Glossary: Endocrine Disruption

What It Means, How It Happens & Why It Matters in Research

Endocrine disruption refers to the process by which external chemicals interfere with the body’s hormonal (endocrine) system – often with far-reaching health effects. These disruptors can mimic, block, or alter hormone signals, leading to changes in development, fertility, metabolism, or even behaviour.

If you’re working with hormone-related compounds like SARMs, SERMs, or synthetic hormones, understanding endocrine disruption is essential.

What Is the Endocrine System?

The endocrine system is the body’s network of glands that produce and regulate hormones. These hormones control:

• Growth and development
• Reproduction and fertility
• Metabolism and energy use
• Mood and cognitive function
• Immune response

Key components include the hypothalamus, pituitary gland, thyroid, adrenals, testes/ovaries, and feedback loops that tightly control hormone levels.

What Is an Endocrine Disruptor?

An endocrine-disrupting chemical (EDC) is any substance – natural or synthetic – that can interfere with this hormonal signalling.

According to the World Health Organization (WHO):

“An endocrine disruptor is an exogenous substance that alters the function of the endocrine system and causes adverse health effects.”

EDCs can:

• Mimic natural hormones (e.g., estrogens or androgens)
• Block hormone receptors
• Disrupt hormone synthesis or clearance
• Alter receptor sensitivity or gene expression

Examples of Known Endocrine Disruptors

How Does Endocrine Disruption Happen?

Disruption can occur at multiple levels:

• At the hypothalamus or pituitary, altering hormone signalling (e.g., LH, FSH)
• At the receptor level, mimicking or blocking normal hormone action
• At the gene expression level, by altering transcription of hormone-responsive genes

Some compounds, like SARMs, are designed to act on androgen receptors, but may also impact endogenous testosterone production, which is a form of endocrine modulation – or disruption, if unregulated.

See PMC2726844 – Endocrine Disrupting Chemicals for an in-depth review.

Further reading: Enclomiphene Mechanism

Health Risks Associated with Endocrine Disruption

The U.S. National Institute of Environmental Health Sciences (NIEHS) lists potential effects of endocrine disruptors:

• Male and female infertility
• Altered puberty or sexual development
• Thyroid dysfunction
• Metabolic disorders (e.g., obesity, insulin resistance)
• Neurological and behavioural changes
• Hormone-sensitive cancers (e.g., breast, prostate)

Further reading: Ostarine Side Effects

Regulatory Perspective

Many endocrine-disrupting chemicals are restricted or banned in the EU, UK, and US due to reproductive toxicity or carcinogenic potential.

The EU’s REACH regulation defines an EDC as a substance of very high concern (SVHC).

• UK REACH continues to evaluate and restrict EDCs post-Brexit.
• The FDA and EPA in the US maintain databases of suspected EDCs (e.g., EDSP list).

UK/EU researchers should consult:

• UK REACH Guidance
• ECHA EDC Classification

Further reading: UK Sarms Law

Summary: What You Should Know About Endocrine Disruption

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