If you've just started UV phototherapy for vitiligo — or you're about to — one of the first questions you'll ask is: when will I see results?
It's a fair question. And the honest answer is: it depends, but there is a pattern. After 30 years of clinical evidence and thousands of patients treated with NB-UVB phototherapy, dermatologists have a clear picture of what the journey looks like, month by month.
This guide gives you that picture — not the optimistic version, and not the discouraging one. The realistic one.
Before You Begin: What UV Therapy Is Actually Doing
NB-UVB phototherapy doesn't paint pigment back onto your skin. It works by stimulating melanocytes — the cells responsible for producing melanin — that are either dormant or hiding in hair follicles around the depigmented patch.
This is why results take time. You're not covering a patch; you're coaxing your own cells back to work. That's a biological process, and biology doesn't move fast.
The wavelength matters too. UVThera devices use 311nm NB-UVB, which is the clinically validated optimal wavelength for activating melanocytes without causing unnecessary skin damage. At 311nm, you're getting the therapeutic benefit with the best possible safety profile.
Month 1: Nothing You Can See (But Everything Is Starting)
What's happening: Your skin is being calibrated. In the first few weeks, your dermatologist (or the MED protocol on your UVThera Pro) is establishing your Minimum Erythema Dose — the lowest dose that produces a faint pink response in your skin. This baseline is the foundation of your entire treatment.
Sessions are typically three to five times per week, starting at a low dose and increasing gradually by 10–20% per session as your skin builds tolerance.
What you'll notice: Probably nothing visible in terms of repigmentation. Some patients notice mild pinkness after sessions — this is expected and indicates the therapy is reaching the right depth. Any burning, blistering, or pain is not expected and should be discussed with your dermatologist immediately.
What to focus on: Consistency. Missing sessions in the first month slows progress more than at any other stage. Your skin needs repeated, cumulative UV exposure to begin reactivating dormant melanocytes. Think of it like building a habit — the first month is about establishing the pattern.
Realistic expectation: No visible repigmentation. This is completely normal. Do not be discouraged.
Month 3: The First Signs — Small, But Real
What's happening: This is typically when patients see the first visible change, and it looks nothing like what most people expect.
Repigmentation in vitiligo almost always begins as perifollicular repigmentation — tiny dots of pigment appearing around individual hair follicles within the white patch. These look like small freckles or specks of colour scattered across the depigmented area. They are easy to miss unless you're looking closely in good natural light.
This happens because melanocytes migrate outward from hair follicle roots, which is why patches on the scalp, face, and trunk — areas with more hair follicles — tend to respond earlier than patches on hands, feet, and wrists.
What you'll notice: Small pigmented dots within white patches, especially on the face, neck, and trunk. The edge of the patch may also start to show slight darkening.
What to focus on: Photograph your patches consistently, ideally at the same time, in the same lighting, every two weeks. Progress at this stage is subtle enough that you may not notice it day-to-day but will clearly see it when comparing photos taken 4–6 weeks apart. The UVThera app is designed for exactly this.
Realistic expectation: Early perifollicular dots in responsive areas. No change yet in acral areas (hands, feet, lips, fingertips). Patches that haven't shown anything by month 3 may still respond — they're often just slower.
Month 6: Dots Connecting — Visible Repigmentation
What's happening: The perifollicular dots from month 3 are now growing and merging. What started as isolated specks is beginning to form islands of pigmentation within the white patch. In well-responding areas, these islands may coalesce into significant coverage — sometimes 30–50% of a patch.
Patients with vitiligo on the face, neck, upper trunk, and proximal limbs typically see the most dramatic change at this stage. These are the areas with the highest density of hair follicles and the best blood supply for melanocyte migration.
At six months, you'll also have a clearer picture of which patches are responding and which are not. Not all patches respond equally, and some areas — particularly the hands, feet, and areas around the mouth — are known to be significantly more resistant.
What you'll notice: Actual visible repigmentation in responsive patches. Islands of colour that are spreading and merging. The overall appearance of the patch may be visibly smaller, or it may be a patchwork of pigmented and depigmented areas (this is normal — uniform repigmentation comes later).
What a dermatologist looks for at 6 months: At least 25% repigmentation in the treated areas is considered a positive treatment response. If you're seeing this or better, you're on track. If a specific patch has shown no response at all by six months, your dermatologist may recommend reassessing whether that patch is likely to respond.
Realistic expectation: Meaningful, visible change in responsive areas. Less or no change in acral areas. You should feel encouraged — you're past the hardest part of the journey.
Month 12: The Year Mark — Where You Stand
What's happening: A full year of consistent NB-UVB therapy (3–5 sessions per week) represents approximately 150–200 treatment sessions. At this point, patients fall broadly into three groups:
Strong responders (roughly 30–40% of patients): Greater than 75% repigmentation in treated areas. The patches may be nearly or completely invisible. The newly pigmented skin will look slightly lighter than the surrounding skin initially — this evens out over time with continued UV exposure.
Moderate responders (roughly 40–50% of patients): 25–75% repigmentation. Significant cosmetic improvement, particularly on the face and trunk. Acral patches may still have limited response. Many patients in this group continue treatment and see continued improvement beyond 12 months.
Limited responders (roughly 10–20% of patients): Less than 25% repigmentation despite consistent treatment. This is more common in patients with long-standing vitiligo (over 5–10 years), complete absence of any remaining melanocytes in the patch, or predominantly acral disease. For these patients, a dermatologist may recommend reassessing the treatment approach.
What to focus on at month 12: Maintenance. Repigmented skin is not permanently immune to further depigmentation. Most dermatologists recommend a maintenance protocol — typically once or twice weekly sessions — to preserve what's been achieved.
Realistic expectation: Highly variable, but a full year of consistent therapy will give you a clear, honest picture of your personal response. For the majority of patients, the change over 12 months is meaningful and visible.
The Factors That Determine Your Timeline
Your individual timeline depends heavily on several variables that have nothing to do with how faithfully you follow treatment.
Location of your patches matters most. The face, especially around the eyes and mouth, the neck, and the upper trunk respond best. Hands, feet, fingertips, lips, and wrists are the most resistant sites — sometimes showing no response even in patients who repigment well elsewhere.
How long you've had vitiligo. Recent patches (under 2 years) tend to respond faster and more completely than patches you've had for a decade. This is because recently depigmented areas are more likely to still have some viable melanocytes.
Your skin type. Darker skin types (Fitzpatrick IV–VI, which includes most Indian patients) tend to show repigmentation more visibly and often respond well to NB-UVB — though the contrast between pigmented and depigmented skin also makes patchy repigmentation more noticeable during treatment.
Dosing consistency. This is the one factor you control entirely. Timer-based devices introduce dose variability as the UV tube ages — the tube loses approximately 20% output by 1,000 hours, but the timer still says 30 seconds. Devices with real dosimetry, like UVThera Pro, compensate for this automatically, delivering the prescribed dose in mJ/cm² regardless of tube age.
Session frequency. Three to five sessions per week is clinically recommended. Dropping to one or two sessions per week significantly slows response and may stall it altogether.
What to Do If You're Not Seeing Progress
If you've reached month 3 with no perifollicular dots whatsoever, or month 6 with no visible change in any patch, don't stop treatment without speaking to your dermatologist first. A few things worth checking:
Are you hitting your prescribed dose? If you're using a timer-based device, your tube may be delivering significantly less than you think.
Are your sessions frequent enough? Life gets busy. It's worth honestly counting how many sessions you've actually completed.
Is your starting dose appropriate? If your dermatologist set a conservative MED, a dose adjustment may be needed.
Are the patches you're treating in high-response areas? Acral patches require a longer timeline and sometimes don't fully repigment regardless of treatment.
Some patients also benefit from combining NB-UVB with topical treatments like tacrolimus, especially for acral and facial vitiligo. This is a conversation for your dermatologist.
A Note on Photos
Keep taking them. Month-to-month change in vitiligo is often too gradual to notice by looking in the mirror daily — but comparing a photo from month 1 to month 6 can be genuinely surprising. Many patients who feel like "nothing is happening" are actually making steady progress that only becomes apparent in the comparison.
Take photos in the same lighting, at the same distance, at the same time of day. Consistent photography is one of the most useful things you can do for your own understanding of where you are in the process.
Summary
Timepoint | What to Expect |
Month 1 | No visible change; calibration and dose-building phase |
Month 3 | Perifollicular dots in responsive areas (face, trunk, neck) |
Month 6 | Dots merging into visible repigmentation; clear indication of response |
Month 12 | Significant repigmentation in responders; maintenance phase begins |
Vitiligo treatment is a long game. The patients who see the best outcomes are the ones who remain consistent through the first three months — when there's nothing visible to motivate them. If you can get past that, the odds are genuinely in your favour.
UVThera devices deliver clinically precise NB-UVB therapy at 311nm — the same wavelength used in leading dermatology clinics. UVThera Pro uses real dosimetry to ensure every session delivers exactly the prescribed dose, even as the lamp ages. See devices →
Always consult a dermatologist before beginning UV phototherapy.