Understanding Hair Growth and Loss Mechanisms

Andrew Huberman explores the science behind hair growth, loss, and effective treatments to slow or reverse hair loss.

### Understanding Hair Growth and Loss: A Comprehensive Guide
* 💇 - Hair growth is a complex process involving **stem cells, blood flow, and hormonal regulation**.
* 🔬 Each hair has its own stem cell niche in the follicle, with different growth durations depending on location (e.g., **4-8 years for head hair**, **months for eyebrows**).
* 🧬 Hormones like dihydrotestosterone (DHT) play a crucial role in hair growth cycles, with DHT **shortening the anagen (growth) phase** and promoting **catagen (recession) and telogen (rest) phases**.
* 💊 Treatments like minoxidil (Rogaine) work by **increasing blood flow to the scalp**, extending the anagen phase and **slowing hair loss**.
* Minoxidil, originally a hypertension medication, can have side effects like **changes in blood pressure** and hormone levels (e.g., **increased prolactin**).
* 👨 Understanding the biology of hair growth is essential for **evaluating and choosing appropriate hair loss treatments**.
* The podcast also dispels common myths about hair loss, such as the "**maternal grandfather myth**" and the belief that **stress directly causes hair loss**.
* 🎙 The episode highlights the psychological impact of hair loss, noting that **approximately 50% of people notice significant hair loss by age 50**, leading to **anxiety in many cases**.

### Understanding and Managing Hair Loss: Minoxidil, Caffeine, and Growth Factors
* 💊 Minoxidil dosing is crucial for managing hair loss, with oral dosages ranging from **0.25 to 5 milligrams per day**, and topical solutions typically at **5% concentration once daily**.
* 🔬 Minoxidil works by **increasing blood flow to the hair follicles' stem cell niche**, promoting hair growth and maintenance.
* Topical treatments like PRP injections and micro-needling are also used to stimulate hair growth by **increasing blood flow and triggering stem cell activity**.
* - Genetic factors, particularly androgen receptor distribution on the scalp, play a **significant role** in pattern hair loss.
* ☕ Caffeine can indirectly stimulate hair growth by increasing **IGF-1 and cyclic AMP levels**, making it a potential alternative to Minoxidil with **fewer side effects**.
* 📈 Growth factors like IGF-1 are **key regulators of hair growth**, and their levels can be influenced by factors like **sleep quality** and **insulin sensitivity**.
* 🚫 Prescription drugs like growth hormone and sermorelin can directly increase **IGF-1 levels**, but come with potential side effects like **increased cancer risk**.
* 📚 Further research is needed to **fully understand and optimize** the use of these treatments for hair loss management.

### Hair Growth: Understanding the Biology and Treatment Options
* Dihydrotestosterone (DHT) is a key hormone in hair loss, **shortening the growth phase** and **miniaturizing hair follicles**.
* 💊 Finasteride is a common treatment that reduces DHT levels, increasing hair count by **up to 20%** and reducing hair loss in **90% of users**.
* Topical finasteride is believed to have **fewer side effects than oral finasteride**, but can still lead to **systemic absorption**.
* 🌿 Saw palmetto is a natural 5-alpha reductase inhibitor, but its effectiveness for hair loss is **less clear**.
* 🚿 Ketoconazole shampoo can disrupt fungal growth on the scalp, leading to a **mild reduction in DHT levels** and **maintaining hair that would otherwise be lost**.
* 🔬 Microneedling, a mechanical treatment, combined with finasteride has shown **impressive results in stimulating hair growth**.
* 💉 Dutasteride is a more potent 5-alpha reductase inhibitor than finasteride, reducing DHT levels by **95% at a dose of 0.5mg to 2.5mg**.
* "The holy grail of all this hair stuff is in understanding that **no one specific treatment is magic**, and in fact, there are now a **number of good meta-analysis** comparing the various treatments we've talked about today alone or in combination."

The Science of Healthy Hair, Hair Loss and How to Regrow Hair | Huberman Lab Podcast

Welcome to the official Huberman Lab YouTube channel. 

The Huberman Lab podcast is hosted by Dr. Andrew Huberman, a neuroscientist and tenured professor of neurobiology and ophthalmology at Stanford School of Medicine. The podcast discusses neuroscience and science-based tools, including how our brain and its connections with the organs of our body control our perceptions, our behaviors, and our health, as well as existing and emerging tools for measuring and changing how our nervous system works.

The podcast is frequently ranked in the top 10 of all podcasts globally and is often ranked #1 in the categories of Science, Education, and Health & Fitness.


Andrew Huberman

Hair has a unique biological significance, with each strand having its own stem cell niche that determines its growth duration.

The podcast discusses various factors influencing hair loss, including hormones, stress, and genetics, while also dispelling common myths about balding.

Additionally, it explores scientific approaches to halting and reversing hair loss, such as minoxidil, dutasteride, and microneedling.

ROKA offers eyeglasses and sunglasses designed to compensate for the visual system's challenges, with a variety of styles for sports and everyday wear.

Hair loss is a common issue, affecting 50% of people by age 50, and is linked to both psychological well-being and hormonal regulation.

The episode explores the mechanics and chemicals involved in hair growth, as well as interventions to halt or reverse hair loss.

Hair growth is driven by endogenous stem cells, which are present from the beginning of life and give rise to various cell types.

Each hair has a root and a shaft, with stem cells located in a bulb-shaped pocket at the base of the root, dividing and producing daughter cells that make up the hair.

Melanin-producing cells in the bulb contribute to hair color, while sebaceous glands nearby produce sebum, which plays a crucial role in waterproofing the skin and supporting hair growth.

The Role of Sebum and Hair Follicles in Hair Growth

Sebum, the oily substance produced by our skin, plays a crucial role in waterproofing and providing an immune barrier to prevent infections.

The arrector pili muscle, which contracts in response to cold or fear, causes hair to stand up and trap air, helping to warm the body.

Hair growth occurs in three phases, with stem cells and melanocytes in the hair follicle's bulb region receiving vital blood flow for hair production and pigmentation.

Hair growth occurs from the bottom up, with the anagen phase being the longest, lasting 2 to 8 years for scalp hair.

Different body hairs have varying anagen durations, explaining why some can grow longer than others.

The hair growth cycle also includes the catagen phase, where hair recedes, and the telogen phase, which is a resting period before the hair follicle can potentially reenter the anagen phase.

The Role of Hormones in Hair Growth and Loss

Hormonal signals are crucial for hair growth, with dihydrotestosterone (DHT) playing a key role in hair loss by shortening the anagen phase and promoting the catagen and telogen phases.

Minoxidil, a drug originally developed for hypertension, increases blood flow to the hair follicles, extending the anagen phase and slowing hair loss.

The use of minoxidil can also lead to increased prolactin levels, which may have a complex relationship with dopamine, the hormone associated with motivation and drive.

Minoxidil can increase prolactin levels, leading to side effects like reduced libido, apathy, and in extreme cases, gynecomastia and milk letdown.

The drug is available in both oral and topical forms, with a wide range of dosages.

Its primary function is to increase blood flow to the hair follicle, aiming to slow down hair loss rather than reverse it.

Using Low-Dose Tadalafil and PRP for Hair Loss

5-5 mg) is being prescribed to increase blood flow to the scalp and hair stem cell niche, potentially slowing hair loss.

PRP (platelet-rich plasma) injections are also used for hair loss, aiming to deliver nutrients to the scalp, but they are not the same as stem cell treatments.

Micro-needling is another method being used to stimulate hair growth by reactivating stem cells and augmenting hormone-based hair regrowth treatments.

The Impact of Micro-Needling on Hair Growth

Micro-needling and PRP injections can stimulate cell activity and reactivation of stem cell populations through low levels of inflammation.

The procedure's microdamage and inflammation are key to promoting hair growth, especially when combined with treatments like Minoxidil.

A systematic review highlights the positive effects of micro-needling in both men and women, with longer needle lengths being more effective, and the combination of micro-needling and Minoxidil showing the best results in recovering hair growth from dead zones.

The Role of Minoxidil and Botox in Hair Loss Treatment

Minoxidil is a lifelong commitment for hair loss treatment, as stopping it leads to losing gained hair.

LMNT offers a science-backed electrolyte drink essential for cell function and hydration.

Botox is increasingly used for hair loss by relieving scalp tension and increasing blood flow, but its efficacy is not yet clear, and it requires skilled administration and repeat treatments.

The Impact of Cutis Verticis Gyrata on Hair Loss

Cutis verticis gyrata is linked to pattern hair loss and hormone-related issues.

Botox injections have been shown to relieve the condition and improve hair growth.

Key chemical players in hair growth regulation include IGF-1 and cyclic AMP as accelerators, while PDE and TGF-beta-2 act as brakes.

Androgens, particularly dihydrotestosterone (DHT), play a significant role in hair loss by inhibiting growth through the reduction of IGF-1 and cyclic AMP.

The pattern of hair loss varies among individuals due to differences in androgen receptor distribution on the scalp, which is inherited from the mother's side.

Caffeine has been found to be a potent PDE inhibitor, indirectly stimulating IGF-1 and offering a potential topical treatment for hair loss.

Caffeine and Hair Loss: A Potential Solution

Caffeine is commonly found in hair maintenance treatments, but drinking more caffeine won't effectively target hair loss due to its distribution in the body.

Caffeine ointments, applied three times a week, may offer a better chance of reaching the scalp and hair follicles.

Additionally, caffeine may help stimulate IGF-1, reduce apoptosis, and maintain the stem cell population, making it a promising option for hair growth and retention.

Managing Insulin Resistance and Hair Loss

Insulin resistance and obesity can lead to hair loss, making it important to address these issues through prescription treatments, exercise, and maintaining a healthy body fat percentage.

Over-the-counter supplements like myo-inositol, berberine, and metformin can improve insulin sensitivity, while iron levels are crucial for proper hair growth.

Dihydrotestosterone (DHT) negatively affects hair maintenance, and reducing its production through substances like saw palmetto can help extend the hair growth phase.

Saw Palmetto and Ketoconazole for Hair Loss

Saw palmetto, taken in 300 mg doses throughout the day, may help prevent hair loss and promote new hair growth by reducing DHT levels.

Herbal compounds for hair growth have variable effects and are often taken in combination, making it difficult to determine their efficacy.

Ketoconazole, an antifungal shampoo, has been shown to maintain hair loss with an 80% response rate, but its role in stimulating new hair growth is less clear.

Managing Hair Loss: Treatments and Their Effects

Hair loss can be challenging to address, especially in thinning areas of the scalp.

Ketoconazole shampoo, with a 2% concentration, is recommended for use 2-4 times a week to stimulate hair growth and offset hair loss.

Finasteride, by reducing DHT levels, has been shown to increase hair count and thickness, but its effectiveness and side effects can vary among individuals.

Understanding Finasteride: Forms, Dosing, and Effects

Finasteride is available in oral and topical forms, with the latter often used in a 1% solution to target hair follicles.

The drug was developed to lower DHT levels, aiming to treat prostate enlargement and hair loss.

Dosing for finasteride varies widely, with low doses effectively reducing DHT, but the drug's systemic absorption can lead to side effects, making it important to start with the lowest effective dose.

Finasteride: Dosage, Side Effects, and Post-Finasteride Syndrome

5mg to 1mg per day are effective for many, but some may experience side effects and need to adjust their dosage.

Topical finasteride is associated with 30-50% fewer and less severe side effects compared to the oral form.

Post-finasteride syndrome, characterized by severe side effects like reduced libido and mood changes, has become a significant concern, particularly in younger males.

The Impact of Finasteride and Dutasteride on Hair Growth

High dosages of finasteride for hair growth are linked to post-finasteride syndrome, which occurs more in younger males.

Dihydrotestosterone (DHT) plays a crucial role in male development and maturation, with its effects extending into the 20s and 30s.

Dutasteride, a potent inhibitor of all three isoforms of 5α-Reductase, works 2-5 times faster than finasteride in reducing DHT and inducing hair regrowth, but is associated with significant side effects.

Microneedling and finasteride are the most effective treatments for hair regrowth, with the potential to combine them with ketoconazole shampoo and saw palmetto.

Individual responses to these treatments can vary, making it important to start with minimal dosages and consult a medical professional.

The podcast also emphasizes the importance of both mechanical and chemical approaches to stimulate hair growth and offers a zero-cost newsletter for additional resources.