Height can often be a source of anxiety for young men, especially in teenage years.
Sometimes it can seem like everyone else is rocketing up. While you're very much grounded.
One common question people ask is: when will I stop growing? After all, people can have late growth spurts.
There's lots of information out there, some of it quite misleading and damaging to people who might be a bit worried.
So here's the honest answer.
Is it possible to grow after you turn 18?
Yes it absolutely is. But it's not common.
If you're over 18, you'll probably stay the height you are now.
You can find many accounts of people who grew an inch or two after turning 18.
And that makes sense. Humans aren't robots, and 18 is just a number: there will always be outliers.
People also ask: can I grow after 16? Or even, can I grow after 14?
The answer to this is definitely yes, and this is much more common.
The reason for this is in your growth plates.
What are growth plates and when do they close?
Growth plates are a layer of cartilage near the end of long bones like the tibia or femur. They're also known as epiphyseal plates.
This is where bone growth occurs in children. Eventually the growth plates close or ‘fuse’. This means that the cartilage turns into solid bone, and no more growth can take place.
So the big question is: when do growth plates close? Until this point, there is still a chance to grow taller.
I found this study. The abstract says the following:
All females demonstrated complete fusion by 16 years. Complete fusion in males occurs as early as 14 years. All males demonstrated complete fusion by 19 years.
So that's reasonably interesting. Boys can grow after 18. And girls generally stop growing earlier.
But it's worth noting that this study was only 570 people, and only 300 males. A larger sample would no doubt give larger outliers.
But, as a rule of thumb, we can say that boys will stop growing between 14 and 19 years old.
What are the actual chances of growing beyond 19 years of age?
It's less than 1%, based on the data in this study.
If you're interested in why, then read on. But if you hate maths, don't bother. I deliberately put this in dropdown because it's a bit involved.
We can estimate the probability using the Rule of Three.
This is a rule of thumb in statistics, which lets you estimate the chance of something occurring when it didn't occur in a smaller sample.
It works like this:
3/n = p
Where n is your sample size (in this case 300) and p is the probability.
So we get 3/300 = 1%
As you can see, the larger the sample, the less likely it gets. If our sample had been 3000, and no-one grew over 19, it would be a 0.1% chance.
Thank you for attending this lecture. If you have better data please do send it, and I'll update the article.
What determines your height?
It's almost all genetic. Scientists estimate it's 80% genetic, and the rest is other factors like nutrition.
However, 80% is just an estimate. This is not an exact science, presumably because there are so many genes and environmental factors to account for.
Basically, after a lot of reading, I took the following away:
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Most of your height is genetically predetermined and you can't do anything about it
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Sometimes you might have a hormonal imbalance or other disorder, which can sometimes be treated. But these are extreme cases.
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Exercise can help, as it stimulates human growth hormone
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Nutrition is a controllable factor, and will let you reach your optimal height. Calcium and protein. However, you can't ‘eat your way taller’.
So, do exercise and eat well. Why do doctors always say that?
Summary
If you're reading this, you might be a young person worried about your height, or about ‘catching up’ with other people you know.
That's natural.
But when it comes to height, everyone really is running their own race.
It's all in the genes. So by all means blame your parents. But don't stress over it.
Jack, Founder of Ruler of London