Growing pains are real, but despite the name, they almost certainly have nothing to do with actual growing. No study has ever linked these pains to periods of rapid bone growth, and many researchers consider the term a misnomer that has stuck around since it was first coined in 1823. The honest answer to why kids get growing pains is that nobody knows for sure, though several promising theories point toward muscle fatigue, lower pain sensitivity, and other factors.
What Growing Pains Feel Like
Growing pains show up as an aching or throbbing sensation in the legs, most often in the front of the thighs, the calves, the shins, or behind the knees. They typically affect both legs, hit late in the day or evening, and disappear by morning. The pain is in the muscles, not the joints. Episodes come and go, sometimes with pain-free stretches of days or weeks in between. Some children experience them a few times a week, others only occasionally.
The typical age range is three to twelve years, with a peak around seven or eight. Somewhere between 10 and 20 percent of children experience them at some point during childhood.
Why “Growing” Pains Aren’t About Growth
The name dates back to an 1823 French medical text called “Maladies de la Croissance” (diseases of growth), and the assumption seemed intuitive: kids are growing fast, so growing must hurt. But the evidence never materialized. Children don’t experience these pains more during growth spurts, and many kids going through their fastest growth phases never have them at all. This disconnect has led researchers to suggest alternative names like “benign nocturnal limb pains of childhood” or “recurrent limb pain in childhood,” though none have caught on with parents or doctors.
A 2019 systematic review of the research confirmed it plainly: no evidence has linked growing pains with phases of especially high growth velocity. The word “growing” persists only because two centuries of habit are hard to break.
What Might Actually Cause Them
Several theories have been proposed, and researchers are still sorting through them. None has emerged as the definitive explanation, which is part of why growing pains remain one of the more puzzling conditions in pediatrics.
Muscle Fatigue From Activity
One long-standing idea is that active children accumulate muscle fatigue during the day, and the pain surfaces once they stop moving and settle down for the evening. This would explain the timing: pain after a busy day, gone by morning after rest. However, studies testing this theory have produced mixed results, and researchers at the University of Sydney have noted that muscle fatigue in active children is among the theories “steadily being debunked.”
Lower Pain Thresholds
Some children may simply be more sensitive to normal physical sensations. One study found that children with growing pains had measurably lower pain thresholds than children of similar age and sex who didn’t experience them. This doesn’t mean the pain is imagined. It means their nervous systems may amplify signals that other children barely register.
Temperament and Emotional Factors
An Australian longitudinal study on temperament found that children with growing pains were more likely to be rated by their parents as having negative moods or behavioral difficulties. Interestingly, their teachers didn’t rate them any differently from other kids, which suggests the connection between mood and pain may play out more at home, in the evening, when growing pains typically strike. Fatigue, stress, and emotional state can all influence how the body processes pain signals.
Vitamin D and Other Nutritional Factors
Vitamin D deficiency has been investigated multiple times as a possible contributor, and it’s one of the few theories that keeps generating interest. Low vitamin D affects bone and muscle health, and some small studies have found that children with growing pains are more likely to have insufficient levels. This line of research hasn’t produced a definitive answer yet, but it’s the nutritional factor with the most attention behind it.
Proposed theories involving flat feet, other biomechanical issues, and broader pain syndromes have largely failed to hold up under scrutiny.
How Growing Pains Are Diagnosed
There’s no blood test or scan that confirms growing pains. Doctors diagnose them by checking that the pattern fits (bilateral leg muscle pain, evening onset, no symptoms in the morning) and ruling out other causes. A physical exam should show no joint swelling, no tenderness to touch, no limping, and completely normal movement. If all of that checks out and the child is otherwise healthy, the diagnosis is growing pains.
About a quarter of clinical records in a recent scoping review showed doctors making the diagnosis based on clinical judgment alone, without applying any formal set of criteria. This reflects how straightforward the pattern usually is to recognize, but also how loosely the condition is defined across medicine.
Signs That Something Else Is Going On
Most leg pain in children is harmless, but certain features should prompt a closer look. Pain that affects only one leg is less typical of growing pains. While unilateral pain does show up in about 20 percent of cases, it can also point to localized problems like bone infections or bone tumors. Other signals that warrant medical evaluation include:
- Joint swelling, stiffness, or warmth, which could suggest inflammatory arthritis or infection
- Pain that’s still present in the morning or that worsens over time rather than coming and going
- Limping or refusing to bear weight, which is not consistent with growing pains
- Fever, weight loss, fatigue, or loss of appetite, which can indicate systemic conditions including leukemia
- Redness or warmth over a specific spot on the leg, which may signal infection
If your child’s pain follows the classic pattern (both legs, muscles not joints, evenings only, completely fine by morning), these red flags are unlikely to apply. But any of them showing up changes the picture.
What Helps at Night
The best-studied treatment is a daily muscle stretching routine targeting three muscle groups: the quadriceps (front of the thigh), the hamstrings (back of the thigh), and the calf muscles. In the trial that tested this approach, parents were taught stretches for these areas and had their children do them twice a day, morning and evening, for about ten minutes each session. The evidence is limited to one small trial, but it’s the strongest data available for any growing pains treatment.
For immediate relief during a nighttime episode, the strategies most parents already reach for (rubbing the legs, applying a warm cloth or heating pad) are reasonable and widely recommended by pediatricians. Over-the-counter pain relievers like acetaminophen can help take the edge off a painful episode, though they’re best used occasionally rather than as a nightly routine. For children under two, check with a doctor before giving any pain medication.
Treatments involving vitamin C, magnesium, calcium supplements, and other nutritional add-ons are frequently mentioned online but lack supporting evidence. Stretching should be the foundation of any management plan, with other measures added only when needed.
How Long Growing Pains Last
Most children outgrow them entirely, typically by the early teen years. The episodes tend to become less frequent over time before stopping altogether. While the pain can be disruptive on bad nights, growing pains don’t cause any lasting damage to muscles, bones, or joints. They leave no trace once they’re gone.