A spray of perfume on the neck is a familiar final step before leaving the house. But a viral Instagram post by a cancer specialist has singled out the neck as an area "worth thinking about" because it lies close to the thyroid gland.
Authors
- Ahmed Elbediwy
Senior Lecturer in Cancer Biology & Clinical Biochemistry, Kingston University
- Nadine Wehida
Senior Lecturer in Genetics and Molecular Biology, Kingston University
The caption says there is no evidence that spraying perfume on the neck damages the thyroid. Yet its references to hormone disruption and lifelong chemical exposure through thin skin may suggest a possible link with thyroid disease or cancer. Could a quick spritz really pose a special risk?
Current evidence does not show that applying perfume over the thyroid selectively delivers fragrance chemicals to the gland or exposes it to a higher dose than spraying elsewhere. Research on skin absorption and the anatomy of the neck do not support the idea of a direct, selective route to the thyroid.
The thyroid is a butterfly-shaped gland in the lower front of the neck. It releases hormones that help control how the body uses energy and sits beneath the skin and several layers of connective tissue and muscle.
What happens when perfume reaches the skin?
Skin acts as a barrier. An ingredient may evaporate, remain on the surface, enter the skin's layers or reach the bloodstream. Absorption depends on the chemical, its mixture, skin condition and location, dose and contact time.
Body site can influence absorption. Once a chemical reaches blood vessels in the deeper skin, it can circulate more widely. Applying a substance near an organ does not automatically target that organ.
Safety assessments of sprayable cosmetics also consider inhalation . This route does not give the thyroid special exposure from neck application.
What about phthalates and hormones?
Much of the concern centres on phthalates, a family of chemicals with different uses and health effects. Diethyl phthalate, or DEP, has been used as a solvent and fixative in fragrances. Other phthalates have mainly been used to make plastics flexible. Evidence about one member of the family cannot simply be applied to all the others .
A systematic review published online in 2024 brought together 17 studies involving 5,616 children and adolescents . It reported associations between phthalate exposure and levels of some thyroid hormones, while findings for other hormones were inconsistent. The studies examined exposure from multiple sources. They did not investigate perfume application to the neck or the development of thyroid disease, and cannot establish cause and effect.
Perfume can contribute to DEP exposure. In a study of 337 women , perfume users had higher urinary levels of monoethyl phthalate, a breakdown product of DEP. This supports perfume as a source of DEP exposure. The study did not examine thyroid damage or application site.
An "endocrine disruptor" is an outside substance that changes the hormone system and causes a harmful effect . Risk depends on the chemical, dose, route, timing and duration of exposure. A hormonal effect in a laboratory experiment does not establish the risk from a finished perfume used in everyday conditions.
Repeated use means repeated exposure, although it does not necessarily mean accumulation. Phthalates are converted into breakdown products that pass out of the body quickly in urine , while frequent use can repeatedly renew exposure.
In Great Britain and Northern Ireland , cosmetics must undergo a safety assessment before being placed on the market, although the regulatory systems differ. Assessors consider ingredients, concentrations, intended use and likely exposure. Fragrance mixtures may be listed as "parfum", while specified allergens must be named above prescribed concentrations under Great Britain and Northern Ireland's rules.
The better-established skin risks
For perfume applied directly to skin, the clearest established concern is allergic contact dermatitis, an itchy, inflamed rash caused by contact with an ingredient. A review estimated that fragrance contact allergy affects 0.7% to 2.6% of the general population .
An allergic reaction can develop after someone becomes sensitised, meaning their immune system has learned to react to an ingredient. Later contact can produce itching and an eczema-like red rash . Perfume can also irritate skin without causing an allergy . If a rash persists or returns, patch testing can help identify the cause .
Some fragrance ingredients can cause a phototoxic reaction, a sunburn-like response when a chemical on the skin is exposed to light. A human study of model perfumes found that bergamot oil containing a light-reactive chemical could cause such a reaction after exposure to ultraviolet A, or UVA . The risk depended on the concentration and UV dose, so this does not apply to every perfume.
Long-term sun exposure is considered a main contributor to poikiloderma of Civatte , which causes reddish-brown, thinned skin with visible small blood vessels on the sides of the neck. A small study of 32 patients suggested fragrance allergy might contribute in some people, but could not show that fragrance caused the condition.
Perfume odour can also affect people with migraine. In one clinic-based study , people with migraine frequently named perfume as an odour they believed had triggered attacks. The study relied on recollections, so cannot provide a population estimate or prove causation. It provides no evidence of thyroid damage.
So, should you avoid spraying your neck?
For most people, current evidence provides no thyroid-related reason to avoid the neck specifically. Cancer Research UK reports no evidence that using perfume causes cancer .
If perfume causes burning or an itchy rash, stop applying it to the skin and seek medical advice if the reaction persists . "Natural" fragrances are not automatically gentler because essential oils can also cause allergic contact dermatitis . A "phthalate-free" label does not by itself establish that a fragrance is safer because phthalates differ and replacement products are not automatically safer .
Further research could clarify the effects of repeated exposure to fragrance mixtures. Current evidence does not show that spraying the neck gives fragrance chemicals special access to the thyroid.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
