Aluminium is a common active ingredient in many antiperspirants, as it essentially plugs the sweat gland to minimise perspiration. The problem is that there have been concerns about the use of these compounds in skin products. Once in the body aluminium mimics the effects of oestrogen; a hormone that has been found in high concentrations in many breast cancers. This has led scientists to investigate potential links between breast cancer and aluminium-based deodorants.

Aluminium can also pose a threat to those on low kidney function, plus a study found higher traces of aluminium in the brains of Alzheimer’s patients. Although the correlation (if any) is not yet known, is it worth taking the risk when there are aluminium-free options available?

Many antiperspirants contain alcohol, which is used to dissolve different ingredients and to help the product dry quickly when applied. Alcohol kills some of the bacteria that forms odour, but it can also dry out skin and contribute to irritation. We prefer to use gentler ingredients such as organic coconut oil and magnesium hydroxide for their antibacterial effects.

Parabens are synthetic compounds that are used to control bacteria, fungus and other unwanted microbes in a range of products like toothpastes, shampoos and deodorants. However, parabens can be absorbed by the skin and can mimic the effects of oestrogen in the body, affecting the endocrine system. Parabens have been found intact in breast tumour tissue, and they could be in your body right now – in one study of randomised people, almost 100% of urine samples contained traces of the compound. Denmark has taken the precaution of banning some parabens in products for children under three years old.

While these findings do not link parabens directly to cancer or illness, many people understandably prefer to go paraben-free with their product choices. Natural ingredients such as clove oil can be used for their antibacterial, anti-fungal and antiseptic properties instead.

Propylene glycol is a synthetic organic compound used as a food and manufacturing additive – and also to de-ice aircraft in cold conditions! It’s used in some cosmetics and deodorants to soften their consistency and make the product easier to apply. It’s accepted that you’d need to ingest a whole lot of propylene glycol to experience adverse health effects, but there is another worry. Propylene glycol is used as a penetration enhancer, so if paired with harmful ingredients it could potentially aid the skin’s absorption of those substances. Best not even go there, we say.

Triclosan is used as an antibacterial and preserving ingredient in many deodorants, hand washes and cosmetics, but there are almost certainly safer ways to kill troublesome bacteria. Studies have found that triclosan can disrupt hormonal regulation in animals, and the American Food and Drug Administration recently banned the agent from being used in consumer skin care products. In fact, the FDA classes triclosan as a pesticide!

Phthalates are included in many cosmetics, fragrances and skincare products because they help to dissolve ingredients. Unfortunately, they’re also possibly linked to pre-term births in pregnant women as well as asthma. One type was found to be associated with male genital birth defects and reproductive issues in adult men. We think that for these reasons, phthalates are worth staying away from wherever possible.

Mixture of chemicals that can trigger allergies and asthma. Some linked to cancer. The Environmental Working Group (EWG) reports that, while many popular perfumes, colognes and body sprays contain trace amounts of natural essences, they also typically contain a dozen or more potentially hazardous synthetic chemicals, some of which are derived from petroleum. Dr Susannah Baron, consultant dermatologist at Kent & Canterbury hospital, and BMI Chaucer Hospital. "You don’t react immediately; the body notes that it does not like the chemical and develops “memory cells”, which cause inflammation when the body is next exposed to this chemical.”