Isotretinoin (Isotroin®/Acnetrent®/Acutein®) oral therapy

Hello, I am a doctor at Smart Skin Clinic, an aesthetic dermatology clinic.

Do you have any of these questions or concerns?

In this article, our cosmetic dermatology clinic will address these questions and concerns from a professional standpoint in an easy-to-understand way.

*If you'd like to know the prices, you can jump there from the table of contents below.

Supervisor Information

Group Chief Director, Smart Skin Clinic Group

IshiiIshii KotaKota

Career

Graduated from Juntendo University School of Medicine

Worked at Tokyo Women's Medical University Hospital and affiliated facilities

Worked at a major aesthetic clinic in Tokyo

Affiliations / Qualifications

Board-certified specialist, Japan Surgical Society

Board-certified specialist, Japanese Society of Anti-Aging Medicine

What is isotretinoin?

Simply put, isotretinoin is an oral treatment for acne. It belongs to a class of drugs known as vitamin A derivatives.

Also,"the ultimate weapon in acne treatment,"This is a medication sometimes referred to as

Briefly, in terms of how it works,shrinking the sebaceous glandsis its effect, which in turn provides a therapeutic effect on acne.

Isotretinoin is the name of the active ingredient, and it is sold under several brand names, including Accutane, Isotroin, Roaccutane, and Tretiva.

In Japan, it is not yet covered by insurance,a drug that has been used for many years in other countries.This is the case. Specifically,in Europe for about 35 years now,and in the United States it was approved in 1982.

For moderate to severe acne,the acne treatment guidelines in the United States and Europe strongly recommend oral isotretinoin treatment.Because isotretinoin does carry risks and side effects, it must be prescribed under the examination of a physician.

Part of the actual Western "acne treatment guidelines" appears below. It may be hard to follow in English, but for "Severe" acne,isotretinoin is listed as a treatment with a "high strength of recommendation."

(Source)Nast A et al: European evidence-based (S3) guideline for the treatment of acne – update 2016 – short version. J Eur Acad Dermatol Venereol. 2016, 30, 1261–1268

We also explain this visually on our Instagram below, so if you'd prefer to understand it visually rather than by reading text, please take a look.

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Case Photos (Before/After)

Treatment name	Oral isotretinoin treatment (20 mg)
Treatment details	Aims to improve acne and oily skin through oral isotretinoin. One tablet taken once a day.
Treatment period	On average, 6 to 9 months.
Pricing	10 mg (30-day supply): 7,980 yen 20 mg (30-day supply): 12,980 yen *Tax included; self-pay treatment
Risks and Side Effects	Because of teratogenicity, contraception is essential Dryness of the skin (especially the lips) Changes in liver function, fluctuations in lipid levels, joint and muscle pain, headache, dizziness, visual disturbances, photosensitivity, allergic reactions, changes in bone density

Effects and mechanisms

Effect

In our actual clinical experience, there have been cases where a patient who had continued insurance-covered treatment (oral and topical medications) for two to three years without improvement began taking Isotroin and saw improvement in about three months.

Three mechanisms behind the effects

Mechanism 1: Reduction of skin oil

Isotretinoin regulates sebaceous gland function and reduces oil secretion in the skin.This suppresses the excess sebum production that causes acne, and reduces inflammation and clogged pores.

Isotretinoin also inhibits the activity of lipid-synthesizing enzymes in the sebaceous glands. Specifically, it reduces sebum secretion by inhibiting 5α-reductase and shrinking the size of the sebaceous glands.

As sebum secretion decreases, pores may, as a secondary effect, become less noticeable.

Mechanism 2: Suppression of inflammation

Isotretinoin also helps improve the symptoms of inflammatory acne. It exerts an anti-inflammatory effect on the factors that cause inflammation, easing symptoms such as redness and swelling.

It suppresses inflammation by regulating various mechanisms involved in the inflammatory response. Specifically, it reduces the production of inflammatory cytokines (IL-1, IL-6, IL-8, and others), easing the inflammatory response. It also suppresses T-cell activation and neutrophil migration, thereby reducing inflammation.

Mechanism 3: Improvement of turnover

Isotretinoin has the effect of reducing clogged pores. This also improves pore-related problems such as comedones and blackheads.

By regulating gene expression, it also improves the differentiation and apoptosis (cell death) of epidermal cells. As a result,skin turnover is normalized,and clogged pores are reduced.

an effect of improving abnormal keratinizationit also has. By promoting normal keratinization and suppressing excessive keratinization of the stratum corneum, it reduces clogged pores and inflammation.

Because it improves turnover, the skin may, as a secondary effect, gain a healthy glow.

The concept of cumulative dose | By when should the oral course end?

When undergoing isotretinoin treatment, many people"How long should I take it for?"have this question, don't they?

In fact, the answer to this question isthe "cumulative dose,"which is deeply related to this concept. Here, we'll explain in an easy-to-understand way the idea of cumulative dose and how to determine the oral treatment period based on it.

What is the cumulative dose?

The cumulative dose refers tothe total dose per kilogram of body weight.In isotretinoin treatment, this cumulative dose is an important indicator.

• Target cumulative dose: 120–150 mg/kg
• Calculation method: (daily dose [mg/kg/day]) × (number of treatment days) = cumulative dose [mg/kg]

Why is the cumulative dose important?

Treating based on the cumulative dose offers the following benefits:

1. Long-term improvement of symptoms
2. Reduced risk of recurrence
3. Setting the optimal treatment period tailored to each individual patient

A guide to the oral treatment period based on cumulative dose

The oral treatment period varies depending on body weight and daily dose,but here are some general guidelines:

Gender	Average body weight	Daily dose	Estimated oral treatment period	Cumulative dose
Male	67 kg	10 mg/day	About 30 months	About 134 mg/kg
		20 mg/day	About 15 months	About 134 mg/kg
Female	53 kg	10 mg/day	About 24 months	About 136 mg/kg
		20 mg/day	About 12 months	About 136 mg/kg

*This is only a guideline; actual treatment periods vary from person to person.

On choosing between low and high doses:

1. Advantages of a low dose (10 mg/day):
   • It may lower the risk of side effects.
   • Symptoms such as skin dryness may be milder.
2. Advantages of a higher dose (20 mg/day):
   • Because the treatment period is shorter, results may be achieved sooner.
   • Long-term compliance (staying with the oral course) may improve.

The relationship between cumulative dose and treatment effect

Isotretinoin has the following effects on the sebaceous glands:

1. Reduces the size and activity of the sebaceous glands
2. Long-term suppression of sebum secretion
3. Normalization of abnormal keratinization of the follicular epithelium
4. Suppression of inflammatory cytokine production

By reaching a sufficient cumulative dose, these effects work continuously, leading to improved symptoms and a reduced risk of recurrence.This leads to those outcomes.

The importance of individualized treatment

While the cumulative dose is an important indicator,we do not provide the same uniform treatment to everyone.We take the following factors into account to develop the optimal treatment plan for each individual patient:

• Severity of symptoms
• Body weight
• The presence and degree of side effects
• Responsiveness to treatment
• Lifestyle

For example, internationally the standard approach is 0.5 mg/kg to 1.0 mg/kg taken orally for 15–20 weeks. However, this is merely the global standard, so it is best to tailor it to the characteristics of Japanese patients.

Since Japanese patients tend to have severe acne less often than those overseas, it is considered acceptable to begin treatment at a lower dose. For Japanese patients, treatment often starts at around 0.3 mg/kg.

Summary of cumulative dose

The concept of cumulative dose in isotretinoin treatment is an important indicator for achieving effective and safe treatment.

However, this is only a guideline; in actual treatment, we make careful adjustments to suit each individual patient's condition through regular examinations.

At our clinic, we carefully evaluate each patient's condition to develop the optimal treatment plan. If you are considering isotretinoin treatment, please feel free to consult with us.

An example of the treatment course

Before starting treatment:

Treatment name	Oral isotretinoin treatment (20 mg)
Treatment details	Aims to improve acne and oily skin through oral isotretinoin. One tablet taken once a day.
Treatment period	On average, 6 to 9 months.
Pricing	10 mg (30-day supply): 7,980 yen 20 mg (30-day supply): 12,980 yen *Tax included; self-pay treatment
Risks and Side Effects	Because of teratogenicity, contraception is essential Dryness of the skin (especially the lips) Changes in liver function, fluctuations in lipid levels, joint and muscle pain, headache, dizziness, visual disturbances, photosensitivity, allergic reactions, changes in bone density

Month 1:

You may experience side effects on the skin, eyes, and nose, and especially the lips. This occurs because isotretinoin works by shrinking the sebaceous glands and reducing the skin's oil content.

Some patients may also experience a temporary worsening of acne when they first use isotretinoin. This isalso called the "initial flare" or "purging" period, and it occurs when the medication clears out impurities deep within the skin.It is said.

Month 2:

In most cases,improvement in acne is often seen by this point.On the other hand, skin dryness and other side effects may persist or, in some cases, worsen. At this stage, the physician typically evaluates your response and adjusts the dosage as needed.

Months 3–4:

The majority of patients often show improvement by this point..New acne rarely appears, and existing acne heals.Some people experience side effects, but many patients have learned how to manage them (for example, by applying lip balm).

Months 5–6:

Most patients complete their treatment. The skin becomes clear, with few new acne breakouts. Side effects may persist for a while after discontinuing the medication, but they usually resolve over time.

*Please note that not all patients will improve along exactly this course.

What happens after stopping? What is the recurrence rate?

The course after stopping isotretinoin

The first few weeks after finishing:

Skin dryness and other side effects may persist even after treatment is complete. However, these side effects gradually diminish.

The months after finishing:

In many cases, acne clears completely and new breakouts are kept in check. Skin side effects are almost entirely resolved.

More than 6 months after finishing:

 In some patients, acne may reappear after treatment ends. This is usually less severe than before, and in most cases can be controlled with another course of isotretinoin or other methods.

Recurrence rate

There is no clear data on recurrence rates, but it is fair to say that recurrence is rare. A small number of people do experience recurrence, but in most cases it is not as severe as before.

Why is it unapproved and not covered by insurance in Japan?

In the United States and other countries, it has been an insurance-covered oral medication for more than 30 years, but in Japan it is not covered by insurance.

The reasons involve side effects and the difficulty of risk management.

One example is its effects before birth.

Isotretinoin,if pregnancy occurs during use or within a short period after use, may cause serious fetal malformations or developmental disorders.For this reason, women who use it must strictly practice pregnancy prevention. Such control and monitoring is difficult, and this is thought to be why its use is not approved in some countries.

Here, let us also look at the opinions of physicians in Japan regarding the use of isotretinoin.

(Source)Hayashi Nobukazu, Sasaki Yu, Kurokawa Ichiro, et al., "A survey on the frequency of patients with acne conglobata and severe acne in Japan and dermatologists' attitudes toward oral isotretinoin," Journal of the Japanese Society of Clinical Dermatology, 2021, Vol. 38, No. 4, pp. 629–634

In summary,It seems fair to say that many physicians feel a need for isotretinoin treatment for treatment-resistant acne.I think that's a fair conclusion.

Those who cannot be treated

From what age can it be taken orally?

Western acne treatment guidelines state that"it can be taken orally from age 12,"(conversely, this means it must not be taken by anyone under 12).

So, to begin with, let us explain "Why does age matter?" It comes down to the "effect on bones"—in other words,"it may affect height growth (bone growth)."That is the reason.

This is something that may be mentioned in theory, butaccording to clinical studies (medical papers),taking isotretinoin for a short period of around six months "does not have a significant impact,"it is noted.

Acne carries the risk of leaving lasting marks in the form of "craters" and "hyperpigmentation." As a cosmetic dermatology clinic, we also treat people troubled by craters and hyperpigmentation, and craters in particular are difficult to improve. For this reason, we believe there is great value in treating acne early with isotretinoin.

Risks and Side Effects

Serious side effects

(1) Fetal malformations, miscarriage, stillbirth, premature birth

(2) Serious psychiatric conditions such as depression, psychosis (visual and auditory hallucinations), self-harm, and suicide attempts

Common side effects

(3) Dryness of the skin and mucous membranes

Isotretinoin shrinks the sebaceous glands, reducing the oil in the skin and mucous membranes. This causes dry lips, dry nose, dry eyes, and excessively dry skin.

Dryness of the mucous membranes of the nose may make you more prone to "nosebleeds."

Other side effects

(4) Changes in liver function

Isotretinoin places a burden on the liver and can cause abnormal liver function in some patients. For this reason, periodic liver function tests are required during treatment.

(5) Fluctuations in lipid levels

Isotretinoin may raise blood cholesterol and triglyceride levels. This is especially important for patients at risk of cardiovascular disease.

(6) Joint and muscle pain

Some patients experience joint and muscle pain. This usually improves after treatment is interrupted or completed.

(7) Headache, dizziness, visual disturbances

Some isotretinoin users have been reported to experience headaches, dizziness, or visual disturbances. In particular, changes in visual acuity and reduced night vision may affect daily activities such as driving.

(8) Photosensitivity

Isotretinoin users may become more sensitive to sunlight. Appropriate precautions should therefore be taken to avoid sunburn.

(9) Allergic reactions

In rare cases, isotretinoin may cause an allergic reaction. This can include symptoms such as skin rash, hives, severe itching, difficulty breathing, irregular heartbeat, and swelling (especially of the face and throat).

(10) Changes in bone density

Prolonged use of high-dose isotretinoin may cause changes in bone density and a halt in bone growth.

Notes

・If you have sexual intercourse during the period you are taking the drug and for one month before and after, always use contraception.

・Do not become pregnant, breastfeed, or donate blood during the period you are taking the drug and for one month afterward.

*A blood transfusion given to a pregnant woman may expose the fetus to the effects of isotretinoin.

・Please refrain from chemical peels and waxing during isotretinoin treatment and for 6 months after treatment.

・Invasive laser treatments cannot be performed during treatment.

・Do not share isotretinoin with others.

・Acne may temporarily worsen after treatment begins.

Treatment Flow

Pricing

Features of Smart Skin Clinic

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The efficacy of isotretinoin for "seborrheic dermatitis"

Here, we introduce the efficacy of isotretinoin for the condition known as "seborrheic dermatitis."

There are two reasons why we're introducing this:

➊ The current state of seborrheic dermatitis | No curative treatment has been established

So first, we'll explain "What is seborrheic dermatitis?", "What causes it?", and "What treatments are currently used?", and then we'll share "the basis for saying isotretinoin can be a good option for seborrheic dermatitis."

First, please take a look at this summary of seborrheic dermatitis from a reliable medical source.

Seborrheic dermatitis is a common inflammatory disease of the skin that occurs in areas with a high density of sebaceous glands (for example, the face, scalp, and sternum).The cause is unknown,but a yeast-like fungus that resides on the skin,Malasseziaplays an important role. Seborrheic dermatitis occurs with increased frequency in HIV-infected patients and in patients with certain neurological disorders. It sometimes causes itching, dandruff, and yellowish, greasy scales on the scalp, hairline, and face. Diagnosis is made by examination.Treatment is with antifungals, topical corticosteroids, tar, and keratolytics.

Seborrheic Dermatitis (MSD Manual, Professional Edition)

There are two important points.

In other words, what this means is,"Because the root cause is unknown and no cure has been established, many people have tried various treatments without improvement and continue to struggle with the condition."That is what we mean.

You might wonder, "How can you be so sure?" It's because I was one of those people.

In fact, symptoms such as dandruff had disrupted my life for over ten years. But "when I took isotretinoin for acne treatment, my seborrheic dermatitis cleared up, which was completely unexpected."

From there, I looked into the research and discovered some interesting facts. Next, I'll share "the reasons isotretinoin was effective" and "the medical evidence."

❷ The mechanism by which isotretinoin is effective for seborrheic dermatitis (hypothesis)

As we've explained so far, the main action of isotretinoin is,"shrinking the sebaceous glands = reducing sebum secretion,"that is its action.

The cause of seborrheic dermatitis is not clearly understood, but the following mechanism is thought to be involved.

Malassezia, a mold, is medically called a "fungus." Drugs that combat this fungus are therefore called "antifungals." That is why "antifungals" are listed as one of the treatments for seborrheic dermatitis.

However, if Malassezia is being activated by "some mechanism," you can see that this doesn't address the root of the problem.

In fact, in seborrheic dermatitis,"sebum secretion is increased,"it is also said. And Malassezia,"uses sebum as a source of nutrition,"so the story goes.

In other words, the hypothesis holds that "the root cause is sebum, which in turn activates Malassezia." Viewed this way,"isotretinoin, which suppresses sebum secretion, may provide a fundamental solution,"that's the idea.

Now, up to this point this has been only my hypothesis as a cosmetic dermatologist, so let me show you the actual research papers.

The first paper was published in June 2023 in the medical journal "International Journal of Dermatology."

This study evaluated patients diagnosed with moderate to severe seborrheic dermatitis and treated with oral isotretinoin between January 2019 and December 2020.

Isotretinoin was administered to 48 patients with moderate to severe seborrheic dermatitis, and because the results showed a statistically significant improvement in symptoms, the study concluded as follows.

Given its efficacy and safety, oral isotretinoin can be used to treat patients with moderate to severe seborrheic dermatitis.

Zhang Yanfei, et al. Efficacy and safety of oral isotretinoin in the treatment of moderate to severe seborrheic dermatitis: a retrospective study. Int J Dermatol. 2023 Jun;62(6):759-763.

The second paper was published in January 2017 in the same medical journal.

This study was conducted to determine the efficacy and safety of isotretinoin for the treatment of moderate to severe seborrheic dermatitis of the scalp and face.

Forty-five patients were recruited for the study; half were treated with isotretinoin and half with topical agents.

The results showed that isotretinoin relieved the symptoms, leading to the conclusion that isotretinoin may be an effective treatment for seborrheic dermatitis.

Conclusion: Low-dose oral isotretinoin may be a therapeutic option for moderate to severe seborrhea and seborrheic dermatitis.

Cristhine de Souza Leão Kamamoto, et al. Low-dose oral isotretinoin for moderate to severe seborrhea and seborrheic dermatitis: a randomized comparative trial. Int J Dermatol. 2017 Jan;56(1):80-85.

To summarize the above:

If you are dealing with persistent seborrheic dermatitis, please feel free to consult Smart Skin Clinic.

FAQ

I'm worried about side effects and afraid of isotretinoin. Is it safe?

When you do a lot of research, side effects can certainly become a concern. Because so many side effects are listed, you may worry that one of them is bound to happen. But anything with a non-zero probability has to be listed, which is why they all appear; there's no need to worry about every one of them.

What's important is to carefully weigh the benefits against the side effects and risks. As for benefits, if isotretinoin improves your acne, it could have a significant positive impact on your quality of life.

Isotretinoin has a range of side effects, but the most serious is teratogenicity. As noted in the precautions, the risk of side effects can be lowered through thorough risk management, such as: "If you are sexually active during the period you are taking it and for one month before and after, always use contraception."

In addition, since you'll have regular physician examinations, if any side effects arise, we'll discuss and address them together.

When does it start to work?

This varies from person to person, but in many cases people begin to feel the effects in about two months.

Do the effects persist after finishing the oral course?

Yes, they do persist. However, some sebaceous glands may return to their original state, so please note that not everyone can prevent recurrence. Even if recurrence does occur after stopping the medication, in most cases the symptoms are milder than before treatment.

What should I do if my acne recurs?

Generally, when acne recurs it is usually milder than before. Treatment often involves the same approaches used before starting isotretinoin, such as topical therapy (ointments) or oral antibiotics.

Can I undergo other cosmetic treatments while taking the medication? Is hair removal okay too?

Generally, it's fine. That said, we recommend performing hair removal after you have stopped taking isotretinoin. Recent studies have shown that laser hair removal is safe even while taking isotretinoin, but medical hair removal uses higher output and carries some risk.

What should I do if I forget to take it?

If it's still the same day, take it after your next meal. If you forget a full day's dose, skip it and resume taking one tablet per day the following day. Please be careful not to take two tablets the next day.

Does it also work on body acne, such as back acne, aside from the face?

Yes, it does. It acts throughout the entire body.

References and bibliography

・Advisory regarding ACCUTANE (a treatment-resistant acne medication not approved in Japan) (Ministry of Health, Labour and Welfare)

・Hayashi Nobukazu, Sasaki Yu, Kurokawa Ichiro, et al., "A survey on the frequency of patients with acne conglobata and severe acne in Japan and dermatologists' attitudes toward oral isotretinoin," Journal of the Japanese Society of Clinical Dermatology, 2021, Vol. 38, No. 4, pp. 629–634

・Nast A et al: European evidence-based (S3) guideline for the treatment of acne – update 2016 – short version. J Eur Acad Dermatol Venereol. 2016, 30, 1261–1268

CLINIC LIST

Clinic List

Jimbocho Clinic

〒101-0054
3-16-1 Kanda Nishiki-cho, Chiyoda-ku, Tokyo, EX Kanda Nishiki-cho Building 8F (general reception) / 7F

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About the physician supervision of this site

This site is operated under the supervision of a Smart Skin Clinic supervising physician.

This page was produced in accordance with the Medical Advertising Guidelines Medical Advertising Guidelines revised and enforced in June 2018, under which we produce and provide this information.

• Scope of supervision: treatment descriptions, risks and side effects, price display
• Last supervision date: June 26, 2025

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