At 15, most people still have time to grow. Boys typically experience their fastest growth between ages 12 and 15, with most stopping by 16. Girls usually reach their final adult height around 14 or 15, though the exact timing depends on when puberty started. Whether you can still gain height comes down to whether your growth plates are still open, and what you do now to support the growth you have left.
Your Growth Plates Determine the Window
Height increases happen at the growth plates, strips of cartilage near the ends of your long bones. As long as these plates remain open, your bones can lengthen. Once they harden into solid bone, linear growth stops permanently. For girls, growth plates typically close between ages 13 and 15. For boys, closure usually happens between 15 and 17.
This means a 15-year-old boy likely still has open growth plates and real growth ahead. A 15-year-old girl may be near the end of her growth window, especially if she started her period more than two years ago. After menstruation begins, girls generally gain only 1 to 2 more inches before reaching their final height. If you’re unsure where you stand, a doctor can order an X-ray of your hand and wrist to check whether your growth plates are still open.
Estimating Your Adult Height
Genetics account for roughly 60 to 80 percent of your final height, and pediatricians use a simple formula to estimate where you’ll land. For boys: add your father’s height in centimeters to your mother’s height plus 13 cm, then divide by two. For girls: take your father’s height minus 13 cm, add your mother’s height, and divide by two. The result gives a rough target, typically accurate within about 5 cm (2 inches) in either direction. It’s a ballpark, not a guarantee, but it helps set realistic expectations.
Sleep Is the Biggest Lever You Can Pull
Your body releases the majority of its growth hormone during deep sleep, particularly during the first bout of slow-wave sleep shortly after you fall asleep. Most of the hormone’s secretory peaks happen during these deep sleep stages, with smaller amounts released during lighter and REM sleep. This isn’t a minor effect. Growth hormone directly drives bone lengthening at the growth plates, and poor sleep measurably reduces its release.
For a 15-year-old, the sweet spot is 8 to 10 hours per night. Consistency matters as much as duration. Going to bed at roughly the same time each night helps your body settle into deep sleep faster. Late-night screen use, caffeine after noon, and irregular sleep schedules all cut into the deep sleep stages where growth hormone peaks. If you’re serious about maximizing your remaining growth, sleep is the single most impactful habit to optimize.
Nutrition That Supports Bone Growth
Your bones need raw materials to grow, and a few nutrients matter more than others during adolescence. Calcium is the primary mineral in bone tissue, and teens aged 14 to 18 need about 1,300 mg per day, the highest requirement of any age group. Dairy products, fortified plant milks, leafy greens, and canned fish with bones are the most concentrated sources. Vitamin D helps your body absorb that calcium, with a recommended daily intake of 600 IU (15 mcg) for your age group. Sun exposure, fortified foods, and fatty fish all contribute.
Protein is equally important. Growth hormone can only do its job if your body has enough amino acids to build new bone and muscle tissue. Teens who consistently undereat protein, whether from restrictive dieting, food insecurity, or picky eating, can fall short of their genetic height potential. You don’t need supplements or special foods. A diet with enough calories, adequate protein at each meal, and consistent calcium and vitamin D intake covers what your bones need.
Exercise Helps, and Weightlifting Won’t Stunt Your Growth
Physical activity stimulates growth hormone release and promotes bone density. Weight-bearing activities like running, basketball, and jumping sports place mechanical stress on bones, which signals them to grow stronger and longer while the growth plates are still open. Swimming and cycling are great for fitness but produce less of this bone-loading effect.
One persistent myth deserves a direct answer: weightlifting does not stunt growth. Research has clearly dispelled this idea. Supervised resistance training is recognized as both safe and effective for adolescents, and it may actually reduce injury risk during sports. The concern about growth plate damage from lifting was never supported by good evidence. What does pose a risk is unsupervised lifting with poor form and excessive weight, which can cause injuries to any structure, not just growth plates. If you lift with proper technique and reasonable loads, it supports your development rather than hindering it.
What Can Actually Stunt Growth
While no supplement or exercise will add inches beyond your genetic potential, certain things can cause you to fall short of it. Chronic malnutrition is the most common cause of preventable short stature worldwide. Severe calorie restriction during adolescence, whether from eating disorders, extreme dieting, or insufficient food access, deprives the growth plates of the building blocks and energy they need.
Estrogen plays a key role in triggering growth plate closure. Anything that artificially raises estrogen levels can accelerate this process, effectively shortening your growth window. Anabolic steroids are the most relevant risk for teens. They convert to estrogen in the body and can cause growth plates to fuse prematurely, locking in a shorter final height even if you would have grown several more inches. Nicotine and tobacco use have also been linked to reduced growth, likely through their effects on blood flow and nutrient delivery to growing tissues.
When Slow Growth May Need Medical Attention
Some teens are simply “late bloomers,” a pattern doctors call constitutional delay of growth and puberty. It tends to run in families. If one of your parents was a late bloomer, there’s a good chance you are too, and puberty will proceed normally on its own, just on a delayed timeline. These teens often end up reaching a normal adult height, just later than their peers.
That said, certain signs warrant a visit to a doctor. For boys, if the testicles haven’t begun enlarging by age 14, that meets the clinical definition of delayed puberty. For girls, if breast development hasn’t started by age 13 or menstruation hasn’t begun by age 15, evaluation is recommended. A pediatrician may refer you to an endocrinologist, a specialist in hormonal development, to rule out underlying conditions. Constitutional delay is actually a “diagnosis of exclusion,” meaning doctors confirm it by first ruling out everything else. If your growth has stalled or you’re significantly shorter than expected based on your parents’ heights, getting checked gives you useful information while there’s still time to act on it.