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Does Smoking Weed Stunt Your Growth?

Research has found a correlation between marijuana use and height, but other experts aren’t so sure

It’s not easy being a short king. You’re always wondering if there was something more you could have done to sprout just another few inches. You drank your milk. You ate your veggies. You braved a 90-day NoFap challenge. So, what went wrong? Was it all the ganja you smoked? Or more bluntly (pun unavoidable): Does weed stunt your growth?

A 2015 study conducted in Pakistan suggests it does. In it, researchers compared 217 male subjects, who were described as “marijuana addicts” during boyhood, to 220 male non-users. By age 20, the 420-friendly bunch were, on average, more than four-and-a-half inches shorter and nearly nine pounds lighter than the weed abstainers. 

The researchers also compared their levels of puberty-related hormones, and while testosterone and the luteinizing hormone (which controls the reproductive system) were higher in the stoner group, their levels of growth hormone were lower. They also had higher cortisol (stress hormone) levels, suggesting that the weed smokers were experiencing more chronic stress than the sober guys.

Making the obvious connection, the researchers theorized that all the weed may have prompted a prolonged stress response in the smoker crowd, which provoked early-onset puberty but slowed their growth rate.

While interesting (and alarming), there are some who take issue with studies like these. “There are two problems with these types of observational studies,” explains Jamie Corroon, founder of the Center for Medical Cannabis Education and medical advisor for CV Sciences, the makers of PlusCBD. “First, the findings are purely associations — cause and effect cannot be established.” It’s possible, for instance, that weed-smoking boys in Pakistan just so happen to face other challenges that impact their height and weight, such as the food they have access to.

The other problem Corroon has is that this study doesn’t account for exactly how much weed everyone involved was smoking. “If a study compares users versus non-users, then you’re including chronic, daily users in the same group as those who’ve only used it once or twice, which doesn’t make sense,” he says. “To draw a strong conclusion, there would need to be a dose-response relationship whereby more frequent use was associated with shorter stature, after adjusting for other factors that influence height. I haven’t seen that study.” 

Corroon isn’t the only one who feels this way, either. A 2018 systematic review of studies on how cannabis affects puberty found that no available research met their “eligibility criteria.” As such, the review concludes, “Our results highlight a significant gap in existing literature regarding the effects of cannabis use on puberty.”

That means, as is often the case with cannabis, we simply don’t know if smoking a whole bunch makes you shorter. But if you want to give yourself the best chance of being tall, consider saving your first toke until after you’ve turned 20 if you’re a guy and 15 if you’re a woman, as you’re unlikely to grow any more after that. 

It’ll be worth the wait.