Food and skin

BHA and BHT (E320, E321): Antioxidant Preservatives and the Skin

BHA (E320) and BHT (E321) are antioxidant preservatives in fatty foods, and they turn up in cosmetics too. Both are occasional skin triggers. What they are, who reacts, and where they hide.

What they are

BHA (butylated hydroxyanisole, E320) and BHT (butylated hydroxytoluene, E321) are synthetic antioxidants. Their job is to stop fats and oils going rancid, so they extend the shelf life of fatty and oily foods. The same two ingredients are also widely used in cosmetics and personal-care products as preservatives, which makes them one of the clearest examples of a single ingredient that spans your kitchen and your bathroom shelf.

Who reacts, and how it shows on the skin

BHA and BHT are better known as contact allergens in cosmetics than as food triggers: applied to the skin they can cause contact dermatitis and contact urticaria in sensitised people. Eaten, they are occasional triggers of hives in a sensitive minority. Because the same person may meet them in food and in skincare, a reaction can be confusing until you realise both routes share the ingredient.

Where they hide

In food: crisps and savoury snacks, breakfast cereals, chewing gum, vegetable oils and fats, margarine, instant mashed potato, and some processed meats. In cosmetics: moisturisers, lipsticks, and other products containing oils. Look for BHA, BHT, butylated hydroxyanisole, butylated hydroxytoluene, E320 or E321.

What to do if you think you react

Because these cross between food and cosmetics, track both. If a skin reaction does not line up with anything you ate, check your skincare and lip products for BHA and BHT too. A food-and-skin diary that also notes the products you applied is the quickest way to spot the overlap. For persistent contact reactions, a dermatologist can patch test for them specifically.

Check it against your own list

A free scanner like Yuka gives a packaged product a general health score, a useful broad read, though that verdict is the same for everyone rather than tuned to your skin. Fig is genuinely good if you are managing a defined eating pattern. To check a product against the specific things that make your skin react, a personal-list app like ClearaScan lets you save your triggers once and scan any product, food, medication or cosmetic, against your ingredient guard list, flagging only yours. Because BHA and BHT span food and skincare, scanning both against one list is exactly the case it is built for. Its Reaction Journal lets you tie a flare back to the product that caused it, a shared Care Circle lets family scan for you, and a Trusted Products list keeps what you have cleared. It is currently in early access. (Disclosure: our editor co-founded ClearaScan, and we are not paid to mention the others.)

More on food and skin

Brilliant Blue (E133): The Synthetic Blue Dye and the Skin

Brilliant Blue (E133) is a synthetic blue colour in drinks, sweets and even mouthwash. Reactions are less common than with azo dyes, but they happen. What it is, who reacts, and where it hides.

Carmine and Cochineal (E120): A Natural Red That Still Reacts

Carmine (E120) is a natural red made from insects. Natural does not mean inert, it can cause hives and, rarely, more serious allergy. What it is, who reacts, and where it hides.

Chronic Hives and Food: Which Triggers Are Worth Checking

When hives keep coming back, food is a common suspect. Here are the additives and natural foods most often linked to chronic urticaria, and a calm way to find your own triggers.

Monosodium Glutamate (MSG): What the Skin Evidence Actually Says

MSG (E621) is a flavour enhancer often blamed for reactions. For skin symptoms the honest evidence is weak and mixed. What it is, what the science shows, and how to test it for yourself.

Common questions

Are BHA and BHT safe?

They are permitted within limits in food in the UK, EU and US. There is some ongoing scientific debate about them, but the everyday issue for this site is the skin reactions in sensitive people.

Is this the same BHA as in acne products?

No. Skincare "BHA" usually means salicylic acid, an exfoliant, which is completely different from butylated hydroxyanisole. The shared initials cause real confusion, so check the full ingredient name.

Why does an ingredient guard list help here?

Because BHA and BHT appear on both food and cosmetic labels, one saved list that you can scan against either is genuinely useful.

A note on this content. The Sensitive Skin Lab publishes general educational information, not medical advice. If you suspect you have an allergy or sensitivity, consult a qualified dermatologist or allergist. Product formulations and labels change without notice, so always check the ingredients on the product itself.