The manager of my local coffee shop went through a years-long battle with breast cancer. She’s currently in recovery. As her energy has returned, our interactions have become more and more lively. One minute at the cash register with her now gives as much of a boost as the coffee she serves.

Her bubbly demeanor was the best indicator I had of the return of her health. But last week, I realized I’d also been noticing the return of her hair. It was growing back thick and lush, similar to how it looked before, but it was now also considerably wavier.

I remembered watching my father’s hair come back after chemo, and the difference in how it grew in — less thick and wispier in his case, but perhaps that was because he was much older than my coffee shop friend, and continued to be ill.

People undergoing chemo often lose their hair, regardless of which cancer they’re fighting or which drug they’re taking. This might sound very confusing. After all, there are several different kinds of chemo drugs that have different actions.

Just a couple are alkylating agents that damage DNA and mitotic inhibitors that stop cell mitosis. Beyond type, there are dozens of individual medicines. How could so many different drugs have a similar side effect?

Why your hair falls out

The answer is that most chemo drugs attack rapidly dividing cells — and that’s what your hair cells are. Your fingernails and toenails are also made up of rapidly dividing cells. Chemo can affect them as well.

Though hair loss is common during chemo — and isn’t just limited to your head — it can affect the hair all over your body. The degree to which you experience hair loss depends on which medicine you’re prescribed. Your doctor and the rest of your medical team can talk with you about what they’ve noticed about hair loss associated with the particular drugs they’re prescribing.

Make sure you talk to the nurses and assistants you encounter in your chemo sessions and elsewhere during your treatment. They may have a broader perspective than your doctor has.

Can hair loss be prevented?

Some people claim that covering your head with ice packs can reduce the blood flow to your head and stop the chemo drugs from reaching your hair cells. This process is called scalp cooling.

The DigniCap and Paxman cold caps have been studied and cleared by the U.S. Food and Drug Administration for market. While cold caps have been proven to be effective for some people, they don’t work for everyone. According to BreastCancer.org, cold caps were effective for 50 to about 65 percent of women.

The type of chemotherapy involved also plays a role in how effective these treatments are. In general, more research is needed on the effectiveness of cold cap treatments.

What happens after chemo

You should begin to see hair regrowth a few weeks after your chemotherapy ends. Be prepared for a little shock — the initial growth is going to look different. Unless you’ve undergone chemo before, you very likely haven’t grown your hair out from complete baldness.

The first inch or so of growth tends to stand straight up for people of European, Native American, Asian, Middle Eastern, and Indian descent. For people of African descent, the new hair usually curls over after the first stage of growth.

That said, people have reported many different kinds of regrowth. Some people have curlier hair than before, while many others have thinner hair than before. Some people’s hair experiences a reduction in color and shine, or the hair grows out gray. This less lustrous hair is often replaced over the years by hair more similar to your pre-chemo hair, but not always.

Because everyone’s hair grows differently, it’s hard to say when your hair will look the way you remember it before you started chemotherapy. You’ll probably feel like you “have” hair again within three months.

The takeaway

Hair loss during chemo is one of cancer’s most diabolical side effects. It’s bad enough to feel sick — who wants to look sick, too? Hair loss can also broadcast to the world a health status you’d rather keep private. Fortunately, it usually grows back.

Biotin is another name for vitamin B-7, though it’s sometimes referred to as vitamin H. It’s been shown to slow baldness in some cases, but more tests are needed.

Bear in mind that your post-chemo hair could be different from the hair you were born with, as texture and color can change.