Sweating is not a problem. This natural phenomenon is useful in regulating our body temperature, but the cosmetic products we use to combat its effects are sometimes toxic.

What is the role of perspiration and sweat glands?

Perspiration or sweating is a natural phenomenon that plays an essential role in the regulation of the internal temperature of the body. It allows the body to maintain a stable temperature (around 37 ° C) regardless of the circumstances: when it is hot or when the body is overheating (fever or physical exertion). Only humans, monkeys and some mammals like horses sweat. Other animals use other means to cool themselves down.

We have between 2 and 5 million sweat glands distributed throughout our body. The majority of these are "eccrine" glands and are found in large numbers on the soles of the feet, palms, forehead, temples and armpits. They produce 1 liter of sweat per day, on average, but this figure can rise to 10 liters under intense exertion or great stress. This sweat is odorless, it is mostly water. But it also contains salt, hence its salty taste, and other products such as urea or ammonia. Usually, it is this type of sweat that is involved in hyperhidrosis (excessive sweating).

The other type of sweat glands is called "apocrine". The apocrine glands are concentrated in the armpits, genitals and ears. They are associated with the hair system and do not appear until puberty. They secrete a thick liquid rich in fatty substances. When this fluid comes into contact with bacteria on the skin's surface, it produces a characteristic "body odor".

What triggers sweating?

Both the eccrine glands and the apocrine glands are activated by the nerves of the sympathetic system. These nerves respond to a variety of stimuli, including:

• Messages from the brain that the body is too hot
• Hormonal secretions
• Physical activity or exercise
• Certain foods (chocolate, coffee, peppers, etc.)

In people with excessive sweating or localized hyperhidrosis, the sweat glands (the eccrine glands in particular) overreact to these stimuli, they are usually overactive and produce more sweat than necessary.

What is the effect of sweating on the skin microbiome?

The pH of eccrine sweat is between 3.8 and 6.5. It is generally more acidic in men and more basic in women. This sweat is composed of Water (99%), Mineral Salts (Sodium Chloride), Vitamin C, Antibodies, Urea, Uric Acid, Ammonia and Lactic Acid. Due to its composition and its acidic pH, upon reaching the surface of the skin, this sweat will little alter the balance of the microbiome.

Conversely, apocrine sweat at basic pH and mainly composed of fatty substances will raise the skin pH and provide a favorable environment for the development of bacteria responsible for perspiration odors.

How do conventional hygiene products work?

Most of the hygiene products we use have an alkaline pH much higher than that of the skin. Natural soaps (pH 9), alcohol-based deodorants (pH 7) or baking soda (pH 8.4) alter the pH of the skin, which is already raised by the emission of sweat. These alkaline pHs destroy the acid mantle and the resident bacterial population. First, the smell disappears with the fatty compounds and a large part of the bacteria that make up the microbiota, leaving the skin defenseless. Then the bacterial population recolonizes the epidermis in an anarchic manner. Ditto for anti-perspirant products which destroy bacteria and temporarily block the emission of sweat by blocking the sweat ducts.

Numerous studies have shown that the more these products are used, the greater the rebound effect: the smell of perspiration is reinforced as soon as use is stopped. Scientists now estimate that a healthy person's natural skin pH should be 4.5. However, dermatological studies carried out around the world show an increase in this pH to 5.5 or more, an immediate consequence of the regular use of hygiene products with an excessively alkaline pH. This rise in skin pH could be the cause of the explosion of atopic diseases, allergies and skin sensitization.

How are daydry probiotics products different?

BIOSME and DAYDRY deodorants and washing gels respect the natural process of perspiration. They act in synergy with the skin microbiome, without clogging the pores and without destroying the resident flora. Rich in lactic acid and probiotic ferments, they will limit the growth of bacteria responsible for odors (corynebacteria) while helping the skin to maintain an acidic pH. So the more you use BIOSME products, the more you help your microbiome to maintain its balance, which is why deodorant effectiveness increases over time. Enriched with moisturizing active ingredients and composed of mild surfactants, they preserve the hydrolipidic film of the skin and protect against irritation and dryness. All the formulas have been validated under dermatological control on a panel of testers with sensitive skin.