[The Science] Root Cause of Hair Loss

Alopecia Universalis Reversed with in-office laser treatments

There are several reasons for hair loss, also known as alopecia, but the most common hair loss issue I am seeing now is a temporary form of hair loss due to stress, called Telogen Effluvium. This type of shedding is not a true hair loss but rather a shifting of the natural hair cycles. It usually becomes noticeable about 3-4 months after the stress, which makes it a bit of a mystery to the person experiencing it. The stress is often gone, but the hair shedding is just beginning.  Fortunately, in most cases there is complete recovery by about 6-9 months. Telogen Effluvium can occur after a major physiologic or emotional stress such as childbirth, Covid or other major illness, job or relationship change, significant weight change and more. 

 Hair Loss Facts: 

If you’re suffering from hair loss, you are most certainly not alone. The facts are that in the US alone, over 80 million people are affected by hair loss and well over 50% of women will experience some form of hair loss in their lifetime. It can start as young as in your teens or as late as in your 80’s. Therefore, it is no surprise that each year, Americans spend more than $2 billion dollars trying to avoid or reverse the effects of hair loss.


  • 50% of American men experience hair loss before age 50
  • 25% experience hair loss before 30
  • By age 35, 40% experience some degree of hair loss
  • After age 50, the percentage of men experiencing significant thinning goes up to 85% - over the next few decades


  • Account for up to 40% of American hair loss sufferers
  • 50% of American women will suffer hair loss at some point in their life
  • 40% have visible hair loss by age 40
  • Now, women are showing signs of significant thinning at earlier ages, sometimes as teens or in their early 20’s and 30’s

That’s what we see on the surface, but it goes deeper - data shows that two thirds of those suffering from hair loss think about their hair loss daily and, nearly half report that hair loss makes them feel judged and affects their sex life. Nearly 90% said hair loss makes them depressed and that they envy individuals with thick hair. The causes of loss can range from stress induced, autoimmune, genetic, medication related, and certain medical conditions that can be associated with hair loss. Diet is also particularly important and too often overlooked in managing hair loss.


Scarring vs Non-Scarring

There are two important, broad categories of hair loss. The first is more common, which is non-scarring alopecia. This means the follicle is still alive and has the potential to be restored. 

The second type is called scarring alopecia. In this type of hair loss, the follicle is no longer present and the hair can no longer be recovered. Our goal in these cases is to prevent it from progressing as much as possible.  The only hope is to minimize the amount of scarring and hair loss that goes with it. 

The way to distinguish between the two is relatively simple: in the non-scarring patterns, the hair follicle is intact and is visible from the surface of the skin, while in the scarring forms of hair loss there is no evidence of a follicle. As dermatologists, we are trained to evaluate the skin of all parts of the body, including the scalp and we can distinguish between the two patterns. Sometimes a biopsy can be helpful to confirm and to offer more detail but most of the time it is a clinical diagnosis, based on the experience and expertise of the dermatologist..

Patterns of Hair Loss


  • Androgenetic Alopecia, aka hereditary hair loss: This is the most common type of hair loss. Hereditary hair loss accounts for over 80% of all hair loss in both men and women and it can be inherited from either the mother's or father's side. 
  • In both men and women, it can start in their teens. In men, it usually starts as recession at the temples, progresses to the crown, and then meets in the middle with total loss of the frontal scalp leaving a semicircle zone of hair just above the ears going to the back of the scalp. 
  • Women have a fear of going bald, but they present in a different pattern than men, where the frontal hairline is usually retained but the midline part slowly widens and the hair thins in the crown region at the top of the scalp.. In some cases, this can become severe, leading to near total loss, but in most cases the thinning is usually centered over the top of the scalp in the crown. The reason women often have a milder course than men may be because women have ½ the amount of 5-alpha reductase enzyme that men have and also women have more aromatase enzyme in follicles that aromatizes testosterone to estradiol.
  • Telogen effluvium aka stress shedding: This is not true hair loss, but rather a hair shedding process that usually occurs about 3-4 months after a major physiologic stress. The process is self-limited and the hair will grow back on its own in about 3-4 months. Factors such as hormonal shifts from pregnancy along with crash dieting and certain medications have been shown to trigger Telogen Effluvium.
  • Alopecia areata aka autoimmune hair loss: Alopecia Areata is a type of hair loss that occurs when the immune system mistakenly attacks hair follicles, which is where hair growth begins. It usually begins when clumps of hair fall out, resulting in totally smooth, round, hairless patches on the scalp. It can occur anywhere on the body where hair grows, but is most bothersome when it occurs on the scalp or in the beard area for men. It may also be associated with other autoimmune diseases, but having one or treating one does not affect the other. There is a genetic predisposition with an increased occurrence in 1st degree relative. The underlying cause remains unclear but it may be triggered by environmental factors. It can happen at any age, and usually the younger the person is when it happens, the less likely they are to recover the hair. The great news here, and it is absolutely fantastic news, is that there is a new class of drugs called JAK Inhibitors that are now FDA approved to treat severe alopecia areata. We are now able to regrow hair beautifully in these cases. It’s absolutely incredible to see.
  • Hair loss due to medication: There are many drugs that have hair loss mentioned in the label. This is sometimes confusing because it simply means that people taking the medication also reported hair loss and is not an otherwise absolute known cause. SSRI’s (a class of antidepressants) is one medication that stands out in this category. Other medications known to cause hair loss are chemotherapeutic agents used in the treatment of cancer. This is a temporary hair loss and in the vast majority of cases the hair grows back, often thicker and better than before treatment. There are now caps and other protective measures being used to minimize the hair loss around cancer treatments and it has had a very positive impact on patients.


  • Traction alopecia (can start out as non-scarring): This occurs from wearing tight braids, ponytails or extensions over years. 
  • Central centrifugal cicatricial alopecia (CCCA): The cause remains unknown
  • Systemic or Discoid Lupus erythematosus
  • Folliculitis decalvans
  • Pseudopelade of Brocq

Stress and Hair Loss

Effects of stress directly lead to multiple factors, which can impede hair growth.

  • Release of cortisol induces catagen and follicle regression
  • Reduced hair follicle keratinocyte proliferation
  • Premature induction of intrafollicular keratinocyte apoptosis and HF regression (catagen)
  • Mast cell-dependent neurogenic inflammation.

Stress can also impact the hair follicle indirectly.  Chronic activation of the stress response disrupts other systems in the body tied to hair growth - namely the endocrine and digestive system, which can be discussed with your physician in depth.


This is critical to understanding which type of hair loss you are dealing with. In the physical exam, the dermatologist will examine your scalp as well as the hair itself. We look at the entire scalp, the brows and other parts of your face and body for patterns of excess hair growth or loss in different areas, and to see if there is acne or if there are other medical or hormonal issues. 

Clues to hair loss issues are: 

  • Increased spacing between the hairs
  • Patchy hair loss, or focused loss in certain areas. A pull test may be helpful here as well. 
  • Variations in diameter and length of hair and whether the ends of the hairs are blunt or tapered. 
  • Evaluation of the overall pattern: it’s important to note if the frontal hairline is retained, if there’s recession at the temples, and if there are any areas of loss of follicles or scarring.
  • Evaluation of hair growth on the brows, lashes, upper lip and chin. A sign of excess loss or growth gives us clues to underlying conditions that may be contributing to the hair loss on the scalp


Your dermatologist will determine if lab work or a biopsy is necessary.

  • Vitamin D levels
  • Sex hormone levels
  • Thyroid hormone levels
  • Iron blood studies


Products for hair growth:

  • Topical Minoxidil – The FDA approved concentration of 5% minoxidil, available over the counter, is now the same for both men and women with androgenetic alopecia. Men need to use it twice a day and women only once a day. 
  • Active and Daily Drops:  My version of minoxidil is an upgraded formula with 6% along with niacinamide and caffeine for better penetration and anti-inflammatory benefits. While it is something you will have to use indefinitely, the good news is that as long as you keep using it, it keeps working!
  • Daily Drops +: contains the above along with topical finasteride. Great for those who don’t want to take pills but want the benefits.
Hair Growth Kit: This is my 3-step system for hair re-growth, consisting of a specially formulated shampoo, that removes daily build-up and a conditioner, that adds fullness to thin lifeless hair, which work together to prepare the scalp for the Rapid Regrowth Serum. Visible results can usually be seen within 30 days of use.Rapid Regrowth Serum. Visible results can usually be seen within 30 days of use.
  • Supplements: A proper diet is critical for healthy hair. Essential proteins like Arginine, Histidine, and Lysine are found in meat, fish, poultry, and eggs and are important for new hair growth.  Essential fatty acids, like Omega-3 are found in salmon, sardines, herring, and mackerel and are the most important for shiny, healthy hair. Adequate levels of flax, antioxidants, and vitamins, (especially B and D vitamins) make the difference between a full, thick, shiny head of hair and thin, brittle, dull hair that sheds and breaks easily. Green tea can also reduce inflammation in a follicle if inflammation is present. While a healthy diet is critical, supplements are also becoming popular for the management of all forms of hair loss. Below are my favorite hair supplements:
    • Nutrafol- contains a blend of ingredients shown to have data supporting hair growth. It contains: 
      • Rhodiola, Shcisandra, and Reishi Mushrooms: adaptogens that lowers elevated stress hormones triggered by emotional and physical stressors and also protect the body from the effects of stress with powerful immune modulating properties.
      • Tocomax 20%™: can increase hair growth on average by 34%
      • Sensoril® Ashwagandha: decreases the levels of hair damaging stress hormone, Cortisol
      • BCM-95® BioCurcumin: a potent anti-inflammatory and anti-oxidant clinically proven to lower inflammatory biomarkers, like CRP.
      • Cyantine® HNS: provides the building blocks of hair to improve hair strength and brightness
      • Hydrolyzed Marine Collagen & Hyaluronic Acid: rebuild the structural integrity of the hair follicle environment, improve moisture, and promote diffusion of nutrients.
    • Viviscal Professional: this is a supplement to nourish thinning hair and promote existing hair growth. It has excellent clinical data and the formulation includes: 
      • AminoMar Marine Complex: provides the essential proteins needed to nourish thinning hair and encourage growth of existing hair
      • Horsetail Extract: an organic form of silica which increases the strength of the hair and revitalizes lifeless hair
      • Vitamin C from the Acerola Cherry (one of the richest sources of Vitamin C available)
      • This contains fish and shellfish and is not appropriate for those allergic to these ingredients or for those with celiac disease.
    • Prescription Medications:
      • Oral Minoxidil noted in detail above. In my opinion this is not a top-line option.
      • Spironolactone is used off-label for women with hair loss. It works by blocking the action of dihydrotestosterone at the androgen receptor. The appropriate dose and side effects will be reviewed with you by your physician.
      • Propecia is a prescription drug for male pattern baldness that slows progression in 83% of the men who take it and restores hair 66% of the time.
      • Dutasteride is used off label for men, studies are underway for hair loss.
  • Laser and Light
  • Fotona Dynamis: The Hairlase in-office treatment has helped so many of my patients achieve excellent results, when used alone and also in combination with other therapies to help restore hair growth through a process called photobiomodulation. We do treatments at two week intervals for 12 sessions and then once every three months for maintenance. We always prime our PRP treatment with the laser and have found it amplifies the benefits for our patient.


  • Low Level Light Therapy (LLLT): There are in-office laser devices as well as at home devices which are FDA cleared for hair growth. They influence hair growth in 3 stages:
      • Stop hair loss
      • Current hair becomes thicker and fuller
      • Regrowth of new hair where the hair follicle grows terminal (thicker) hair in place of very thin “peach fuzz” (vellus) hair.
      • The early hair combs are now also offered in versions that look like baseball hats that cover a broader surface area of the scalp, leaving your hands free and making treatments easier and more efficient. They also have better diodes, providing excellent energy while covering a broad area of scalp at one time. The brands I have researched that stand out as superior for at home lasers include: Theradome, Capillus, The Laser Cap.
  • PRP: After years of researching and reviewing data and devices for PRP for the scalp I am happy to now offer it as a component of my hair growth program, for the right candidate.
  • The hair promoting effects of PRP are supported by studies showing a faster transition to the growing (anagen) phase of hair cycling back from the resting and transitional phases, and an increase in the number of newly formed follicles and earlier hair formation. 

    The process is an in-office treatment as follows:

    • We start with extracting a small amount of blood into a specialized test tube. The test tube is the key to the process as it contains filters to optimize growth factors for injection. 
    • We place the test tube in a centrifuge which spins at rapid speeds, to separates out and concentrate the platelet-rich plasma which is packed with growth factors 
    • The growth factors are extracted and placed into a series of syringes.
    • While the solution is spinning, we do a Hairlase treatment to help start the process of follicle stimulation
    • We gently and surprisingly painlessly inject the solution into the areas of concern on the scalp. 

    Once you are evaluated in the office, it will be determined if you are a good candidate for PRP. We always do a Hairlase (see above) treatment immediately prior to injecting the PRP and have found that this has amplified the PRP benefits for our patients.

    • Cortisone injections: This is done by your dermatologist and in my view works well for all types of hair loss including genetic male and female types. I do low concentration injections at monthly intervals for 5 months and then switch to treatment every 3 months. At the concentrations and volume I use, I have never seen any systemic side effects or atrophy (thinning of the skin of the scalp).
    • Hair Transplantation: this is an effective treatment for men and women with a good donor area. Other treatments still need to be considered to maintain the surrounding hair. Today’s grafts are microscopic and after 12-15 months, the hair in the transplant area will be long and strong.

Bottom Line

Hair growth is complicated scientifically, physically and emotionally. The pathways that drive hair loss are not yet fully understood so there is no single reliable, precise mode of treatment. For every patient, I recommend an evaluation by a board certified dermatologist along with working to manage stress and optimize your diet and possibly using one, or a combination of hair growth treatments to help maintain and grow the healthiest, most beautiful hair possible.



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