Undecanoate is a slow release injectable ester of the anabolic male hormone testosterone. This is one of the most effective and dominant bulking aides available. It gives dramatic effects in muscle and strength increases and has a dramatically extended half-life, allowing for an infrequent injection schedule. Some of the best manufacturers include Cooper Pharma, Alpha Pharma and Eminence Labs. For some of the best brands, look for, Testobolin-XR and Testosterone Undecanoate.