Post-injection pain. Why it may occur and how to avoid it

Post-injection pain, or PIP, generally speaking is the pain experienced after taking an intramuscular shot of a certain substance, in our case a mixture of a hormone salt, any concentration of solvent, preservatives/antiseptics, and a carrier. Most of the pain is caused when carrier and solvents are absorbed by the body and the crystals are left behind in the muscle pocket.

In this article, we’re going to go over the main causes for PIP:

  1. How long the ester is: shorter esters (e.g., propionate or acetate) form harder, stronger crystals, with a melting point close to 100ºC, while longer esters often have a melting point closer to a human’s body temperature of around 30 to 40ºC, the exception being cypionate, a longer ester with higher melting point.
  2. Concentration of hormone: for explanation purposes, let’s say it takes the body 24h to absorb 1ml of carrier oil + solvent + 50mg of testosterone propionate. If your gear is cooked at 50mg/mL, then it’s about the same time and there should be little to no PIP. Now we all know it’s hard to find gear at that concentration, with the norm being 100mg/mL for this particular substance. In this case, after 24h, there would still be 50mg of propionate left in the muscle pocket, which will tend to crystallize inside the muscle tissue and possibly cause some extent of pain, although light to moderate. This effect gets even more noticeable when using a blend of esters in the same carrier. Also, this is the reason why water-based suspensions usually causes more pain, as water is extremely easily absorbed by the muscle, leaving crystals behind.
  3. Solvents used: not all solvents are made the same, for example regular gear may use a combination of benzyl benzoate (BB) as a solvent and benzyl alcohol (BA) as a preservative/antiseptic. For usual concentrations, about 20% BB and 2% BA is to be expected with the rest being just a standard organic oil as a filler/carrier. On the other hand, a gear using for example 2% BA, 5% Guaiacol which is a super solvent much stronger than BB, 10% Benzyl Salicylate (basically liquid aspirin) and the filler substrate being 50% Ethyl Oleate (an oil with solvent properties) and 50% regular oil will result a significantly less painful experience to the user, but is also much costlier to produce, as these chemicals will add to the final price of the product.
  4. Injection position, speed and repeatability: If you shoot yourself, you probably already know the classic spots for self-shooting: deltoids and glutes. There are charts and pictures all over the internet showing the correct injection places on these muscles and if done correctly, will cause minimal pain. Also, 25 to 30mm needles are possibly the best choices and will give you the best depth of the pocket. However, if you’re injecting daily or every other day, you’ll probably run out spots to take your gear. In that case, you can use your thighs, chest, triceps, even forearms and calves, but be careful and do your research first, as these spots are trickier and will require more care, always using the correct sized needle. Also, try to inject at a rate of about 3 seconds for every mL on the syringe. Choosing the right gauge needles can be helpful as they will force you to move slowly with the liquid.
  5. Virgin Muscle: If it’s your first time shooting in a particular spot, you may experience a little discomfort and have to use more pressure on the syringe, as the muscle fibers are all bundled together as a virgin tissue and you will need to tear them apart with the liquid to form a pocket. However, this won’t last long and by your third application it will feel normal again.
  6. Carbolic Acid and/or other particles: These substances (although sterile) may be present in your gear and will not cause and infection but may cause PIP before your body can absorb/expel them. Testosterone Enanthate is particularly prone to having higher concentrations of Carbolic Acid due to manufacturing processes involved as it costs a whole lot more to ensure the crystals are 100% pure.
  7. Individual response to pain: Some guys just have a higher pain threshold than average, while others quite the opposite. For that reason, the very same gear shot with the same syringe/needle by the same person can have different effects in different people.

If you’re experiencing really intense PIP and cannot bear with it, a few things you can do are: cutting your shots up to 50/50 (in the syringe) with sterile filtered oil; you’ll have to shoot a much higher total volume, but it’ll be less painful; and warming up your vials before you draw from it by leaving them in hot water for maybe 2 to 3 minutes and lastly applying hot packs to the region affected (never use ice). The PIP should go away after 3 to 4 days. If none of that solves the issue, you may have to switch brands of gear to one that uses different components.

Marco D Angelo

PhD in biochemistry, specialized in enzymology and metabolic biochemistry with a background in pharmacology, he works in a molecular biology laboratory and in his spare time works as a high-performance trainer in addition to assisting other coaches.