Natural shedding cycle and growing out hair dye?

[Amara]

Hey all! I did my last henna summer 07, so it's been about two years. I have virgin hair around shoulder-APL depending on what hair you're looking at. My hair is just a bit past tailbone, so I have a BUNCH of hennaed length.

I guess my question is - if hair replaces itself, on average, every 6 years, then my henna should be fading in time, right? Like, it's been 2 years, so 1/3 of the hairs I had orginally hennaed should have been shed by now right? (I realize I'm assuming I do follow the average 6 year shed cycle exactly, and that it's a continuous process during those 6 years). Then in another 2 years I should have shed out 2/3 of the hair I had hennaed.

Right? Is my logic flawed? So 4 years from now all of my hennaed hair would be gone?

Now, I know this is not going to be the case, since my hair grows 1/2" per month and if I had a 6 year cycle I would be right around terminal now, but I'm still growing regularly and my hemline is still thick.

So I'm not really sure where my point was going. I was just fantasizing about having all my hennaed length magically shed away and replaced by my virgin hair, I guess, without having to cut any length off. :D

[Arctic]

I have heared it's a seven year cycle.

Hmmm, assuming you wouldn't trim and your hair would shed to the speed you estimated, would that mean your hemline would be 1/3 thinner after two more years than it is now, and now it would be 1/3 thinner than it was 2 years ago?

ETA: I feel hair just cannot be counted like that but I'm no way expert :)

[Amara]

I have heared it's a seven year cycle.

Hmmm, assuming you wouldn't trim and your hair would shed to the speed you estimated, would that mean your hemline would be 1/3 thinner after two more years than it is now, and now it would be 1/3 thinner than it was 2 years ago?

ETA: I feel hair just cannot be counted like that but I'm no way expert :)

Well... I suppose the hemline wouldn't be any thinner, because some other hairs previously would have been part of the grow/shed cycle and it would just be new hairs taking over their place rather than the total every decreasing or increasing...

I don't think hair can really be predicted or counted that way either. I guess what I'm thinking is, even if my shed cycle is longer than 6 years, eventually, with no trims, I should just reach a point where I've shed all the dyed hair and am left with only virgin hair. Right? The only question is how long that will take!

[Fractalsofhair]

Well... I suppose the hemline wouldn't be any thinner, because some other hairs previously would have been part of the grow/shed cycle and it would just be new hairs taking over their place rather than the total every decreasing or increasing...

I don't think hair can really be predicted or counted that way either. I guess what I'm thinking is, even if my shed cycle is longer than 6 years, eventually, with no trims, I should just reach a point where I've shed all the dyed hair and am left with only virgin hair. Right? The only question is how long that will take!

The shed cycle is the average per year. A hair is generally not growing for 1-2 years I've heard, so add that onto your growth rate. So it might end up being more like 20 years...

[Arctic]

Xandergrammy is growing out colour without trims and I've seen her wondering about the same thing. It really interesting! (I'm growing out henna too :)) Hope someone else has some more ideas, my brain hurts from thinking all the hairs and their growth and sheds :laugh:

[Amara]

Xandergrammy is growing out colour without trims and I've seen her wondering about the same thing. It really interesting! (I'm growing out henna too :)) Hope someone else has some more ideas, my brain hurts from thinking all the hairs and their growth and sheds :laugh:

I know, I was sitting here thinking about it until my head hurt, so I thought I'd post it and make your head hurt. :D

[spidermom]

It's been interesting to watch Xandergrammy's colors progress. She's more than 3 years into it already, and her natural colors have moved about 60% down her length. Having colored hair and stopping seems a really good way to find out how long it takes for all the dyed hair to shed out.

[Addy]

I think eventually, I'll just cut all my dye ends off so I don't get a head ache. :D

[Amara]

It's been interesting to watch Xandergrammy's colors progress. She's more than 3 years into it already, and her natural colors have moved about 60% down her length. Having colored hair and stopping seems a really good way to find out how long it takes for all the dyed hair to shed out.

Yeah, I'm enjoying seeing the natural growth pattern. I'll maybe chat with Xandergrammy. :)

[fluffybunny]

If you shed 100 hairs per day, and you have 100,000 hairs on your head, then it takes only a thousand days to shed them all, which is around three years. Take the other ends of the estimates for shed and hairs per head and you get the range:

120,000 hairs per head divided by 50 shed per day = 6.57 years
80,000 hairs per head divided by 100 shed per day = 2.19 years

The two year one seems way off because that's only a twelve inch terminal length (assuming 6 inches per year). Hmmm... so I wonder if you can compute this more simply just by taking your terminal length and dividing by your growth rate. That gives your hair lifespan. If you wait one entire hair lifespan, then all hairs should have turned over, right?