Four guided photos give you one score. You log your routine in about five seconds a day. Over months, the two together answer the question the mirror never can: is what you're doing actually holding the line? Retain does not regrow hair and does not sell you anything to put on your head. It measures, and it tells you what it sees.
One slow turn. The app fires each shot when your head reaches the right angle, so every scan is captured the same way as the last one, and it rejects a photo it cannot read honestly rather than guessing from it.
Consistency is the whole product. A score you can't repeat means nothing. So the capture is strict first, and clever second.
From the first photo set you get a description of where the thinning is: the front, the temples, the crown, and a Norwood stage when the pattern fits that scale.
It describes where, never why. Retain does not name conditions and does not tell you what to take. If a pattern looks unusual, it says so and suggests showing it to a professional. That's the one piece of advice a measuring instrument should give.
Tap what you took. That's the whole job, and it takes about five seconds.
The streak is the part of this you control. Real progress is slow enough that motivation cannot live on the score alone, so the daily win lives here instead, in the number you can move today.
Every hair grows for years, rests for weeks, sheds after a few months. Nothing about that cycle moves overnight, so Retain measures in months and tells you when scanning again is pointless.
Left alone, thinning tends to continue. So holding steady over months is the routine doing its job, and Retain says so by name. When a change is too small to tell apart from the instrument's own wobble, it calls it unchanged instead of calling it progress.
Where it moved, where it held, and whether your routine is what moved it. One number, one sentence, and the colours are honest: green where something improved, amber where something needs watching, nothing alarming on a picture of your own head.
No vanity dashboard. Every number on the screen serves one question: is what you're doing working. One answer, on a schedule slow enough to be true.
One scan a month, your score, your photo timeline, and a card a week on what is actually happening while you wait. It does not expire, and there is no trial that quietly turns into a charge. Paying adds the part that connects cause to effect: where on your head it changed, and whether your routine is what moved it.
That is the only thing your address gets used for. No newsletter, no drip sequence, no passing it to anyone else.