Let's start with a brief review of anatomy that we covered in a previous post. Your hair has the follicle, the tube like depression in the skin, where all the growth happens, and the strand which is visible above the scalp. The way your hair grows is by cell division. The cells at the base of your hair follicle divide and turn into your hair strand. At the very bottom of your follicle is a structure called the papilla. This is a tiny capillary, a set of blood vessels that are there to feed the cells that make hair. These cells live at the very bottom of the follicle and surround the papilla, and is called the hair bulb. The work going on at the bottom of your hair follicle is pretty rapid. The cells here divide every 23-72 hours, which is faster than any other cells in your body. That is a reason we can loose all our hair during chemotherapy. Chemo affects rapidly dividing cells like cancer, but also gets the ones we want to keep like hair.
Hair growth, the things that impact it.
Your hair grows .3 to .4 mm a day, and that adds up to about 6 inches on average every year. Your hair has a cycle of growth that is 3 phase, the cycles of the follicles are not synched up, and this is why people don’t shed in the fall and or spring.
Your hair growth has an Anagen, or active growth phase, which lasts from 2-6 years. That's a nice and precise number right? When a follicle enters Anagen, cell division begins and the new hair is formed, as that new strand moves up through the follicle toward the surface, the old hair
is then pushed out, and it falls away. If you have always wondered why your hair never gets longer than 12 inches, it could be because your Anagen phase is on the short end at 2ish years. We are only talking about the hair on your head here. Other hair on the body, lashes, arms, legs, etc have a much shorter Anagen phase. Could you imagine if lashes grew for 2 or more years! Interestingly, Anagen is not just the longest phase, it is also the phase that the majority of follicles in a healthy scalp are in. 85%-90% or scalp follicles are in Anagen at any given time.
After Anagen comes Catagen. This is the transitional phase where the strand stops growing, and it is the shortest phase of your hair growth cycle. This is also the smallest percentage regarding follicles in the stage. I’ve seen reports up to 3% of follicles in Catagen, but the majority of research states about 1% of follicles in Anagen at any given time. This phase lasts a short 2-3 weeks. During this phase the bulb of the hair changes, and detaches from the papilla, creating what is called a club hair.
The third phase is Telogen. Telogen is the resting phase for your follicle, and lasts between 2-3 months, I see 80-100 days reported often. In lashes or body hair this phase lasts longer. Weird I know, shorter growth phase, longer resting phase. You’d think that after working hard for 2-6 years, your head follicles would need a longer nap.
During Telogen, the follicle is at rest, hence the ‘resting phase’ and recharging for the next growth phase. 10-15% or your hair follicles are in Telogen at any time in a healthy scalp. If you pull out a Telogen hair, you will see a hard-ish, white, dry material at the base that is pretty solid. The numbers vary greatly, but the average of Telogen or club hairs that are released daily are in the 40-100 or so range. I've seen numbers as low as 30, and as high as 150 in research documents.
Did you know that the number of hair follicles we have is determined by genetics? We get what we get, and never make new ones. This is why it is so important to take care of what we have to ensure we never run out of hair!
There are many things that affect hair growth. Genetics, hormones, health or sickness, stress, medicine, and one that you may not want to hear, because you are 100% in control of it, and that is diet.
Yes, your diet is a big part of how healthy your hair is, and how well it grows. Nutrients like niacin, biotin, zinc, and vitamins A, B6, and C contribute to scalp and hair health. So a varied diet based on the basic food groups should provide ample amounts of these nutrients, and of course supplements that promote overall good health should be used too.
For hair and scalp health, the following is recommended:
Fruits and vegetables
Lean meat, fish, and poultry
Low-fat dairy products
So, yeah, a good sound, healthy diet. I hope it doesn’t bum you out that McDonalds and Oreos are not on the list.
In addition to diet, lifestyle choices that are healthy play a part too. Smoking is detrimental to hair health. If I remember correctly, it is bad for other stuff too, but we are talking about hair here!
Stress causes so much turmoil in our bodies, and that stress comes out in our hair, too. Typically 2-4 months after a stress event you will see an increase in hair fall. It takes quite a bit of energy to produce hair, and if you body is fighting off other things due to stress, it will put less effort into growing hair. It may even halt hair growth on a pretty large scale creating an event called Telogen Effluvium. Effective stress reduction practices, and possibly changing life to relief stress will help here.
Medicines can affect hair growth to an extent, and the growth effect can be multiplied by the illness, or treatment the medicine is used for. Fevers can even create a hair fall event in some people.
Hormones are also a big part of hair growth and or thinning. During pregnancy, many ladies say they had the best hair of their life, then 4 months after, the worst hair, as it started coming out in handfuls. Blame it all on baby hormones.
Testosterone is a big hair thinning culprit. Not necessarily the testosterone itself, but what it turns into in our bodies, DHT. Something like 95% of thinning hair is caused by DHT. You know what else? Ever get those dark, thick, long hairs on your chin, upper lip, or those sideburns that happen after 40, ladies? Yep, you get to send DHT a big ol’ thank you note for that!
Low hormones can do crazy stuff hair and it's growth too, thyroid issues cause a lot of hair issues for a lot of people.
Bottom line is, if you are experiencing low or not growth, thinning of hair, or dramatic hair loss, many things can be at play. Diet is always important, but so is a trusted medical professional. If you are struggling with your hair health, growth and appearance, the best advice I can offer is a visit to your medical professional. There may be something big at play, and yo want to know that so you can act on it. Your hair is an indirect thermometer of your overall wellbeing. If your hair is changing and looking less healthy, allow that to be a trigger to deeper discovery for you.