Will I see results on Accutane in a low dose?

You will definitely see results on 40mg/day, most likely by the end of the first month or so.

However, those results might not last on a long term basis if the course of the low dose treatment isn't long enough.  Therefore it is not whether the 40mg/day will help but if it will be helpful long term and provide you with the target total dose necessary for that long term improvement in cystic acne.

Generally the target dosage for Isotretinoin is 120mg/kg (total dose) of the patients body weight.  Ideally, this is done over a 5-6 month period but it can be extended if a patient is unable to tolerate higher dosages due to side effect or elevated liver enzymes. 

Therefore, if you stay on the 40mg dose you will need closer to 7 months of treatment to achieve your "total dose".

There are a lot of factors to Accutane dosage, including environment, which is a big one. Living in Las Vegas I cannot possibly put people on any higher dosage than 40mg/day period. With this environment no one can tolerate a higher dosage than that. You don't need a specific dosage per day. You need a specific dosage over a set amount of time. Additionally it's usually done in increments of 20mg, and there isn't a 70mg pill or even two 30mg pills, so, there are some settings you just can't control.