Made from nothing but pure mineral salt, the classic crystal deodorant is the O.G. product and still going strong over 20 years later – so we jumped at the chance to put it to the test. It's worth remembering that natural ingredients can still cause skin reactions. For example, bicarbonate of soda can irritate the skin and cause itchiness, especially if used after shaving, and some essential oils that are commonly found in natural deodorants might also cause skin irritation. One user said: 'I've used this one and found it very capable of handling odours across everyday and more strenuous activities, like running, hiking and holidays in the sun, and it lasts for an absolute age.' As for its eco credentials, Akt has a stylish recyclable aluminium tube and cap, and comes in cardboard boxes.

That's a hard no. Salt of the Earth products are made from natural mineral salts, so they're free from aluminium chlorohydrate/chloride. For centuries, natural mineral salts have been used to prevent body odour. One of these natural salts, potassium alum, is the main active ingredient in Salt of the Earth’s Unscented Natural Deodorant Spray. Potassium alum creates an invisible antibacterial layer on the skin’s surface that helps to control the growth of bacteria, preventing body odour. The result is effective, long-lasting protection that allows your skin to breathe. Dr Olioso says: 'It contains good active ingredients, so should be effective, but be aware that arrowroot - the most abundant ingredient - might leave white marks.' There are also fears that aluminium found in everyday items such as aluminium cans, antacids and antiperspirants could cause Alzheimer's. But the Alzheimer's Society says: 'No convincing relationship between amount of exposure or aluminium in the body and the development of Alzheimer's disease has been established.'Some people might still prefer to opt for aluminium-free products, and if you're keen on plastic-free deodorant you might not have any choice, as most are aluminium-free. If organic credentials are important to you, look for a Soil Association certified brand - either a COSMOS Organic logo or COSMOS Natural logo (where products contain lots of ingredients which cannot be organic, such as water, salt or clay, but might contain organic ingredients, too). One user told us the deodorant had done a 'decent' job but that it sometimes needed to be reapplied during the day. You can rub it up and down or use a circular motion. Continue adding water to the stone and applying it until you feel you’ve covered your entire underarm.

Crystal deodorant is available as a stone, roll-on, or spray. Sometimes you can find it as a gel or powder. If you use a stone, it may come on its own or attached to a plastic base. Salt of the Earth's range has evolved into sprays, roll-ons, balms and more since it first launched the Classic Crystal – so it's no surprise that our first impressions were that this is a super no-frills product. Similar to the Natural Deo Co offering, it contains bicarbonate of soda and arrowroot to help prevent odours by altering the skin's natural pH. Many of these chemicals are thought to be harmful to your health and may irritate sensitive skin. It’s important that you read the ingredient list for all deodorants, even if they’re labeled “natural.” You might still want the reassurance of an antiperspirant for important events or busy days - so don't feel you have to commit to one or the other for good.

There are currently three unisex scents available, and the subscription option is easy to change online. Wearing deodorant and antiperspirant may inhibit the release of toxins from your body. Preventing your body from sweating naturally is thought to lead to clogged pores and a buildup of toxins.