To aspirate or not to aspirate, that is the question. Today you’ll finally learn the truth behind the controversy surrounding aspiration – do you really need to aspirate?

When you first enter the world of testosterone replacement therapy, one topic that comes up quite quickly is aspiration.

Aspirating is the process of pulling back on the plunger in the syringe before you inject the testosterone/medication into your muscle.  I did a video on this a while back when I first learnt about it.

The concept and reasoning behind this is to check whether you draw blood or air bubbles.

If you draw blood, then you may be in an area where there are blood vessels or veins.

You would then abort the injection in that spot, and try again in another place where you draw air, not blood.

The fear people have is that if they inject into a blood vessel or vein, it may lead to complications in the heart, or worse, death.

While there are risks to intramuscular injections, most of the information is just hysteria and fear mongering.

Let’s take a look at what the latest research says and finally deal with the facts about aspirating.


One of the most contentious points of discussion on my YouTube channel is aspirating.

I constantly get comments about whether you should or shouldn’t aspirate. From what I can gauge, the majority of people believe that you should aspirate.

There are a wide variety of opinions on this topic. There is also a lot of fear-mongering and it is easy to get caught up in the hysteria. I know from personal experience. I never aspirated in the first video I did on injecting testosterone, and I got lambasted by the viewers.

After that video, I made damn well sure I aspirated. Like many, I learnt from the internet. Still, I wasn’t 100% sure about whether this was necessary, as my previous doctors had never aspirated. Yet, everyone was saying that you had to.

So, for a few years, I followed this process blindly.

More recently, I have seen an increase in the number of people saying that you don’t need to aspirate. Interestingly, many of these comments are coming from medical students, and not those on TRT. I appreciate my viewer feedback and made a note.

I also recently heard some doctors on The TOT Doctors Roundtable podcast say that they no longer aspirate. I was curious and wanted a definitive answer, so I contacted my doctor.

My physician notified me that it was no longer necessary for me to aspirate when injecting into certain muscles. He provided a link to a study, and that led me to do some proper investigation into this matter.

What The Latest Research Tells Us

A number of studies have been done to determine the necessity of aspiration for intramuscular injections.

Most of these studies were not specific to testosterone replacement therapy specifically, but intramuscular injections in general. The principles are still valid.

One guideline from the Canadian Medical Association regarding reducing pain in childhood
vaccinations was identified that made reference to aspirating.  It states:

“Aspiration is not necessary for IM injections because the recommended anatomic sites for IM injections do not contain major blood vessels and it may increase pain when paired with slow injection. Rapid injection without aspiration is thus recommended to reduce pain in children undergoing IM vaccination.”

There were a few more studies related to vaccinations and general intramuscular injections that had the same findings.

I did manage to find a study that was more applicable to TRT, titled “Aspirating during the intramuscular injection procedure: a systematic literature review”, by Helen Sisson.

This study was highly informative and indicated that aspirating during the administration of an intramuscular injection is unnecessary when using the deltoid, ventrogluteal and vastus lateralis muscle sites.

However, it also concluded that aspiration SHOULD be practiced when injecting into the dorsogluteal muscle, owing to its proximity to the gluteal artery.

Injection sites where aspirating is not necessary.

To Aspirate Or Not To Aspirate

Based on the studies published, we seem to have two scenarios when it comes to aspiration.

IT IS NOT NECESSARY  to aspirate when injecting into the delt (deltoid), glute (ventrogluteal method) or quad (vastus lateralis), because the anatomic sites recommended are devoid of large blood vessels.

IT IS NECESSARY  to aspirate in other intramuscular sites due to the proximity of large blood vessels and arteries. This includes the dorsogluteal muscle.

The dorsogluteal injection site

I want to especially highlight the fact that they do recommend aspiration for the dorsogluteal muscle, as I have injected here before and published videos on this injection site.

Also, due to the proximity and number of blood vessels in the quad, you might want to consider (and it has been recommended) that you aspirate if you are not sure where exactly the  vastus lateralis is located.

Aspiration is not necessary for sub-cutaneous injections as you are injecting into fat and not a muscle.


There you have it.

Aspiration is not necessary for delt, ventrogluteal and quad injections. However, it is recommended for other injection sites, including the dorsogluteal muscle.

Hopefully that clears everything up when it comes to aspiration.

I certainly learnt a lot going while researching this article.

I may consider giving up aspiration in future. For now though, it gives me peace of mind, and only takes a couple of seconds extra. So personally, I will keep aspirating.

Has this changed your mind about aspirating in future? Are you going to continue to aspirate, even if it’s not necessary? Let me know your thoughts in the comments.


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Paolo Broccardo

I help men take control of their testosterone, health and lives. Testosterone Replacement Therapy turned my life around and my goal is to help other men with low testosterone do the same.

2 CommentsLeave a comment

  • I quit aspirating 3 years ago. However, it got to the point to where nearly every time I would inject my ventrogluteal muscles I would taste/smell the testosterone as well as get a slight cough… extreme dizziness, anxiety and cough follows immediately after. I know that is a pulmonary oil microembolism… Needless to say, I quit injecting my ventros and only do deltoids now. But now I’m starting to develop knots in my delts from frequent injections. It sucks.

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