It sure seems to me that some individuals would benefit from a dosing interval of testosterone cypionate that is more frequent than every 7 days. If the idea is that the best compromise in terms of keeping a relatively stable blood level of T - while avoiding an excessive number of injections - might be obtained by having the injections correspond to the half-life of the drug, then it seems like it needs to be taken into consideration that the half-life is going to be different depending on the individual.
When Pfizer (formerly the Upjohn Co.) states here: http://www.pfizer.com/pfizer/download/uspi_depo_testosterone.pdf
that the half-life of Depo-Testosterone is approximately 8 days (for an IM injection), that doesn't mean that it's 8 days for everyone. That's an average. The reality, I'm sure, is that it is 8 days plus or minus several days depending on the individual. There are enormous differences in metabolic clearance rates among individuals.
I'm also finding a big drop off beginning about the 5th day as I'm doing 100mg T-cyp injections every 7 days. So I'm thinking that it would work better, and probably be healthier/safer too, to do 100mg every 5 days (the equivalent of 140mg/wk) versus uping the dose to, say, 150mg every 7 days. Why flood the body with that much T all at once, which will likely cause a greater increase in E2 and DHT levels, etc. (and expose the liver to a greater concentration of T) than presumably would a smaller more frequent dose?
Aside from having to do the injections on a different day each time, I just don't see any great inconvience from injecting (if you're self-injecting, that is) every 5 days compared to every 7 days. Any more thoughts on this subject?