Butyl hydroxytoluene (BHT)
What are the aims of this patient information leaflet?
This leaflet has been written to help you understand more about your contact allergy. It tells you what a contact allergy is, what causes this allergy and what you can do about it.
What is contact allergy?
Dermatitis, also known as eczema, describes a type of inflammation of the skin. Contact dermatitis or contact eczema is a term used when this inflammation is caused by direct or indirect skin contact with something in your environment. Allergic contact dermatitis occurs when your immune system causes allergy to a very specific chemical or substance that has been in contact with the skin.
What causes your specific allergy?
Your patch tests indicate that you have a contact allergy to Butyl hydroxytoluene (BHT) .
What is Butyl hydroxytoluene (BHT) ?
It is a synthetic antioxidant used in a range of industries including food, food packaging, pharmaceuticals and cosmetics to prevent fats and oils becoming rancid and to extend the shelf life of products. It also has the E-number E321 on food labelling. Butyl hydroxytoluene is also known as 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-p-cresol E321 in non personal care products.
What are some products that contain Butyl hydroxytoluene (BHT) ?
- Foods, particularly oils, fats, and chewing gum.
- Cosmetics, including fragrances, shower gel, hair shampoo, hair conditioner, body lotion, face cream, hand cream, deodorants, hair styling products, liquid foundation, make-up remover, eye shadow, mascara, and eyeliner.
- Oral care products, such as toothpaste and mouthwashes
- Medical devices, dressings and adhesives (glues). Please discuss with your doctor.
- Medicated creams and external preparations (see below)
- Personal protective equipment – respirator masks
- Petroleum based products including rubbers, fuels, gloves and plastics
What are some products that contain butyl hydroxytoluene?
Some medicated creams and external preparations (prescription-only and over-the-counter) which contain BHT are listed below:
| Balneum® bath oil | Calcipotriol/Betamethasone gel |
| Care Pain Relief (diclofenac diethylamine) | Curatoderm® Ointment (tacalcitol monohydrate) |
| Diclofenac Gel 2.32% w/w | Dovobet® gel (calcipotriol/betamethasone) |
| Voltarol® Joint & Back Pain Relief Gel | Voltarol® Max Strength Pain Relief Gel |
| Enstilar® cutaneous foam | Fucidin® ointment |
| IMVAGGIS® Pessary (estriol) | Indometacin suppositories |
| Lamisil™ AT (terbinafine) Gel | Ledaga® (chlormethine hydrochloride) gel |
| Locoid Crelo® (Hydrocortisone butyrate | Mometasone furoate Ointment |
| Nicorette® QuickMist spray mouthspray | Nicotinell® chewing gum |
| Permethrin Cream | Protopic® (tacrolimus) ointment |
| Regaine® for Men Extra Strength Scalp Foam Cutaneous Foam | Regaine® for Women Once a Day Scalp Foam Cutaneous |
| Rennie® (calcium carbonate) Medicated Chewing Gum | Tolak® (4% 5-fluorouracil) |
| Tostran® (testosterone) transdermal gel | Treclin® Gel (clindamycin/tretinoin) |
Chemicals related to butyl hydroxytoluene which may cause problems in some people:
- Tert-butyl hydroquinone (TBHQ) and butyl hydroxyanisole (BHA):
- Antioxidants in the same family as BHT
- Both can also be found in foods, cosmetics and plastic packaging.
- TBHQ can also be found in medical devices and adhesives (glues).
BHA can also be found in medicated creams and external preparations
Present in: Boots Diclofenac Diethylamine 2.32% w/w Gel
Non present in: Boots Diclofenac Diethylamine 1.16% w/w Gel
Present in Care Pain Relief 2.32% w/w Gel
Present in Diclofenac 2.32% gel by Zentiva
Not present in Motusol 1.16% w/w Gel
Not present in Voltarol 1.16% Emulgel, gel
Not present in Voltarol Back and Muscle Pain Relief 1.16% Gel
Present in Voltarol Joint & Back Pain Relief 2.32% Gel
Present in Voltarol Max Strength Pain Relief 2.32% Gel
Non present in Voltarol Osteoarthritis Joint Pain Relief 1.16% Gel
Always check the ingredient listing on the product, package or package insert as these lists can never be complete and ingredients change. This is particularly important for any products purchased outside the EU where some allergens may not be banned.
Remember, always check the label, these lists can never be complete and ingredients change.
How can I manage my allergy?
This means that you should avoid putting products containing Butyl hydroxytoluene (BHT) onto your skin in the future.
This means that you should avoid putting products containing BHT onto your skin in the future and consider also avoiding related chemicals (as listed above) if they are problematic for you.
Contamination around the lips/ skin around the mouth may cause a rash/eczema and occasionally may cause symptoms in the mouth but unlikely to cause symptoms once eaten.
Self-care (what can I do?)
Always check the ingredient listing on the product, package or package insert as these lists can never be complete and ingredients change. This is particularly important for any products purchased outside the EU where some allergens may not be banned.
Created: 2026