When you read about the benefits of intermittent fasting, they sound almost too good to be true…

It can help you lose weight and belly fat. It can slow aging. It can reduce your risk of diabetes, heart disease, cancer and Alzheimer’s and is linked to a longer lifespan.

How exactly can the simple act of skipping some meals have so many benefits?

Well, not to diminish any of the benefits associated with intermittent fastings, there’s one thing that might be a deal breaker for you…

If you’re worried about thinning hair, time-restricted eating might not be the right choice for you.

Super slow hair regrowth

A warning that impacts hair growth comes from researchers at Westlake University in Zhejiang, China, who, knowing how fasting improved the stress resistance of stem cells associated with blood, intestinal and muscle tissue, were hoping to see the same remarkable effects in skin and hair tissue.

To check it out, the scientists started their study in mice that were shaved and then subjected to different intermittent fasting regimes. While some mice ate during an 8-hour period and fasted 16 hours a day, others underwent alternate-day fasting (ADF).

But instead of seeing improvements in hair stem cells, the results brought up concerns…

The scientists discovered that instead of improving hair regeneration, fasting inhibited it. While the control mice with unlimited access to food had regrown most of their hair in just 30 days, mice on both intermittent fasting regimens experienced only partial hair regrowth after 96 days.

And mice weren’t the only ones adversely affected…

The team studied the effects of fasting in 49 healthy young adults and found that 18 hours of fasting per day for 10 days reduced the average speed of hair growth by a full 18%.

“We don’t want to scare people away from practicing intermittent fasting because it is associated with a lot of beneficial effects — it’s just important to be aware that it might have some unintended effects,” said senior author, Bing Zhang.

Follicle cells on fasting

So why would fasting cause hair thinning?

According to the scientists, it’s all because when you’re fasting, your body has to switch from burning glucose to burning fat — something that’s great for your waistline but not so much for your scalp.

That’s because hair follicle stem cells (HFSCs) aren’t able to cope with the oxidative stress associated with this change, which keeps them dormant instead of actively growing hair.

In fact, the research showed that while the control mice’s follicles began to become active around day 20 post-shaving and remained active until their hair had regrown, the hair follicles of fasting mice underwent apoptosis (programmed cell death) due to a build-up for free radicals.

The same thing happened in human in vitro testing.

“During fasting, adipose tissue starts to release free fatty acids, and these fatty acids enter the HFSCs that were recently activated, but these stem cells don’t have the right machinery to use them,” explained Zhang.

Supporting hair growth during fasting

So do you have to give up fasting if you want to keep your hair thick and full?

Not necessarily…

The research also resulted in some good news for those of us who want to get all of the benefits of time-restricted eating without hair loss worries.

Because free radicals in the follicles were the culprit behind hair regrowth issues, the team decided to see if antioxidants, which neutralize free radicals, could mitigate their effects.

And sure enough, they found that both topical application of vitamin E and increasing antioxidant capacity helped hair follicles survive fasting and become active again.

This means that if you do decide to use intermittent fasting to improve your overall health, you can support your hair health by rubbing vitamin E into your scalp and getting more antioxidants into your diet in the form of food and supplements.

Sources:

Intermittent fasting inhibits hair regeneration in mice — Science Daily