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Isotretinoin Dose Calculator

Created by Aleksandra Zając, MD
Reviewed by Dominik Czernia, PhD and Jack Bowater
Based on research by
Rademaker M. Isotretinoin: dose, duration and relapse. What does 30 years of usage tell us?; The Australasian journal of dermatology; August 2013See 1 more source
Goldsmith, L. A., Bolognia, J. L., Callen, J. P., Chen, S. C., Feldman, S. R., Lim, H. W., Lucky, A. W., Reed, B. R., Siegfried, E. C., Thiboutot, D. M., Wheeland, R. G., American Academy of Dermatology American Academy of Dermatology Consensus Conference on the safe and optimal use of isotretinoin: summary and recommendations; Journal of the American Academy of Dermatology; June 2004
Last updated: Jan 18, 2024

If you struggle with skin conditions and your doctor has suggested giving oral retinoids a chance, the isotretinoin dose calculator (or Accutane® dosage calculator) is here to help you. With this tool, you will be able to count your cumulative isotretinoin dose, the daily Accutane® dosage, and the duration of the whole treatment.

If you want to know more, check out the sections on isotretinoin's side effects and the drug's mechanism of the action below. We explained what isotretinoin is, how does isotretinoin work, and how to reduce the side effects of isotretinoin. Keep reading!

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. If any health condition bothers you, consult a physician.

What is isotretinoin? What is Accutane®?

Accutane® is the most popular brand name for a drug called isotretinoin. It is one of the vitamin A derivatives from the family called retinoids. We use isotretinoin to treat severe forms of acne. Accutane® comes as jelly capsules, and you can buy it in doses of 10, 20, and 40 mg of isotretinoin in one capsule.

How long does Accutane® take to work? Treating acne with the right Accutane® dosage takes time as the therapy usually lasts for months or even more than a year. However, it is supposed to treat your skin for the rest of your life. Sometimes, in cases of relapse, the course can be repeated.

How to use the isotretinoin dose calculator? Accutane® dosage

Isotretinoin dose calculator can be helpful with few problems regarding Accutane dosage. It has a built-in Accutane® dosage chart. To use it, follow the below instruction:

  1. Start by typing in your weight. You can switch between kg and lbs. You will then see the range of your isotretinoin cumulative dose. It varies between 120 mg and 150 mg of the drug per kilogram of your weight.
  2. In the next field of the isotretinoin dose calculator, you can calculate how much time (approximately) it will take to administer the full cumulative dose. It takes a mean value of a cumulative dose, which is 135 mg per kilogram.
  3. You can also change the result and switch to counting how much isotretinoin you have to take daily if you want to take the full cumulative dose within a certain amount of time.
  4. Alternatively, if you know your full dose (e.g., because your dermatologist has counted it for you), you can switch to the Advanced mode of this Accutane® dosage calculator. Then, type your cumulative isotretinoin dose and the parameter that you know - either the duration of your therapy or your daily dose. The calculator will then provide the other number.

How to set a daily dose?

You usually start with a low introductory dose, and, if you feel okay, you can increase it to around 1 mg/kg per day - the recommended maximum dose for most people. However, singular severe cases of adult acne can benefit from increasing it to even 2 mg/kg per day. However, the cumulative isotretinoin dose does not change. Your leading doctor should always have the last word in terms of your daily and cumulative dose.

How does Accutane® work?

While you now know "What is Accutane®?" you may still be wondering - how does isotretinoin work on my skin?

There are three main mechanisms of acne:

  1. Sebum overproduction - If you happen to have oily skin or oily hair, you know what we are talking about;
  2. Presence of specific bacteria - Such as Propionibacterium acnes; and
  3. Intense keratinization - This means that the skin cells produce more of the protein keratin than usual. It thickens our skin and traps the oil and bacteria in the skin, causing inflammation and pimples.

An individual can experience one, two, or all three phenomena and have acne because of this.

There are, of course, multiple drugs and cosmetics for acne. Some of them are antibiotics, and some types of acids, like azelaic acid; you may also meet topical retinoids or topical isotretinoin. However, oral isotretinoin is the only one that works on every level.

First, it promotes cell turnover so that keratinization slows down. Then it shrinks the sebaceous (oil) glands of the skin, so they don't have as much sebum. Lastly, using the proper Accutane® dosage chart stops the acne bacteria from multiplying. This results in less inflammation and reduced redness.

How to reduce the side effects of isotretinoin?

Every drug has possible side effects, and Accutane® is no exception. The drug is also quite potent, and it can cause some complications as well. The list is quite long and can be scary sometimes. That's why during treatment, you should check your blood often, be mindful of any symptoms and if you're a woman, take care of effective contraception.

The side effects observed in some people due to oral isotretinoin are:

  1. More common
  • Dryness of the lips and skin;
  • Dry eyes;
  • Skin sensitive to sunlight. Every retinoid (so isotretinoin as well) is a photosensitizer, which means that it makes your skin very sensitive to sunlight. Using a high SPF product is a must!
  • Dry nose and nosebleeds;
  • Dry throat and mouth; and
  • Headache, back pain, joint pains.
  1. Less common, but more severe
  • Birth defects if taken by a pregnant woman - that's why you should always stay on effective contraception while taking isotretinoin;
  • Fatigue;
  • Changes in your blood lipids - an increase of LDL and total cholesterol, increase of triglycerides that can potentially cause pancreatitis. This is why you should take blood tests regularly;
  • Liver damage and an increase of the liver enzymes AST and ALT;
  • Blood sugar increase;
  • Changes in your blood test - e.g., anemia; and
  • Mood drop and depression.

You can learn how to reduce the side effects of isotretinoin in the next section in more detail.

How to manage your therapy with Accutane®?

The isotretinoin dose calculator may be helpful to check the proper Accutane® dosage, but you still need to pay attention to the following points:

  1. Be cautious of your symptoms and don't forget to take regular blood tests. If you catch the signs early, you might address them immediately and prevent potentially severe conditions. Sometimes a decrease in dose is all it needs.

  2. Stay away from alcohol for the duration of the treatment. Alcohol and isotretinoin are not a good match, as taken together, they work synergistically and can damage your liver, pancreas, and blood sugar.

  3. Remember about the photosensitivity that your skin experiences. Don't go expose yourself to any unnecessary direct sunlight; avoid sunbathing and solariums too. Use high SPF sunscreens and hats and stay in the shade. Better safe than sorry!

  4. Take care of your whole body. You might experience dryness not only on the skin but also of your eyes, lips, and mouth. Use gentle but rich moisturizers for your face and hands. You might want to refrain from contact lenses for some time and may find soothing eye drops beneficial. And buy yourself a nice protective lip balm so you don't end up with cheilosis.

  5. You know how does Accutane® works, but do you know it first needs to be absorbed properly? Vitamin A (and its derivatives, like retinoids) belong to the group of fat-soluble vitamins. The group, besides vitamin A, includes vitamins D, E, and K. To effectively absorb those micronutrients, you need to take them preferably with a fatty meal. You don't have to go keto all the way - just eat your isotretinoin dose with a proper dinner, not a fruit snack.

  6. Don't play around with your dose unless your dermatologist tells you so. Never exceed your daily dose, even if the Accutane® dosage calculator tells you so. You should listen to the experts who know your individual case.

  7. If you're a woman, use effective contraception before, during, and one month after the treatment. It is preferred to use two different methods at once (preferably one physical and the other hormonal). Your doctor can also ask you for a regular pregnancy test. Don't forget about it.

Take a look at the few tools that can help you manage Accutane® therapy:


What is isotretinoin?

Isotretinoin is a drug derived from vitamin A, commonly used in cases of severe acne. It can be taken orally (which is sold as Accutane®) or topically in the form of a gel or cream.

Is isotretinoin an antibiotic?

Despite some anti-bacterial properties that stop the acne bacteria from spreading, isotretinoin is not technically an antibiotic.

Be sure to consult your dermatologist if you have any doubts about what isotretinoin is to avoid or at least reduce potential side effects.

When does isotretinoin start to work?

You will notice signs of isotretinoin working in the first couple of weeks - you will feel the dryness of the skin and can experience flares around weeks 4 - 6.

The acne usually starts improving in about a month of taking the drug and continues to do so up to two months after the therapy.

How long do you take isotretinoin?

An isotretinoin therapy usually lasts for 4 - 6 months (16 - 24 weeks). You aim to take your cumulative dose (about 120 - 150 mg/kg of body weight) - no more, no less.

Is isotretinoin Accutane?

Yes. Accutane® is a drug in the form of jelly capsules that contains the active ingredient - isotretinoin. Although Accutane® is not the only formulation of oral isotretinoin, it is the most widespread one. You can find Accutane® in a dose of 10, 20, or 40 mg per capsule.

Aleksandra Zając, MD
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The calculations here are based on a mean cumulative dose of 135 mg/kg. Click on Advanced mode if you know your exact cumulative dose.
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