This is a harm-reduction education resource for people who inject drugs and the workers who serve them. It does not encourage use — it assumes injection is already happening and aims to reduce overdose, bloodborne disease (HIV, HCV, HBV), bacterial infection (abscesses, endocarditis, cotton fever), and vein damage. The safest option is always not to inject; the next safest is to inject as cleanly and carefully as possible, ideally with supplies and support from a syringe services program (SSP).
1. Sterile solution — water, filtering & the shot
Not all water is equally safe to inject. The widely cited harm-reduction ranking, safest to least safe:
| Rank | Water | Notes |
|---|---|---|
| 1 | Sterile water for injection (SWFI), unopened ampoule | The gold standard. Single-use — once opened it is no longer sterile. Available through many SSPs. |
| 2 | Bacteriostatic water | Sterile water with a small amount of preservative (e.g. 0.9% benzyl alcohol); useful if a solution may sit more than a few minutes. |
| 3 | Pharmaceutical sterile saline | Acceptable, though plain sterile water is generally preferred for dissolving. |
| 4 | Freshly boiled, then cooled, water | Standard advice when no ampoule is available. Boiling does NOT remove endotoxins or reliably kill all spores, so it is not equivalent to true sterile water. Use fresh. |
| 5 | Cold tap water (potable) — last resort | Where drinking water is treated, clean cold tap beats bottled "spring" water. Never use water from a toilet. |
Cookers, cottons & filters
Use your own clean cooker (single-use disposable cookers are available from SSPs). Use a fresh sterile cotton pellet or a manufactured wheel filter every time, placed with clean fingertips. Filtering removes undissolved particulates that cause vein damage, granulomas, and "cotton fever." Avoid cigarette filters (they shed fibres and additives). Never reuse or share filters.
Acidifiers (only when needed)
Some base-form substances (crack cocaine, some forms of heroin) need an acid to dissolve. Ascorbic acid (vitamin C) is gentler on veins and is preferred; citric acid is acceptable. Avoid lemon/lime juice — it is harsh on veins and carries a documented risk of Candida fungal infection, including sight-threatening eye infection. Use the minimum amount; excess acid damages veins and tissue.
Preparing the shot
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1
Wash hands and work on a clean surface
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2
Combine the drug with the smallest effective amount of sterile/boiled water in a clean cooker
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Add acidifier only if required, in the minimum amount
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4
Apply gentle heat only if needed to dissolve, then let it cool before drawing up
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Place a fresh filter and draw the solution up through it
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6
Tap out air and expel the bubble before injecting
2. Intramuscular (IM) — "muscling"
Many substances given IM come pre-prepared as a liquid. When drawing from a multi-dose vial, use a sterile needle/syringe each time to avoid contaminating the supply. Rotate sites with each injection to prevent abscesses and scar tissue.
Materials (IM)
- Sterile drug solution (prepared as above)
- Sterile syringe with a longer needle — typically 21–23 gauge, 1 to 1.5 inches (enough to reach muscle)
- Alcohol swab
- Sterile cotton / gauze
- Sharps container
Site selection (self-injection)
Best to least convenient for self-injection: vastus lateralis (outer thigh) — easiest and safest, use the middle-outer third; ventrogluteal (hip) — anatomically very safe but awkward to reach yourself; deltoid (upper outer arm) — convenient but small, limit to ~1 mL; dorsogluteal (upper-outer buttock quadrant) — traditional but carries sciatic-nerve risk, so the ventrogluteal site is preferred.
IM technique
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1
Swab the site and let the alcohol dry fully Wet alcohol stings and is less effective.
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Insert straight in at 90° with a quick, controlled motion into the muscle belly
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3
Aspiration isn't routinely needed at standard IM sites If uncertain or near a vessel you may pull back gently — if blood appears, withdraw and restart with a fresh needle and site.
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Inject slowly Reduces pain and the fluid pocket, which may lower abscess risk.
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Withdraw at the same angle; apply gentle pressure with clean cotton or gauze
| Site | Max volume |
|---|---|
| Deltoid | ~1 mL |
| Thigh / gluteal (larger muscles) | ~3 mL |
3. Intravenous (IV) — "mainlining"
IV carries the highest risk of overdose (fastest onset), bloodborne disease, and vascular damage. Good vein care and a sterile single-use set every time are essential.
Materials (IV)
- Sterile drug solution (prepared as above)
- Sterile syringe — surface arm veins typically use a fine needle, ~27–30 gauge, ½ inch or shorter
- Tourniquet / tie at least ~1 inch wide; an elastic tie or stocking is gentler than a belt; tie a slip knot so it releases instantly
- Alcohol swab
- Sterile cotton / gauze and a bandage
- Sharps container
Vein selection (safest first)
Forearm veins are the first choice — accessible, visible, lower risk. The back of the hand is usable but smaller and more fragile. Start with veins farther from the heart (e.g. forearm before the inner elbow): if a vein blows, the ones closer to the heart are still available. Avoid the neck (jugular), groin (femoral), legs, and feet entirely — high risk of serious injury, clots, ulcers, and hitting an artery. Needing those sites is a strong signal to connect with clinical or SSP support.
IV technique
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1
Raise the vein Use gravity (hang/swing the arm), warmth, and make a fist. Apply the tie a few inches above the site — snug enough to engorge the vein but loose enough to still feel a pulse below it. Don't leave it on long; release if the limb goes numb or blue.
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2
Swab the site and let the alcohol dry
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3
Insert bevel (opening) up at a shallow 15–35° angle, pointing toward the heart A shallow angle reduces the chance of going through the far wall of the vein.
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4
Register — pull back gently on the plunger Dark red blood flowing in means you are in a vein.
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Release the tie BEFORE you inject Injecting against a tied-off vein raises pressure and blows the vein.
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Inject slowly Avoids overloading and rupturing the vein.
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Withdraw at the same angle; apply pressure with clean cotton/gauze — do not rub Elevate the limb. Don't use alcohol on a fresh injection wound (it makes it bleed more). Bandage once bleeding stops.
Vein care & complications
Use one new sterile needle per injection — reused needles develop barbs that tear veins and carry infection. Use the smallest gauge that works, rotate sites, and give a vein a couple of days to heal before reusing it. A blown vein (blood leaking into tissue, with swelling and bruising) needs the tie removed, pressure and ice, and rest until it heals. A missed shot (drug left outside the vein) is painful and raises abscess risk — injecting slowly and confirming register reduces it.
✓ Do
- Use one new sterile set every time — water, cooker, filter, needle, tie, swab.
- Keep naloxone on hand and don't use alone.
- Register before injecting and release the tie before you push.
- Rotate sites and seek care early for any infection.
✕ Don't
- Don't share anything — including water and filters.
- Don't use the neck, groin, legs, or feet.
- Don't inject against a tied-off vein, or rub the site afterward.
- Don't ignore an artery hit, a fever, or spreading redness.