According to one study, lavender oil found in soaps, shampoos, diffusers and laundry detergents can cause young boys and girls to develop their breasts before puberty.
The researchers studied four children – one of whom was only three years old – who had abnormal breast growth and who discovered that they often used lavender-based products.
A child had visited the doctor after a year seated near his teacher's office where lavender was released all day by a broadcaster.
All of their symptoms disappeared when they stopped being exposed to oil, known for its calming effect.
Other tests done in the laboratory suggest that oil disrupts chemicals in the body, promoting a greater amount of estrogen and blocking testosterone.
Lavender oil is an essential oil derived from lavender and is used by millions of people in products such as skin creams, pills and to scent homes.
According to a study, lavender oil found in soaps, shampoos, diffusers and laundry detergents causes breast development in young boys and girls before puberty
A boy of nearly 12 years old had noticed breast hypertrophy since the age of four and had been exposed to Crusellas Violet Water Cologne (pictured) since childhood.
Researchers from the National Institute of Environmental Health Sciences (NIEHS), a branch of the US government, wrote the report.
They examined the case of four children under the age of seven at Nicklaus Children's Hospital and CHOC Children's Clinic in Miami.
Lead author J. Tyler Ramsey said, "The public should be aware of these findings and consider all the evidence before deciding when to use essential oils.
"It seems that essential oils have the potential to cause premature breast growth in girls and boys."
Dr. Campbell, a medical student, added, "So it may be better to stop using them on children."
Premature Thelarche is defined as breast growth before the age of eight years without any other signs of puberty, such as pubic hair.
WHAT IS BREAST GROWTH BEFORE THE PUBERTY?
Thelarche is a medical term referring to the onset of breast development in girls, which usually occurs after the age of eight, accompanied by other signs of puberty, including a growth spurt.
Premature Thelarche describes girls who develop a small amount of breast tissue without any other sign of puberty.
A girl who has started puberty will show an increase in the size of her breasts within six months.
But a girl with premature ejaculate can go a year or more with little or no change in breast size and sometimes they will become smaller, according to the Pediatric Endocrine Society.
Usually both breasts are dilated, but sometimes the prematurity of the skin only affects one side.
Premature tartar differs from true precocious puberty, in which the typical signs of puberty develop at an early age.
We do not know what causes this early breast development.
Gynecomastia is a common condition in the development of breast tissue in humans, but it is rare that this occurs before puberty.
It is most often caused by too high male estrogen levels or by an imbalance with testosterone levels.
It is also believed that some drugs and environmental exposures play a role, such as alcohol, heroin, marijuana and antidepressants.
Gynecomastia is a common affection of mammary tissue development in humans, but it is rare that this occurs before puberty, the researchers said.
When interviewed, the family found that children with premature breast growth had used lavender products since infancy.
The first patient, a seven-year-old girl, was exposed early to Mi Tesoro Agua de Violetas. She had on the left side a breast tissue 4 cm by 3 cm in diameter.
The youngest patient, a girl of almost four, was bathed in lavender and chamomile for the Baby Magic Calming Baby Magic bath. Her breast tissue, on the right side, was 3 cm by 3 cm in diameter and 1.2 cm deep.
A seven-year-old girl had inhaled the fumes from her teacher's lavender oil diffuser that worked all day long. A year later, she was taken to the doctor with an abnormal breast development, rated at two on a five-point scale.
A boy almost 12 years old had noticed breast enlargement since the age of four and had been exposed to Crusellas Violet Water Cologne since his childhood.
The authors indicated that he had breast development measuring 4 cm by 4 cm in diameter and 3 cm deep.
In most cases, a medical examination by a doctor was sufficient to measure the tissue. For the three-year-old girl, an ultrasound confirmed that growth came from the breast ducts – not adipose tissue.
All of the patient's breast tissue "dissipated" after three to six months after removing the lavender oil products from their environment.
The researchers then tested the effects of eight components of lavender and other essential oils on various human cells in a petri dish.
Levels of various hormones, including estrogen – the main female hormone responsible for sexual development – have been measured over a period of time.
They determined that certain components of essential oils mimicked estrogen and blocked testosterone, called "anti-androgenic" effects.
The blockage of testosterone is not directly related to breast growth, but the hormone would normally inhibit breast development, said the team.
This added to the case where lavender oil was the source of breast growth in children in the case study.
Mr Ramsey said it was important "that doctors know that lavender and tea tree oils contain chemicals that disrupt the endocrine system."
The endocrine system consists of a set of glands that produce hormone regulation processes in the body, such as growth and development, reproduction, sleep and mood.
In previous research, topical applications of lavender and tea tree oil have been associated with premature breast growth in boys.
But the effects of the popular calming product on the growth of breast tissue in girls have not been studied so far.
According to the results, the link between lavender-based products and stain is more common in Hispanic communities.
The researchers said this could be due to the fact that Hispanic families use lavender oil more often or are genetically more sensitive to the effects of oil.
Several limitations were discussed in the study. For example, the larvae can often disappear on their own and can explain the resolution of the larvae of children.
The researchers published their findings in the Endocrine Society's Journal of Clinical Endocrinology and Metabolism.