What are the natural sources of BHT?

December 12, 2025 •

3 min read

Although most people know BHT as a synthetic additive, the compound butylated hydroxytoluene can also be produced naturally by various organisms. A range of species, including specific phytoplankton, fungi, and plants, have been identified as producing BHT for their own protective antioxidant purposes.

Quick Summary

BHT is naturally produced by organisms such as green algae, cyanobacteria, and fungi that grow on olives. Certain plants like lychee and specific shrubs also contain naturally occurring BHT, which acts as a protective antioxidant.

Key Points

Dual Nature: BHT is a compound found in both synthetic, lab-produced forms for commercial use and in natural forms produced by various organisms.
Microbial Producers: Freshwater phytoplankton, including specific green algae (Botryococcus braunii) and cyanobacteria (Microcystis aeruginosa), have been confirmed to produce BHT naturally.
Fungal Emissions: Certain fungi, like Aspergillus conicus found on olives, naturally emit BHT during pre-processing storage.
Plant-Based Occurrence: The fruit of the lychee and the shrub Cytisus triflorus are among the higher plants confirmed to contain naturally occurring BHT.
Antioxidant Function: Organisms produce natural BHT primarily for its antioxidant properties, which help protect their cells from oxidative damage, especially from light.
Not for Commercial Use: Natural BHT is not used in commercial products because it is not cost-effective to extract; industries use a synthetic version instead.

Understanding BHT's Dual Nature

Butylated hydroxytoluene (BHT) is widely known and used as a synthetic antioxidant in the food, cosmetic, and pharmaceutical industries. It is added to products to prevent oxidation, thus extending shelf life. However, scientific research has increasingly revealed that BHT is not exclusively a man-made chemical; it also has a surprising array of natural origins. This dual nature—being a lab-synthesized compound for commercial use and a naturally occurring substance in various organisms—is a key distinction that is important for consumers and researchers alike. The discovery of natural BHT sources highlights a fascinating aspect of biochemistry and offers potential avenues for exploring new, naturally derived antioxidants.

Microscopic Producers: Algae and Cyanobacteria

Several species of phytoplankton, including the green algae Botryococcus braunii, are known to produce BHT naturally in freshwater ecosystems. Additionally, three specific cyanobacteria species – Cylindrospermopsis raciborskii, Microcystis aeruginosa, and Oscillatoria sp. – have been identified as BHT producers. Environmental factors, such as higher light intensity, can increase BHT production in phytoplankton, suggesting a role in protecting against photooxidative stress. This indicates that these microorganisms use BHT as a natural defense mechanism.

Fungal Emissions in Olive Oil Production

Specific fungi that colonize olives during storage have been found to emit volatile compounds, including BHT. Research on fungi isolated from stored olives showed that eleven out of fourteen strains produced BHT, with Aspergillus conicus emitting particularly high levels. The BHT produced by these fungi may contribute to the stability and shelf life of olive oil.

Higher Plants with Natural BHT

Natural BHT has also been identified in some higher plants and fruits. The pericarp of the lychee fruit contains naturally produced BHT. The shrub Cytisus triflorus, found in the Mediterranean region, also contains BHT in its aerial parts. Another plant known to contain BHT is the halophyte Mesembryanthemum crystallinum. While detected in other plants and insects, the exact origin (plant or associated microorganism) is not always clear.

The Commercial Contrast: Natural vs. Synthetic BHT

Despite the existence of natural BHT, the version used commercially is primarily synthetic. While chemically identical, they differ significantly in origin, production, and cost.


Feature	Natural BHT	Synthetic BHT
Origin	Produced by living organisms (e.g., algae, fungi, specific plants).	Artificially synthesized in laboratories through chemical reactions.
Production Scale	Exists in very small, biologically relevant quantities; not produced on an industrial scale.	Mass-produced in large industrial plants to meet high commercial demand.
Cost	Not commercially viable to extract and purify from natural sources due to low yields.	Highly affordable due to efficient, large-scale industrial manufacturing processes.
Primary Role/Use	Functions as a natural antioxidant and protective compound for the host organism.	Added to commercial products (food, cosmetics, etc.) to extend shelf life and prevent oxidation.
Commercial Availability	Not available as a commercial ingredient for industrial use.	The standard commercial form readily used by many industries worldwide.

What This Means for Consumers and Industry

For consumers, the natural sources of BHT are primarily of scientific interest as commercial products use the synthetic version. However, for the industry, the discovery of natural BHT sources is relevant to the growing demand for natural ingredients and 'clean label' products. Understanding how organisms naturally produce BHT can guide research into developing new, sustainable natural antioxidants as alternatives to synthetic additives.

Conclusion

While predominantly known as a synthetic industrial additive, butylated hydroxytoluene (BHT) is also produced naturally by various organisms. Freshwater algae and cyanobacteria, certain fungi found on olives, and specific plants like lychee and Cytisus triflorus all contribute to the natural occurrence of BHT, using it as a protective antioxidant. The quantities of natural BHT are too low and costly for commercial use, so the synthetic version remains the industry standard. However, the identification of these natural sources is valuable for research into developing natural and sustainable alternatives to synthetic additives.

Frequently Asked Questions

No, the vast majority of BHT used in industrial applications, such as in foods and cosmetics, is a synthetic, lab-made chemical.

The green algae Botryococcus braunii and certain cyanobacteria like Microcystis aeruginosa are known producers of natural butylated hydroxytoluene.

While some fungi on olives naturally produce BHT, the amount is likely very small and not a significant dietary source compared to the synthetic version used as a food additive.

Chemically, the compound is identical. The difference lies in its origin, with natural BHT produced by organisms and synthetic BHT created in a lab.

For microorganisms like phytoplankton, BHT production appears to be a protective mechanism. Studies show production increases under high-intensity light to help protect cells from photooxidative stress.

Besides lychee pericarp and Cytisus triflorus, research indicates the presence of BHT in the halophyte plant Mesembryanthemum crystallinum.

No, the commercial food and cosmetic industry uses large-scale, cost-effective synthetic BHT. The naturally occurring quantities are too small for industrial application.

While chemically identical, the natural origin of BHT is part of the broader conversation about developing and utilizing natural alternatives to synthetic additives, which is often favored by consumers.