What did @newtonbuilt actually say?
On camera, mid-injection, @newtonbuilt told his 2.8 million viewers he had just hit a vein, then immediately said hitting a vein is "super unlikely." That's the entire claim, compressed into a moment of visible panic. It's actually a two-part statement: something bad just happened, and also that thing almost never happens. Both halves deserve scrutiny.
To his credit, he didn't catastrophize or give dangerous follow-up advice. He didn't tell people to push through a vein strike, change the dose, or do anything reckless. He just reacted, labeled it rare, and moved on. That restraint matters in a 2.8 million view context.
Does the science back this up?
Yes, mostly. Inadvertent intravascular injection during intramuscular (IM) injection is genuinely uncommon, and the data supports calling it unlikely. The mechanism that makes it rare is anatomical: the gluteal, vastus lateralis, and deltoid sites used for testosterone injections sit in muscular tissue with relatively small-caliber vessels, not major veins.
A 2015 systematic review by Nicoll and Hesby in the Journal of Infusion Nursing found that aspiration before IM injection, historically used to check for vein entry, was not evidence-based and has largely been abandoned in clinical guidelines, precisely because vascular placement at standard IM sites is uncommon enough that the practice added no meaningful safety benefit. The World Health Organization formally recommended against routine aspiration for most IM sites in 2015.
That said, "super unlikely" doesn't mean impossible, as @newtonbuilt just demonstrated live. Estimated rates of inadvertent intravascular injection at IM sites range from less than 1% to around 2% depending on technique, needle length, and injection site.
What did they get wrong (or right)?
He got the core fact right: hitting a vein during a standard intramuscular testosterone injection is a low-probability event. The literature supports this. Where the video falls short is what it doesn't say, which matters a lot given the audience size.
What actually happens when you do hit a vein during a testosterone injection? The risk isn't bleeding out. The real concern is oil embolism. Testosterone cypionate and enanthate are suspended in carrier oils, typically cottonseed or sesame. If that oil gets pushed into a vein, it can travel to the lungs. Case reports of pulmonary oil microembolism (POME) from intravascular testosterone injection exist in the literature. Lunning et al. (2014, JAMA Internal Medicine) documented POME cases presenting with coughing, chest tightness, and dizziness within minutes of injection.
The tell-tale sign he didn't mention: if you aspirate blood into the syringe, or if you get a sudden cough, chest pain, or feel faint immediately after injecting, those are red flags that warrant stopping and seeking care. A passing "oh fuck" doesn't cover that ground.
What should you actually know?
If you inject testosterone at home, here is what the evidence actually recommends. First, hitting a vein during a proper IM injection is uncommon, under 2% in most estimates, and @newtonbuilt is right about that. Second, the consequences when it does happen are not trivial. Oil embolism from oil-based testosterone injections is a documented, real adverse event, not a scare tactic.
Current clinical guidance from the Endocrine Society (2018 clinical practice guidelines) recommends standard IM injection technique at validated sites. Many clinicians have moved to subcutaneous injection for testosterone, which carries essentially zero vascular placement risk and has shown comparable pharmacokinetics for depot formulations (Spratt et al., 2021, Journal of Clinical Endocrinology and Metabolism).
Signs of possible pulmonary oil microembolism include immediate or near-immediate coughing, chest discomfort, shortness of breath, or feeling faint after injection. If those occur, stop the injection immediately and contact a medical provider. This is not a "walk it off" situation. If you are self-injecting testosterone without clinical supervision, this video is a good reminder that a telehealth provider relationship is not optional, it is a safety layer.
The bottom line
@newtonbuilt's offhand claim that hitting a vein is "super unlikely" during a testosterone injection is accurate by the numbers. The problem is what he didn't say: when it does happen with an oil-based hormone preparation, there's a documented path to pulmonary complications. A 2.8 million view moment of panic deserved a 30-second explanation. It didn't get one.