Lavender and Tea Tree Oils: Skin Reactions and the Hormone (Gynecomastia) Question

Safety first. Neither oil is for swallowing. NCCIH says tea tree oil taken by mouth can cause serious symptoms such as confusion, unsteadiness, inability to walk and coma. [1] Poison Control describes a toddler who became extremely drowsy and confused after swallowing a small amount of lavender extract. [2] If a child or pet may have swallowed either oil, call Poison Help at 1-800-222-1222 (US). Call 911 for collapse, a seizure or trouble breathing. If a rash appears, Poison Control says to stop using the product and gently wash it off. [2] Difficulty breathing after any essential oil is a medical emergency. [2]

Two separate questions

This page covers two different concerns. The first, skin reactions, is well documented. The second, whether topical use can affect hormones in children, is unresolved. The oils are lavender oil from Lavandula angustifolia Mill. (family Lamiaceae) [3] and tea tree oil, steam-distilled from the leaves of Melaleuca alternifolia (Maiden & Betche) Cheel (family Myrtaceae). [4][1] Full profiles are at lavender oil and tea tree oil.

Skin irritation and allergy

Irritation (redness, stinging) and allergy (an immune reaction that can appear after repeated use) are different. NCCIH says most people can use topical tea tree products without problems, but some develop redness or irritation, which may be more likely if the product is old or has been exposed to heat, light or air. [1] A review of tea tree oil allergy says fresh oil is a weak to moderate sensitizer but oxidation (reaction with air) increases its allergenic potency. [5] Lavender oil also oxidizes on air exposure and can form allergenic compounds. [6]

These figures come from people referred to skin clinics, so they do not show how common reactions are in everyone. Most tea tree reactions are caused by applying the pure oil. [5] The EMA, the European medicines regulator, reviewed lavender in 2012 and found no major concern about human toxicity, noting contact dermatitis may occur in rare cases. [11] See patch testing and what to do after a reaction and tea tree oil allergy.

The hormone (gynecomastia) question

Gynecomastia means breast tissue growth in boys or men. Here is what each source read says.

NIEHS also notes a 2019 report of abnormal breast growth in girls exposed to lavender-fragranced products that resolved when exposure stopped. [13] NCCIH says a few cases were reported and it is unclear whether lavender was responsible. [17] NIEHS says using essential oils is up to the individual, and that its researchers want the public to be aware of the findings. [13] The EMA monograph says use of lavender oil medicines in children under 12 has not been established because of a lack of adequate data. [18] It does not give hormones as the reason. Positions of other regulators were not described in the sources we read.

What a reader can do

• Check ingredient lists on children's skin and hair products for lavender and tea tree oil, and ask a pediatric clinician before using them on a child. See essential oils around babies and children and children and teens.
• If a child develops breast tissue swelling, see a clinician rather than guessing the cause. NCCIH notes the condition has many causes. [17]
• For tea tree oil, store it well and avoid old oil; a toxicity review says reactions may be reduced by avoiding ingestion, using diluted oil and storing it correctly. [19]
• NCCIH says topical tea tree products may be safe in pregnancy and breastfeeding. [1] Ask a clinician about your own situation.
• Report reactions as described in side effects and reporting.