Dogs pant, pigs roll around in mud, and cats lick their paws. Humans sweat to cool down – and we should be happy we do. Sweat gave early hunter-gatherers an evolutionary leg-up – only two mammals, horses and humans, sweat enough to sustain running for long periods of time. Without sweat, there would be no marathons…
Skin holds two types of sweat glands. Eccrine glands are found all over the body and open directly onto the skin surface. When triggered by a rise in body temperature, they cool the body down by releasing sweat. Being 99% water plus a bit of salt, proteins, and carbs, eccrine sweat has no smell – barring health issues or a spicy meal!
Apocrine glands, primarily found in armpits and near genitals, continuously secrete a fatty, protein-rich substance into hair follicles. When hormones (cortisol and adrenalin) are released by stress or excitement – think anxiety, pain, fright, spicy food, strenuous, heart-pumping exercise, or close encounters – this fatty secretion gets expelled onto the skin. (Surprisingly its exact function remains unknown!) While thicker and slightly acrid, apocrine sweat does not smell either!
Sweat detox is largely a myth! Sweat releases water, sodium chloride, and potassium, and flushes out dirt from clogged pores but hardly any toxins. Sure, heavy metals and BPA have been detected in sweat but only in trace amounts. Hot yoga, saunas and other towel-soaking activities bring a myriad benefits, but detoxing really isn’t one of them. That work is left to the liver and kidneys.
So why does sweat smell?
Pure sweat doesn’t smell! But when sweat carries proteins onto the surface of the skin, bacteria break down those proteins into odorous fatty acids – especially underarm and below the belt!
Moisture is a breeding ground for bacteria. Choose workout clothes made of moisture-wicking and breathable fabric to avoid trapping sweat and wash and dry them thoroughly soon after workouts. Bacteria left dormant in the fabric will make themselves known when they come in contact with sweat on your next workout!
Antiperspirants and deodorants
Antiperspirants – many of which self-describe as ‘antiperspirant & deodorant’ – prevent sweat from being released by blocking sweat ducts with aluminum.
The FDA regulates antiperspirants as an OTC drug for which the only recognized active ingredients are aluminum compounds. In other words, anything claiming to be antiperspirant must use aluminum. Aluminum has been associated with breast cancer and Alzheimer’s, and although the scientific evidence is actually quite murky – or because it is – many choose to avoid antiperspirants.
‘Deodorants’ leave sweat glands and skin pores alone and instead absorb sweat, inhibit odor-causing bacteria, and use scents to mask residual odors. Since sweat has a legitimate function and does not even stink, that strikes us as a far better approach…
‘Clean’ Deodorant Ingredients
Odor-causing bacteria strive in a pH-neutral environment – most ingredients aiming to control bacteria are alkaline and raise pH to make your armpits a less hospitable playground.
Sodium Bicarbonate: Baking soda is highly effective, but exceeding the natural pH of skin can result in armpit irritation and redness. Other ingredients will often be introduced to counteract this. For instance, coconut oil is acidic, balancing out the pH of baking soda while soothing and moisturizing skin.
Magnesium hydroxide: magnesium is alkaline as well, but it is less water-soluble than baking soda and releases more slowly when it comes in contact with sweat – which doesn’t disrupt the skin’s natural pH as sharply and reduces the potential for irritation. Because magnesium hydroxide does not absorb moisture as effectively as baking soda, it’s often combined with other ingredients such as arrowroot powder or corn starch.
Alpha hydroxy acids: a few deodorants enlist AHA’s to lower pH instead.
These include baking soda, clays like bentonite and kaolin, starches and powders like cornstarch, arrowroot or rice starch, and activated charcoal.
Essential oils: oils may be ‘natural’ but as always, tread carefully if you have any known sensitivities and patch test when using a product containing anything new to you.
Zinc Ricinoleate: Instead of killing bacteria, zinc ricinoleate (a derivative of castor oil) seems to directly absorb odor molecules. It’s a complex process which scientists have yet to understand but have definitely observed. Zinc oxide has also been claimed to fight odors – but its effectiveness for this purpose is less clear cut than its role in sunscreen.
What you will not find in a ‘clean’ deodorant
- Diethanolamine (DEA)
- Butane, Isobutane, Benzene (watch for those in sprays)