Our genes determine what our skin secretes in sweat and, consequently, how we smell. No two body odours are alike as we all have our own unique “cocktail” of bacteria that break down sweat to release volatile substances. But there are people who do not smell ... and they even use deodorant.
Our body odour develops when skin bacteria degrade certain substances produced by the sweat glands: steroid hormones, fatty acids and sulphur compounds. Our genetic characteristics determine the amount and proportion of each such substance secreted and, consequently, differences in how we smell. However, in a recent UK study of 6 500 women it was found that 2% had virtually no smell because of their particular version of the ABCC11 gene. However, over 75% of these women used underarm deodorant – out of habit. Identifying this genetic trait could lead to odourless people both saving money and reducing their exposure to chemicals. Such studies also open the way for the future application of genetics to the field of personal hygiene.
Alum crystal, used by ancient civilizations, has come back into fashion with the rise of natural cosmetics. It has many properties, including as a body deodorant. How does it benefit the skin? Is the aluminium it contains hazardous?
Alum crystal is a naturally occurring sweet-tasting mineral that looks like translucent glass. It is usually composed of an aluminium sulfate and a sulfate from another metal. The most commercially exploited alum is the hydrated form of potassium aluminium sulfate (potassium alum), which comes from a volcanic igneous rock called aluminiferous trachyte; it can also be manufactured industrially, however. Read More
Have you ever wondered why people smell different even though they wear the same perfume? Individual skin naturally contains a particular cocktail of chemicals that, rather like a fingerprint, leaves a unique aroma. When perfume blends with a person’s body odour it takes on a life of its own and creates a unique mark of identity.
At perfumeries, fragrances always smell just as their creator designed them. But they take on a different life on individual skin. We now know that we all give off a different body odour because everyone’s skin is composed of various chemical substances that, on evaporation, are transmitted by air and can be perceived by smell. These substances, known as volatile organic compounds, are part of all living organisms. Humans secrete them though two types of skin gland that produce sweat: eccrine and apocrine glands. When we apply a perfume, our natural body odour and the fragrance blend together and produce a specific, unique cocktail. But how do they blend? And why, once we are wearing it, does a perfume smell nothing like its creator planned? Read More
When we go shopping and touch coins, our hands begin smell of metal. This seems logical, as it was thought that metals have a specific odour. Not true. The metallic smell of our hands comes from certain chemicals in our skin that react with steel or with the copper in coins.
When shopkeepers give us back change, the coins carry their body odour; the coins themselves actually have no smell. When we touch coins, the metals immediately react with our skin to produce a new odour. The aromatic compounds are aldehydes and ketones, which instantaneously appear when our skin oils react with copper or steel. Other factors, such as our flora or our skin pH, mean that reactions differ between individuals. So, just as everybody has a unique body odour, so also do individuals create subtly distinctive metallic smells when they receive their change in a café.