#603

By any chance do you practice intermittent fasting? If not, just out of curiosity: there’s 1 mice study that investigated intermittent fasting regimens impact somatic stem cells and tissue biology of hair follicule. Chen et al. (2025) wrote:
“Here, we report that commonly used intermittent fasting regimens inhibit hair follicle regeneration by selectively inducing apoptosis in activated hair follicle stem cells (HFSCs). This effect is independent of calorie reduction, circadian rhythm alterations, or the mTORC1 cellular nutrient-sensing mechanism. Instead, fasting activates crosstalk between adrenal glands and dermal adipocytes in the skin, triggering the rapid release of free fatty acids into the niche, which in turn disrupts the normal metabolism of HFSCs and elevates their cellular reactive oxygen species levels, causing oxidative damage and apoptosis.”
https://www.sciencedirect.com/science/article/abs/pii/S0092867424013114

#604

Yes, ~16/8. At this stage of my life I really don’t pay any attention to my hair follicles.

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#605

Targeting IGF1-Induced Cellular Senescence to Rejuvenate Hair Follicle Aging
The insulin-like growth factor-1 (IGF-1) signaling pathway is known as a potent aging modifier, disruption of which consistently associates with lifespan extension across diverse species. Despite this established association, the mechanisms by which IGF-1 signaling modulates organ aging remain poorly understood. In this study, we assessed age-related changes in IGF-1 expression across multiple organs in mice and identified a more prominent increase in skin IGF-1 levels with aging—a phenomenon also observed in human skin. To explore the consequences of elevated IGF-1, we developed transgenic mice ectopically expressing human IGF-1 in the epidermis, driven by the bovine keratin 5 promoter (IGF-1 Tg). These mice exhibited premature aging of hair follicles, as evidenced by accelerated hair graying and loss. Single-cell RNA sequencing analyses of dorsal skin highlighted an upsurge in cellular senescence markers and the senescence-associated secretory phenotype (SASP) in hair follicle stem cells (HFSCs), alongside a decline in hair growth and HFSC exhaustion. Our findings indicate that excessive IGF-1 triggers HFSC senescence, thereby disrupting hair follicle homeostasis. Remarkably, interventions in IGF-1 signaling via downstream mechanisms—specifically blocking Ac-p53 activation via SIRT1 overexpression or senolytic treatment for senescent cell clearance, or reducing IGF-1 through dietary restriction—significantly reduced senescence markers, mitigated premature hair follicle aging phenotypes, and restored the stem cell pool. Our findings provide fundamental insights into the biological processes of hair aging and highlight the therapeutic promise of targeted interventions to rejuvenate aged HFSCs and promote hair follicle health.

https://onlinelibrary.wiley.com/doi/10.1111/acel.70053

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#606

Great article and yes… since I have been on 3.3 iu HGH for 6 months, the hair on top of head has taken a big hit.

Elevated IGF-1 Levels in the Epidermis Enhance Cellular Senescence and Accelerate Aging in Hair Follicles.

To explore the consequences of elevated IGF-1, we developed transgenic mice ectopically expressing human IGF-1 in the epidermis, driven by the bovine keratin 5 promoter (IGF-1 Tg). These mice exhibited premature aging of hair follicles, as evidenced by accelerated hair graying and loss.

Our findings indicate that excessive IGF-1 triggers HFSC - hair follicle stem cells, thereby disrupting hair follicle homeostasis.

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#607

TRT already raises IGF-1 I think. I guess I’ll keep off the HGH and secretagogues.

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#608

Exactly.

That’s the idea is higher IGF-1 for thymus regeneration. And, overall growth and health from T-cell production.

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