How does a hair transplant simulation work?

Almost everyone considering a hair transplant asks the same first question: “How will I look afterwards?” Photo-based simulations that try to answer it have become common. A well-designed simulation can genuinely help a decision; a poorly designed one disconnects expectations from reality. Here we explain, in plain terms, what the Folyara simulator does behind the scenes.

1. The photo: it all starts with light and angle

A simulation can only be as good as the photo it starts from. The best results come from a face photographed straight on, with the camera at eye level, the forehead visible, hair brushed back and even, daylight-like lighting. When you use the camera option, an oval guide tells you live whether your face fits the frame, whether the light is sufficient and whether your head is tilted.

2. Analysis: facial landmarks and a hair mask

Once the photo is loaded, a computer vision model running in your browser marks 478 points on your face: brows, eyelids, nose, lips and the facial outline. A separate model separates hair pixels, and another separates the person from the background to find the top of the head. From these three sources we derive:

• Head tilt and turn
• The position of the current hair boundary and temple recession
• Forehead height relative to facial proportions
• Current hair colour (or a brow or beard sample if there is no hair)
• An estimated stage of loss (Norwood or Ludwig)

3. Scale: why the iris matters

A photo has pixels, not centimetres. The simulator uses the coloured part of the eye — the iris, about 11.7 mm across and very consistent in adults — as a ruler. This lets us approximate the open area in cm². Because the scalp is curved, the area seen from the front is smaller than the real one, so a correction factor is applied. It remains an estimate: precise measurement happens at examination.

4. Rendering: thousands of strands, one by one

Based on the hairline and hairstyle you choose, a “flow field” is built over your scalp — the direction hair will lie at every point. Thousands of strands are then drawn along that flow in clumps, with variation in length and thickness. The natural irregularity of single-hair grafts is imitated at the hairline, colour is sampled from your photo, and highlights and a soft shadow on the forehead are added according to the light direction. The aim is an image that reads as a photograph at first glance, yet is clearly labelled as illustrative.

What a simulation cannot show

• Your donor capacity: how many grafts can be safely harvested is only known after dermatoscopic measurement.
• Your hair calibre and future loss: thinning may continue in untreated areas.
• Your healing: redness, shock loss and growth speed vary between people.
• A definite result: a simulation is a planning and conversation tool, not a promise.

The privacy of your photo

In the Folyara simulator, analysis and rendering take place entirely on your device; the photo is never uploaded. It is only shared for review if you choose “Send to doctor” and give explicit consent. No share links are created, and “Delete my photo” removes everything with one click.

Treat the simulation as a starting point: to compare hairlines on your own face, to talk to your doctor over the same image and to ground your expectations in reality.

The information on this page is general and does not replace a medical consultation. The method, graft number and timeline suitable for you can only be determined after an examination. Simulations are illustrative and are not a promise of results.