BHT

BHT, or butylated hydroxytoluene, is a synthetic antioxidant closely related to [BHA](/glossary/bha), used to stabilise fats and prevent them from turning rancid. Like BHA, it works by interrupting the chain reaction of fat oxidation, protecting both the palatability of the food and its fat-soluble vitamins over the shelf life, which is why the two are often used together and discussed in the same breath. Its use in animal feed is subject to regulatory limits, with defined maximum inclusion levels and a declaration requirement in the European Union (EU additive regulation). BHT sits at the centre of the same consumer debate as BHA: synthetic antioxidants attract concern from owners seeking a cleaner ingredient list, and although regulatory bodies authorise their use within set limits, that unease has driven a clear market shift. Many premium manufacturers now prefer natural antioxidant systems, principally mixed [tocopherols](/glossary/tocopherols) derived from [vitamin E](/glossary/vitamin-e), along with rosemary extract and [vitamin C](/glossary/vitamin-c), even though these natural options protect the fat for a shorter time and can be more costly. The trade-off is real: synthetic antioxidants are highly effective and stable, while natural ones suit shorter shelf lives and a label many buyers prefer. On a pack, BHT appears among the additives, sometimes under an E number. See the [Petipedia glossary](/glossary).

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