There’s no shortage of celebrities and influencers endorsing the health benefits of collagen supplements. But are they safe for people undergoing treatment for breast cancer? And can they help with the side effects of breast cancer treatment?

MyBCTeam members have wondered about taking collagen. One member shared, “I’m four weeks post-mastectomy with tram flap reconstruction, and I was thinking of starting collagen to speed up recovery.” Other members expressed concerns about collagen’s safety. One asked, “Are collagen supplements safe to take if you have estrogen-positive breast cancer?”

Although there aren’t specific studies about the use of collagen supplementation in people with breast cancer, scientists have studied how collagen interacts with breast cancer. This article will get you up to speed on collagen, the uses of collagen supplements, and what research shows about collagen and breast cancer.

What Is Collagen?

Collagen is the most common protein in your body — it makes up about 30 percent of all the protein in your body. It provides structure and strength to your skin, muscles, bones, connective tissues, and organs.

There are five types of collagen (sometimes written with Roman numerals, e.g., type I, type II, etc.):

• Type 1 — The most common type of collagen that gives your skin, bones, tendons, and ligaments their structure
• Type 2 — Supports your joints
• Type 3 — Found in your muscles, blood vessels, and organs
• Type 4 — Supports your skin
• Type 5 — Found in your eyes, skin, and hair

Collagen levels decrease naturally as you age. If you have decreased collagen, you may notice:

• Wrinkles or sagging skin
• Muscle loss or muscle aches
• Joint pain or stiff joints

What Is Collagen Used For?

Collagen is used in cosmetics and medicine as wound dressing, blood vessel prosthetics, and a dermal filler (for smoothing lines and wrinkles). It’s also sold as a supplement you take as a tablet, capsule, or powder. It’s been promoted for many uses, including:

• Reversing wrinkles and signs of aging
• Improving skin elasticity (your skin’s ability to stretch and bounce back)
• Improving joint pain and bone defects
• Healing wounds
• Increasing muscle mass
• Improving wound healing
• Stabilizing dental implants and crowns

Clinical research on the use of collagen is lacking, although some studies have examined collagen’s effect on skin and joint health. Collagen may improve skin elasticity, joint mobility, and joint pain. However, most of these studies are funded by the supplement industry, and positive results may not be reliable.

Collagen Supplements for Breast Cancer Therapy Side Effects

Some breast cancer therapy, such as chemotherapy, radiation, and hormone therapy, can cause unpleasant side effects that some people treat with collagen supplements. A MyBCTeam member shared, “I’m taking letrozole. My wrinkles are getting worse and worse, and I’ve got them everywhere! Even on my arms, legs, and stomach.”

Other possible side effects of breast cancer treatment include:

• Joint pain
• Weakened bones
• Dental problems
• Wound healing after surgery
• Nail and skin problems

Some MyBCTeam members have reported noticing benefits when they take collagen. One member said, “I really endorse collagen tablets. The first time I took them, my daughter asked if I had a facial. Wrinkles disappear on the forehead and elsewhere on the face.” Another member shared, “Collagen did help me with stiffness from my arthritis.”

Collagen and Breast Cancer

There haven’t been any clinical trials specifically studying the effect of taking a collagen supplement in people with breast cancer. However, cancer research has been studying how collagen in your body interacts with cancer for many years.

The amount of collagen in your breasts can influence your risk of getting breast cancer and the prognosis (likely outcome). Increased fibrous tissue made up of collagen produces dense breast tissue, which raises a person’s risk of breast cancer.

Cancer cells can also influence the way collagen is formed. Researchers have found an association between increased collagen expression and a worse breast cancer prognosis (outlook). Studies have found that type 1 collagen is associated with a poor prognosis and breast cancer recurrence (when cancer comes back).

Collagen and Estrogen-Positive Breast Cancer

Estrogen receptor-positive (ER-positive) breast cancer is a type of cancer with increased estrogen receptors on the surface of breast cancer cells. These hormone receptors allow the cancer cells to use estrogen to help them grow. Studies have found an increased association between high levels of type 1 collagen and decreased survival rates in ER-positive breast cancer.

A study involving mice found that type 1 collagen may change hormonal signals to drive the tumor growth of ER-positive breast cancer and increase the risk of metastasis (cancer spreading to other organs).

Collagen Supplements and Breast Cancer

Cancer research has found that collagen in the body plays a role in how cancer cells grow and spread. However, researchers haven’t studied how taking a collagen supplement might have an impact on breast cancer. Until more research is done, we don’t know how collagen supplements might affect breast cancer.

As with all supplements, taking collagen supplements can be potentially risky because you can’t be certain you’re getting exactly what’s on the label. The U.S. Food and Drug Administration (FDA) doesn’t evaluate supplements for safety or efficacy. Supplements may contain significantly more or less of the active ingredient on the label. They may also be contaminated with harmful substances such as heavy metals.

Talk to your health care team before you take any supplement, including collagen. Dietary supplements may have harmful side effects or interact with your cancer treatment. It’s important your doctor and oncologist know about all supplements, vitamins, and minerals you take. Your doctor or a registered dietitian may be able to recommend other ways to boost collagen, such as eating a balanced diet with foods that contain or promote collagen.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 63,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you taken collagen supplements to help with the side effects of breast cancer treatment? Share your experiences in the comments below, or start a conversation by posting on your Activities page.