Will ADHD Medication
Stunt My Child’s Growth?
The honest answer every parent deserves — with the research behind it, stated plainly. No dismissals. No false reassurances. Just the truth.
I’ve had this conversation thousands of times over twenty-five years. A parent sits across from me, arms folded, and says: “I’ve heard the medication stops them growing. I’m not doing it.”
Or it’s a teenage boy, arms even more tightly folded, who has been told by someone at school that Concerta will make him short. He is refusing to take his medication because he is sixteen and six feet is the plan.
Both deserve an honest answer. Not a dismissive one. Not a “don’t worry, it’s perfectly safe.” The truth — with the research behind it.
ADHD stimulant medications can affect growth. That is the truth. The question is: by how much, for how long, and does it actually matter in practice?
— Dr John Flett, Developmental PaediatricianWhat the Research Actually Shows
The MTA study — the largest and most important long-term study ever done on ADHD treatment — followed children for sixteen years. Children who took stimulants consistently showed a possible reduction in adult height of approximately two to four centimetres. Most other studies show a considerably smaller effect — closer to one centimetre — particularly in the first year or two of treatment, with most children returning to their expected growth trajectory after about three years.
Some children may be approximately 1 cm shorter and slightly lighter than expected. This is the period of maximum measurable effect. Appetite suppression is also most pronounced during this phase as the body adjusts.
The body adapts. Appetite usually normalises. The child continues growing, and the gap between their current height and expected trajectory begins to close. Weight typically stabilises after the first month.
The majority of children return to their genetically-determined growth path. Adult height is not significantly affected for most children. Long-term studies are reassuring — the gap narrows and closes over time.
Only 9% of children in the MTA study used medication consistently throughout the entire follow-up period. The majority — 66% — used it inconsistently, and those children showed minimal growth effects. The effect, where it exists, is related to consistent long-term use and is not an automatic consequence for every child.
Two Separate Pathways — Why Eating Well Isn’t the Whole Answer
Parents often stop me here: “But my child eats fine on medication. So the growth concern doesn’t apply to us, right?” The honest answer: eating well helps enormously, but it doesn’t eliminate the conversation entirely. There are two separate ways in which stimulant medication can influence growth.
Stimulants boost dopamine and noradrenaline, which act on hunger signals. The brain is told it’s satisfied even when the body hasn’t eaten enough.
Most pronounced 30–60 minutes after taking medication. Typically lasts several hours. Appetite drops by ~30% during peak medication hours.
Yes — directly. Smart meal timing (solid breakfast before peak, good evening meal when appetite returns) significantly protects growth through this route.
Stimulant medication may subtly alter growth hormone release pulses — independent of what the child eats. Growth hormone is released during deep sleep and physical rest.
This effect is separate from appetite entirely. Even a well-nourished child may experience this small direct effect. It cannot be fully mitigated through diet alone.
Small — we’re talking 1–2 cm in the first year or two, not inches per month. Your child’s genetic blueprint is far more powerful than this effect.
Which Medications Affect Appetite Most?
Not all ADHD medications have the same impact on eating. Understanding this helps you know what to expect and allows a useful conversation with your prescriber if appetite or growth is a genuine concern.
If Medication Is Started in the Teenage Years — Is the Risk Significant?
This question comes up more and more in my consulting room, especially as late diagnosis in adolescence has become more common. And it is one of the most reassuring conversations I have.
The answer is: no, the growth impact when medication is started in adolescence is not clinically significant for most teenagers. Here is why.
The growth concern primarily relates to children starting treatment between ages 6–12 and using it consistently through major childhood growth years. A 14-year-old starting medication has already grown through the most sensitive period unmedicated.
Growth happens at the growth plates near the ends of long bones. By mid to late adolescence, these plates begin to close. Remaining growth potential is limited — the medication is starting too late in the process to have meaningful cumulative impact on adult stature.
A sixteen-year-old who is genuinely hungry in the evening will eat. Appetite suppression during school hours, managed with a good breakfast and substantial evening meal, is considerably easier to compensate for nutritionally than the same challenge in a small, picky eight-year-old.
The MTA study followed children who started medication at ~age 8 and continued for a decade. Those findings cannot be directly applied to a teenager starting at 15 or 16. The exposure duration and growth stage are fundamentally different.
In clinical practice, I am not concerned about stunted growth in a teenager who begins ADHD medication at fourteen, fifteen, or sixteen. I still measure height and weight at every review — that is standard care regardless of age. But the “this may affect final height” conversation I have with parents of a seven-year-old does not apply in the same way to a sixteen-year-old. The risk profile is genuinely different.
The Argument That Works for Teenage Boys
Every teenage boy with ADHD who refuses medication because of height has heard something on the rugby field, in the locker room, or from a video online. The fear is real. At sixteen, height matters. I understand it. Here are the exact words I use.
“Your height is written in your genes. Your father and grandfather gave you a blueprint, and no medication is going to overwrite it. The concern about medication and height is real for young children who take it for many years from age seven or eight. You’re sixteen. That window has mostly closed. Your growth plates are already well into the process of completing.
What will make a genuine difference from here? Eating enough protein. Getting enough sleep. Not skipping meals while you’re medicated. A solid breakfast before your tablet kicks in, something at lunch even if you’re not that hungry, and a proper meal in the evening when the medication has worn off. You’re in control of those things. The medication effect at this stage is negligible. Your habits are not.”
The Side Effects of NOT Treating — Nobody Talks About These
Here is what does not make it into anxious Facebook posts about medication and growth. Untreated ADHD has its own effects on a child’s physical development.
significant sleep problems
in unmedicated ADHD
elevated cortisol
The child who is medicated, sleeping better because the brain has a pause button, eating more structured meals at home, managing the school day without constant stress — that child may actually have better overall growth conditions than their unmedicated counterpart. We never weigh those realities against each other honestly enough.
What I Monitor and When to Be Concerned
At every follow-up appointment — minimum every three to four months — I measure height and weight and plot them on a growth chart. We are not looking at single measurements. We are looking at the trajectory.
Even if it’s the 25th centile — this is fine. Consistent trajectory is what matters.
Consistent downward drift across multiple measurements needs a medication review.
Eating most calories in the evening is the expected pattern. Total daily intake matters more than whether lunch was eaten.
Zero measurable height gain across two consecutive appointments warrants discussion.
Normal in the first month as the body adjusts. Weight typically stabilises as appetite adapts.
Weight loss continuing beyond the first few months, or that appears severe, needs prompt medical attention.
Write down everything your child actually ate today. Not what was served — what was consumed. Be honest. Look at the timing: when did most eating happen?
Was breakfast eaten before or after medication? A solid breakfast before the medication peaks is the single most effective growth-protection strategy you have. Food first, then tablet.
When appetite returns in the evening, is the meal substantial and nutritious? This is often when your child will eat most. Make it count — protein, carbohydrates, healthy fats.
At the next appointment, ask your doctor to show you the plotted trajectory over time. One measurement tells you little. The line across multiple appointments tells you everything.
Your child’s genes determine the vast majority of their adult height. Medication plays a small role — and when started in adolescence, the risk is even smaller.
The height concern is real enough to take seriously and monitor carefully. It is not real enough to let it stand between your child — or your teenager — and the treatment that changes their daily life. Understand the risk properly, manage what you can manage, measure what needs measuring, and keep your eyes on the bigger picture.
Medical note: Growth is monitored at every review appointment, at minimum every three to four months. Discuss any concerns about your child’s height, weight, or nutrition with your prescriber. This article provides general information and does not replace personalised medical advice for your specific child. Contact The Assessment Centre on 031 1000 474 or assessment@drjohnflett.com.