Source and origin
Peru balsam is the exudate of a tree native to Central America. The trees grow in an area stretching from Guatemala to Nicaragua, but the conditions needed to produce the balsam can only be found in a small region of El Salvador, in the highlands an hour's drive west of the capital San Salvador. Today it is extracted under a handicraft process, and is mainly exported from El Salvador. Myroxylon balsamum is a large, slow-growing tree that reaches 45 metres in height. Peru balsam and tolu balsam are both products of the resin of Myroxylon balsamum, extracted from different varieties in different ways. The species, which also goes by the names Santos mahogany and Cabrueva, is native to tropical forests from southern Mexico through the Amazon regions of Peru and Brazil, at elevations of 200 to 690 metres. It grows in well-drained soil in evergreen humid forest. The crown is round with dense foliage, and the yellowish bark has a pungent odour. The flowers are white, and the fruit is a flat winged pod about 8 centimetres long. The tree has also been planted for balsam production in West Africa, India and Sri Lanka.
Chemistry
Peru balsam contains 25 or so different substances, including cinnamein, cinnamic acid, cinnamyl cinnamate, benzyl benzoate, benzoic acid and vanillin. It also contains cinnamyl alcohol, cinnamaldehyde, farnesol and nerolidol. A minority of it, approximately 30-40%, contains resins or esters of unknown composition. Benzyl benzoate is the ester of benzyl alcohol and benzoic acid. Benzyl cinnamate is the ester derived from cinnamic acid and benzyl alcohol. Tolu balsam is similar to Peru balsam and is frequently confounded with it. Tolu balsam is tapped from Myroxylon balsamum var. balsamum and contains a fairly large amount of benzyl benzoate and benzyl cinnamate.
Tolu balsam compared
The fresh tolu balsam is a brownish, sticky, semifluid mass that gradually becomes a brittle solid and softens again when warm. It is collected by cutting a V-shaped wound on the trunk and fixing a calabash there to catch the exuded resin. The name comes from Tolú in Colombia, from where the balsam was shipped to Europe.
Trade and certification
Peru balsam and tolu balsam are marketed through a series of intermediaries and exporters. Their destinations are Germany, the United States, England and Spain, where they are used in the manufacture of cosmetics and medicines. The harvesters of Peru balsam rely on the collection of balsam for the majority of their income. One ingredients provider supplies more than 2 tons of FairWild-certified Peru balsam resin every year, and this was the first FairWild certification for El Salvador.
Allergy and labelling
Balsam of Peru can cause allergic reactions, and numerous large surveys place it among the "top five" allergens most commonly causing patch test reactions. A study in 2001 found that 3.8% of the general population patch tested was allergic to it. In a retrospective analysis of 12 030 patients patch tested in 13 Italian dermatology clinics between January 2018 and December 2019, 3.6% had a positive patch test reaction to balsam of Peru. In that study, 1.0% of patients reacted to both the balsam and fragrance mix 1, and 2.6% reacted to the balsam only. Single sensitizations to the balsam were clinically relevant in 75.2% of cases. Of patients tested with a baseline series, 4% to 8% still show positive reactions to balsam of Peru. Balsam of Peru may cause redness, swelling, itching, and blisters. The reactions can include allergic contact dermatitis, stomatitis, cheilitis, hand eczema, rhinitis and conjunctivitis. In fragrances it may simply be covered by an ingredient listing of "fragrance", so doctors often have to contact the manufacturer to learn whether a product contains it. The presence of balsam of Peru in a cosmetic will be denoted by the INCI term Myroxylon pereirae.
