How long do I need to take isotretinoin (roaccutane) for?

By Dr Magnus Lynch
MA(Cantab) DPhil(Oxon) MRCS FRCP
Consultant Dermatologist & Dermatological Surgeon

Isotretinoin is taken as a course of treatment. An average course of treatment lasts 6-12 months.

Different dermatologists have differing approaches to the prescription of isotretinoin. The principles are that you complete a course of treatment that leads to a long lasting improvement in your skin even when the course is completed. My approach is to prescribe a course of treatment according to your body weight - for each kilogram that you weight you need to complete a total of around 120mg of isotretinoin. For example, if you weight 60kg, you need to take 60x120 i.e. 7200mg for the entire course. If you are taking one 20mg tablet of isotretinoin per day this would take a total of 360 days - almost a year.

You will start with a relatively low dose since there can be a temporary flare in your acne at the beginning of treatment and to allow you to get used to any side effects. After the first month or so the dose can be increased since this will shorten the duration of treatment - for example if you take two 20mg tablets daily then the length of the course is halved, although this must be balanced against the increased potential for side effects. You can use an app to help track your dosage and side effects.

Related Articles

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• How effective is isotretinoin?
• When should I consider isotretinoin (Roaccutane) for my acne?

About Dr Magnus Lynch

I am a London-based Consultant Dermatologist and Dermatological Surgeon. My NHS practice is at Guy's Hospital and is focused on Mohs micrographic surgery and the treatment of complex skin cancers. My private practice additionally focuses on laser treatments, regenerative dermatology, rosacea, acne, pigmentation and scarring. I have particular expertise in the diagnosis and treatment of skin cancer, including minimally-invasive techniques, Mohs micrographic surgery, and facial reconstructive surgery. I studied at the Universities of Cambridge and Oxford, and completed my dermatology training and Mohs fellowship at the prestigious St John’s Institute of Dermatology. I graduated from medical school in 2003 and have worked exclusively in Dermatology since 2012.

I lead a research team at King’s College London investigating the molecular biology of skin cancer and skin cancer diagnostics, and I constantly aim to translate the latest findings into better patient care. You can learn more about my Research.

In recent years I have been involved in Media Appearances, including the Channel 5 series 'Skin A&E', where I perform skin surgeries and treat various skin conditions. Filming for the next series has recently completed and the series will be released later in 2025.

How I can help

I consult with private patients at several well-appointed and conveniently located sites across central London:

• London Bridge Hospital: Conveniently situated within The Shard, next to London Bridge station.
• Skin55 Ltd: Located at 55 Harley Street, this beautiful Edwardian building houses one of the largest private dermatology facilities in the UK with a comprehensive laser suite.
• OneWelbeck: Located close to Bond Street underground station. Mohs surgery, lasers, and other skin surgeries are performed in the state-of-the-art surgical suite here.

A new consultation is £250, a follow up consultation is £220. For more information on fees, please visit Prices.