Dr. Pawd's Notes on Science of Healthy Hair, Hair Loss and How to Regrow Hair
Detailed Notes From Dr. Pawd on the Huberman Lab Podcast Episode on Hair Loss
Based on feedback from some of the readers I decided to write this post. In this post we will cover detailed notes from the latest episode of The Huberman Lab Podcast - The Science of Healthy Hair, Hair Loss and How to Regrow Hair. This post provides short notes covering the most important facts, points, tips and protocols from the episode, I have tried to be as through as possible but few things might have been missed. I highly recommend watching the full episode.
This was yet another amazing episode from Dr. Huberman and a must watch on an important topic because almost everyone goes through the problem of hair loss and they want to find out what are the science backed protocols to keep the hairs healthy. So without much delay, let’s get started!
In this episode Dr. Huberman delves into the fascinating world of hair, its biology, and ways to slow or reverse hair loss. He discusses the cellular biology and stem cells involved in hair growth, highlighting that every hair strand has its own stem cell niche. An interesting fact is that hair growth varies depending on the location on the body, for example head hair growth lasts 4-8 years while eyebrows have a shorter growth period.
The episode dispels myths about balding, hair replacement, and hair regrowth. For example it debunks the idea that one inherits balding patterns from their mother's father. While certain genes that influence predisposition to baldness are inherited, it isn't as straightforward as looking at a photo of one's maternal grandfather.
Structure of the Hair
The hair structure consists of the shaft (visible part), root (below the skin), and the hair bulb, which contains stem cells and melanin-producing cells responsible for hair color.
Sebaceous glands: located next to the hair root, secrete sebum, which helps waterproof the skin and maintain its oily properties.
Sebum: An oil that provides waterproofing for our skin and hair and has strong antibacterial and anti-microbial properties. It plays a crucial role in our immune system function and protects us from infections.
Arrector Pili Muscle: A muscle that lies diagonally between the bulb portion of the hair and the surface of the skin. It contracts when we get cold or scared, causing goosebumps and making our hair stand up. This mechanism helps trap air between hairs, providing insulation and warmth.
Blood Flow: Capillaries deliver nutrients, oxygen, and blood flow to the stem cells and melanocytes in the hair bulb. This is important for hair growth.
Hair Growth: There are three basic phases of hair growth: Anagen (growth phase), which lasts from two to eight years for scalp hair; Catagen (transition phase); and Telogen (resting phase). The duration of the Anagen phase varies for different body regions and individuals, which affects the perceived rate of hair growth.
Factors Affecting Hair Growth and Loss
Blood flow and hormones play a significant role in these phases. The delivery of nutrients and oxygen through blood flow is essential for hair growth, and hormones act as accelerators and brakes on each phase.
Hair growth is regulated by various hormones in the body such as estrogen, thyroid hormone, insulin-like growth factor, and androgens.
Androgens are mainly responsible for hair loss as they control the size of the stem cell pool that gives rise to hair growth. Testosterone, a type of androgen, is converted into dihydrotestosterone (DHT) by an enzyme called 5-alpha reductase. DHT is the most powerful androgen in humans and is responsible for several desirable traits such as mental and physical vigor, strength, and libido. However, as people age, there is more 5-alpha reductase activity converting testosterone to DHT, which inhibits hair growth by reducing IGF-1 and cyclic AMP. This is why by the age of 50, about 50 percent of people experience pattern hair loss or Androgen-dependent alopecia.
The health and activity of stem cells in the hair follicle is another factor which determines the rate of hair growth.
Other factors behind hair loss can be genetics (distribution of androgen receptors on the scalp), psychological state, stress, hormonal and chemical imbalances, mechanical changes in the scalp (e.g. reduced blood flow).
The episode also delves into the relationship between dopamine and prolactin hormones, highlighting their antagonistic nature.Dopamine is related to hair growth and prolactin is related to hair loss and a balance between the two is needed for a healthy scalp.
Treatments for Hair Loss
Minoxidil
Minoxidil, a drug initially developed to treat hypertension, has been found to slow hair loss rates and promote hair growth by increasing blood flow to the hair follicles. This extends the anagen phase, allowing hair to grow longer.
Dosages
Oral dosage ranges: 0.25 mg to 5 mg per day
Topical dosage: 5% concentration, once or twice daily
Need to leave solution on scalp for 3-5 minutes for absorption
Correct dosage determined by trial and error, starting with lowest dose
Side Effects
Dizziness
Lower blood pressure
Reduced libido
Edema (swelling caused by too much fluid trapped in the body's tissues)
Hyperprolactinemia (a condition of elevated prolactin levels in blood)
Alternative to Minoxidil
Low-dose Tadalafil: 2.5 mg to 5 mg per day
Increases blood flow to various body parts, including the scalp
May slow hair loss but unlikely to reverse it
Increasing Blood Flow for Hair Growth
Massaging the scalp
Red light therapy
Heating/lighting of the scalp
Minoxidil increases blood flow continuously
Platelet-Rich Plasma (PRP)
PRP involves drawing a person's own blood and the basis of PRP is to encourage nutrient delivery to a particular region using the person's own platelets.
PRP injections are not stem cell injections, but platelet-rich plasma injections are aimed at encouraging nutrient delivery through platelets.
The success of PRP injections is often transient and patients undergo many treatments, which can be expensive.
There are not sufficient clinical data to suggest PRP as a treatment right now especially given the cost of many thousands of dollars for many treatments.
Microneedling
Microneedling involves using small needles that cause microdamage and micro-levels of inflammation to stimulate hair growth by reactivating semi-quiescent populations of stem cells.
It increases blood flow, oxygen delivery, and nutrients to the region of the scalp, which can improve hair growth.
Needle lengths of 1-2.5 millimeters are more effective than shorter needle lengths.
Microneedling can be combined with other hair regrowth tools and pharmacology like minoxidil, finasteride, and caffeine.
The combination of microneedling and minoxidil is more effective than either treatment alone, and it can recover dead zones, regions of the scalp with no stem cell population.
Microneedling causes physical disruption, bleeding, and inflammation, but this is part of the process by which it improves hair growth.
The micro part of microneedling is critical because scarring can result in no hair growth.
Microneedling is not very painful, but it can cause bleeding of the scalp, which is apparent in the front of the head or bald regions.
Microneedling is able to induce low levels of inflammation, which is the necessary trigger for biological function cascades that relate to proliferation of stem cells or maintenance of stem cell populations.
Botox for Hair Growth
Botox injections can be applied to the scalp to relieve tension and decrease the squinting nature of the scalp skin.
Botox treatment to the scalp can lead to less squinting of the scalp, which can improve blood flow to the stem cell follicle area and therefore, hair growth in those regions.
Botox injections have to be done repeatedly as the botulinum neurotoxin wears off eventually.
The efficacy of Botox for offsetting hair loss is not clear, and there aren't a lot of large-scale clinical studies on this yet. However, it seems to be a safe alternative to things like minoxidil.
Caffeine
Caffeine can be a potent PDE (Phosphodiesterase) inhibitor which indirectly stimulates IGF-1 and can increase hair growth or maintain hair growth in a region.
Topical caffeine application can be as effective as minoxidil application for offsetting hair loss without lowering things like blood pressure.
Caffeine appears to reduce apoptosis which is naturally occurring cell death of that stem cell niche.
Caffeine can offset the death of that niche and maintain the stem cell population longer making caffeine a good choice in conjunction with various chemical treatments.
Ingesting caffeine will not accomplish the goal of offsetting hair loss; rather, topical applications are required.
Caffeine ointments should not be applied every day, and dosages of caffeine vary tremendously.
Caffeine does not carry all the other blood pressure-related effects and hyperprolactinemia effects that minoxidil does.
Caffeine is a safer alternative to minoxidil with lower incidence of side effects.
There is no evidence to show that caffeine creates new hair growth.
Finasteride
Finasteride is a 5-alpha-reductase inhibitor that is effective at lowering DHT.
Finasteride comes in two forms, oral and topical. Topical finasteride is typically applied as a 1% solution rubbed into the scalp or used in shampoos.
Topical finasteride is thought to make it into the hair follicle and inhibit DHT there, which can allow for more hair growth.
While the topical application is harder to dose than oral finasteride, it has fewer side effects and is recommended as a starting point for those treating hair loss.
The effective dosages of finasteride range from 0.01 milligrams per day to 5 milligrams per day, with the lower dosages already leading to a 50% reduction in DHT.
Increasing doses of finasteride taper off their effectiveness and can lead to more side effects, so taking the lowest effective amount is recommended.
Topical finasteride is associated with fewer and less severe side effects than oral finasteride.
A starting point for oral finasteride is 0.5 milligrams to 1 milligram per day, while topical finasteride is 1 milliliter of 0.25% solution applied once per week. It is important to work with a doctor and monitor hormone levels while taking finasteride.
Dutasteride
Dutasteride is a molecule similar to finasteride that inhibits all three isoforms of the 5-alpha reductase enzyme, reducing DHT by 95% at concentrations as low as 0.5 milligrams.
Dutasteride works about 2 to 5 times faster than finasteride in inducing hair regrowth and is typically taken orally at a dosage of 0.5 milligrams to 2.5 milligrams.
However, dutasteride is associated with a lot of side effects related to the DHT pathway, such as gynecomastia and reduction in sex drive and overall drive.
People take dutasteride when they are impatient and concerned about their hair loss and do not want to wait a full 30 to 50 weeks to see hair regrowth.
Ketoconazole
Ketoconazole acts as an anti-fungal that disrupts some fungal growth on our scalp that contributes to hair loss.
It reinforces the properties of sebum in keeping out other fungal infections.
It has been shown to give about an 80% response rate of maintaining hair that would otherwise be lost when used in shampoos 2-4 times per week with a scalp contact time of about 3-5 minutes.
It can offset some of the reductions in the antigen phase and some exacerbation of the telogen phase.
Using a shampoo that contains at least 2% concentration of ketoconazole is important.
The side effects of ketoconazole shampoo may include irritation of the scalp or thinning and brittleness of the hair which can be offset by using shampoos that contain things like biotin.
The use of ketoconazole alone may not stimulate new hair growth but can maintain hair that's already there in areas where hair is thinning.
Combination treatments and their benefits
Microneedling with chemical treatments (e.g., minoxidil) can be more effective than microneedling alone
Microneedling and minoxidil together are more effective in recovering dead zones on the scalp
Botox injections can be used to relieve tension in the scalp, promoting hair growth
Factors to consider when choosing treatments
Pain and discomfort levels associated with microneedling and PRP injections
Cosmetic implications of microneedling (e.g., bleeding, inflammation, and temporary damage to hair follicles)
Long-term commitment to minoxidil treatment
Other Alternative Treatments and Factors for Hair Growth and Maintenance
Hormonal factors
Increasing IGF-1 can help in hair growth and maintenance. Prescription drugs such as growth hormone and sermorelin (a peptide that increases growth hormone secretion) can help increase IGF-1. However, they come with side effects, such as increased cancer risk and growth of small tumors.
Insulin sensitivity
Insulin resistance can lead to hair loss. To maintain healthy hair growth, it is crucial to be insulin sensitive. This can be achieved through regular exercise, maintaining a healthy body fat percentage, and managing type 2 diabetes. Supplements like Myo-inositol (900 mg before sleep), berberine, and metformin can help improve insulin sensitivity.
Iron
Sufficient iron is essential for maintaining proper hair growth. Iron and ferritin play a crucial role in cell growth pathways related to hair growth. Ensuring adequate iron intake can help in promoting hair growth and preventing hair loss.
Conclusion
In conclusion, there are multiple factors which govern the rate of hair growth and loss. These include stress, hormone imbalances, genetics, nutrition, insulin sensitivity among others. There are various treatments available with varying rates of success and side-effects. These treatments include things like minoxidil, dutasteride, ketoconazole, microneedling, and PRP and topical caffeine. There are other factors as well such as insufficient iron or reduced insulin sensitivity, fixing those can also improve hair growth and reduce the loss of hair.
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