No.
The so called relief that deca brings joints (joints, not tendons) is only due in fact to it "lubricating" properties. (don't get me started on this one).
Tendonitis can affect many people whether they play tennis or not. Massage therapists are especially prone to this ailment due to their constant pushing and dragging motion that they do on people and using their bodyweight to "sink down" on the patient to get a deeper depth (like when doing neuromuscular therapy or fascia stretching). The only thing that is going to help is ibuprofen, ice, rest and and direct cross fiber friction massage at the center point of inflammation. You can do the cross fiber massage anytimes, especially sitting in your car at red lights. Just locate the central area where the pain is the greatest. you will know it when you find it. Press directly down with your thumb or finger and in very tiny movements, push the finger back and forth over the tendon. You have to press hard because you don't want to just be pushing flesh around, you want to break up the microfibril that has formed in the area and bring blood and nutrients to the area. You can do it in 30-40 seconds, which is ideal for red light waits.
When in doubt, always use ice, not heat. Heat causes inflammation on it's own. You don't want that. Instead, if it hurts, ice it. and just be patient. The more you aggravate it, the more permanent it becomes. You don't want to be 45 years old and having a fucked up elbow simply because you were too lazy to take two months rest ten years earlier.
