Estrogen is one of the most potent sex hormones in the body. Its role affects everything from fertility to bone health. It also plays a significant part in breast development at every stage of a woman’s life. So a common question is whether estrogen makes your breasts bigger or smaller. The short answer is that estrogen does impact the size of your breasts, but these effects can be temporary or fluctuate depending on different factors.
Breasts begin to form before a baby comes into this world. In the mother’s uterus, the unborn baby develops a thickening in the breast area referred to as the milk line or mammary ridge. Thus, the baby already has the beginnings of a milk-duct system at birth, even though the chest is flat with only nipples. Even at this early stage, estrogen is helping to develop the milk-duct system and will continue to play a part as the baby grows.
During puberty, the amounts of estrogen and progesterone increase to help form more developed breasts. The increased estrogen levels generate breast tissue in the form of lobes or smaller groups of breast tissue. At this point, mammary glands develop the newly formed lobes. Estrogen activates the mammary glands causing the appearance of breasts.
Puberty brings about many changes in young girls, and developing breasts is one of them. But the size and shape of breasts are different for each person. Women can even have one breast more prominent than the other. The size difference may not be noticeable to the naked eye, but a woman or partner can feel the difference. Within size, you also have a different fullness and nipple shape.
Estrogen also plays a prominent role in menstruation. The ovaries produce estrogen and help form eggs. So, during a woman’s cycle, she produces various amounts of estrogen as needed to have a healthy monthly cycle and conception. Estrogen can make breasts feel sore or tender as a woman moves through menstruation.
Breasts continue to form and change even after puberty. Having a baby and breastfeeding can cause changes in the size and shape of a woman’s breasts. But something else happens in the mid-30s, the milk ducts vital for producing breast milk begin to change.
The mammary glands start to diminish, and the subdivision of lobes that helped form the glands shrinks. This is a slow process but typically begins around age 35. The shrinkage causes the appearance and feel of smaller breasts.
Menopause is a biological fact of a woman’s life. You can’t avoid it, but this doesn’t mean the process has to be painful when there is treatment with hormone therapy. Menopause is the direct result of low estrogen.
A woman’s body has used copious amounts of the hormone, and suddenly, almost without warning, the ovaries stop producing optimal levels. Low hormone levels can cause all kinds of uncomfortable symptoms, from hot flashes to insomnia. It also can result in breast changes.
Estrogen helps build breast tissue, and without it, breasts can feel smaller or different. This change may not be noticeable to anyone but the woman, but the difference is there. Skin ages as well, and this can cause breasts to be smaller. There are many factors in play regarding a woman’s body, but estrogen definitely is vital throughout a woman’s life.
One may think there is only one kind of estrogen, but the hormone comes in three main types, including:
Men can also produce estrogen but in lower amounts. Low levels of estrogen for men can result in low sex drive. Conversely, high amounts of estrogen can cause male breasts to grow.
Hormone therapy is the process of changing hormone levels through supplementation. It can increase the size of your breasts, but the amount varies. For some, it’s pretty small, and for others, a more considerable difference can occur.
The process of feminization is typical for nonbinary or transgender women assigned male at birth and desire to transform their bodies to have more “feminine” features.
Feminization usually involves estrogen therapy to reduce testosterone while producing secondary female characteristics, such as breasts and a higher voice. The other part of the treatment includes taking anti-androgens. They limit the effects of the male hormones in the body responsible for morning erections and facial hair growth.
Estrogen supplementation can lead to breast development. In a small study, breast size increased on average by 3.2 centimeters during the first year of estrogen hormone therapy for 229 trans women. Most of this growth occurred in the initial six months.
For non-trans women, hormone replacement therapy (HRT) will increase breast size as well. A few different studies have shown this effect. However, the biggest impact came from combination therapy with estrogen-plus-progestin. Progesterone is the other female sex hormone and works with estrogen in a woman’s body to optimize fertility, menstruation, bone health, and other bodily functions.
The amount of breast development depended on the woman’s age and breast density before hormone therapy. If a woman was over 70, the breast development was more prominent, and this seems to be due to how age can shrink breasts, so the growth is more extensive with hormone therapy. Other factors that affect breast density are genetics and physical activity.
Taking estrogen can increase breast size. The best type of supplement is a high-quality estrogen cream taken daily. If you’re thinking about taking estrogen to increase the size of your breasts, speak to your healthcare provider about whether the treatment is right for you.