Progesterone in oil (PIO) shots hurt primarily because the oil is thick, the needle is large, and you’re doing it every single day for weeks. The good news: nearly every part of the process can be optimized to reduce pain significantly. From warming the oil to choosing the right needle to what you do in the 10 minutes after injection, small changes add up fast.
Warm the Oil Before Injecting
PIO is suspended in a carrier oil (usually sesame oil or olive oil) that is viscous at room temperature. Thick oil pushes through the needle slowly, which means more time with the needle in your muscle and more pressure at the injection site. Warming the vial thins the oil and makes it flow faster, reducing both injection time and discomfort.
The simplest method: tuck the filled syringe between your hands and roll it for a few minutes, or hold it against your body while you prep the site. Some people place the vial in a warm (not hot) cup of water for five minutes or use a heating pad. You want it comfortably warm to the touch, not hot enough to degrade the hormone. If the oil flows easily when you push the plunger slightly, it’s ready.
Use the Right Needles
Most clinics prescribe two separate needles: a thicker one (18-gauge) for drawing the oil into the syringe, and a thinner one (22-gauge, 1.5 inches) for the actual injection. If your clinic only gave you one needle size, ask about switching to this two-needle system. Drawing through a thick needle and then swapping to a thinner one for injection makes a noticeable difference in how much the stick hurts. The draw needle also dulls slightly from puncturing the vial stopper, so injecting with a fresh, sharp needle matters.
For body weight under 130 pounds, a 1-inch needle may be sufficient for intramuscular delivery. Between 130 and 200 pounds, 1 to 1.5 inches is standard. Over 200 pounds, 1.5 inches is typically needed. Your clinic can confirm the right length for your body. Using a needle that’s too short means the oil deposits into fat instead of muscle, which causes more lumps and slower absorption.
Nail the Injection Site
The ventrogluteal site (the side of your hip, not the back of your buttock) is generally considered safer and less painful than the traditional dorsogluteal site on the upper-outer quadrant of the buttock. The dorsogluteal area carries a risk of hitting the sciatic nerve, which can cause sharp, shooting pain down the leg. The ventrogluteal site has a thicker muscle layer, fewer major nerves, and less subcutaneous fat, so the medication absorbs more reliably.
To find the ventrogluteal site: place the heel of your hand on the bony prominence at the top of the outer thigh (the greater trochanter), point your index finger toward the front of the hip bone and spread your middle finger toward the back, forming a V. The injection goes into the center of that V. If you’re not sure, ask your clinic to mark the spot with a pen or walk you through it at your next appointment. Alternate sides each day to give tissue time to recover.
Apply a Topical Numbing Cream
Over-the-counter numbing creams containing lidocaine and prilocaine can take the sting out of the needle itself. The key detail most people miss is timing: these creams need at least 60 minutes under an occlusive dressing (a piece of plastic wrap or a transparent adhesive bandage) to reach full effectiveness. Peak numbness occurs at two to three hours and lasts one to two hours after you remove the cream. Apply about half a tube’s worth over a small area roughly the size of a credit card.
This won’t eliminate the deeper muscle ache from the oil itself, but it removes the surface pain of the needle piercing skin, which is often the part that causes the most anxiety.
Slow Down and Relax the Muscle
Injecting into a tense muscle hurts more and creates more soreness afterward. Before the needle goes in, take a few deep breaths. If you’re standing, shift your weight entirely onto the opposite leg so the injection-side glute is relaxed. Some people prefer lying on their stomach on a bed with toes pointed inward, which naturally relaxes the glute muscles.
Once the needle is in, inject slowly and steadily. Rushing the plunger creates a sudden pocket of oil in the muscle that causes more pressure and pain. A slow, consistent push over 10 to 15 seconds lets the tissue absorb the oil more gradually. After injecting, wait about 10 seconds before pulling the needle out to let the oil settle and reduce leakage.
Consider an Autoinjector
If the mental hurdle of pushing a large needle into your own body is a major source of distress, an autoinjector device can help. These spring-loaded tools insert the needle quickly and at a consistent depth, which tends to hurt less than a slow, hesitant manual insertion. People who use them consistently describe the shots as nearly painless, largely because the speed of insertion reduces the time the needle spends passing through the skin’s pain receptors. They’re also helpful if a partner is giving the shots and feels nervous about the process. Several brands are available online without a prescription.
What to Do Right After the Shot
Post-injection care is just as important as technique. Immediately after pulling the needle out, press a gauze pad firmly on the site for 10 to 15 seconds. Then apply a heating pad or warm compress for five to ten minutes. Heat increases blood flow to the area, which helps the muscle absorb the oil and prevents it from pooling into a painful lump.
Movement matters too. Doing 20 to 25 bodyweight squats, walking up and down stairs, or even just walking around for a few minutes right after the injection activates the large glute muscles and disperses the oil through the tissue. People who combine heat and movement consistently report fewer knots and less next-day soreness than those who sit or lie still. A massage gun on the area (not directly on the puncture site, but around it) for about a minute can also help break up the oil deposit.
Ask About a Different Carrier Oil
Standard PIO uses sesame oil or olive oil as a carrier, but some compounding pharmacies offer progesterone in ethyl oleate, a synthetic carrier that is significantly thinner. The lower viscosity means it draws up faster, requires less force on the plunger, and can sometimes be injected with a smaller gauge needle. People who have switched from sesame oil to ethyl oleate frequently report less soreness, fewer lumps, and no need to warm the oil before injecting.
There’s a catch: some people react to ethyl oleate with itching or irritation, just as others react to sesame oil. If you’re developing welts, persistent itching, or spreading redness at your injection sites, it may be worth asking your clinic whether switching carriers could help. An allergy to the oil itself can mimic the normal discomfort of PIO shots but is actually a separate, treatable problem.
When Lumps and Pain Aren’t Normal
Some soreness and small lumps at the injection site are expected with daily PIO. But if the pain worsens at night, feels like a sharp tingling rather than a dull ache, or if swelling spreads beyond the injection area into your lower back, inner thigh, or groin, that’s a sign of a deeper tissue reaction called panniculitis, where the fat layer beneath the skin becomes inflamed. This condition responds to physical therapy (typically ultrasound therapy or warm compresses guided by a provider) and does not require antibiotics unless there are signs of actual infection like fever, spreading redness, or warmth with pus.
A hard lump that doesn’t resolve within a few days, or one that grows rather than shrinks, is worth mentioning to your clinic. Most of the time it’s a sterile knot of oil that the body eventually absorbs, but your provider may want to adjust your injection site rotation or technique.