What did @colbert_fitnes8 actually say?
The creator walked viewers through combining testosterone and nandrolone decanoate ("deca") into a single syringe before injection. The tutorial covers drawing 0.5 mL of each compound, capping the needle, swapping to a fresh injection tip, purging air bubbles, and acknowledging that a small residual bubble is acceptable. The whole thing is framed as a practical convenience tip for people already on both compounds.
The specific process described: draw testosterone first, then draw deca into the same syringe, swap to a fresh needle, and push to the tip until the bubble clears. The creator also mentions pulling back slightly after the needle swap to recover any testosterone left in the hub, which is a real technique used by experienced self-injectors.
Notably absent from the video: any mention of a prescribing clinician, sterility protocols, injection site rotation, or the fact that nandrolone is a Schedule III controlled substance in the United States that requires a prescription.
Does the science back this up?
The chemistry of mixing oil-based anabolic steroids in a single syringe is not inherently dangerous, but the clinical evidence base for this practice is thin, and the regulatory and safety context is almost entirely missing from this video.
Testosterone and nandrolone decanoate are both oil-based injectable esters. They are physically compatible in the same vehicle, meaning they do not precipitate or chemically react when combined. A 2021 review by Mulhall et al. in the Journal of Sexual Medicine confirmed that combination androgen regimens are used in clinical hypogonadism treatment, though that context involves physician oversight and compounded formulations prepared under sterile conditions.
The real concern is not chemical compatibility. It is sterility. Drawing from multiple vials into one syringe increases the number of needle entries and the risk of contamination if technique is sloppy. The CDC's guidance on injection safety (2011, updated 2019) explicitly warns that multi-dose vial use requires strict aseptic technique to prevent bloodborne pathogen transmission and vial contamination. None of that is addressed here.
What did they get wrong (or right)?
Credit where it is due: the needle swap technique is correct. Swapping to a fresh injection tip after drawing is standard practice, since the drawing needle becomes dull and potentially contaminated from piercing vial stoppers. The creator also correctly identifies that small residual air bubbles at the tip are not dangerous for intramuscular injections, which aligns with clinical injection guidelines.
What is missing or wrong is more significant. First, there is no mention that nandrolone is a prescription controlled substance. Second, the video implies this is a routine DIY activity with no clinical oversight required. Third, the creator never mentions aspiration technique, injection site selection, or how to recognize signs of infection, all of which matter for patient safety. Drawing from two separate vials also doubles the contamination risk surface if either vial stopper is not properly cleaned with an alcohol swab, which the video does not show.
The framing, "maximize gains," positions this as performance enhancement content, not TRT education. That is a meaningful distinction regulators and clinicians take seriously.
What should you actually know?
If you are on a legitimately prescribed regimen that includes both testosterone and nandrolone, combining them in one syringe is a technique some clinicians discuss. It is not inherently dangerous when done correctly. But "done correctly" involves a lot more than this video covers.
Sterile technique is not optional. Each vial stopper should be wiped with a fresh 70% isopropyl alcohol swab before every needle entry. Needles should never re-enter a vial after they have touched skin or any non-sterile surface. The 2019 CDC injection safety guidelines are explicit on this point.
More importantly: nandrolone decanoate is not a supplement. It is a Schedule III anabolic steroid under the Controlled Substances Act. Using it without a prescription is illegal in the United States. A telehealth provider prescribing nandrolone for documented hypogonadism in an appropriate clinical context is very different from following a TikTok tutorial to stack compounds for gym performance.
- Always confirm your injection technique with the clinician or pharmacist who prescribed your medication.
- Wipe vial stoppers with alcohol before every draw, a step this video skips entirely.
- If you notice redness, warmth, or swelling at an injection site, contact a healthcare provider promptly.
- Combining compounds not prescribed together by your provider is outside the scope of your treatment plan, regardless of what you see on social media.