Every article about this gives you a number of weeks. We are not going to, and the reason is worth two paragraphs.
What we can do is tell you what the best available evidence says about the dose, which is the part you control.
Why nobody can give you a timeline
Flexibility outcomes depend on where you start, your age, your history, your proportions, how consistent you are and how your nervous system responds. Those vary enough between people that a single number would be wrong for most readers.
Lucy makes no promise that using it will make you more flexible. That is in the terms, and it is not legal hedging: it is the honest position. Bodies differ, and so do results.
What is not vague is the dose. That has been measured.
What the research actually found
In 2025, Sports Medicine published a meta-analysis pooling 189 studies covering 6,654 adults, designed specifically to establish the optimal frequency, intensity and volume of static stretching for flexibility. Four findings are worth knowing.
Thirty-second holds worked as well as sixty-second ones. The review found no additional benefit from longer holds. Longer is just longer.
Within a session, gains flattened at about four minutes per muscle group. Beyond that point, more time in one sitting added nothing measurable.
Across a week, gains flattened at about ten minutes per muscle group. That is the number to plan around.
How you split the week made no difference. Three sessions and six sessions produced the same result, provided the weekly total was reached.
Taken together, that is a surprisingly small and surprisingly flexible prescription. Ten minutes per area per week, in whatever chunks suit you, with no need for long holds.
The finding that should change how you start
The same review reported that the largest improvements came from the people who started out the least flexible.
This is the opposite of how most people reason about it. The usual thought is that stretching is for people who are already bendy, and that you should get a bit more flexible before you take it seriously.
The evidence points the other way. If you cannot reach your toes, you are in the group with the most to gain. Not reaching your toes is the reason to start, not a reason to wait.
We went into that specific case in why can't I touch my toes.
What to measure instead of weeks
Since the calendar will not tell you much, pick something that will.
Range before the compensation starts. In a forward fold, the useful marker is how far you get before your back starts rounding, not where your fingers land.
The first few seconds of a familiar stretch. How it feels on entry changes earlier than how far you can go.
Whether the stretch is the limit, or something else is. If a position is limited by balance, by a joint pinching or by breathlessness, flexibility is not the variable.
Compare months, not mornings. Range varies day to day with sleep, temperature and how long you have been sitting, and reading much into a single bad session is a good way to stop.
If nothing changes at all
Give it a fair trial: several weeks of hitting roughly that weekly total for the area in question.
If there is genuinely no change in that time, the limiting factor is probably not flexibility, and more stretching is not the answer. That is the point to ask a physiotherapist or doctor rather than to push harder. A joint that is restricted structurally, or a muscle that is guarding for a reason, will not respond to volume.
When to stop, and when to ask someone
Stretching is general fitness, not treatment. Stop anything that produces pain, pins and needles, numbness, dizziness or anything that feels wrong. Discomfort and pain are not the same thing, and only you can judge the difference from the inside.
Never force a stretch to reach a shape in a picture. The figure shows a movement, not a target. Our fitness and safety note has the rest.
Where Lucy fits
Lucy is an iPhone app of short guided stretching routines for people who sit all day. Every routine runs four to six minutes, which lines up with that four-minute-per-session finding without anyone having to think about it.
Three routines are built as longer projects rather than single sessions: Path to Touching Your Toes, Path to a Full Split and Path to a Deep Squat. Each one is the same movement from several angles, which is how a restricted area tends to respond.
The app records the days you completed a routine. It does not count the days you missed, because a missed day is not a failure state.
One routine is free in full. The rest is a subscription with a 7-day free trial, priced in your own currency on the App Store.
FAQ
How many minutes of stretching per week do you need?
About ten minutes per muscle group per week is where the Sports Medicine meta-analysis found gains levelling off. For someone targeting a few areas, that works out at a handful of minutes most days rather than a long weekly session.
Is it better to stretch every day or a few times a week?
The review found no difference, as long as the weekly total was the same. Three sessions and six produced equivalent results. Daily is useful mainly because it is easier to remember.
Do longer stretches work better?
Not according to that review. Thirty-second holds matched sixty-second ones, and within a session the gains flattened at roughly four minutes per muscle group. Extra time is better spent on a different area.
Can you get flexible at any age?
The research covers adults broadly rather than answering that cleanly, and how any individual responds is a question for a professional who can look at you. What the review does say is that the people with the least range at the start improved the most.
Will stretching make you less stiff in the mornings?
That is a claim about your body, and we are not going to make it. What is fair to say is that morning stiffness is common among people who sit all day, and that the dose above is what the evidence supports for improving range.
Lucy makes the short daily version easy to actually keep up.