Fasting Harms Hair Growth. But There’s an Easy Solution

Summary

New research published in the journal *Cell* reveals a surprising side effect of intermittent fasting: it can harm hair growth. The study found that fasting triggers the release of fatty acids in the skin, which overwhelm hair follicle stem cells and cause their death. However, the researchers discovered that applying topical antioxidants, like vitamin E, can protect hair follicles from this damage. While the findings were observed in both mice and humans, the research suggests that further studies are needed to optimize fasting methods and explore ways to minimize its negative effects on hair growth.

Takeaways

• 😀 Intermittent fasting has been shown to have various health benefits but can negatively affect hair growth.
• 😀 Research on both animal and human models suggests that intermittent fasting impairs hair follicle regeneration.
• 😀 Fasting increases markers of apoptosis (cell death) in hair follicle stem cells, leading to inhibited hair growth.
• 😀 Longer fasting periods (e.g., 20 hours fasting) have worse effects on hair growth than shorter periods (e.g., 16 hours fasting).
• 😀 Chronic intermittent fasting for 48 months can cause hair follicle degeneration and baldness in mice.
• 😀 The mechanism behind this hair loss involves fat burning in skin fat cells (dermal adipocytes) during fasting.
• 😀 Fatty acids released during fasting overwhelm the hair follicle stem cells' mitochondria, leading to oxidative stress and cell death.
• 😀 While fasting benefits the whole body, it can suppress hair regeneration due to a localized metabolic response in the skin.
• 😀 Adding topical antioxidants like Vitamin E can mitigate the negative effects of fasting on hair growth.
• 😀 A study on 49 humans showed that 18:6 intermittent fasting reduced hair regrowth by 18%, supporting the findings from animal models.

Q & A

What does the new research reveal about intermittent fasting and hair growth?

The research reveals that intermittent fasting, as practiced by many people, can harm hair growth by impairing the regeneration of hair follicles. The study found that fasting increases apoptosis (programmed cell death) in hair follicle stem cells, ultimately inhibiting hair growth.

Does the research claim that fasting is harmful overall?

No, the research does not claim that fasting is harmful overall. In fact, it acknowledges the health benefits of fasting, such as improving the function and stress resistance of multiple body stem cell populations. However, it also highlights that fasting can have negative effects on hair growth.

What biological process drives hair growth in the skin?

Hair growth in the skin is driven by the cyclic activation of hair follicle stem cells (HFSCs). These stem cells reside in a niche, which integrates systemic signaling with local signaling to adapt to various stressors, including intermittent fasting.

What was the impact of intermittent fasting on hair follicle stem cells in mice?

The research found that intermittent fasting, including regimens like 16:8 and alternate day fasting, impaired hair follicle regeneration in mice. It caused hair follicle stem cells to be repeatedly activated during feeding periods but eliminated during fasting, leading to inhibited hair follicle growth.

Did the mice adapt to chronic intermittent fasting over time?

No, the mice did not adapt to chronic intermittent fasting over time. After 8 months of fasting, the mice experienced baldness in some regions, indicating hair follicle degeneration driven by stem cell loss.

What is the mechanism behind hair follicle stem cell damage during fasting?

The mechanism involves the breakdown of fat cells in the skin, called dermal adipocytes, during fasting. This fat burning process releases free fatty acids into the hair follicle stem cell niche, leading to oxidative stress, mitochondrial dysfunction, and apoptosis of the stem cells.

How does the adrenal gland relate to the impact of fasting on hair growth?

The adrenal glands play a critical role in the process. Upon fasting, the drop in leptin levels activates the hypothalamic-pituitary-adrenal axis, which triggers the release of stress hormones like epinephrine and cortisol. These hormones cause fat burning in dermal adipocytes, which releases free fatty acids that harm hair follicle stem cells.

What happens when the adrenal glands are removed in the fasting experiment?

When the adrenal glands were removed from the mice, fasting no longer caused the death of hair follicle stem cells, indicating that the effect of fasting on stem cell apoptosis is dependent on the adrenal glands.

How does oxidative stress affect hair follicle stem cells during fasting?

Oxidative stress overwhelms the mitochondria in hair follicle stem cells, leading to mitochondrial dysfunction and programmed cell death (apoptosis). This process is adaptive because it diverts energy away from hair growth during fasting in favor of more critical bodily functions, such as gut and immune system maintenance.

Can the negative impact of fasting on hair growth be mitigated?

Yes, the negative impact can potentially be mitigated by applying topical antioxidants like vitamin E. In the study, the researchers found that adding antioxidants to the skin alleviated the inhibitory effect of fasting on hair follicle regeneration, suggesting a possible strategy for counteracting fasting's impact on hair growth.