Clenbuterol is a very harsh drug on the system. With that said, yes I have used it and will use it again. Every time before I use it I get checked by my doctor for blood pressure and heart issues as these will pay a price every time you use it.
I recommend starting with as small of a dose as possible maybe 10 or 20 mcg. Use that for a week and as long as you are tolerating it well you can jump up 10-20 mcg for the second week. Take 2 weeks off and now you can start at your new higher level on your second cycle. Every week add 10-20 mcg until you start having sides effects you can not deal with. 2 weeks on 2 weeks off, back and forth. For me that is around 80 mcg, but I have heard of others tolerating almost double that. Females though do tend to be more sensitive to it. Not sure if that is more because of the fact of being a female or they just are not used to dealing with some of the sides you get with some of the harsher steroids. My wife gets migraines at the lowest dose possible, so it is a no go for her.
You will need to take potassium supplements and a liver support as well. Also who ever is responsible for making medical decisions for you in the case of you being incapacitated needs to know you are taking it. Honestly they should have a list of all drugs (legal and illegal) you take and the doses.
Now with all that Clen will not excuse you from having a poor diet and exercise routine. It is not a magic weight loss pill. To get the best results I recommend you have an extremely controlled and measured diet and exercise routine. Also might want to look into low dosing Anavar with it. Being your first experience with PED's you may want to have a coach help you with your diet and exercise routine. Those that put the work in can see dramatic changes in a relatively short amount of time, but will completely fail if they have no discipline.
Note: I am not a doctor and my advice does not constitute medical advice. PED's react differently in different people based on genetics and other issues.