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The Science of Hair Growth: Understanding the Hair Growth Cycle + Strategies to Mitigate Hair Loss

We are going to delve into the fascinating world of hair growth and explore the factors that influence hair health. We'll start with a brief overview of stem cells and their role in hair follicle growth, then proceed to understand the three basic phases of the hair growth cycle.


By connecting these concepts, we will uncover the reasons behind hair loss and explore strategies to encourage hair growth and maintain healthier hair.




Let's dive in:

  1. The Hair Follicle Structure: Before delving into hair growth, let's familiarize ourselves with the hair follicle's basic structure. The hair follicle consists of a bulb at its base, then the bulge region slightly above the bulb, and then within this same region is the the arrector pili muscle that keeps the hair follicle upright and in place.

  2. Stem Cells and Their Role in Hair Growth: Stem cells are remarkable cells capable of self-replication and differentiation into various cell types. In hair follicles, two types of stem cells play crucial roles in hair growth: a. Epidermal Stem Cells: Located in the bulge area, these stem cells differentiate into keratinocytes during the anagen phase, forming the hair shaft. b. Dermal Papilla Cells: These mesenchymal stem cells reside in the bulb region at the base of the hair follicle. They secrete signaling molecules and growth factors that regulate hair growth.

  3. The Hair Growth Cycle: The hair growth cycle consists of three phases: a. Anagen Phase: The active growth phase when hair follicle stem cells rapidly divide and differentiate into keratinocytes, resulting in hair growth. Dermal papilla cells release growth factors to promote this phase. b. Catagen Phase: A transitional phase where the hair follicle regresses, and the lower part of the hair detaches from the blood supply. c. Telogen Phase: The resting phase when the hair follicle remains inactive for several weeks to months. Old hairs shed during this phase before the hair follicles re-enter the anagen phase for a new growth cycle.

  4. Nutrients Supporting Anagen-Phase Hair Growth: During the anagen phase, keratinocytes require specific nutrients to support healthy hair growth. These nutrients include biotin (Vitamin B7), protein, sulfur, zinc, copper, iron, vitamin C (for collagen production), omega-3 fatty acids, and more (though the nutrients listed above are the heavy-hitters).

  5. Strategies to Mitigate Hair Loss: Hair loss occurs when there is an imbalance in the hair growth cycle, leading to more hairs in the telogen phase and fewer in the anagen phase. To address hair loss and promote hair growth, the following strategies have been used or studied:

a. Increasing Scalp Blood Flow: Scalp massage, acupressure, microneedling, and platelet-rich plasma therapy (PRP) are some methods to boost blood flow to the scalp, delivering essential nutrients to hair follicles. b. Topical Caffeine Application: Topical caffeine application has shown promise in stimulating hair growth, comparable to minoxidil, a popular hair growth treatment. c. Natural DHT Blockers: Some natural DHT blockers like rosemary and saw palmetto can help prevent miniaturization of hair follicles caused by the hormone DHT. d. Peptides for Hair Growth: Thymosin beta 4 and AHK-Cu are peptides that have been studied for their effects on hair growth following topical application. They may help activate hair follicle stem cells and stimulate dermal papilla cell proliferation, respectively.

  1. Lastly, Consider the Impact of Heavy Metals and Toxins on Hair Growth: Heavy metals like lead, mercury, arsenic, cadmium, and toxins like BPA and phthalates can disrupt the hair growth cycle, leading to hair loss and thinning. Lead, mercury, and arsenic are all, in fact, associated with telogen effluvium which is a condition where the telogen phase lengthens; this results in severe hair loss.

Conclusion: Understanding the science of hair growth is essential for maintaining healthy hair and preventing hair loss. By nourishing the hair follicles with essential nutrients, increasing blood flow to the scalp, and minimizing exposure to harmful substances, balancing hormones, and uncovering any triggers of scalp inflammation that disrupt the stem cells involved in the anagen phase, you can more-easily promote healthy hair growth and prevent loss.


If you're experiencing hair loss, consider seeking professional guidance to address any underlying hormonal imbalances or environmental factors contributing to the issue.

2 Comments


Love that you breakdown the science! will have to try this

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I am finding that my hair needs some boosts like these! I will definitely be trying some of this!

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