Endocrine system: definition, role, and interactions with disruptors

Much of what keeps us balanced happens behind the scenes. Quietly, without us really thinking about it, our body constantly adjusts its internal settings. The endocrine system, also called the hormonal system, is part of these discreet but essential mechanisms: it regulates, coordinates, and adapts many vital functions using chemical messengers, the hormones.

Today, this balance is increasingly put to the test. The chemicals present in our environment raise more and more questions about their long-term effects on our hormonal health.

So, what is the endocrine system really for? How does it work? And why is there so much talk about endocrine disruptors?

What is the endocrine system?

The endocrine system includes all the glands that produce hormones and release them directly into the blood. Unlike the nervous system, which acts quickly through electrical signals, the hormonal system works over a longer time but with lasting effects.

Hormones are messengers: they circulate in the body and act only on cells capable of recognizing them through specific receptors. This mechanism regulates functions as varied as growth, metabolism, stress management, and reproduction.

 This system plays a key role in maintaining homeostasis, that is, the body's internal balance. Blood sugar levels, temperature, available energy, hydration... everything is constantly adjusted.

It is this fine tuning that makes the endocrine system particularly vulnerable. When an external substance disrupts hormonal signals, even in small doses, the balance can progressively become disturbed, sometimes without immediate symptoms.

The main endocrine glands

The endocrine system relies on several glands, distributed throughout the body, each with a specific role.

• The hypothalamus and pituitary gland: located in the brain, they act as a control center. They coordinate the activity of other glands and regulate essential functions such as growth, reproduction, water management in the body, and the stress response.
• The thyroid: at the base of the neck, it influences metabolism, body temperature, and energy level.
• The parathyroids: small glands located behind the thyroid, they regulate calcium, essential for bones and muscles.
• The adrenal glands: they produce adrenaline and cortisol, which are involved in the stress response.
• The pancreas: it regulates blood sugar through insulin.
• The ovaries and testicles: they are involved in reproduction and the development of sexual characteristics. 

Vital functions controlled by our hormones

The hormonal system accompanies all major life stages. Its influence affects both the body and emotional balance.

Growth and development

From pregnancy, hormones contribute to organ formation, brain development, and fetal growth. At this stage, even the slightest imbalance can have lasting effects, which explains the attention given to endocrine disruptors during pregnancy.

After birth, the endocrine system continues to orchestrate growth, puberty, and tissue maturation. Childhood and adolescence are particularly sensitive periods because regulatory mechanisms are still developing.

Energy, stress, and emotions

Energy level, sleep quality, or the ability to manage stress largely depend on hormonal balance. Cortisol, melatonin, and thyroid hormones help the body adapt to daily rhythms.

When this balance is disrupted, fatigue can set in, sleep can become more fragile, and mood more unstable. These imbalances are often gradual and difficult to immediately link to a specific cause.

Biological cycles

The endocrine system also structures biological cycles, notably the menstrual cycle. Hormonal variations enable ovulation, determine fertility, and influence many daily parameters: energy, appetite, emotional sensitivity.

When these variations occur harmoniously, they contribute to the body's overall balance. When disrupted, the entire system can become weakened.

Endocrine disruptors: interferences in the hormonal system

Hormonal language is very precise. Endocrine disruptors interfere with this communication by imitating, blocking, or modifying the action of natural hormones. 

They can act in several ways:

• by mimicking a hormone and sending a false signal,
• by blocking a receptor, preventing the natural hormone from acting,
• or by modifying the production and elimination of hormones.

Their action is often slow and cumulative. Repeated exposure, even at low doses, can weaken hormonal balance in the long term, especially during sensitive periods like pregnancy, childhood, or puberty. This is partly explained by the cumulative effects of endocrine disruptors which can interact with each other and amplify their impacts. 

Another particularity: the effect is not always proportional to the dose. Chronic low exposure can sometimes have more impact than a stronger occasional exposure.

The possible consequences notably include:

• Pregnancy, with effects on fetal development.
• Child development, sometimes with visible effects later on.
• Fertility, in both women and men.
• Metabolic balance, with a possible link to overweight or diabetes.
• Certain hormone-dependent cancers, for which links are studied or suspected.

How to protect your hormonal balance daily?

You can't control everything, but it is possible to reduce your exposure by adopting simple habits.

Lighten your beauty routine and environment

The skin absorbs part of the substances applied to it. Learning to read the INCI list of cosmetics helps identify certain ingredients to avoid. Cosmetic labels can also serve as a guide.

Some practical steps

• Perfumes: favor a perfume without endocrine disruptors to limit exposure to phthalates* and synthetic musks.
• Diet: when possible, choose organic products to reduce exposure to pesticides.
• Lifestyle : promote habits that support the body’s natural elimination capacities, as explained in this article on eliminating endocrine disruptors from the body.
• Fixative agents often hidden under the generic term “Perfume” or “Fragrance.”

By simplifying your environment and making more conscious choices, you don’t eliminate all risks, but you give a bit more leeway to an already heavily stressed hormonal system.

Sources

• ANSES (National Agency for Food, Environmental and Occupational Health Safety): reports on the exposure of the French population to chemical substances and endocrine disruptors.
• Public Health France: PESTIPAO and ESTEBANE studies on population exposure to environmental pollutants.
• French Society of Endocrinology (SFE): educational sheets on the functioning of endocrine glands and homeostasis.
• Inserm (National Institute of Health and Medical Research): thematic files on the mechanisms of action of endocrine disruptors on human health.
• WHO (World Health Organization): state of scientific knowledge on chemicals disrupting the endocrine system.