Hair extensions are widely used to add length, volume or style flexibility. But a new scientific study has raised serious concerns about what might be hidden inside these popular beauty products.

According to research published on February 11, 2026, in theEnvironment & Health, researchers analysed 43 different hair extension products — including synthetic fibres, real human hair extensions, eyelash extensions and plant-based options.

What the Study Found

Scientists detected more than900 different chemicalsacross the tested samples. Out of these, 169 were specifically identified. The list included:

• Phthalates

• Pesticides

• Organotin compounds

• Flame retardants

Many of these chemicals are known or suspected to affect thehormone system, immune response and metabolic regulation.

Notably, 12 of the identified chemicals appear onCalifornia Proposition 65, which flags substances linked to cancer or reproductive harm.

How These Chemicals Could Affect Health

Hair extensions are often treated with dyes, flame-retardant coatings, waterproofing agents and conditioning chemicals to improve durability and appearance. While these treatments enhance performance, they may introduce potentially harmful compounds.

Users have reported:

• Skin irritation and itching

• Swelling or allergic reactions

• Eye, nose and throat irritation during heat styling

When extensions are exposed to high heat — such as straightening or blow-drying — certain chemicals may release fumes. Prolonged exposure to these emissions could potentially impact the liver or nervous system, though researchers note that the exact long-term absorption and health effects remain unclear.

Why This Matters

Hair extensions are not just occasional fashion accessories. For many Black women and others, they are an important part of cultural expression, protective styling and routine hair care. Studies suggest that more than 70% of Black women who use extensions wear them at least once a year.

The widespread use of these products makes chemical exposure a public health concern — especially because many brandsdo not provide full ingredient disclosure. Consumers may unknowingly expose themselves to substances with documented health risks.

How to Reduce Potential Risk

While no extension product can be guaranteed completely risk-free, experts suggest practical precautions:

• Choose products clearly labelled non-toxic or toxin-free

• Wash your hair before installation to reduce scalp irritation

• Avoid excessive heat styling

• Look for transparent ingredient lists instead of vague “natural” claims

• Limit prolonged wear if irritation occurs

Until stronger regulations and clearer labelling standards are implemented, informed consumer choices remain the best line of defence.

The study highlights an important reminder: beauty products may enhance appearance, but understanding what they contain is essential for long-term health and safety.