Thank you for your question. Accutane (isotretinoin) dosing is based on an individual's weight, which is 1 mg per kilogram for a minimum of 4 months. Therefore, since you weigh 70 kg, then your minimum recommend total dose will be isotretinoin 70 mg per day for four months. But if you can only tolerate 30 mg daily due to side effects or lab abnormalities, then your therapy will be extended to 8 months. Some providers prefer to start patients on lower doses to help patients acclimate to any side effects and to monitor for any changes in lab work. The dose may be increased depending on your tolerance of the medication and if your blood work is normal. I highly recommend you consult with your prescribing physician regarding your questions and concerns about Accutane treatment. Take care and good luck.