Whitey's Guide to Solvents, Compounds, Concentration, and Injection Pain
Basic Information on Commonly-used Solvents:
Benzyl Alcohol (BA):
A fairly potent solvent, whose main function for our purposes is keeping a solution bacteriostatic. It's presence as low as 0.9% is enough to prevent practically all microbial growth in solution.
Benzyl Benzoate (BB):
A co-solvent that serves several functions: helps dissolve the hormone, helps keep it in solution in depot (injection site), and thins the gear so it is easy to draw and inject.
Ethyl Oleate (EO):
A relatively new solvent in the realm of bodybuilding, EO is Oleic Acid with an ethyl ester. EO is an excellent solvent for lipophilic compounds in injectable preparations. Its oxidative stability helps extend the shelf life of compounds, and its low viscosity provides for easy injections.
What causes pain?
Short answer:
A complex interaction between the hormone/ester, the concentration of hormone in solution, and the solvents and ratios of solvents used.
BA, itself:
High enough levels of BA are sufficient to cause pain, per se. What level depends on the individual. 5% - perhaps, but perhaps not; 10% - most likely. I have heard some say that BA does not cause pain at all. I cannot agree. While I haven't yet injected straight BA just to gauge the pain, I did inject straight BA with IGF-1 LR3 back in the day, albeit in very small quantities. Just a few ius had a very decent bite to it. If you don't believe me, grab a syringe, pull a little BA, and go to town. The soreness can be impressive with even just a tiny amount of BA injected.
Hormone Concentration & Crashing in Depot:
There is another problem with BA, though - it is very water soluble. So much so, that once gear is injected, the BA will flee the solution and dissolve into aqueous fluids inside the body. What result? Depends. Let's assume for whatever reason, BA was your only solvent. What happens, most likely, is some of the hormone crashes in the depot, crystallizing in your muscle, causing irritation and near-crippling pain. The severity will depend on the hormone/ester and concentration (which affects the total amount of hormone crashed.) This is where BB, and other, newer solvents such as EO come in. These solvents are better at holding the hormone in solution in depot, thereby preventing a crash.
You can see why a high BA % would correlate with a crash in depot: if BA is being utilized as a solvent, rather than just a bacteriostatic agent, there's a chance there's not enough other solvents to hold all of the hormone once injected and the BA has leeched out. But it may not have been the BA that caused the pain at all, you see?? It was the hormone crashing, and the cause of that was a poor recipe.
Here's a guideline that I don't know 100% to be true, but in my experience, it has been. BA pain (caused by irritation from BA itself) may have a somewhat quicker onset, and fade more quickly than hormone pain. If you inject straight BA, you'll feel it immediately, it will do some tissue damage, and it will be out of the system relatively quickly. In an oil solution, it will not take effect as quickly, as it's still in the oil. As it leeches out, it does some tissue damage and causes some pain. On the other hand, I've never known hormone/ester pain to onset within 24 hours, and often it lingers for 48-72 hours as the crystals continue to irritate muscle fibers as they are slowly broken down. The distinction is a fuzzy line though, and probably will not give a conclusive answer in most cases as to the cause of injection pain.
Bottom line:
I think we tend to blame painful gear on BA too often. I personally do think that 10% BA is definitely high enough to cause a good amount of pain on it's own, though some have sworn it's painless. Others maintain that 4-5% BA will cause injection pain on its own. Just remember how many factors are at play here, and that will help you understand why there are so many conflicting opinions and theories on injection pain and ideal solvent ratios for different compounds and concentrations. I think it would be a mistake to try to finger just one of them as the culprit.
Basic Information on Commonly-used Solvents:
Benzyl Alcohol (BA):
A fairly potent solvent, whose main function for our purposes is keeping a solution bacteriostatic. It's presence as low as 0.9% is enough to prevent practically all microbial growth in solution.
Benzyl Benzoate (BB):
A co-solvent that serves several functions: helps dissolve the hormone, helps keep it in solution in depot (injection site), and thins the gear so it is easy to draw and inject.
Ethyl Oleate (EO):
A relatively new solvent in the realm of bodybuilding, EO is Oleic Acid with an ethyl ester. EO is an excellent solvent for lipophilic compounds in injectable preparations. Its oxidative stability helps extend the shelf life of compounds, and its low viscosity provides for easy injections.
What causes pain?
Short answer:
A complex interaction between the hormone/ester, the concentration of hormone in solution, and the solvents and ratios of solvents used.
BA, itself:
High enough levels of BA are sufficient to cause pain, per se. What level depends on the individual. 5% - perhaps, but perhaps not; 10% - most likely. I have heard some say that BA does not cause pain at all. I cannot agree. While I haven't yet injected straight BA just to gauge the pain, I did inject straight BA with IGF-1 LR3 back in the day, albeit in very small quantities. Just a few ius had a very decent bite to it. If you don't believe me, grab a syringe, pull a little BA, and go to town. The soreness can be impressive with even just a tiny amount of BA injected.
Hormone Concentration & Crashing in Depot:
There is another problem with BA, though - it is very water soluble. So much so, that once gear is injected, the BA will flee the solution and dissolve into aqueous fluids inside the body. What result? Depends. Let's assume for whatever reason, BA was your only solvent. What happens, most likely, is some of the hormone crashes in the depot, crystallizing in your muscle, causing irritation and near-crippling pain. The severity will depend on the hormone/ester and concentration (which affects the total amount of hormone crashed.) This is where BB, and other, newer solvents such as EO come in. These solvents are better at holding the hormone in solution in depot, thereby preventing a crash.
You can see why a high BA % would correlate with a crash in depot: if BA is being utilized as a solvent, rather than just a bacteriostatic agent, there's a chance there's not enough other solvents to hold all of the hormone once injected and the BA has leeched out. But it may not have been the BA that caused the pain at all, you see?? It was the hormone crashing, and the cause of that was a poor recipe.
Here's a guideline that I don't know 100% to be true, but in my experience, it has been. BA pain (caused by irritation from BA itself) may have a somewhat quicker onset, and fade more quickly than hormone pain. If you inject straight BA, you'll feel it immediately, it will do some tissue damage, and it will be out of the system relatively quickly. In an oil solution, it will not take effect as quickly, as it's still in the oil. As it leeches out, it does some tissue damage and causes some pain. On the other hand, I've never known hormone/ester pain to onset within 24 hours, and often it lingers for 48-72 hours as the crystals continue to irritate muscle fibers as they are slowly broken down. The distinction is a fuzzy line though, and probably will not give a conclusive answer in most cases as to the cause of injection pain.
Bottom line:
I think we tend to blame painful gear on BA too often. I personally do think that 10% BA is definitely high enough to cause a good amount of pain on it's own, though some have sworn it's painless. Others maintain that 4-5% BA will cause injection pain on its own. Just remember how many factors are at play here, and that will help you understand why there are so many conflicting opinions and theories on injection pain and ideal solvent ratios for different compounds and concentrations. I think it would be a mistake to try to finger just one of them as the culprit.