Your face transforms more dramatically during puberty than at any other point after infancy, with changes that reach the bones, cartilage, fat pads, skin, and even the microbial communities living on your surface. The lower jaw outpaces the upper jaw by roughly two to one in growth from childhood to young adulthood, the nose reaches its mature projection years before the chin finishes reshaping, and the faces of boys and girls diverge into recognizably different proportions driven largely by testosterone and estrogen. These changes unfold on different timelines depending on your sex, your body composition, and even how you breathe.
The Jaw Does Most of the Heavy Lifting
If you look at photographs of the same person at age ten and again at eighteen, the most striking difference is usually in the lower half of the face. That is because the mandible, or lower jaw, grows far more than the maxilla, the upper jaw. Research tracking jaw dimensions from age six to twenty found that the mandible grew in length about twice as much as the maxilla over that span.1PubMed. Comparison of maxillary and mandibular growth This disproportionate growth is especially pronounced in males, and it continues well after the upper jaw has largely finished expanding.2PubMed Central. Craniofacial Growth in Adolescence and its Influence on the Mandibular Incisor Crowding
This is one reason the face shifts from the rounder, shorter proportions of childhood toward the longer, more angular look of adulthood. The chin projects further forward, the jawline becomes more defined, and the overall shape of the face moves from a wider-at-the-top, narrower-at-the-bottom profile to something closer to an oval or rectangle. In practical terms, it also explains why your teeth can start crowding during adolescence even if they were straight in childhood: as the mandible grows and rotates, the lower front teeth can tip backward and bunch together.
How Male and Female Faces Diverge
Before puberty, the faces of boys and girls are similar enough that it can be genuinely hard to tell them apart from bone structure alone. Puberty changes that. Girls reach their final facial dimensions earlier, while boys continue growing longer and end up with larger overall facial measurements.3PubMed. Facial growth: men and women differ The specific areas where male faces become larger include the brow ridge, the cheekbones, the angle of the jaw near the ear, and the nose. Female faces tend to retain somewhat more of the proportional relationships of the pre-pubertal face, with less brow prominence and a relatively longer upper face compared to its width.
A study using MRI-derived facial measurements in adolescents aged twelve to eighteen found that the features most reliably signaling a male face to observers were a broader forehead, chin, jaw, and nose. These specific features were associated with plasma testosterone levels, even after accounting for age.4PubMed. Testosterone-mediated sex differences in the face shape during adolescence: subjective impressions and objective features In other words, it is not just that older teenagers look more masculine or feminine; the degree to which their faces masculinize tracks with how much testosterone is circulating. Boys with higher testosterone at the same age tend to have more pronounced jaw and brow development.
Evolutionary analysis supports the idea that this dimorphism is not simply a byproduct of body size differences. Male and female growth trajectories diverge at puberty for facial width but not for facial height, meaning men end up with relatively shorter, broader upper faces and women with relatively taller, narrower ones. The lower third of the male face, corresponding to the mandible, enlarges more than the middle and upper thirds, a pattern that deviates from what you would expect if male faces were just scaled-up versions of female faces.5PLOS ONE. Biometric Evidence that Sexual Selection Has Shaped the Hominin Face
The Nose Gets There First
While the jaw is still adding length well into the late teens, the nose follows an earlier timeline. A cephalometric study of adolescent nasal growth found that nasal height and the length of the nasal bridge reached full maturity at around fifteen in males and twelve in females. Nasal tip protrusion approached its adult size by fifteen in males and thirteen in females.6PubMed. Adolescent growth patterns of the bony and cartilaginous framework of the nose: a cephalometric study The upper and lower nasal dorsum and nasal depth all finished growing about two years earlier in girls than in boys.
This staggered timeline partly explains why early and mid-puberty can feel like an awkward period for facial proportions. The nose may reach its adult size while the jaw is still catching up, giving a temporarily imbalanced look. It also means that the face you see at fourteen is not the face you will have at twenty, particularly for boys, whose jaw and brow growth continues years after the nose has stopped changing shape.
What Happens to the Soft Tissue
Bones and cartilage provide the scaffolding, but the skin, fat, and muscle draped over them matter just as much for how your face actually looks. A study tracking thirteen facial soft-tissue parameters in boys and girls from age nine to sixteen found that the tissues around the eyes grew very little during puberty and were already close to their adult size by the start of the measurement period. Meanwhile, soft tissues in the lower face continued developing substantially. Girls were generally smaller in absolute measurements but more developmentally advanced at each age, fitting the broader pattern of earlier female maturation.7PubMed Central. Normal growth and development of the lips: a 3-dimensional study from 6 years to adulthood using a geometric model – Section: Abstract
Lip dimensions follow a similar sex-linked pattern. At every age measured, boys had larger lip dimensions than girls, with exceptions during the early age groups that coincide with the earlier female growth spurt. In girls, lip dimensions had nearly reached their adult size by ages thirteen to fourteen, while boys still had significant growth ahead. The upper lip reached adult size faster than the lower lip, and this was especially true in girls.8PubMed Central. Normal growth and development of the lips: a 3-dimensional study from 6 years to adulthood using a geometric model
Fat distribution in the face also shifts during puberty, though less is known about the precise mechanics. Children tend to carry more buccal (cheek) fat, which is why their faces appear rounder. As puberty progresses, these fat pads thin out relative to the growing skeleton, especially in the lower face, creating the more sculpted cheekbone and jawline appearance associated with adulthood. This process is more dramatic in males, partly because testosterone promotes leaner soft-tissue composition in the face.
Skin, Sebum, and the Puberty Microbiome Shift
Puberty does not just reshape the structure of your face; it fundamentally changes the surface. Rising androgen levels stimulate sebaceous glands to produce more sebum, the oily substance that coats and protects the skin. This ramp-up in oil production is why puberty is synonymous with acne for so many people, and it also creates a different environment for the microorganisms living on your face.
Research tracking the facial skin microbiome across pubertal stages found a significant shift in microbial diversity between the early and late stages of puberty, coinciding with the increase in sebum production.9Journal of the European Academy of Dermatology and Venereology. Evolution of the facial skin microbiome during puberty in normal and acne skin In practical terms, the bacterial ecosystem on your face as a sixteen-year-old is meaningfully different from the one you had at ten. The species that thrive in oily environments become more dominant, and the overall diversity of the community changes. This microbial shift interacts with sebum composition and immune responses to influence whether someone develops acne and how severe it becomes.
Skin texture and pore visibility also change. As sebaceous glands enlarge, pores become more visible, particularly across the nose, forehead, and chin. Skin thickness increases under the influence of androgens, more so in boys than girls. These changes tend to persist into adulthood, giving adult male skin its characteristically thicker, oilier quality compared to female skin.
The Growth Spurt Is Not the Same for Everyone
People often talk about “the growth spurt” as if it were a single, universal event, but the pubertal growth peak varies considerably in both timing and duration. A study comparing skeletal classes found that the average duration of the pubertal growth peak was about eleven months in children with typical jaw relationships, but only about seven months in children with a Class II skeletal pattern (where the lower jaw is set further back) and over seventeen months in children with a Class III pattern (where the lower jaw is more forward).10PubMed Central. The duration of pubertal growth peak among three skeletal classes The differences were large enough to be clinically meaningful, and they help explain why some adolescents seem to grow into their jaw proportions quickly while others take much longer.
Body composition adds another layer of variability. A study of over three hundred adolescents found that growth begins earlier in overweight and obese adolescents and continues at a rate similar to normal-weight children during the treatment period, resulting in larger final skeletal dimensions.11European Journal of Orthodontics. Influence of BMI percentile on craniofacial morphology and development in adolescents, Part II: elevated BMI is associated with larger final facial dimensions So adolescents with higher body mass tend to start their facial growth changes sooner and finish with somewhat larger craniofacial measurements. This does not mean that weight gain during puberty automatically produces a larger jaw, but the hormonal and metabolic environment associated with higher body fat appears to shift the timing and end point of skeletal development.
When Facial Asymmetry Peaks
No face is perfectly symmetrical, but the degree of asymmetry is not constant across a lifetime. A cross-sectional study from adolescence to mid-adulthood found that the largest normal asymmetry values appeared in the adolescent group, with females showing slightly more asymmetry than males of the same age.12PubMed. The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood This may partly reflect the fact that the two sides of the face do not always grow at exactly the same rate or on the same schedule during puberty. As growth slows and finishes, asymmetry tends to decrease somewhat, though it never disappears entirely.
If you have ever looked in a mirror during your teens and felt that one side of your face looked different from the other, this is completely normal. The asymmetry that bothers adolescents is usually well within the range seen in healthy faces and often becomes less noticeable with age. For the small number of people who develop clinically significant asymmetry, orthodontic or surgical evaluation may be warranted after growth is complete, but premature intervention during active puberty is generally avoided because the face is still a moving target.
How Mouth Breathing Reshapes the Growing Face
One of the most consequential environmental influences on pubertal facial development is whether a child habitually breathes through the nose or the mouth. Chronic mouth breathing during the growth years can measurably alter the skeletal development of the face. A systematic review and meta-analysis found that mouth-breathing children showed a backward and downward rotation of both the mandible and the maxilla, a steeper occlusal plane, a tendency toward forward-tilting upper front teeth, and narrower airways compared to nasal-breathing children.13PubMed Central. Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis
These are not trivial changes. The pattern of downward and backward jaw rotation produces what clinicians sometimes call “long face syndrome,” with a longer lower face, a more open lip posture, flatter cheekbones, and a narrower dental arch. A study that examined mouth-breathing effects across different cervical vertebral maturation stages found that the impact on both hard and soft tissue measurements persisted from the earliest stages of skeletal maturation through the latest, suggesting that the effects are not limited to one critical window but accumulate throughout the growth period.14BMC Oral Health. Effects of mouth breathing on maxillofacial and airway development in children and adolescents with different cervical vertebral maturation stages: a cross-sectional study
The practical takeaway is that if you notice a child or teenager chronically breathing through their mouth, whether due to allergies, enlarged adenoids, or habit, it is worth addressing with a pediatrician or ENT specialist. The earlier the obstruction or habit is corrected, the less opportunity it has to shape the developing skeleton in ways that may later require orthodontic or even surgical correction.
Jaw Pain and Joint Trouble During Puberty
The temporomandibular joint, where the lower jaw hinges to the skull, is actively remodeling during puberty as the mandible grows and the bite relationship shifts. This remodeling process can bring new symptoms. An epidemiological study of adolescents found that clinical diagnoses of temporomandibular disorders increased with pubertal development itself, with adolescents who had passed through puberty showing roughly one-and-a-half to two times the odds of a TMD diagnosis compared to those who had not yet entered puberty. Self-reported TMD symptoms like jaw clicking and soreness were more common in girls than boys, but the clinical diagnoses were tied more to pubertal stage than to sex alone.15PubMed. Are temporomandibular disorder symptoms and diagnoses associated with pubertal development in adolescents? An epidemiological study
If you are a teenager experiencing jaw clicking, popping, or aching, particularly on one side, this does not necessarily mean something is wrong. The joint is undergoing significant growth-related remodeling, and transient symptoms are common. Persistent pain, locking of the jaw, or difficulty opening the mouth fully do merit professional evaluation, but occasional clicking during a period of rapid mandibular growth is the joint doing its job under unusual mechanical demands.
The Role of Hormones Beyond Growth
Testosterone and estrogen do not just dictate how much your bones grow; they influence the type and quality of bone tissue itself. Androgens, including testosterone, affect skeletal health throughout life, with particularly strong effects at puberty. The relationship is complicated by the fact that testosterone can be converted to estradiol by the aromatase enzyme, so some of testosterone’s apparent skeletal effects are actually estrogen-mediated. Current evidence suggests that estradiol plays a larger role than testosterone in maintaining bone health overall, though androgens have direct beneficial effects on bone as well.16PubMed Central. Androgens and bone
For facial development specifically, this means that the heavier, denser bone of the male brow ridge and jaw is not purely a testosterone story. Estrogen levels matter for both sexes, influencing when growth plates close and when facial bones stop adding length. This is why conditions that disrupt normal pubertal hormone levels, whether from endocrine disorders, certain medications, or delayed puberty, can leave measurable marks on adult facial structure. A boy whose puberty is significantly delayed may end up with a somewhat less prominent brow and jaw than his peers, while a girl exposed to elevated androgens may develop a slightly broader, more angular facial shape.
When Your Face Stops Changing
There is no clean finish line. Different structures reach their adult form at different ages, and the answer depends on sex. For girls, the nose is largely mature by twelve to thirteen, lip dimensions are close to final by thirteen to fourteen, and most craniofacial growth has wrapped up by the mid-teens. For boys, the nose finishes a couple of years later, the jaw and brow may continue growing into the late teens or even early twenties, and lip dimensions are still increasing when girls’ have already plateaued.6PubMed. Adolescent growth patterns of the bony and cartilaginous framework of the nose: a cephalometric study Slow, subtle changes in facial soft tissue continue well beyond the end of skeletal growth, driven by shifts in fat distribution, skin elasticity, and muscle tone rather than bone remodeling.
For anyone considering elective procedures that depend on stable facial dimensions, whether orthodontics, rhinoplasty, or jaw surgery, the implication is clear: timing matters. Most surgeons prefer to wait until craniofacial growth is confirmed to be complete, which typically means the late teens for girls and the early twenties for boys, though individual variation means growth assessment with imaging is more reliable than age alone.