How do synthol injections work?
 

Synthol is an oil that is injected directly into a muscle causing it to expand in size.

Bodybuilder initially thought that the synthol injected into a muscle would remain in the muscle for 5 years or more. However, this is not accurate. Injected synthol dissipates gradually over a period of several months. However, during this time, injected synthol stretches the fascia of the synthol treated muscle. Muscle fascia is a matrix of tissue which can be thought of as a body casing or sheath (think about a tight rubber body suit). Interestingly, muscle fascia, by fully covering a muscle, acts to prevent muscle growth. However, the more stretched the fascia is the more the muscle will have room to grow. When injected, synthol acts as an agent to stretch the muscle fascia allowing it to grow much bigger.

As the injected synthol oil dissipates over time, the “space” left behind is replaced with new muscle tissue growth. Of course this assumes that weightlifting is taking place along with proper nutrition, recovery and supplementation. After synthol use, x-rays performed on some of the most extreme synthol freaks, the guys with the 25+ inch arms, there was no synthol found to be present in the examined muscle at all. The synthol itself was absorbed by the body and through bodybuilding, it was replaced by real muscle.

Obviously, fascial stretching with injected synthol will hurt some. However, over time, the pain decreases the more synthol is injected, until essentially, injections are no longer painful.

All site injection oils are painful at first; however, it is reported that the Syntherol brand of synthol hurts much less due to its high level of refinement - making for a very thin, pharmaceutical grade oil