At what age can one begin using deodorant?

Puberty generally occurs around age 11 in girls and between ages 12 and 13 in boys, although these benchmarks can vary among individuals.

Puberty marks the gradual transformation of a child’s body into that of an adult. This period, which lasts on average five years, is triggered by a progressive rise in sex hormones, particularly androgens in boys and estrogens in girls. One of the signs of this transition is the emergence of body odors associated with sweating. If infants and young children already sweat, their perspiration is odorless. This change at puberty is primarily due to the activation of a new type of sweat gland. The human body actually has two types of sweat glands:

• The eccrine glands, present from birth, produce sweat composed mainly of water and mineral salts. Their function is primarily thermoregulatory, allowing heat to be released to maintain a stable body temperature.

• The apocrine glands, on the other hand, are primarily located in the armpits, groin, and chest. They remain inactive during childhood and only become active at puberty under the influence of sex hormones.

Sweat produced by apocrine glands is thicker and richer in lipids, proteins, and organic compounds. This specific composition makes it an ideal substrate for bacteria present on the skin surface. By feeding on these molecules, these microorganisms produce volatile odorant compounds, particularly fatty acids, which are responsible for unpleasant sweat odors. This phenomenon is also linked to changes in the skin microbiota during adolescence. Before puberty, the latter is characterized by high bacterial diversity, with a predominance of bacteria of the genus Bacillus. This richness gradually decreases as sebaceous glands become more active under the influence of sex hormones. The skin becomes enriched in lipids, which favors the colonization by lipophilic microorganisms, such as Cutibacterium and the fungus Malassezia.

Furthermore, the emergence of body hair, under the control of sex hormones—particularly androgens—accentuates bacterial proliferation and the production of unpleasant odors. Indeed, hair, especially in the underarm region, creates a warm, humid, and poorly ventilated environment, conducive to microbial growth. It also traps sweat, extending its contact time with the skin and thereby intensifying odors.

In short, the main factors responsible for the emergence of unpleasant odors are:

• The activation of apocrine glands by sex hormones, producing a richer sweat.

• Evolution of the cutaneous microbiota and the predominance of lipophilic microorganisms.

• The emergence of hair, which promotes the development of microorganisms.

Several studies have highlighted increased sweating during adolescence. Notably, one study published in Medicine & Science in Sports & Exercise examined eccrine sweat gland responses to exercise in boys at different stages of pubertal maturity. To this end, three groups of prepubertal, midpubertal, and postpubertal adolescents were exposed to two consecutive bouts of moderate exercise to stimulate sweating. The results show that overall sweat rate increases as puberty progresses, rising from 4.95 mL·min⁻¹·m⁻² in prepubertal children to 6.70 mL·min⁻¹·m⁻² in postpubertal adolescents.

It should be noted that it’s not so much the number of active glands that changes—scientists have shown that their density decreases with age—but rather their individual efficiency. Researchers have observed that, although prepubertal children possess more active sweat glands per cm² (128 ± 8 glands·cm⁻²), each gland produces less sweat (4.6 nL·min⁻¹) than in older adolescents (9.6 nL·min⁻¹). This means that sweating becomes more abundant not because more glands are recruited, but because each gland produces a larger volume of sweat.

Deodorant use is appropriate as soon as the first body odors associated with puberty appear, typically between 9 and 13 years of age.

There is no contraindication to begin using a deodorant at this stage if the need arises. However, it is recommended to choose gentle formulas, alcohol-free, especially for younger, more sensitive skin. The timing also depends on the child’s own perception and needs: having a conversation with them allows this transition to be approached with kindness and respect.

Deodorant, antiperspirant, and sweat suppressant : Which one should teenagers choose?

These three product types are often confused, but their mechanisms of action differ. Deodorants act solely on unpleasant odors: they mask them with fragrances and, when they contain antibacterial agents, inhibit their formation. Antiperspirants both limit odors and reduce the amount of sweat produced for several hours. Finally, clinical antiperspirants are intended for cases of excessive sweating, known as hyperhidrosis. Their effect is more intense and longer-lasting (up to five days), and they are generally recommended by healthcare professionals. There is no specific contraindication to using any of these products in adolescents. Nevertheless, in most cases, a simple deodorant is sufficient to start.

Any additional recommendations for reducing body odor?

If using a deodorant is relevant for limiting unpleasant odors, it will not suffice without proper hygiene. Taking a daily shower, thoroughly drying the skin (bacteria thrive in moist areas), and if needed, removing hair from the armpits in cases of particularly troublesome odor, adopting a healthy diet (spicy or fatty foods tend to increase perspiration) and learning to manage stress (strong emotions promote sweating) are all habits that make a difference.

• MEYER F. & al. Sweat lactate in exercising children and adolescents of varying physical maturity. Journal of Applied Physiology (1991).

• DUNCAN J. & al. Sweat gland response to exercise in the heat among pre-, mid-, and late-pubertal boys. Medicine & Science in Sports & Exercice (1992).

• BRZEZINSKA-WCISLO L. & al. Dermatological problems of the puberty. Advances in Dermatology (2013).

• HAVENITH G. & al. Body mapping of sweating patterns of pre‑pubertal children during intermittent exercise in a warm environment. European Journal of Applied Physiology (2021).

• KONG H. H. & al. Shifts in the skin bacterial and fungal communities of healthy children transitioning through puberty. Journal of Investigative Dermatology (2022).