The facial thirds, and why they are only a rough guide
Artists split the face into three parts of about equal height: from the hairline to the point between the brows, from there to the base of the nose, and from the nose to the chin. By that rule, a forehead clearly taller than the other two parts looks big. Real faces seldom follow it. When researchers measured 153 young adults in North America, the vertical thirds matched the classical rule worse than any other proportion they tested, and a later study found the three parts unequal in every group it measured, with the forehead typically taller than the lower face in its Chinese, Vietnamese and Thai participants. A tall upper third is an ordinary variation, not a sign of hair loss.
Based on: Farkas et al. 1985; Le et al. 2002
What a big forehead looks like
A forehead that is simply tall has a hairline that sits high but follows an even line or curve from temple to temple. The corners at the temples are shallow or gently rounded and look alike on both sides, the hairs along the edge are as thick and as long as the hairs just behind them, and photos from your teens show much the same height. In a study of 456 healthy Japanese adults, the distance from the point between the brows to the middle of the hairline averaged about 6 centimetres in women and nearly 7 in men: an average, not a standard to meet. Many hairlines also rise a little in early adulthood as they mature, which can make a forehead look bigger without any hair loss.
Based on: Kashiyama et al. 2021; Rassman et al. 2013
What a receding hairline looks like
In male-pattern hair loss the temple corners usually recede first while the middle of the hairline holds, so the forehead grows taller mainly at the sides and the outline turns into an M. On the Norwood scale that is stage II, and stage III once the corners are deep. Hair follicles shrink before they stop, so the hairs in the corners turn fine, short and see-through, and the change carries on from season to season. The American Academy of Dermatology notes that it can begin in the late teens or early twenties. In women the front usually stays put while the top thins, but a hairline that moves back as a band along the front and sides, often with thinning eyebrows, can be frontal fibrosing alopecia and needs a dermatologist.
Based on: Norwood 1975; American Academy of Dermatology
How to tell from a photo
Take a photo straight on, with the camera at eye level, your face relaxed and your hair dry and pushed back. Then check three things. First, proportion: on the photo, compare the distance from the hairline to the point between the brows with the distance from there to the base of the nose. A forehead noticeably taller than that middle part is tall, but that alone says nothing about hair loss. Second, the corners: how far does each temple corner sit behind the middle of the hairline, and is one side deeper? Third, the edge: fine, wispy hairs suggest active recession, while hairs as dense as their neighbours suggest a stable line. Finally, put the photo next to an older one, such as an ID or holiday picture.
Photo traps that make a forehead look bigger
Small changes in how a photo is taken can add or remove centimetres of apparent forehead. A phone held above eye level, or a chin tipped down, shows more of the forehead and the top of the head, and a close-up selfie enlarges whatever is nearest the lens. Raised eyebrows lift the skin, wet or slicked-back hair exposes more scalp along the edge, harsh light from above can make fine edge hairs vanish, and a fresh short cut uncovers corners that longer hair hid. Clinics that follow hair over time photograph it the same way at every session for exactly these reasons, and the same rule works at home: same place, light, distance and angle, every time.
Based on: Canfield 1996
When to ask a dermatologist
A tall forehead that has always been tall needs no treatment, and how you style it is a matter of taste. A hairline that is moving back is worth a conversation with a dermatologist whenever you want to know your options; in pattern hair loss, results tend to be better when treatment starts early. Some changes deserve an appointment soon: a hairline that recedes quickly, a band of lost hair along the front and sides, thinning eyebrows, patchy loss, a sore or flaky scalp, or broken hairs and recession where tight ponytails, braids or extensions pull at the hairline. Hair loss from tight styles can become permanent if the pulling continues.
Based on: American Academy of Dermatology