Holy crap i cannot stand the fact that i can never make a decision and the research is frying my little brain but i found some info that might be useful or downright ugly to read i found it online so have fun let me know any experiences you guys have had because i decided i am adding one of the two to my first real cycle... along with the TRT Test cyp i am on from script!! ;) and throwing some masteron enathanate on top...

"Testosterone propionate is one of the most common short acting testosterone esters available. The propionate ester consists of three carbons and gives the testosterone an active half-life of around four days. Like always, the literature differs on the quoted half life. One thing I can tell you is the sex drive peaks rapidly with this drug and so does the onset of mild androgen euphoria. Testosterone propionate is a potent form of testosterone.

Personally, I feel best on the second to third day after a shot of propionate. The effective range for this drug varies greatly. I have known individuals taking 200mg per day and others taking 100mg 2x per week. The important thing to remember with propionate is that less is more. Remember that the ester weight is reflected in the total mg dosage listed for the drug. For example, the molecular weight of testosterone alone is 288.43 g/mol (don’t worry about the units, this is chemistry abbreviations for grams per mol; a mol is a single molecule of a substance). The testosterone propionate weighs 344.49. So, let’s get rid of the decimals just to make this simple. By simple division of 288/344, you can calculate precisely how much active testosterone present in 1ml or 1cc of testosterone propionate. If we round our numbers off and you do the division above, you will see that roughly 84% of testosterone propionate is active testosterone.

Just in case you didn’t catch the math (calculus was always a bitch for me personally), we just took the weight of a single molecule of testosterone propionate (344) and the weight of a single molecule of testosterone (288) and got the percentage of pure testosterone per 100 mg of testosterone propionate. The percentage when you take 288 and divide by 344 is roughly 84%. This is a very functional and useful tactic to use for your testosterone esters. You can know exactly how much pure testosterone you are putting in your system.

So back to the practical application; the most popular strength for testosterone propionate is 100mg/cc. By our calculation and accounting for the ester weight, we now know that 100mg of testosterone propionate contains roughly 84mg of pure testosterone. Contrast this with a long acting ester such as cypionate and the power of knowledge becomes quickly evident. Testosterone enanthate weighs 401g/mol (rounding up, actually it is 400.594). If we do the same division trick we take the molecular weight of testosterone (288) and divide it by the weight of the molecule we are using (test enanthate= 401). Our new percentage gives us roughly 72%. This means that enanthate is only 72% pure testosterone. So, a typical 1cc, 200mg shot of enanthate only contains an actual 144mg of testosterone.

A very interesting note concerning esters of testosterone is the form testosterone phenylpropionate. This is a propionate form of ester with a phenol group added to it, yet still has a half life very close to propionate (3-4 days). The phenol group is a carbon ring which adds considerable weight to the ester. Who cares you say? Just want to take your shot you say? Hold on a minute, this has huge application for getting huge. Test phenylpropionate weights 420.584g/mol (let’s round this up to 421. Take the 288 (weight of testosterone molecule) and divide it once again by the total molecular weight of the drug you are using (phenylpropionate=421). This gives us a percentage of 68%. Phenylpropionate is found in testosterone mixture, when found alone it is usually 100mg per cc (just like regular propionate). However at only 68% pure testosterone, a 100mg shot of phenylprop has only 68mg of testosterone!!

Think about this, if you poke yourself three times per week on a typical eod schedule, you are barely getting 200mg of testosterone in your system for the week (68 x 3 = 204). If you took 3cc’s of either phenylprop or prop per week you would be getting 204mg of pure test from the phenylprop and 252mg from the prop. The names sound very similar, they act with the same speed of release, but their potency is totally different. The 48mg difference (252-204=48) per week represents roughly 24% of the total phenylprop and 19% of the prop amount of pure testosterone in your system. In functional terms what this means is that using two drugs which are suppose to be similar actually equate to a 1/5 difference on the low end and a ¼ difference on the high end with respect to your total weekly dosage. Don’t you think increasing your dosage by 20% is significant? How about getting a minimal of a 20% DECREASE------YIKES. We all know decreasing dosages is so much fun----YEAH RIGHT!! But this is what happens if you take equal amounts of these two drugs. You will get about 20% more active, pure testosterone in an equal amount of testosterone propionate than testosterone phenylpropionate."

http://www.anabolicsteroids-hormoneknowledge-bigmuscles-drugs.com/testos...

Disclaimer- this is not mine... i take no credit other than finding this lol..