Monday, 11 July 2011

Hair and Ageing: Thickness and Growth Rate

As we age, hair turns grey (gray),silver or white -  though technically the hair is losing pigment and is in fact going colourless.

However, well before the hair goes grey, the hair with pigment already begins to change.

There are two main changes to pigmented hair as we age
1. Hair thickness.
2. Hair growth rate.

In one study, they classed women into three groups
  • Young - Average age - 19 years old (range 15-21)
  • Menopausal - Average age - 43 years old (range 38-48)
  • Post Menopausal - Average age - 61 years old (range 50-65)
 For pigmented hair (i.e NOT grey) they found that the younger the woman, the thicker the hair strand and the faster the growth rate (Eur J Dermatol, 14: 28–32,  2004).

Young Menopausal Post Menopausal
Hair Growth Rate (inches/yr) 6.2 5.9 5.2
Hair Thickness* (μm) 74 69 59

Therefore the reason why hair may appear to thin down as we age is in part because it is growing slower and the strand size is decreasing.

* Hair thickness was taken as average diameter (remember hair is slightly elliptical)

Image Credit : No attribution given by websites - gorgeous hair though!


  1. I always thought this was the case. But it's good to have some science to back it up! What I would like to know is: are there differences between the races, men and women or even based on hair type e.g. straight vs curly vs kinky.

    I think it's important to be gentler with your hair as you grow older i.e. styling practices as well as products. I recall reading that hair styling practices made a huge contribution to hair loss among African American women. This is even worse when people continue to use relaxers, wear tight braids etc as they get older. While hair thinning may be emotionally distressing for men, I think it's much more so for women.


  2. Is this decline in thickness and growth rate thought to be an effect of age or of hormones? I notice that the groups are delineated by menopause but it seems like age and hormones are confounding factors (a few days scouring your blog and I'm already talking fancy science stuff lol).

  3. Sue - Science studies rarely if ever do comprehensive studies covering race and hair type. The truth is when the question is does hair thin as as we grow older? Scientists tend to answer it without looking at additional factors such as curly or straight hair.

    Thembi - lol If that is the effect of the blog? Good!!! Yes I do think that in part this is to do with hormones in addition to age though the study did not look at it in detail. A separate study did find that higher testosterone levels helped men get thicker hair strands. Women also have testosterone and I would think that its level would vary according to age.

  4. I'm 32 and I have a few gray hairs. But they are way thicker then the rest of my hair, they kind of feel like wire. Are you saying that this may change as I get older?
    Also the curl pattern of my gray hairs are more loose. My gray hairs are wavy and the rest of my hair is kinky coily.

  5. Hi Dee - I'm just setting up todays post because there is a difference between the hair with pigment and grey hair hair. You are correct to say that the grey hair is thicker (or atleast your observation agrees with the science lol). The hair with pigment is the one thinning down, the grey hair actually gets thicker.

  6. Great post (it's been in my reader for forever, but I'm just getting to it)! I'll definitely share this with my aunts and family!

  7. My hair grows slow enough! This isn't fair! :(

  8. Thanks Mo - I also saw your hair change! Eeek! I will drop over your blog.

    Lela- But when it fully goes grey, it grows faster!

  9. Ok. Here's my scenario. I will be 60 in a few months. I have had locs for over 25 years. They are still growing pretty fast; however, the top of my hair is thinning. I don't know if it is a result of aging or the weight of my locs. No gray.

    What's your take on Ovation Cell Therapy?



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