its toxicological safety, antioxidant mechanisms, and some cellular effects. While there is extensive toxicological data and some in vitro and animal studies, high-quality human clinical trials or systematic reviews on its effects as a supplement are notably scarce, indicating a moderate evidence base primarily for its preservative role.

Benefits

Propyl gallate's primary benefit stems from its strong antioxidant activity, where it effectively scavenges free radicals and inhibits lipid peroxidation, which is crucial for its role as a preservative. In vitro studies using human adipose-derived mesenchymal stem cells have indicated an anti-adipogenic effect, showing that PG can inhibit fat cell formation by downregulating specific markers (PPAR-γ, C/EBP-α) through the ERK signaling pathway. This suggests potential metabolic regulatory effects, though these findings are currently limited to laboratory settings and their clinical relevance in humans remains unconfirmed. There is no robust clinical evidence to support direct health benefits from propyl gallate supplementation in humans.

How it works

Propyl gallate functions primarily as an antioxidant by donating hydrogen atoms to neutralize reactive oxygen species (ROS), thereby preventing oxidative damage, particularly to lipids. It also modulates enzymatic antioxidant systems; in vitro data suggest it can decrease superoxide dismutase activity while increasing catalase activity in human pulmonary fibroblasts, influencing cellular redox balance. Furthermore, it has been shown to inhibit adipocyte differentiation by modulating the extracellular regulated kinase (ERK) pathway in stem cells. When ingested, propyl gallate is well absorbed orally and subsequently hydrolyzed into propyl alcohol and gallic acid, which are then further metabolized and excreted from the body.

Side effects

Propyl gallate is generally recognized as safe at approved levels, with an acceptable daily intake (ADI) of 0.5 mg/kg body weight per day established by regulatory bodies. At typical exposure levels, no significant adverse effects are commonly reported. However, at high concentrations, in vitro studies have shown that PG can induce oxidative stress, mitochondrial dysfunction, apoptosis, and spindle disturbances in cells. Animal studies indicate hematological and liver enzyme changes at high doses, with a No Observed Adverse Effect Level (NOAEL) around 135 mg/kg/day in rats. A notable concern is its potential for sensitization; patch testing has revealed a relatively high prevalence (~33.9%) of skin sensitization to gallate mixtures in some populations, indicating a risk for allergic contact dermatitis. There are no well-documented drug interactions, but caution is advised for individuals with known sensitivities. Use in infants and young children is subject to strict limits due to limited safety data in these populations.

Dosage

Propyl gallate is not typically used as a dietary supplement, and consequently, there are no established dosing guidelines for supplementation. Its primary application is as a food additive, where its use is strictly regulated. The acceptable daily intake (ADI) for propyl gallate, established by regulatory bodies, is 0.5 mg/kg body weight per day. This ADI represents the maximum safe intake level for exposure through food additives. There are no clinical dosing guidelines available for therapeutic use, as its role is not therapeutic but rather preservative. Consumers should not attempt to supplement with propyl gallate beyond its regulated presence in food products.

FAQs

Is propyl gallate safe to consume?

Yes, at regulated levels in food and cosmetics, propyl gallate is considered safe by regulatory agencies, with an established acceptable daily intake.

Does propyl gallate provide health benefits as a supplement?

There is insufficient evidence to support health benefits from propyl gallate supplementation; its primary role is as an antioxidant preservative in products.

Can propyl gallate cause allergic reactions?

Yes, skin sensitization and allergic contact dermatitis have been reported in some individuals, particularly with gallate mixtures.

How is propyl gallate metabolized?

Propyl gallate is hydrolyzed in the body to propyl alcohol and gallic acid, which are then further metabolized and excreted.

Research Sources

https://www.cir-safety.org/sites/default/files/RR_PropylGallate.pdf – This safety assessment by CIR reviews in vitro and animal data, indicating that high doses of propyl gallate can induce oxidative stress, mitochondrial dysfunction, apoptosis, and show estrogen antagonist activity. It highlights comprehensive toxicology but notes the absence of human clinical trials.
https://www.rivm.nl/bibliotheek/rapporten/2019-0217.pdf – This regulatory risk assessment by RIVM, based on animal studies and exposure data, established a NOAEL of 135 mg/kg/day and an ADI of 0.5 mg/kg/day for propyl gallate. It confirms low acute toxicity but adverse effects at high doses, emphasizing its regulatory authoritative nature despite lacking human clinical data.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4400308/ – This experimental cell study demonstrated that propyl gallate inhibits adipogenesis in human adipose-derived mesenchymal stem cells via the ERK pathway, reducing adipocyte markers. While providing mechanistic insight, it is limited to in vitro findings with no clinical data.
https://pubmed.ncbi.nlm.nih.gov/37178593/ – This narrative review synthesizes literature on propyl gallate's pharmacokinetics and toxicology, concluding it is well absorbed and metabolized with no safety concerns at current use levels. It provides a high-level overview of toxicology but acknowledges the absence of clinical trials.