What did @trtsgtmaj2 actually say?
The creator walked through their personal testosterone self-injection routine, emphasizing subcutaneous (subQ) injection into the glutes and a technique called "backfilling" an insulin syringe with oil drawn from the vial using a larger needle. They recommend drawing "way more oil than what I need" as a buffer for mistakes, and stress that you cannot draw viscous testosterone oil through a small insulin needle directly. The tutorial is conversational, based on personal experience, and invites viewers to share their own methods. There is no dosing information given, which is notable. The advice is procedural rather than medical, but it reaches tens of thousands of viewers who may be self-injecting without clinical supervision.
The core claims: subQ glute injections work, backfilling is a valid technique, insulin needles cannot draw oil efficiently, and drawing excess volume reduces injection errors. Let's look at each of those.
Does the science back this up?
SubQ testosterone injection is legitimately supported by research, and backfilling is a widely practiced technique with reasonable logic behind it. The evidence for subQ administration has grown substantially in the last decade.
A 2017 study by Kaminetsky et al. in Journal of Clinical Endocrinology and Metabolism found that subcutaneous testosterone cypionate produced stable serum testosterone levels comparable to intramuscular delivery, with potentially lower peak-to-trough variability. The subQ route is increasingly used in clinical practice precisely because it is less intimidating and easier for patients to self-administer. The glute as a subQ site is less conventional than the abdomen or thigh, but it is used in practice.
Backfilling, the act of pushing oil into an insulin syringe from the back rather than drawing it through the fine needle tip, is a well-documented workaround in patient communities and is acknowledged in pharmacy and nursing literature on viscous injectables. The physics are sound: fine-gauge needles create high resistance to thick oil. Drawing directly through a 28 or 29-gauge insulin needle is genuinely impractical with testosterone in an oil carrier.
What did they get wrong (or right)?
They got the core technique right. Backfilling is not a fringe hack. It is a practical solution to a real problem with viscous oil-based injectables. The instruction to avoid putting the plunger in before reinserting into the vial to prevent spillage reflects genuine hands-on experience. Credit where it is due.
However, there are real omissions worth flagging. The creator does not mention needle recapping safety or disposal, both of which are relevant when you are handling two needles. The instruction to clean the vial top and injection site with alcohol swabs is correct but incomplete: the CDC and WHO injection safety guidelines recommend allowing the alcohol to dry fully before injecting, a step not mentioned here.
More significantly, "subQ in the glutes" is a somewhat imprecise anatomical target. The glute has variable subcutaneous fat depth depending on body composition. Injecting too deep in a lean person at that site risks intramuscular delivery, which changes absorption kinetics and may increase local irritation with oil-based testosterone. A 2020 review by Kohn et al. in Sexual Medicine Reviews noted that subQ injection sites with more consistent fat depth, like the lower abdomen or lateral thigh, tend to produce more predictable absorption.
What should you actually know?
SubQ testosterone delivery is clinically legitimate and increasingly preferred in patient-centered TRT protocols, but technique details matter more than this video acknowledges. A few things worth knowing:
- Allow alcohol to dry for at least 30 seconds before injecting. Wet alcohol can carry surface bacteria into the injection site and cause stinging.
- The backfilling technique is valid, but the larger drawing needle should be replaced or at minimum handled carefully to avoid contamination before use as a drawing tool into the syringe barrel.
- SubQ glute injections are feasible but not the most anatomically consistent subQ site. The lateral abdomen or thigh provides more predictable fat depth for most people.
- "Drawing more than you need" as a mistake buffer is understandable advice, but accurate dosing matters clinically. Eyeballing a slightly-over-filled syringe and then pushing out excess is acceptable if you are precise about your final volume marker.
- Testosterone vials are multi-use. Maintaining sterile technique, including not touching the cleaned stopper and using a new needle each time, is not optional. Contaminated vials have caused serious infections in documented case reports.
This video is a useful peer-to-peer walkthrough for people already on a prescribed TRT protocol. It should not substitute for instruction from a prescribing clinician or pharmacist. If you are starting TRT for the first time, ask your provider to walk you through injection technique directly.