Growth spurts do not arrive on a fixed schedule, and the single most common reason you have not had yours yet is that your biological clock runs a bit behind the average. The pubertal growth spurt can begin anywhere from age 8 to 14 in girls and 10 to 16 in boys, and even within those ranges the variation is enormous. Genetics account for the largest share of that variation, but nutrition, sleep, chronic health conditions, and body composition all play a role. Understanding what drives the timing can help you figure out whether you are simply a late bloomer or whether something worth investigating is going on.
When the Growth Spurt Typically Happens
Puberty brings a burst of skeletal growth that accelerates and then decelerates over roughly two to three years. The initiation, duration, and total amount of growth during this spurt vary considerably from person to person.1Europe PMC. Advances in pubertal growth and factors influencing it: Can we increase pubertal growth? Girls generally hit their peak growth rate around age 11 to 12, roughly two years after the first signs of breast development. Boys tend to peak later, usually around age 13 to 14, about a year after the testicles begin to enlarge. But population averages can be misleading. Research comparing individual growth curves to group averages found that the average smoothes out the real picture: individual boys hit peak height velocity about three and a half months later than the population curve suggests, and individual girls about ten months later.2PubMed Central. Estimating peak height velocity in individuals: a comparison of statistical methods In other words, the textbook ages you see online are shifted earlier than what many individuals actually experience.
If your friends shot up over the summer and you did not, it may simply mean they entered puberty earlier. A difference of a year or two in the start of puberty is unremarkable and does not say anything about where you will end up in height.
Genetics Set Most of the Timeline
Your genes are the strongest predictor of when your growth spurt will begin, how intense it will be, and how long it will last. Twin studies estimate that genetic effects account for roughly 82 to 86 percent of the variation in pubertal growth timing.3PubMed Central. Genetic and environmental influences on pubertal timing assessed by height growth A large genome-wide study identified 26 genes tied to various aspects of the pubertal growth spurt, including its scale, timing, and intensity.4Genome Biology. Study finds genetic link between growth during puberty and long-term health conditions Broader estimates place the genetic contribution to pubertal timing somewhere between 50 and 80 percent of total variability, with the rest accounted for by environmental factors.5PubMed. Trends in puberty timing in humans and environmental modifiers
The practical takeaway: ask your parents when they hit their growth spurts. If your father did not shoot up until 15 or 16, or if your mother was a late developer, there is a good chance you inherited a similar timeline. This kind of familial late blooming has a clinical name.
Constitutional Delay of Growth and Puberty
The medical term for being a healthy late bloomer is constitutional delay of growth and puberty, or CDGP. It is the most common cause of what looks like a “missing” growth spurt, especially in boys. Children with CDGP grow at a normal rate before puberty but enter puberty later than average, which means their growth spurt is simply postponed. They are typically short for their age compared to classmates, but their bone age (a measure of skeletal maturity taken from a hand X-ray) is delayed by the same amount, indicating they still have growing to do.
The traditional reassurance is that these kids will grow for a longer time than average and eventually reach a normal adult height that matches their genetic potential. The reality is a little more complicated. One long-term follow-up found that males with CDGP ended up about 5 cm shorter than their target height based on their parents’ stature, and females fell about 5 cm short as well.6Pediatrics. Constitutional delay of growth: Expected versus final adult height Another study found that near-final height in boys with CDGP came in about 5 cm below their predicted adult height and about 6 cm below their midparental target height.7PubMed Central. Evaluation of near final height in boys with constitutional delay in growth and puberty The shortfall may partly reflect the fact that the most delayed children are the ones who get referred to specialists, creating a selection bias in the data. Still, the idea that every late bloomer catches up completely is not always accurate.
Nutrition and Body Weight
Your body needs adequate fuel to launch and sustain puberty. Severe or chronic malnutrition can delay the onset and progression of puberty significantly.8PubMed Central. Nutrition and pubertal development In one study of chronically malnourished children, the early stages of sexual maturity were delayed by about three years in boys, and the age of first menstruation was pushed back by about two years in girls.9PubMed. The effect of chronic childhood malnutrition on pubertal growth and development This is not just an issue in developing countries. Adolescents with eating disorders, extremely restrictive diets, or chronic caloric deficits from intense athletic training can experience similar delays.
Female athletes who begin intense training before puberty are at particular risk. Disruption of normal hormonal function in the context of disordered eating or chronic energy deficiency can contribute to low bone density and may lead to growth restriction.10PubMed Central. 2025 Update to the Female Athlete Triad Coalition Consensus Statement Part 1: State of the Science and Introduction of a New Adolescent Model Male athletes in sports that emphasize leanness, such as wrestling, distance running, or gymnastics, can face parallel issues, though the research on boys is thinner. The key point is that your body interprets chronic energy shortage as a signal that conditions are not favorable for reproduction and growth, and it postpones puberty accordingly.
On the other end of the spectrum, excess body fat can actually push puberty earlier rather than later. Population-level trends over the past few decades have shown a shift toward earlier puberty in both girls and boys, and rising childhood obesity is one of the suspected drivers.11PubMed. Endocrine-disrupting chemicals and their effects on puberty So if you are underweight or chronically undereating, that is a plausible reason your growth spurt has not started. If you are at a healthy weight and eating reasonably well, nutrition is unlikely to be the bottleneck.
Sleep and Growth Hormone
Growth hormone does not trickle out evenly throughout the day. A large surge of it is released during deep slow-wave sleep, especially shortly after you fall asleep.12Frontiers in Endocrinology. Complex relationship between growth hormone and sleep in children: insights, discrepancies, and implications This peak in growth hormone during sleep supports muscle development, tissue repair, and bone growth. Chronic sleep deprivation, whether from late-night screens, early school start times, or anxiety, can blunt that nightly growth hormone pulse. That does not mean one bad night stunts your growth, but consistently sleeping fewer than seven or eight hours through adolescence is working against your biology. Teens actually need more sleep than younger children, and the irony is that puberty itself shifts the internal clock later, making it harder to fall asleep early.
Chronic Illness and Hidden Health Conditions
Sometimes a delayed growth spurt signals an underlying medical condition rather than just normal variation. Chronic diseases that involve inflammation, poor nutrient absorption, or hormonal disruption can all interfere with pubertal timing. Celiac disease is a classic example. It can progress silently for years, and some children are not diagnosed until adolescence, when they present with pubertal delay and short stature rather than the digestive symptoms people associate with gluten intolerance.13PubMed. Two cases presenting with pubertal delay and diagnosed as Celiac disease Inflammatory bowel disease, poorly controlled asthma requiring long-term corticosteroids, chronic kidney disease, and congenital heart conditions can all slow growth.
Hormonal conditions matter too. Growth hormone deficiency and hypothyroidism both dampen the growth process directly. Hypogonadism, a condition in which the sex hormones that drive puberty are not produced in adequate amounts, can cause puberty to stall or never begin on its own. Distinguishing between simple late blooming (CDGP) and permanent hypogonadism is one of the trickier challenges in pediatric endocrinology, because in both cases the child shows low sex hormones and no signs of puberty.14PubMed Central. Delayed puberty versus hypogonadism: a challenge for the pediatrician The distinction matters enormously for treatment, which is why seeing a doctor is important if puberty has not started by age 14 in boys or age 13 in girls.
What a Doctor Actually Checks
If you are referred to a pediatric endocrinologist, the evaluation typically starts with a detailed history: your growth pattern from birth, your parents’ heights and pubertal timing, your diet, sleep habits, any medications, and whether you have any chronic health issues. Then comes a physical exam to assess what stage of puberty you are in (if any), along with blood work to check thyroid function, sex hormone levels, and sometimes markers of celiac disease or other conditions.
One of the most useful tools is a bone age X-ray. A single X-ray of the left hand and wrist shows the maturity of your growth plates, and a specialist compares that image to reference standards to determine your skeletal age.15PubMed Central. Evaluation of Bone Age in Children: A Mini-Review If your bone age is two years behind your calendar age, it means your skeleton still has the growth potential of someone two years younger, which is reassuring. If your bone age matches your calendar age despite the absence of a growth spurt, that narrows the window of remaining growth and warrants further investigation.
Growth hormone stimulation tests are sometimes ordered when deficiency is suspected. These tests involve giving a substance that should trigger the pituitary gland to release growth hormone, then drawing blood at intervals to see how much appears. The tests are imperfect and affected by variables like the specific drug used, the cutoff value chosen, and even the assay used to measure the hormone, but they remain a standard part of the workup.16PubMed Central. Growth Hormone Stimulation Testing: To Test or Not to Test? That Is One of the Questions.
Treatment Options for Late Bloomers
For children with confirmed CDGP who are otherwise healthy, the first-line approach is often watchful waiting with regular monitoring. But when the psychological burden is heavy or the delay is extreme, short courses of low-dose sex steroids can kickstart puberty and the associated growth spurt. In boys, this usually means low-dose testosterone injections given monthly for three to six months. In a randomized trial, both oral testosterone and an anabolic steroid called oxandrolone produced a significant growth acceleration that continued even after treatment was stopped, and spontaneous puberty progressed normally in all participants.17PubMed Central. Oral treatment for constitutional delay of growth and puberty in boys: a randomised trial of an anabolic steroid or testosterone undecanoate
A meta-analysis of retrospective studies found that androgen therapy increased final adult height by about 1.8 cm on average compared to untreated controls. Short-course, low-dose regimens were the most effective, adding roughly 1.9 cm, while medium- and high-dose regimens did not show a clear benefit over no treatment.18PubMed Central. Effects of androgen therapy on final adult height in boys with constitutional delay of growth and puberty: a meta-analysis of retrospective cohort studies In another placebo-controlled trial, oxandrolone-treated boys grew at 9.5 cm per year compared to 6.8 cm per year in the control group, and predicted adult heights did not change, suggesting the treatment sped up growth without sacrificing final stature.19PubMed. Oxandrolone therapy in constitutionally delayed growth and puberty
For children with true growth hormone deficiency or conditions like Turner syndrome or chronic renal failure, recombinant growth hormone injections are the standard treatment and can substantially improve adult height. These therapies require a confirmed diagnosis and close monitoring by a specialist, and they are not appropriate for children whose only issue is being a late bloomer.
Growth Plates and the Finish Line
You stop growing taller when the growth plates at the ends of your long bones close. These plates are thin discs of cartilage where new bone is continuously formed during childhood and adolescence. Cartilage cells in the growth plate divide, stack up in columns, enlarge, and are eventually replaced by hard bone. Over time, the supply of dividing cells in the plate dwindles, the cartilage thins, and the plate fuses shut.20PubMed Central. Growth plate closure and therapeutic interventions Once that happens, no further lengthening of that bone is possible.
Estrogen is the primary hormone that drives growth plate closure in both sexes. This is why early puberty tends to shorten the overall growing period (estrogen levels rise sooner and close the plates sooner), while late puberty extends it. It is also why children with CDGP are often reassured that they will have extra time to grow. The reassurance is partly true: their plates do stay open longer. But as the studies above showed, that extra time does not always fully compensate for the delayed start.
A hand X-ray can give a rough sense of how much growth plate activity remains. If you are 15 and your bone age reads 12, there is substantial growing left to do. If your bone age is 16 or 17 at any calendar age, the plates are nearing closure and the remaining height gain will be small. There is no reliable way to reopen a growth plate once it has fused.
The Emotional Side of Growing Late
Being the shortest person in your class or the last one who still looks like a child can be genuinely distressing. Research has found associations between disrupted puberty (whether delayed, incomplete, or absent) and difficulties with psychosexual development, including how comfortable people feel with their bodies and their sense of identity during adolescence.21PubMed Central. Psychosexual effects resulting from delayed, incomplete, or absent puberty Delayed puberty has also been linked to lower educational achievement and, in some studies, a higher risk of metabolic and cardiovascular issues later in life, though separating cause from correlation is difficult.22PubMed Central. Adult Consequences of Self-Limited Delayed Puberty
The psychological toll is a legitimate reason to seek evaluation, even if the likely diagnosis is benign CDGP. Sometimes the value of a short course of testosterone for a 14-year-old boy is less about the centimeters gained and more about reducing the social and emotional gap between him and his peers. Doctors who treat these patients weigh both dimensions.
Environmental Chemicals and Shifting Trends
Over the last several decades, puberty has been arriving earlier on average in both boys and girls around the world.11PubMed. Endocrine-disrupting chemicals and their effects on puberty Improved nutrition explains part of the historical shift, but the trend has continued even in well-nourished populations, leading researchers to look at other factors. Endocrine-disrupting chemicals, substances found in plastics, pesticides, flame retardants, and personal care products, are under scrutiny. Some compounds have been weakly associated with earlier puberty, while others (like lead) have been associated with delayed puberty.5PubMed. Trends in puberty timing in humans and environmental modifiers The epidemiological evidence is still thin and the observed effects are modest, especially compared to the overwhelming influence of genetics. But the trend is worth knowing about: if the population average is shifting earlier, a child developing at what would have been a perfectly average pace a generation ago might look comparatively late today.
None of this means you can blame your delayed growth spurt on a plastic water bottle. The genetic component is too dominant for any single environmental exposure to matter much at the individual level. But at a population level, these shifts help explain why some kids feel more out of step with their peers than their parents’ generation did.
Why Humans Are Wired for a Late Spurt
If it is any consolation, the human growth spurt is already unusually late compared to other primates. Researchers studying primate growth patterns have noted that while humans experience growth spurts that are comparable to those of other primates in many respects, the human spurt is shifted to much later absolute ages. The long delay before our growth spurt begins may be evolutionarily significant, allowing for an extended childhood during which the brain develops and complex social learning takes place. In that sense, a late growth spurt is not a design flaw. It is one of the defining features of being human, stretched even further in some individuals by the same genetic variation that makes us all a little different from one another.