Do ADHD Meds Stunt Growth? What the Research Shows

Stimulant medications for ADHD do slow growth during active treatment, but the effect is modest for most children and the picture gets complicated over the long term. Early studies suggested kids eventually caught up entirely, but the largest and longest follow-up to date, from the landmark Multimodal Treatment of ADHD (MTA) study, found that children who took stimulants consistently for years ended up measurably shorter as adults than those who didn’t. The gap was real but not enormous, and the answer depends heavily on how long a child stays on medication, what type, and what dose.

What Happens in the First Couple of Years

The pattern is fairly consistent across studies: children who start a stimulant like methylphenidate (Ritalin, Concerta) or an amphetamine (Adderall, Vyvanse) tend to grow a bit slower in the first year or two compared to peers. A large observational study of real-world patients found that stimulant treatment was associated with a relative reduction in body weight and a temporary halt in height gain, with a measurable lag persisting through at least 72 months compared to where those children started on the growth charts.¹ The weight loss tends to hit first, with fat loss occurring within the first six months, followed by a subtler slowing in height velocity.²

A review in Canadian Family Physician summarized the general consensus: the rate of height loss is relatively small and appears to be reversible when treatment is stopped.³ That reassurance held up for years in clinical practice. But “relatively small” and “likely reversible” leave a lot of room for nuance, and the picture has shifted somewhat as longer-term data have come in.

Does the Growth Gap Close by Adulthood?

For decades, the working assumption was that any growth suppression from stimulants was temporary and that children would reach their expected adult height once they stopped the medication or grew through puberty. Older studies did tend to show no significant difference in final adult height between treated and untreated groups. A longitudinal study that tracked children through their pubertal growth spurt found that neither ADHD itself nor stimulant treatment was associated with differences in the size of the peak growth spurt or in final adult height.⁴

But a more recent and much larger study challenges that optimistic picture. A 2025 analysis of over 200,000 individuals in JAMA Network Open found that ADHD by itself was not associated with a meaningful reduction in adult height (the difference was a fraction of a centimeter and not statistically significant). However, children who had actually used methylphenidate did end up significantly shorter as adults.⁵ This is an important distinction: the condition didn’t shrink them, but the medication may have.

The MTA Study and What Consistent Use Does

The most detailed evidence on long-term stimulant effects comes from the MTA study, the largest randomized treatment trial for childhood ADHD, which followed participants for 16 years into adulthood. Researchers divided participants into groups based on how consistently they took stimulant medications over that period: consistent users, inconsistent users, and those who took little or no medication. There was also a comparison group of children without ADHD.

The results were striking. Adults who had taken stimulants consistently throughout childhood were about 4 cm (roughly 1.6 inches) shorter than those in the negligibly medicated group and about 3.3 cm shorter than the comparison group without ADHD.⁶ People who used stimulants inconsistently fell in between. A review of the MTA and other research characterized the situation this way: early studies showed growth suppression during treatment but no difference in final adult height, while the MTA, with its longer follow-up and better dose tracking, suggested that consistent use of significant doses during childhood may compromise final height to a clinically meaningful degree.⁷

That four-centimeter gap is not trivial, but it also represents the extreme end of the spectrum: children who took substantial doses for years without significant breaks. Most children with ADHD do not stay on medication that consistently for that long. Still, the MTA finding shifted the clinical conversation from “they’ll catch up” to “it depends on how much and how long.”

Does ADHD Itself Affect Growth?

One question that complicates every study on this topic is whether ADHD itself, separate from medication, is linked to growth differences. This matters because if children with ADHD are already on a different growth trajectory, you need to account for that before blaming the medication.

The evidence here is mixed but leans toward yes, at least in some populations. Research on previously institutionalized children found that both ADHD and delayed foster care placement were independently associated with slowed, prolonged growth in height and head circumference.⁸ Another study found that the degree of skeletal maturation delay in children with constitutional growth delay correlated with ADHD medication use, consistent with a shared maturational delay hypothesis, though this didn’t establish that one caused the other.⁹

There’s also an intriguing biological finding that speaks to this. When researchers gave children with ADHD an exercise challenge and measured their growth hormone response, the kids with ADHD had a significantly blunted response compared to children without ADHD, regardless of whether they were on medication.¹⁰ Methylphenidate actually slightly improved the growth hormone response, though it still didn’t reach normal levels. This suggests something about ADHD itself may involve atypical growth hormone signaling, which makes it harder to tease apart what the medication is doing versus what the condition was already doing.

Despite these clues, the JAMA Network Open study mentioned earlier found that ADHD without medication was not associated with shorter adult height. So while ADHD may involve some maturational differences, the evidence currently points to medication, not the diagnosis alone, as the main driver of any final height difference.

Why Stimulants Might Slow Growth

The mechanism behind stimulant-related growth suppression is not definitively pinned down, which is a bit surprising given how long these medications have been used. The most obvious explanation is appetite suppression: stimulants reduce hunger, children eat less, and growing bodies with fewer calories grow more slowly. The early weight loss and fat loss that show up within months of starting treatment support this idea.

But appetite suppression alone doesn’t fully explain the height effects, because interventions designed to increase caloric intake have been shown to improve weight gain without improving height gain (more on that below). This suggests something more direct is happening to the growth process itself.

Researchers have looked at whether stimulants interfere with growth hormone or thyroid hormones, the main endocrine drivers of height. One study found no changes in thyroid or growth hormones associated with low-dose ADHD medications within a year of treatment.¹¹ That study’s limitation is the “low-dose” and “one year” qualifiers; higher doses over longer periods might tell a different story. The growth hormone response to exercise in children with ADHD is already blunted, as described earlier, and dopamine signaling, which stimulants directly affect, plays a role in growth hormone regulation. So the hormonal angle isn’t closed, just not clearly proven.

Non-Stimulant Medications and Growth

Not all ADHD medications are stimulants, and the growth picture differs for the alternatives. Atomoxetine (Strattera), a selective norepinephrine reuptake inhibitor, has been studied fairly extensively for growth effects and generally comes out looking better than stimulants.

A two-year study found that after treatment, observed weight and height were close to predicted values based on where children started. Height increased an average of 13.3 cm, which was only about 0.44 cm less than expected. Children who were smallest at baseline actually gained in their height percentile, while those who were already large tended to lose some ground.¹² A five-year follow-up showed a similar pattern: patients were slightly shorter than expected early on, but height returned to predicted levels by about 24 months. The researchers concluded that continuous atomoxetine treatment for up to five years had little or no long-term effect on growth and final stature for most patients, though some larger-than-average children did show persistent decreases.¹³

A separate study of Korean children on atomoxetine found that height z-scores did decrease during the first year of treatment but then stabilized, with no further decline after that initial period.¹⁴ So atomoxetine does seem to have a small early effect on growth, but it’s milder and more transient than what’s seen with stimulants.

Newer non-stimulant options are still being evaluated. Viloxazine ER (Qelbree) showed relatively normal weight and height trajectories over 12 months in an open-label extension trial, with only small changes in height-for-age z-scores. Alpha-agonist medications like guanfacine and clonidine, sometimes used for ADHD, have actually been associated with increases in BMI, which is a completely different profile from stimulants.¹⁵

Drug Holidays and Interventions That Have Been Tried

Given the growth concerns, clinicians and families have tried various strategies to offset them. The most commonly discussed is the “drug holiday,” where medication is paused during summers, weekends, or school breaks. A review of four decades of international experience with drug holidays found evidence of a positive impact on child growth with longer breaks from medication, and shorter breaks could reduce insomnia and improve appetite.¹⁶

However, the most rigorous test of growth interventions painted a more sobering picture. A randomized controlled trial assigned children experiencing stimulant-related growth suppression to three strategies: caloric supplementation (adding calories), structured drug holidays, or enhanced monitoring alone. All children continued on their stimulant medications. The good news was that caloric supplementation and drug holidays both increased weight gain beyond what monitoring alone achieved. The bad news: none of the interventions improved height velocity. Over the entire study, participants continued to decline in height z-scores.¹⁷

This is one of the more frustrating findings in this area. You can get weight back on a child by feeding them more or taking breaks from medication, but the height effect seems harder to reverse while a child remains on stimulants. A report from Brown University’s psychopharmacology group put it plainly: drug holidays, more calories, and increased monitoring can help children gain weight, but they won’t help them grow taller.¹⁸

Puberty Timing and the Growth Spurt

One persistent question is whether stimulants delay puberty, which could explain at least part of the temporary height difference during childhood. If puberty comes later, the growth spurt comes later, and a 12-year-old on medication might look shorter than a 12-year-old who is not, even if they end up the same height at 18.

There is some evidence for this timing shift. A longitudinal study found that among boys treated with stimulants, longer duration of stimulant use before their peak growth spurt was correlated with reaching that growth spurt at a later age.⁴ In that particular study, the size of the peak growth spurt and final adult height were still normal, just delayed.

A study of Australian adolescent boys on stimulants found a dose-dependent relationship with height velocity during mid-puberty. In boys aged 14 to about 16, higher daily doses were significantly associated with slower growth. But the medication dose was not associated with the stage of puberty itself, suggesting stimulants may not delay the onset of puberty so much as slow down growth once it is underway.¹⁹ The dose effect was specific to the older teen years, not the early pubertal period, which makes sense if the highest growth rates are where interference is most detectable.

Effects on Bone and Body Composition

Growth isn’t only about height. The effects of stimulants on what’s happening inside the skeleton and body matter too, and the research here is less reassuring than many parents realize.

A national survey-based study found that stimulant use was associated with lower bone mineral content and bone mineral density at both the spine and the hip, even after adjusting for factors like age, sex, and physical activity. Children who had been on stimulants for three months or longer had significantly lower spinal bone density compared to non-users.²⁰ A prospective study that tracked body composition over three years found significant reductions in lean tissue, bone mineral content, and bone mineral density on standardized z-scores, alongside the expected fat loss in the first six months.²

Whether these bone changes during childhood translate into fracture risk later in life is not yet clear. Childhood and adolescence are when most bone mass is built, so reductions during that window are at least theoretically concerning. This is another area where the research is still catching up to the duration that many children now spend on these medications.

Making Sense of Dose and Duration

If there is a practical takeaway from the growth research, it’s that dose and duration matter more than a simple “stimulants yes or no.” The MTA data showed that the growth deficit scaled with consistency of use: kids who took stimulants on and off ended up between the consistent users and the negligible users in adult height.⁶ The observational cohort studies show a similar gradient. The Australian adolescent data showed a dose-response pattern during mid-puberty, with higher daily doses linked to slower growth velocity.¹⁹

This doesn’t mean that lower doses are always safe for growth or that high doses always cause problems. Individual variation is large. Some children grow perfectly normally on stimulants for years; others fall off their growth curve within months. Clinicians generally recommend tracking height and weight at every visit, plotting the results on growth charts, and having a conversation about adjusting the treatment plan if a child shows a consistent downward drift across percentiles. The research on growth suppression is still lacking in many respects, largely because of insufficient follow-up on final adult heights, and because the children being studied today are taking medication for longer continuous stretches than earlier generations did.

For families weighing these tradeoffs, the realistic framing is not “stimulants will stunt your child” or “growth effects don’t matter.” It’s that most children on stimulants will grow somewhat slower during active treatment, some proportion of that effect may persist into adulthood especially with heavy long-term use, and the benefit of treating ADHD effectively is real and has to be weighed against a growth cost that is genuine but, for most children, limited.

1
PubMed Central. The effects of long-term medication on growth in children and adolescents with ADHD: an observational study of a large cohort of real-life patients
2
PubMed Central. Weight loss on stimulant medication: how does it affect body composition and bone metabolism? – A prospective longitudinal study
3
PubMed Central. ADHD stimulants and their effect on height in children
4
PubMed Central. ADHD, stimulant treatment, and growth: a longitudinal study
5
JAMA Network Open. ADHD and Methylphenidate Use in Prepubertal Children and BMI and Height at Adulthood
6
PubMed Central. Trajectories of Growth Associated With Long-Term Stimulant Medication in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder
7
PubMed Central. Effect of stimulants on final adult height
8
PubMed Central. Physical and neurophysiological maturation associated with ADHD among previously institutionalized children: a randomized controlled trial
9
PubMed. Skeletal Maturation Delay and ADHD Medication Use in Children with Constitutional Growth Delay: A Retrospective-Prospective Study
10
PubMed. The effect of methylphenidate on the dopamine and growth hormone response to exercise in children with attention-deficit hyperactivity disorder
11
PubMed. Growth Hormone and Thyroid Function in Children With Attention Deficit Hyperactivity Disorder Undergoing Drug Therapy
12
Pediatrics. Effects of Atomoxetine on Growth After 2-Year Treatment Among Pediatric Patients With Attention-Deficit/Hyperactivity Disorder
13
PubMed. Effects of atomoxetine on growth in children with attention-deficit/hyperactivity disorder following up to five years of treatment
14
PubMed Central. Effects of Atomoxetine on Height and Weight in Korean Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: A Retrospective Chart Review
15
PubMed Central. Attention deficit hyperactivity disorder medications and BMI trajectories: The role of medication type, sex and age
16
PubMed. Drug Holidays From ADHD Medication: International Experience Over the Past Four Decades
17
PubMed Central. A Randomized Controlled Trial of Interventions for Growth Suppression in Children With Attention-Deficit/Hyperactivity Disorder Treated With Central Nervous System Stimulants
18
The Brown University Child & Adolescent Psychopharmacology Update. Interventions can improve weight but not height: growth study of ADHD stimulant medication
19
Medical Journal of Australia. Growth and pubertal development of boys with attention deficit hyperactivity disorder on stimulant medication
20
JAMA Pediatrics. Association of Stimulant Medication Use With Bone Mass in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder