How to Inject IM and SubQ: The Complete Guide for Every Site

Here is a stat that should make you double-check your technique: research shows only 32 to 52 percent of intramuscular injections actually reach the muscle (Polania Gutierrez & Munakomi, 2023). In women, that failure rate climbs to 92 percent. The rest ends up in subcutaneous fat, where absorption is unpredictable and complications are more likely.

Whether you are pinning your first TRT dose or rotating through six sites on a blast, proper injection technique is the most important harm reduction skill you can learn. This guide covers every site, every route, and every compound type, with the evidence behind each recommendation.

Equipment: what you need before your first pin

Before drawing anything, lay out your supplies on a clean surface. Here is what you need:

Syringes:

• Standard 3 mL syringe for oil-based compounds (testosterone enanthate, cypionate, nandrolone, trenbolone)
• 1 mL insulin syringe (29-31G) for HCG, peptides (ipamorelin, sermorelin), and HGH

Needles (use separate needles for drawing and injecting):

• Drawing needle: 18-21G, 1-1.5 inch. A larger bore pulls oil faster and keeps the injection needle sharp.
• Injection needle: see the compound-specific table below.

Other supplies:

• Alcohol swabs (70% isopropyl)
• Sharps container (never recap and reuse needles)
• Band-aids
• Clean, flat surface

Our dosage calculator can help you determine exact volumes and syringe sizes for your protocol.

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Needle selection by compound and route

Intramuscular injection sites

IM injections deliver compounds directly into muscle tissue, where the blood supply is dense enough for consistent absorption. The sites below are ordered from safest and most beginner-friendly to advanced.

Ventrogluteal (recommended for beginners)

The ventrogluteal site (gluteus medius) is the safest IM site available. It has the thickest muscle layer (40 mm average) and the least subcutaneous fat (20 mm average) (Yalcin Atar et al., 2024), with no major nerves or blood vessels in the injection zone.

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How to find it:

1. Place the heel of your opposite hand on the greater trochanter (the bony prominence on the side of your hip).
2. Point your index finger toward your anterior superior iliac spine (the front hip bone).
3. Spread your middle finger back toward the iliac crest, forming a V shape.
4. The injection zone is in the centre of that V.

Technique: 90-degree angle, 1-1.5 inch needle. Accepts up to 4 to 5 mL per injection.

Dorsogluteal (upper outer quadrant)

The dorsogluteal site is the traditional "glute shot" that most people picture when they think of IM injections. It targets the gluteus maximus in the upper outer quadrant of the buttock. While widely used, it carries more risk than the ventrogluteal site because the sciatic nerve and superior gluteal artery run through the area. Incorrect landmarking can hit either one.

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How to find it:

1. Visually divide one buttock into four quadrants with an imaginary cross.
2. The injection site is the upper outer quadrant (marked with X in the diagram).
3. Stay well away from the midline and the lower half to avoid the sciatic nerve.

Technique: 90-degree angle, 1.5 inch needle (required due to the thick subcutaneous fat layer over the glutes). Accepts up to 4 to 5 mL. This site requires a partner for proper injection in most cases, which is a practical downside compared to the ventrogluteal or vastus lateralis.

Vastus lateralis (outer thigh)

The vastus lateralis is the easiest site for self-injection because you can see exactly what you are doing. It is the middle third of the outer thigh, between the knee and the hip.

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How to find it:

1. Sit down and place your hand flat on the outside of your thigh.
2. Divide the thigh into three equal sections from knee to hip.
3. The middle section is your target zone.

Technique: 90-degree angle, 1-1.5 inch needle. Accepts up to 3 to 5 mL depending on muscle development. More PIP-prone than the ventrogluteal site due to more nerve endings.

Deltoid (upper arm)

The deltoid is convenient for small-volume injections but limited by muscle size.

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How to find it:

1. Feel the acromion process (the bony point at the top of your shoulder).
2. Measure two to three finger widths below it.
3. The injection zone is the thick part of the deltoid, forming an inverted triangle.

Technique: 90-degree angle, 1 inch needle (1.5 inch if BMI is over 25). Maximum 1 to 2 mL. A 1-inch needle successfully reached muscle in 98.6 percent of men under 260 lbs (Sebro, 2022).

Advanced sites: lats, pecs, triceps, traps

These sites are used by experienced injectors who need to spread volume across many sites on frequent protocols. There is no peer-reviewed safety data on these sites for IM injection, so they carry more risk than the three primary sites above.

• Lats (latissimus dorsi): Reach behind and inject into the meaty portion of the lat, below the armpit. Limit to 1 to 2 mL.
• Pecs (pectoralis major): Inject into the outer, thickest portion of the chest muscle, away from the sternum. Limit to 1 to 2 mL.
• Triceps (lateral head): Inject into the outer head of the triceps, midway between elbow and shoulder. Limit to 1 mL.
• Traps (trapezius): Some advanced users pin the upper traps. High nerve density makes this the most PIP-prone site. Limit to 1 mL.

How to inject IM: step by step

Step 1: Preparation

1. Wash your hands thoroughly with soap and water.
2. Draw the compound: attach the drawing needle (18-21G) to the syringe. Pull back the plunger to fill the syringe with air equal to the dose volume. Insert the needle into the vial, inject the air (this equalizes pressure), then invert the vial and draw the desired volume.
3. Switch needles: replace the drawing needle with your injection needle. This keeps the injection needle sharp and sterile.
4. Remove air bubbles: tap the syringe with the needle pointing up. Flick any bubbles to the top and push the plunger until a small drop appears at the needle tip.
5. Swab the injection site with an alcohol wipe. Let it dry for 10 seconds.

Step 2: The Z-track method

The Z-track technique reduces oil leakage into subcutaneous tissue by about 31 percent (Yilmaz et al., 2016) and is standard procedure for oil-based injections.

1. Use your non-dominant hand to pull the skin 2 to 3 cm to one side of the injection site.
2. Hold the skin displaced while you insert the needle and inject.
3. After removing the needle, release the skin. It slides back to its natural position, sealing the needle track and preventing oil from leaking back through the path.

Step 3: Inject

1. Insert the needle at a 90-degree angle in one smooth, confident motion. Hesitating halfway causes more pain.
2. Aspiration (optional): pull back slightly on the plunger for 5 to 10 seconds. If blood enters the syringe, withdraw and try a different spot. The WHO and CDC no longer recommend routine aspiration for deltoid, ventrogluteal, or vastus lateralis sites (Yildiz Karaahmet & Senturan, 2025). However, if you use the dorsogluteal site, aspiration is still recommended due to proximity to the superior gluteal artery.
3. Inject slowly and steadily. For 1 mL of oil, aim for about 10 seconds.
4. Wait 5 seconds after the plunger is fully depressed before withdrawing.
5. Remove the needle in one smooth motion, release the Z-track, and apply light pressure with a cotton ball or gauze.

Subcutaneous injection technique

SubQ injections deliver compounds into the fat layer between skin and muscle. This route is standard for HCG, peptides, HGH, and GLP-1 agonists, and increasingly used for TRT-dose testosterone.

When to use SubQ

• TRT-dose testosterone (0.25 to 0.5 mL per injection): SubQ produces comparable testosterone levels to IM, with lower estradiol and lower haematocrit (Choi et al., 2022).
• HCG: standard SubQ at 250 to 500 IU, two to three times weekly.
• Peptides: ipamorelin, sermorelin, BPC-157, TB-500 are all SubQ by default.
• HGH: always SubQ.
• GLP-1 agonists: semaglutide, tirzepatide are SubQ.

SubQ is not appropriate for large-volume injections above 1 to 2 mL or for blast-dose protocols. The volume limitation makes it practical only for TRT, cruise doses, and small-volume compounds.

SubQ injection sites

• Abdomen: The preferred site. Inject at least 2 inches from the navel. The abdomen tolerates the largest SubQ volumes (up to 3 mL in studies) and retains adequate fat even at low body fat percentages (Usach et al., 2019).
• Love handles (flanks): A good alternative with consistent fat depth.
• Upper outer thigh: Works well, but lean individuals risk accidental IM delivery. A 4 mm needle at the thigh has a 1.6 percent chance of reaching muscle; with an 8 mm needle, that rises to 25 percent.
• Upper arm (posterior): The fat pad behind the triceps. Harder to self-inject but a useful rotation option.

How to inject SubQ: step by step

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1. Clean the site with an alcohol swab. Let it dry.
2. Pinch a fold of skin between your thumb and index finger. Lift it away from the muscle.
3. Insert the needle at 45 degrees into the skin fold. If you have substantial body fat at the site, 90 degrees is fine with a short (0.5 inch) needle.
4. Inject slowly. For insulin-syringe volumes (0.1 to 0.5 mL), this takes only a few seconds.
5. Hold for 5 to 10 seconds after the plunger is fully depressed, then withdraw.
6. Release the skin fold and apply gentle pressure. Do not rub.

SubQ vs IM for testosterone: what does the evidence say?

The data is clear: for TRT doses, SubQ and IM produce equivalent total testosterone levels.

• The Al-Futaisi pilot study found 100 percent of men on weekly SubQ testosterone enanthate maintained testosterone within the normal range (Al-Futaisi et al., 2006).
• McFarland et al. measured stable mean testosterone of 627 ng/dL across a weekly SubQ cypionate dosing interval in transgender men (McFarland et al., 2017).
• A direct comparison of 234 men found SubQ testosterone enanthate produced lower post-therapy estradiol (p<0.001) and lower haematocrit (p<0.001) versus IM cypionate, with equivalent trough testosterone (Choi et al., 2022).

The flatter pharmacokinetic curve from SubQ means lower peak testosterone, less aromatisation to estradiol, and less erythropoietic stimulation. For long-term TRT users worried about polycythaemia, SubQ is worth discussing with your doctor.

For blast doses, IM remains the practical choice. You cannot push 2 to 3 mL of oil into subcutaneous fat without significant discomfort and unpredictable absorption.

Compound-specific injection notes

Not all injectables behave the same way. The carrier oil, ester length, and concentration all affect technique.

Oil-based long esters (enanthate, cypionate, undecanoate)

Testosterone enanthate and cypionate in sesame or cottonseed oil are moderate viscosity. They flow well through 23 to 25G needles with moderate pressure. Warming the vial in your hands or placing it in warm water for two to three minutes before drawing lowers viscosity and makes the injection smoother.

Testosterone undecanoate (Nebido/Aveed) is formulated in castor oil at 4 mL per dose. Castor oil is significantly thicker. Use a 21G needle, inject over 60 seconds, and expect moderate PIP. Sartorius et al. found 80 percent of men reported pain following undecanoate injection, peaking immediately and lasting one to two days, with full resolution by day four (Sartorius et al., 2010).

Short esters (propionate, acetate)

Testosterone propionate and trenbolone acetate are injected every one to three days due to their shorter half-lives. Short esters are notorious for PIP because the compound can crystallise as the solvent diffuses out of the depot. IM is strongly preferred over SubQ for short esters.

Tips for short esters:

• Warm the oil before injection.
• Use a rotation schedule with at least six sites to give each location time to recover.
• Inject slowly. Rapid injection of a crystallisation-prone compound concentrates it in a small area.

Water-based compounds

Water-based testosterone suspension and injectable stanozolol contain steroid particles in suspension, not solution. They settle in the vial, so you must swirl (not shake aggressively) immediately before drawing. Use a 21 to 23G needle as the particles can clog finer gauges. These compounds cause the most acute PIP because crystals precipitate directly in tissue without an oil buffer.

Peptides and HGH

Peptides (ipamorelin, sermorelin, BPC-157, TB-500) and HGH are reconstituted from lyophilized powder using bacteriostatic water. Key points:

• Always use bacteriostatic water (0.9% benzyl alcohol), not plain sterile water. Bacteriostatic water allows multi-use over 30 to 60 days refrigerated. Plain sterile water must be used within 24 hours.
• Reconstitute gently. Aim the water stream at the side of the vial and let it trickle down. Never shake.
• Store reconstituted peptides in the fridge. Never freeze reconstituted product.
• Use insulin syringes (29-31G, 0.5 inch) and inject SubQ.
• For daily protocols, rotate between four to six abdominal sites minimum.

HCG

HCG follows the same reconstitution and SubQ protocol as peptides. SubQ bioavailability is 40 to 50 percent, equivalent to IM (Trinchard-Lugan et al., 2002). Standard doses for fertility preservation on TRT are 250 to 500 IU two to three times per week. For more on HCG protocols, see our HCG, fertility, and TRT guide.

Managing post-injection pain (PIP)

Some PIP is normal, especially with virgin muscle (a site you have never injected before). But understanding why it happens helps you minimise it.

Why PIP happens

1. Solvent crystallisation: High-concentration preparations (300+ mg/mL, common in UGL products) use high levels of benzyl alcohol and benzyl benzoate to keep the steroid dissolved. When the oil depot cools to body temperature, solvents diffuse out faster than the oil, and the steroid precipitates into microcrystals. These crystals trigger acute sterile inflammation.
2. Virgin muscle response: First-time injection into any site causes more inflammation because the tissue is not accustomed to an oil depot.
3. Oil volume: Injecting more than a site can comfortably hold stretches the muscle fascia.
4. Carrier oil reactions: Some people are more sensitive to certain oils. Cottonseed oil may cause more irritation than grapeseed in some users.
5. Injection speed: Counterintuitively, injecting too slowly can increase PIP because the muscle is under prolonged pressure.

How to reduce PIP

• Warm the oil: hold the loaded syringe in your closed hand for two minutes or place the vial in warm (not hot) water before drawing. Lower viscosity means the oil disperses more evenly in the muscle.
• Use the Z-track method: it prevents oil leaking into the subcutaneous layer where it causes more irritation.
• Rotate sites aggressively: use a minimum of six sites. A ventrogluteal, vastus lateralis, and deltoid rotation on each side gives you six sites.
• Inject at a moderate pace: for 1 mL, aim for about 10 seconds. Not too fast (tissue shock), not too slow (prolonged distension).
• Choose lower-concentration preparations: if you have the option, 200 mg/mL causes less PIP than 300 mg/mL of the same compound.
• Consider the SubQ route: for TRT doses, SubQ was rated as less painful with lower pre-injection anxiety in a crossover study (Wilson et al., 2018).

When PIP means something is wrong

Normal PIP: mild soreness starting 12 to 24 hours after injection, peaks at 48 hours, resolves within three to five days.

Seek medical attention if you notice:

• Progressive redness that expands beyond the injection site
• Heat and swelling that worsen after 48 hours instead of improving
• Fever above 38 degrees Celsius
• Pus or discharge at the injection site
• Red streaks radiating from the site (lymphangitis, a sign of spreading infection)
• Numbness, tingling, or weakness below the injection site (possible nerve injury)

Injection site infections are most commonly bacterial, and risk increases proportionally with injection frequency (Phillips et al., 2017). If you suspect infection, monitoring your white blood cell count and neutrophils on your next blood test can confirm systemic inflammation.

Site rotation strategy

Repeated injection at the same site causes measurable tissue damage. Ultrasound studies show significantly increased skin thickness and collagen remodelling at non-rotated sites (Murao et al., 2022). In insulin users, 63 percent had lipohypertrophy from poor rotation, and those injecting into damaged tissue had significantly more unpredictable absorption (Bochanen et al., 2022).

The same applies to AAS and peptide injections. Scar tissue changes how your compounds absorb, making blood levels less predictable.

Sample rotation schedules

TRT (2x per week IM): Monday: left ventrogluteal, Thursday: right ventrogluteal. Alternate with left/right vastus lateralis every other week. This gives you four sites with each site getting two weeks of recovery.

Short ester or EOD protocol (3-4x per week IM): Rotate through six sites: left VG, right VG, left VL, right VL, left deltoid, right deltoid. Each site gets at least 10 days of recovery between injections.

Daily peptide SubQ: Rotate around the abdomen using a clock pattern. Imagine the navel as the centre of a clock. Inject at 12 o'clock on day one, 2 o'clock on day two, and so on. Move at least 2 cm from the previous site. Alternate with flanks and thighs weekly.

Key takeaways

• Only 32 to 52 percent of IM injections actually reach muscle, so technique and needle selection matter more than most people realise.
• The ventrogluteal is the safest IM site. Start there if you are new to injecting.
• Use separate drawing and injection needles. Switch to a fresh needle before injecting.
• The Z-track method reduces oil leakage by about 31 percent. Use it for every oil-based injection.
• Aspiration is no longer recommended by WHO/CDC for the ventrogluteal, deltoid, and vastus lateralis. Treat it as optional at those sites, but still do it for the dorsogluteal.
• SubQ testosterone at TRT doses produces equivalent levels to IM, with lower estradiol and haematocrit. It is not practical for blast-volume injections.
• PIP from UGL gear is mostly caused by high solvent concentration and crystal precipitation. Warming oil, using lower-concentration preparations, and rotating sites all help.
• Rotate through at least six sites. Scar tissue from repeated injection at the same spot impairs absorption and increases discomfort.
• Know the warning signs of infection: expanding redness, fever, pus, and red streaks. Injection frequency is the strongest predictor of soft tissue infections.
• For peptides and HCG, always use bacteriostatic water and insulin syringes. Reconstituted peptides last 30 to 60 days refrigerated.

For more on how injection timing and route affect your blood test results, see our blood test timing guide. If you are starting TRT, our complete guide to starting TRT in Australia covers the full process from clinic selection to first injection.

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References

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