A hormone shot is an injection that delivers a specific hormone directly into your body, either to replace a hormone you’re not making enough of, to trigger a biological process like ovulation, or to prevent pregnancy. Hormone shots cover a wide range of medical uses, from fertility treatments and birth control to testosterone replacement, menopause symptom relief, and growth hormone therapy. The type of hormone, the injection site, and how often you need a shot all depend on what condition is being treated.
How Hormone Shots Work
Most hormone shots are injected either into a muscle (intramuscular) or just beneath the skin (subcutaneous). When injected, the hormone forms a small depot at the injection site that slowly releases into your bloodstream over days or weeks. This slow-release effect is what allows many hormone shots to be given on a weekly or even monthly schedule rather than daily.
Common injection sites include the upper arm, thigh, abdomen, and buttocks. Subcutaneous shots use a shorter needle and go into the fatty tissue just under the skin, while intramuscular shots use a longer needle to reach the muscle beneath. Both routes are effective, and the choice often comes down to the specific hormone being used and patient comfort.
Birth Control Shots
The most widely known contraceptive shot is a progestin-only injection given once every three months (13 weeks). It works by preventing ovulation and thickening cervical mucus so sperm can’t reach an egg. With typical use, about 6 out of 100 people will become pregnant in the first year. That rate drops significantly for those who stay on schedule with every shot.
The main appeal is convenience. You don’t have to remember a daily pill or deal with a device. The tradeoff is that you need to return for your shot on time, and it can take several months for fertility to return after stopping.
Testosterone Shots
Testosterone injections are prescribed for men with clinically low testosterone levels, a condition that causes fatigue, reduced muscle mass, low sex drive, and mood changes. A typical starting dose is 75 mg injected subcutaneously once a week, with adjustments based on blood work.
Testosterone shots are also a core part of gender-affirming hormone therapy for transgender men and some nonbinary individuals. The same types of testosterone are used, and providers monitor blood levels mid-cycle to make sure concentrations stay in the target range. One longer-acting form requires less frequent injections and is monitored slightly differently, with blood drawn just before the next dose rather than mid-cycle.
Estrogen Shots
Injectable estrogen is used in two main contexts: menopause symptom relief and gender-affirming care for transgender women. The two most commonly prescribed forms are estradiol valerate and estradiol cypionate, both given as intramuscular or subcutaneous injections every one to two weeks.
For menopausal women, estrogen shots help reduce hot flashes, night sweats, vaginal dryness, and bone loss. However, oral estrogen combined with a synthetic progestin carries a higher risk of blood clots, stroke, and heart disease, particularly in older postmenopausal women. Transdermal and injectable forms appear to carry lower clot and stroke risk than oral formulations. Estrogen-only therapy (for women who have had a hysterectomy) has a more favorable safety profile than combined estrogen-plus-progestin therapy.
Fertility Hormone Shots
Fertility treatments often rely on injectable hormones to stimulate the ovaries to produce multiple eggs. The key hormones involved are FSH (follicle-stimulating hormone), which drives egg development, and hCG (human chorionic gonadotropin), which triggers the final maturation and release of eggs.
These hormones work in sequence. FSH is given first to encourage several follicles to grow. Once the follicles are mature, an hCG injection triggers ovulation. Notably, hCG alone can’t promote egg development without FSH doing its job first. This combination approach, called controlled ovarian stimulation, significantly increases pregnancy rates during IVF cycles compared to natural ovulation alone.
Fertility shots are typically self-administered subcutaneously in the abdomen over a period of 8 to 14 days, with frequent ultrasound monitoring to track follicle growth.
Growth Hormone Shots
Adults who don’t produce enough growth hormone develop a recognizable pattern: increased belly fat, decreased muscle mass, reduced exercise capacity, unfavorable cholesterol changes, lower bone density, and diminished quality of life. This can happen after pituitary surgery, head trauma, or as a result of structural damage to the pituitary gland.
Diagnosing growth hormone deficiency in adults isn’t straightforward because there’s no single obvious symptom. Blood levels of a marker called IGF-I can help, but they’re often normal even in deficient adults, so a stimulation test is usually needed. When three or more pituitary hormones are already deficient and IGF-I levels are very low, the diagnosis can be made with about 95% accuracy without further testing.
Growth hormone replacement is given as a daily subcutaneous injection. When dosed properly, it reverses many of the changes caused by deficiency: body composition improves, exercise capacity increases, cholesterol profiles get better, and quality of life scores go up. Side effects are uncommon at appropriate doses.
Emergency Hormone Injections
Some hormone shots are lifesaving rather than routine. People with adrenal insufficiency, where the adrenal glands don’t produce enough cortisol, are at risk of adrenal crisis, a sudden, dangerous drop in cortisol triggered by illness, injury, or stress. This requires an immediate injection of hydrocortisone, 100 mg given into a muscle or vein, followed by IV fluids.
People with known adrenal insufficiency are advised to carry an injectable hydrocortisone kit with a needle and syringe at all times. Family members and close contacts are often trained to give the injection in an emergency. Once the crisis is stabilized, hydrocortisone continues at high doses until the person is stable enough to switch back to oral medication.
What Getting a Hormone Shot Feels Like
Subcutaneous hormone shots use a thin, short needle and feel similar to an insulin injection: a quick pinch in the belly or thigh that’s over in seconds. Many people learn to self-administer these at home. Intramuscular shots use a longer needle and go into the thigh or buttock. They can cause a brief, deeper ache and occasionally mild soreness at the injection site for a day or two.
Some injectable hormones are oil-based, which makes them thicker and slightly slower to inject. Warming the vial in your hands for a few minutes beforehand can make the injection smoother and more comfortable. Rotating injection sites helps prevent lumps or irritation from building up in one area.
Common Side Effects
Side effects vary depending on which hormone is being injected, but some patterns are consistent. Injection site reactions like redness, swelling, or soreness are the most common across all types. Beyond that, each hormone carries its own profile.
- Testosterone: acne, increased red blood cell count, mood changes, and fluid retention.
- Estrogen: breast tenderness, headaches, nausea, and an increased risk of blood clots, especially with oral forms or when combined with synthetic progestins.
- Progestin (birth control shot): irregular bleeding, weight gain, mood changes, and a temporary delay in return of fertility.
- Growth hormone: joint pain, fluid retention, and carpal tunnel-like symptoms, typically at higher doses.
- Fertility hormones: bloating, mood swings, and in rare cases, ovarian hyperstimulation syndrome.
For estrogen-based therapies specifically, the risk of blood clots is a key safety concern. Combined estrogen-plus-progestin therapy roughly doubles the risk of pulmonary embolism compared to no treatment. Estrogen-only therapy carries a smaller increase. Transdermal and injectable routes of estrogen appear to carry lower clot risk than pills taken by mouth, likely because they bypass the liver’s first-pass processing of the hormone.