Understanding the Anatomy Behind the Myth
Part 2 of a 3-Part Series
This article is part of a three-part series examining the long-standing rumor that antiperspirants cause breast cancer.
In the previous article, we looked at how a viral chain email helped spread the rumor linking antiperspirants to breast cancer. In this article, we begin examining the specific arguments presented in that message and look at what human anatomy actually tells us.
Myth #1: Antiperspirants Trap Toxins in Lymph Nodes
The email claimed that antiperspirants prevent sweating, causing cancer-causing toxins to build up in the lymph nodes located in the armpits.
This idea is based on a misunderstanding of two completely different systems in the body: sweat glands and the lymphatic system.
They are not connected.
To understand why this claim does not make biological sense, it helps to briefly look at how these systems actually work.
Sweat Glands
Sweat glands and lymph vessels are located in the dermis, the layer of skin just beneath the outer epidermis.
The average human body contains millions of sweat glands, with the greatest concentration found in the palms of the hands and the soles of the feet.
There are two main types of sweat glands.
Apocrine glands
These glands are found mainly in the underarms and the genital area.
Their secretions contain proteins and fats that bacteria on the skin break down, producing body odor.
The glands release their secretions into hair follicles and begin functioning at puberty.
Eccrine glands
These glands are found all over the body and produce a thin, watery sweat. Their primary role is temperature regulation—cooling the body as sweat evaporates. These glands begin functioning at birth, and their sweat is released directly onto the surface of the skin
Both types of sweat glands release their secretions onto the surface of the skin, not into the bloodstream. Sweating is therefore not a major pathway for removing toxins from the body.
The Lymphatic System
The lymphatic system is a network of vessels and lymph nodes that collects excess fluid from tissues, filters it for harmful organisms, and returns it to the bloodstream.
How Lymph Forms and Moves Through the Body
Your lymphatic system works closely with your circulatory system.
As blood moves through tiny capillaries, a small amount of fluid called plasma seeps out through the capillary walls. Once this fluid enters the spaces around your cells, it becomes lymph.
Lymph delivers oxygen and nutrients to nearby tissues, and at the same time, it picks up what the body needs to clear away — extra fluid, bacteria, viruses, and damaged or abnormal cells.
This used lymph then enters small lymphatic capillaries, which carry it into larger lymphatic vessels. Along the way, it passes through small, bean‑shaped filters called lymph nodes, where harmful organisms and unwanted cells are trapped and destroyed by white blood cells.
Despite common terminology, swollen “glands” are actually swollen lymph nodes, not glands.
After being filtered, the cleaned lymph returns to your bloodstream, helping maintain healthy fluid balance and blood pressure.
Because lymph flows through its own closed network of vessels—and not through sweat glands or the skin—there is no way for "toxins" from the armpit to collect in lymph nodes.
Why Myth #1 Doesn't Work
Antiperspirants reduce perspiration by temporarily blocking sweat glands — and that’s where their effect ends.
Sweat glands are located in the skin, while lymph nodes sit deeper, and the two systems do not connect. Because they are separate, blocking sweat cannot cause anything to “back up” into lymph nodes.
The myth also assumes that sweating is how the body removes toxins. It isn’t. The liver and kidneys handle waste removal by processing unwanted substances and eliminating them through bile, urine, and feces.
Sweat’s main job is temperature regulation, not detoxification. It’s made mostly of water and salt, with only trace amounts of other compounds. So even if sweating decreases, the body’s detoxification pathways continue working exactly as they should.
When you put these pieces together, the claim falls apart: antiperspirants don’t interact with lymph nodes, sweat isn’t a toxin‑removal system, and blocking sweat cannot cause toxins to accumulate anywhere.
Myth #2: Breast Cancers Occur Near the Underarm Because of Antiperspirants
Another claim in the viral email was that most breast cancers occur in the upper outer quadrant of the breast—the area closest to the underarm—and that this somehow “proved” antiperspirants cause toxins to build up in nearby lymph nodes.
The lymph nodes in the underarm, called axillary lymph nodes, form a chain that runs from the underarm toward the collarbone. They help drain and filter lymph from the breasts, upper arms, underarm region, and parts of the chest before the fluid returns to the bloodstream.
Their location is important for understanding breast cancer, but not in the way the myth suggests.
It is true that many breast cancers develop in the upper outer quadrant. But this pattern is explained by breast anatomy, not by antiperspirant use.
The four quadrants of the breast are not equal in size. The upper outer quadrant contains more breast tissue because of a structure called the tail of Spence, which extends toward the underarm.
More tissue means more cells capable of becoming cancerous, so more cancers naturally occur there.
Studies show that the higher number of tumors in this region is proportional to the amount of breast tissue present, not related to anything applied to the skin.
There is no evidence linking the location of breast cancers to antiperspirant use. Breast cancer begins in breast tissue and may later spread to nearby lymph nodes—not the other way around.
Understanding the Biology
The claims in the viral email fall apart once you understand how the body actually works.
Sweat glands and lymph nodes have completely different jobs and are not connected, so blocking sweat cannot cause toxins to build up in lymph nodes.
And the higher number of breast cancers found in the upper outer quadrant of the breast is explained by normal anatomy — that region simply contains more breast tissue, and therefore more cells where cancer can develop.
In the next article, we’ll look at two more claims from the email, including the idea that underarm hair protects men from breast cancer and that shaving allows antiperspirants to enter the body.
This article was originally written in 2015 and has been reviewed and updated for clarity.
