Check out this article on SR9009 ->
https://www.evolutionary.org/stenabolic-sr9009-review
Cardarine and SR9009 are PPAR up regulators. Cardarine/SR9009 increases the expression of genes involved in the expenditure of energy, stimulates glucose uptake in skeletal muscle tissue and burns fat by stimulating fatty acid oxidation.
Both are great options and will significantly increase fat loss and endurance. Cardarine is slightly better for endurance and SR9009 is slightly better for fat loss.
The recommended dosage of cardarine is 20mg/day
The recommended dosage of SR9009 is 30mg/day
Cardarine has a half life of 24 hours so you only need to dose it once per day. Due to SR9009's short half life, you want to split up your daily dosage into 3 dosages throughout the day.
The nicest thing about cardarine and sr9009 is that they are not stimulants or hormones so they won't effect sleep, raise cortisol levels or anything like that. It'll cause a huge boost in fat loss with no side effects.
As @Stevesmi mentioned, your best option would actually be to use BOTH