that blocking up sweat glands and preventing the natural process of perspiration may have a negative impact .
Body odour is still seen as undesirable , spurring innovation in the deodorant market to manage odour without preventing sweating . Brands are now shifting their marketing strategies to be ‘ sweatinclusive ’. For example , US brand Superdrip claims it is “ out to build a cooler sweat routine . We believe that freeing sweat from shame and embarrassment starts with celebrating one ’ s own body ." 4
Weapons of deodorisation
Various chemistries are employed in the ‘ natural ’ deodorants dominating the market . Those based on bicarbonate of soda create an alkaline environment on the skin that effectively inhibits bacteria production , thus reducing body
odour . It is very effective but has the drawback of being irritating to the skin . Bicarbonate of soda formulations tend to be anhydrous and are sold in stick or balm format .
While aluminium salts have fallen out of favour , some alternative metals have filled the gap . Magnesium salts have become more popular and are often called out on pack for their deodorising benefits . Magnesium oxide , magnesium hydroxide and magnesium carbonate hydroxide have broad-spectrum antibacterial properties , which help to prevent odourous metabolites developing . These salts form the basis of Dead Sea salt , which is recognised for its skin benefits .
Zinc carboxylates ( zinc ricinoleate and zinc neodecanoate ) are also growing in use . They do not disturb the microbiome but bond directly with odourous compounds containing sulphur or nitrogen functional groups , such as mercaptans or thioethers to minimise their odour . 5 , 6
Acids are another alternative . Mandelic acid is an α-hydroxy acid used for its antimicrobial properties . Influencers on social media have championed the use of glycolic acid as a deodorant , though there are concerns it can cause skin irritation as this is not the products ’ intended use .
While the newer deodorants are not effective at reducing sweat , absorbent powders are added to absorb moisture and maintain a dry skin feel . Some , such as clay or cyclodextrin , have the benefit of absorbing odourous compounds , minimising or reducing the perception of malodour . 7 Claybased masks are also available in skin care routines to detoxify the underarm area .
Tawas is making a resurgence as an alternative to modern formulations . It can be purchased as a crystal-like stone , which can be rubbed onto wet skin . Although it contains aluminium , this is bound into the larger molecule and does not enter the skin like the aluminium salts . The crystal interacts with proteins to reduce the ability of bacteria to reproduce , giving bacteriostatic properties . 8
Essential oils and fragrances create an olfactory signal that reduces a human subject ' s perception of any malodour present . Many essential oils also have antibacterial properties that can benefit deodorising product ' s , though their potential irritation and photostability needs to be considered .
Finally , emollients with bacteriostatic effects are commonly used in deodorant and have the benefit of providing skin softening and moisturising effects , which can help minimise some of the irritation created by the active materials often employed . Typical emollients are caprylyl glycol , propylene glycol and coconut oil
The axillary skin of the underarm is biologically unique and can be prone to irritation . Many of the materials
58 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981