Do Sebum Control Treatments Last One Season?

Three-Line Summary

• Seasonal variation in sebum production is a measured phenomenon. In a study of Korean participants, sebum was highest in summer, and in the cool months sebum fell while stratum corneum hydration dropped and sting sensitivity and skin pH went up instead — changes running the other way. Read the seasons here as the stretches when temperature and humidity climb and fall, since where you live decides when that happens.
• In the studies that measured sebum directly, sebum lowered by treatment generally returned close to baseline somewhere between 8 weeks and 3 months. Microbotox, PDT and Gold PTT all lower sebaceous gland activity for a period rather than removing the gland, so what matters is less how long the effect holds than which stretch of the year you place that window over.
• That said, there is still no randomized study directly comparing treatment in summer against treatment in winter to show better results. Seasonal planning suits people who actually feel the oiliness shifting; where the swing is small, or where comedones and inflammation matter more than oil, a different axis comes before the season.

The Extra Oil in Hot Weather Is Not Your Imagination

When seasons come up in clinic, a fair number of people say they had assumed it was in their head. It is not. It shows up on measurement.

In a study that measured five facial sites repeatedly over a year in Korean participants, sebum came out highest in summer, and the T-zone ran higher than the cheeks. Another study measuring 100 Korean men, split between summer and winter, also found sebum higher in summer, and pore counts were significantly higher in summer as well. An observational study of Czech women grouped by season found stratum corneum hydration and sebum production falling together in winter.

The three studies differ in who they measured, in ethnicity and in climate, but they point the same way. Up as it gets hot, down as it cools.

It Looks Less Like the Gland Growing Than the Output Flowing More Freely

So does the factory that makes the sebum get bigger in the heat? The data says no.

In an older experiment that warmed and cooled the forehead locally while measuring sebum excretion rate, skin temperature was confirmed to affect sebum excretion rate, and reviews since have cited that experiment for a figure of around 10 percent per degree Celsius. A seasonal observational study separately confirmed that this change does not come from a rise in the number of active sebaceous glands. Rising temperature did not increase the count of active glands; it increased only the delivery to the surface.

So shine in the heat looks less like a bigger factory than like a clearer delivery route. That distinction affects the actual plan. Treatments that lower production itself and care that clears accumulated keratin and sebum off the surface work on different points, which is also why putting the two together through the hot months is often what people notice most.

Humidity Is Not Yet at the Stage of Numbers

Hot and humid go together, so humidity feels like it must matter as well, but studies disagree on how humidity relates to sebum. It is more accurate to say we are not at the point of telling you that sebum rises by a given percentage for a given rise in humidity. On the acne side there is separate data linking humidity to flares, and that comes up in the next section.

The Cool Months Move the Other Way

It is hard to read winter as simply the easy season when sebum drops. What is interesting in the study of Korean men mentioned above is that in the same people, skin pH and sting sensitivity came out higher in winter instead.

A small longitudinal study following adolescent boys monthly over a year also found transepidermal water loss higher in the acne group than in controls, with stratum corneum hydration higher in summer and autumn than in winter. Put together, the cool months are a stretch with less to suppress and more irritation to withstand. Those two moving at once is the core of the timing plan discussed further down.

Not Everyone Swings This Far

A clear caveat attaches to all of this. The studies cited above were mostly in people in their twenties to forties, and there is not enough confirmed data on whether the same size of seasonal variation appears outside that age range. It is more accurate to read seasonal planning as an approach that suits people who actually feel the oiliness shifting.

Does the Data Back Up Acne Worsening in the Heat?

More oil and worse acne are not the same claim, so it is worth checking separately.

In hot, humid climates it holds up. A study of 452 acne patients in New Delhi found 229 reporting seasonal variation, and among them 56.33 percent worsened in summer against 16.16 percent who improved. Of those who said summer made it worse, 80.62 percent named sweat and humidity as the cause. Another study following 171 people in Delhi over a year also found summer worsening significantly more common at 40.4 percent, with both temperature and humidity linked to flares.

You may have heard that sun exposure clears acne in the summer, but at least in the humid Asian data the arrow points the other way.

For Some the Peak Sits Later, Into Autumn

It is only fair to give the data pointing the other way as well. The small longitudinal study following adolescent boys monthly over a year found sebum lowest in winter and highest in autumn. With 7 in the acne group and 10 controls it is a small sample and hard to generalize, but it is worth leaving room for a sebum peak that sits from late summer into early autumn.

So what sets the timing is not the calendar but when your own oil curve ran highest. That is why we ask in consultation when the last two or three years were hardest and when things eased off. In the same month of August, one person is already on the way down and another is only starting to climb.

How Long Does Sebum Lowered by Treatment Stay Down?

One number will not answer it. But in the studies that measured sebum directly, levels generally returned close to baseline somewhere between 8 weeks and 3 months. The range is wide because results differ by treatment, and by settings within the same treatment.

First Reason the Numbers Differ — the Measurement Itself Moves

Sebum measurement is more sensitive to conditions than it looks. Measuring what has accumulated on the surface and measuring the excretion rate per unit time are different indices, and values shift a great deal with how long it has been since cleansing, or with indoor temperature and humidity. So the spread between studies carries differences in measurement as well as differences in treatment.

Second Reason — What Was Measured Differs

The more important distinction is what a given study measured. A study that measured sebum and a study that counted acne lesions are not saying the same thing. The point where oil returns and the point where acne comes back are not the same. That difference becomes decisive when reading the duration figures for Gold PTT below.

PDT — About 8 Weeks After a Three-Session Course

With the settings used routinely in Korea, three sessions two weeks apart followed by roughly 8 weeks is a fair way to hold it.

The most concrete number comes from a study of 12 Korean acne patients. Treated three times at weeks 0, 2 and 4 with sebum excretion measured afterward, the average fall was 44 percent two weeks after the first session, but by 8 weeks after the final treatment sebum had returned to an average of 89 percent of baseline. That is despite biopsies showing a clear increase in apoptotic changes within the sebaceous glands. Start in June and finish in July and the arithmetic puts you back where you started around the end of September.

Oil returning and acne returning run on different clocks, though. A Japanese study following a single session out to 12 months found that of the eight patients who could be tracked, four relapsed between 4 and 12 months, with an average of 6 months to worsening.

The reason results differ within PDT is the settings. Sebum suppression grows as photosensitizer concentration, incubation time, light dose and session count go up. In a study run at low intensity, only inflammatory lesions fell, and sebum production did not drop significantly at any site. If you had PDT and the oiliness did not change, it is better to look first at whether that setting was aimed at acne lesions than to conclude the treatment does not suit you. It is also worth weighing that very high intensity settings are uncommon in Korea because of pain and the recovery burden.

Microbotox — Peak at 4 Weeks, Recovery Between 12 Weeks and 4 Months

With intradermal botulinum toxin, commonly called microbotox, the sebum reduction was confirmed in oily skin, and there was no difference in dry or normal skin. In a split-face placebo-controlled study injecting 2 units per square centimeter, the sebum reduction was significant only in the oily skin group and peaked at 4 weeks. Which means there is not yet enough evidence to recommend this treatment for sebum control in someone whose concern is not oiliness.

Other facial studies repeat the same shape: peak effect at 4 weeks, recovery between 12 weeks and 4 months. In a multicenter randomized double-blind placebo-controlled study on the scalp, sebum production after a single injection was significantly lower than placebo at 1 month and 3 months, but the difference was gone at 4 months and 6 months.

Raising the dose changes that. In a double-blind placebo-controlled study giving a single forehead treatment at different doses, the lowest dose group fell short, while the two higher dose groups held the improvement through 6 months from one session. But as the dose goes up, so does the risk of weakening the muscles of expression, and unit conversions differ between products, so the numbers from a study cannot be carried straight across. We set this in clinic while looking at the facial area and at how you use your expressions.

Gold PTT — How Far the Sebaceous Gland Targeting Has Been Confirmed

That it targets the sebaceous gland is itself confirmed on biopsy. Gold-coated silica microparticles are driven into the follicle with vibration and then heated with a laser, and in studies using human and porcine skin these particles absorbed light strongly around 800 nanometers. Across 32 specimens taken after irradiation, local thermal damage at the follicular opening was found in 84 percent and damage to the sebaceous gland itself in 47 percent, at a mean depth of 0.47 millimeters, with no damage to the adjacent dermis and epidermis. In practice it is combined with a 1064 nanometer laser.

Now the sessions and the duration together. This treatment forms a course of three sessions two weeks apart. In a prospective multicenter study following 52 people who completed a course, inflammatory lesions were down 55 percent at 2 months from the start and 68 percent at 12 months. But the protocol included a topical retinoid for 3 to 4 weeks before treatment, so it should not be read as the record of the treatment on its own.

And here the earlier distinction becomes decisive. That 12 months is a count of acne lesions, and there is no data yet measuring sebum that would let anyone state a figure in months. There is a report of skin oiliness falling along with the lesions, but it is a case series of four people evaluated with a photographic analyzer, so taking it as a trend is as far as it goes. Since the mechanism physically damages the sebaceous gland, it is reasonable to expect it to run longer than an approach that blocks the signal alone, but that remains an inference.

The Three Treatments Work at Different Layers

To understand the differences in duration, the quickest route is to look at where each treatment acts. PDT and Gold PTT cause photochemical or photothermal damage to the sebaceous gland tissue itself. Microbotox, by contrast, leaves the gland undamaged and cuts only the signal above it. So as nerve terminal function recovers, the effect fades within 3 to 4 months.

As the table shows, none of the three removes the sebaceous gland; each lowers its activity for a period. So this is not a question of removal but of choosing the timing.

That point decides a good deal of how satisfied people end up. When we give the duration in clinic, some ask back whether a short effect is worth having at all. But starting with the knowledge that it is short lets you decide in advance when to begin, how many sessions to have and when to stop. Start out expecting it to hold indefinitely and you will feel it failed three months later. Same result, different satisfaction.

What It Means to Plan the Timing

Please do not read planning as a way of saying more sessions. Here planning means deciding where to place the same number of sessions. Overlap the window where the effect is still present with the stretch where oil runs highest and the same treatment feels different.

Start Just Before the Temperature Climbs

Starting just before it turns hot — roughly late May to early June in Korea, and wherever you live, the few weeks before temperature and humidity begin to climb — lines up most closely with how long the effects last. Microbotox begins to change things from week 1 and is clearest at 4 weeks, so a start in early June overlaps the July and August peak naturally. If inflammatory acne is part of the picture we look at PDT or Gold PTT first; if oiliness and pores are the main complaint, microbotox comes up first. Which one we use depends on what the examination shows.

The Height of the Heat Is for Completing and Extending the Course

July and August, the hottest stretch of the Korean year, are for finishing the course you started. A PDT course begun in June fades around August, so people who need cover into early autumn add another course here or layer microbotox on top. If your schedule makes repeated visits through the heat difficult, a Gold PTT course of three sessions is easier to plan around because the number is set from the start. This is not a question of which is better but of matching sessions to a schedule.

Early Autumn Is the Handover

September and October are where the effect fading and the temperature dropping overlap. This is where we move toward topicals. As noted earlier, though, some people have their sebum peak sitting into early autumn, so the hot-season plan is sometimes stretched into September.

The Cool Months Are for Lowering Intensity

From November through to April — the cooler, drier half of the Korean year — protecting the barrier takes priority over suppressing sebum. Sebum falls while barrier function drops along with it, so there is less clinical gain in transferring a setting with a heavy recovery burden straight across.

Two Axes That Run Opposite Ways Within the Same Seasonal Plan

One point is easy to misread, so let me mark it here. This does not mean the cool months are a stretch for doing nothing. Sebum suppression and scarring or pigment are separate axes, and the seasonal reasoning often runs the opposite way.

• The sebum suppression axis — it is natural to place the effect window over the stretch where oil runs highest. Microbotox, PDT and Gold PTT sit here.
• The mark and scar axis — treatments that work on what acne leaves behind, such as PicoPlus, CO2 fractional laser and Potenza (microneedle RF), need careful sun protection afterward, so a stretch with less UV exposure is often easier to manage.
• The recovery and calming axis — care that supports the barrier, such as LDM, goes in according to skin condition rather than season. It is often used alongside through stretches where skin turns reactive easily, like the cold months.

This arrangement is not a fixed answer key either. The scar axis does not have to run in the cold months, and where sun protection is manageable it runs in other seasons too. PDT also needs sun protection for as long as the photosensitivity lasts, so even when it is placed in the hot months we go over that part separately.

And You Can Run It for a Year and Then Judge

The advantage of seasonal planning is not greater efficacy. It lies in covering the stretch you feel most while reducing drug exposure and treatment burden. So if you run it for a year and did not notice much, there is no reason to carry it into the next year; and if getting through the hot months was all it took, you simply book that stretch again. It is better not to take it as a program that has to repeat every year.

What Fills the Stretch Between Treatments

Treatments and topicals hold in different ways. A treatment is given and then drains away; a topical holds while you keep using it. So stopping and restarting a topical makes the intended level hard to reach.

Few Topical Ingredients Have Had Sebum Actually Measured

• Topical antiandrogen (clascoterone) — one of the rare ingredients with sebumeter data behind it. In the 12-week interim analysis of an open prospective study of 40 people, sebum fell 27 percent from a baseline of 115.9 to 84.8, and was already significant at 6 weeks with a 22 percent reduction. Over the same period inflammatory lesions fell 54 percent and non-inflammatory lesions 34 percent. It is a prescription ingredient, so availability and indication in Korea need checking in clinic.
• Niacinamide 2 percent — in a double-blind placebo-controlled parallel-group study of 100 Japanese participants, sebum values at 2 weeks and 4 weeks were significantly lower than in the placebo group. Whether that reflects a fall in the production rate itself or in sebum accumulated on the surface is read differently by different authors.
• L-carnitine 2 percent — in a vehicle-controlled randomized study, sebum production rate fell significantly at 3 weeks.

On the Other Hand, Some Ingredients Have Weak or Contrary Evidence for Oil

• Topical retinoids — solid evidence for pores and comedones, but weak evidence for lowering sebum itself. In a randomized controlled study using adapalene, the changes by site were -0.2 percent on the forehead, +6.2 percent on the chin and -6.7 percent on the cheek, and the authors concluded that the clinical effect appeared unrelated to sebum suppression.
• Benzoyl peroxide — in the same study, surface sebum values went up instead: +10.5 percent on the forehead, +10.3 percent on the chin and +25.4 percent on the cheek. It remains an important drug for controlling inflammation, but it is not the ingredient to reach for against oiliness.

So for topicals between treatments, it is more realistic to aim less at cutting sebum sharply and more at making slightly higher sebum less likely to trigger acne, and at lowering the shine that shows on the surface.

Washing Harder Usually Backfires

Many people respond to more oil in the heat by washing more often or switching to a stronger product, and this usually works the other way. Strip the surface sebum and much of it is back within an hour, and the barrier takes the damage in the process. Working on production itself makes more sense in the order of things than raising the intensity of washing.

If surface keratin and sebaceous filaments are part of the problem together, that belongs to separate care rather than to washing intensity. At ABLE Dermatology, surface care such as Aquapeel, GA scaling, LaLa Peel and Pla Peel is placed alongside treatments aimed at the sebaceous glands through the hot months, and scheduled with the intensity and intervals adjusted through the cold months, when skin turns reactive easily. These do, however, serve a different purpose from treatments that lower production itself, so one does not replace the other.

When Sebum Care Is Still Needed in the Cold Months

I would rather none of this read as meaning nothing needs doing in the cold months. There are clear cases where the season is not the reference point.

• Where the seasonal swing is not large — as noted, the studies cited were mostly in people in their twenties to forties, and there is not enough data on whether the same swing appears outside that range. If you shine much the same through all four seasons, there is no reason to take the seasonal curve as the reference.
• Where comedones and inflammation matter more than oil — if oil falls in the cold months but comedones and inflammation carry on regardless of season, that is a separate problem. Here the timing is set by the state of the lesions rather than by the calendar.
• Where the temperature your skin meets differs from the season — apply the experimental finding that temperature affects sebum excretion directly and the reference becomes the temperature your skin is actually exposed to, not the calendar. If you spend the day in heavily heated indoor spaces, or in an environment that turns hot and humid locally, shine can carry on through the cold months.
• Where the peak comes late — for some people the sebum peak sits from late summer into early autumn. Here we move the timing back to fit your own curve rather than to the hot season.

But We Do Not Carry the Same Intensity Into the Cold Months

The cold months run with low stratum corneum hydration and with sting sensitivity and skin pH raised. Which means a stretch with less to suppress and more irritation to withstand. So even where sebum care is needed then, rather than transferring the hot-season settings unchanged, the arrangement lowers the intensity, lengthens the intervals and looks after the barrier alongside.

To put it plainly, this is not saying sebum care is unnecessary in the cold months. It is saying that sebum care in the cold months has a different goal and a different intensity from the hot ones. It helps to read it as a stretch where what to take away comes before what to add.

What This Plan Does Not Claim

Finally, let me be clear about the limits. There is still no randomized study directly comparing treatment in summer against treatment in winter to show better results. The arrangement set out here is not a proven superiority but a plan built by lining up seasonal physiology against how long effects last. Some of the data cited comes from studies with small samples or short follow-up, and for some treatments there is no data measuring sebum itself. Future research may change the reading.

Holding It Down Year-Round With Medication Is a Different Set of Conditions

Besides placing treatments by season, there is the approach of holding sebum at a low level year-round with medication. In a small study comparing very low dose oral isotretinoin at 2.5 to 5 milligrams a day over 6 months, sebum production fell by up to 64 percent and sebaceous gland size on biopsy fell 51 percent. Dosing three times a week produced no lipid reduction, which also showed that a minimum effective exposure exists. In an older study following 20 people after stopping, seven had returned to pretreatment levels by 30 weeks, while eight held sebaceous gland activity at a lowered state for up to 80 weeks. Where a hormonal pattern is clear in women, oral spironolactone is also an option; in a placebo-controlled double-blind study, 3 months of treatment reduced sebum excretion in the female participants, and the clinical response was greater in the higher dose range.

On efficacy alone this route is larger and longer lasting, but it comes with conditions attached: pregnancy plans, liver function, dryness as a side effect, and adherence. It is not a matter of which is better but of options with different conditions, and which to take is decided together in clinic.

The Burden That Comes With Each Treatment Deserves a Look Too

• PDT — pain during the session and erythema, swelling, a temporary acne flare and pigmentation afterward can occur, and sun protection is needed for as long as the photosensitivity lasts.
• Microbotox — bruising, local dryness and weakening of the muscles of expression depending on injection site and dose can occur.
• Gold PTT — erythema, swelling and a temporary increase in lesions after treatment are reported.

Results can differ with individual skin condition and how much sebum you produce, and it is common for the same treatment under the same conditions to draw a different degree of response. And since all three lower sebaceous gland activity for a period rather than removing the gland, the original tendency returns once the effect drains away. It is better to start knowing that from the outset, which is also why deciding not to go ahead is a perfectly reasonable conclusion. The goal of sebum control is not to remove it but to manage it to a level you can live with.

From Consultation to Treatment

A board-certified dermatologist examines you directly, identifies the layer the cause sits in, decides the device and the parameters, and the same dermatologist carries on to perform the treatment. This is not a structure in which a consultant recommends the treatment.

Sessions, intervals, maintenance timing and cost are agreed together before the first treatment.