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

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

Dr. Magnus Lynch, Consultant Dermatologist

About Dr Magnus Lynch

I am a London-based Consultant Dermatologist and Dermatological Surgeon. I am highly experienced in skin cancer diagnosis, Mohs micrographic surgery, acne, rosacea, acne scarring and laser treatments. 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. 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.

My NHS practice is at Guy's Hospital. I consult with private patients at the London Bridge Hospital, OneWelbeck (near to Bond Street station) and on Harley Street. A new consultation is £250. Book A Consultation.

I am the founder of Revessa Health which provides online consultations for acne and rosacea across the UK (see below).

Revessa Health
UK Online Specialist Care

The Online Acne & Rosacea Specialists

Video consultations with specially trained GPs and consultant dermatologists.
Founded by Dr Magnus Lynch, Consultant Dermatologist
GP consultation
£80
Consultant dermatologist
£220
Book Online →
Revessa Health consultation
Back to home