Get the fundamentals right before worrying about technique.
What an injection actually is
An injection delivers a substance into the body using a needle and syringe. It bypasses digestion and allows predictable absorption when dosing and technique are consistent.
The process is simple. Problems happen when fundamentals are rushed, contaminated, or measured incorrectly.
Before you inject: the “pre-flight” checklist
- Confirm your dose (mg/mcg) and your volume (mL/IU units).
- Use brand-new sterile gear every time (needle + syringe).
- Swab vial top and skin and let alcohol fully dry.
- Pick a clean site (no redness, swelling, bruising, or irritation).
- Know your route (SubQ vs IM) and match it to your plan.
Not sure what your volume should look like? Use the syringe visuals in the calculator before you inject.
Why injections are used
- More consistent absorption than oral dosing for many compounds
- Avoids breakdown in the digestive system
- Allows precise, repeatable dosing
- Often required for peptides and injectable hormones
Precision is the benefit—and the responsibility.
Common injection routes
Routes are defined by where the medication is delivered.
- SubQ (subcutaneous): into the fat layer under the skin
- IM (intramuscular): into muscle tissue
Route choice depends on the compound, volume, and the instructions you’re following. If you’re new to TRT, start here: What is TRT?
Basic injection equipment
- Sterile syringe
- Sterile needle
- Alcohol swabs
- Medication vial or ampoule
- Sharps disposal container
Reusing needles is not “saving money.” It’s increasing risk and pain.
Preparation basics
- Wash hands before setup
- Use a clean, stable surface
- Swab vial tops and skin and let alcohol fully dry
- Confirm dose, concentration, and syringe markings before drawing
- Inject slowly (rushing increases irritation and leakage)
If alcohol hasn’t dried, it isn’t clean yet.
Common beginner mistakes
- Rushing setup and contaminating gear
- Confusing units vs volume vs concentration
- Injecting too fast
- Skipping site rotation
- Using dull/reused needles
Most problems come from skipping basics, not advanced technique.
Basic safety rules
- Never share needles or syringes
- Dispose of sharps immediately after use
- Do not inject into irritated or infected skin
- If something looks wrong, stop and reset (or get clinical advice)
Using this for TRT (practical link)
If you’re applying these basics to TRT dosing decisions and execution, read: Dose planning basics.
Where to go next
Master the basics first. Everything else builds on them.
Key takeaways
- Injections are simple, but require discipline.
- Preparation prevents most problems.
- Clean gear + correct measurement beats “confidence.”
- Consistency is what makes results predictable.