Growth hormone is taken as a daily subcutaneous injection, meaning the needle goes just under the skin rather than into muscle. Most people inject in the evening, rotate their injection site each day, and store the medication in the refrigerator. The process is straightforward once you learn it, but the details around timing, mixing, and site rotation matter for both effectiveness and comfort.
How Growth Hormone Is Injected
Growth hormone is always given as a subcutaneous (under-the-skin) injection. You cannot take it as a pill because your digestive system would break down the protein before it reached your bloodstream. The injection itself is shallow, using a short, thin needle angled into a pinch of skin and fat.
The recommended injection sites include the abdomen, buttocks, outer thighs, hips, and the back of the upper arms. The thighs and upper arms carry a slightly higher risk of accidentally injecting into muscle rather than fat, so many people prefer the abdomen or buttocks. Never inject through clothing, and always use a clean injection site.
The single most important habit is rotating your injection site every day. Injecting repeatedly into the same spot causes tissue to break down over time, a condition called lipoatrophy. You can rotate within one general area (moving around different spots on the same thigh, for example) or alternate between different body regions entirely. Some people find a simple rotation grid or pattern helpful for keeping track.
Pen Devices vs. Vial and Syringe
Growth hormone comes in two main forms: pre-filled pen devices and traditional vials that require mixing and drawing up with a syringe. Pen devices are what most people use today. They’re easier to dose accurately, faster to prepare, more portable, and generally less painful because pen needles tend to be thinner and sharper than syringe needles (which must first puncture a rubber vial stopper, dulling the tip slightly). People using pens also tend to miss fewer doses, likely because the process involves fewer steps.
Vial-and-syringe setups are still used, particularly when cost is a factor. They require more manual dexterity: you draw up the correct volume from a vial, check for air bubbles, and inject. If you have vision difficulties or limited hand strength, a pen device is usually the better option.
Mixing (Reconstitution) for Powdered Forms
Some growth hormone products come as a freeze-dried powder that needs to be mixed with a liquid diluent before injection. This step requires care because growth hormone is a fragile protein.
The diluent is typically bacteriostatic water (water preserved with a small amount of benzyl alcohol), which allows the mixed solution to last for multiple doses. If bacteriostatic water can’t be used, such as for newborns or people sensitive to benzyl alcohol, plain sterile water works, but then you must use the entire vial in one dose and discard the rest.
When mixing, slowly inject the water against the glass wall of the vial, not directly onto the powder. Then gently swirl the vial in a circular motion until the powder fully dissolves. Never shake it. Shaking can damage the protein and create a cloudy solution. If you still see lumps or particles, keep swirling gently until everything dissolves. The final solution should be clear.
When to Inject
The standard recommendation is to inject growth hormone in the evening, typically between 8:00 and 9:00 PM. This timing mimics your body’s natural pattern: under normal conditions, the largest burst of growth hormone secretion happens shortly after you fall into deep sleep in the first part of the night. An evening injection produces peak hormone levels about four to six hours later, roughly aligning with that natural midnight-to-2:00 AM surge.
That said, morning and evening injections produce comparable effects on growth and on levels of IGF-1 (the downstream hormone your body makes in response to growth hormone). There is some debate about whether evening injections might slightly disrupt sleep quality. Injected growth hormone stays in the bloodstream for 10 to 16 hours and during that window it suppresses your brain’s own growth-hormone-releasing signals, which play a role in deep sleep. Morning injections, by contrast, would clear before bedtime and allow your natural sleep-related hormone pulses to occur. In practice, most clinicians still recommend evening dosing, but if you notice sleep issues, it’s worth discussing timing with your prescriber.
Consistency matters more than the exact hour. Pick a time you can stick with daily.
Starting Dose and Adjustments
Adults typically start on a low dose, around 0.2 to 0.4 mg per day. Starting low significantly reduces the chance of side effects. From there, the dose is adjusted upward gradually, usually every six to eight weeks, based on how you feel, whether side effects develop, and your blood test results.
The key blood marker is IGF-1. Your prescriber will check this level periodically and aim to keep it within a normal age-adjusted range, generally in the upper half. Women and younger adults often need higher doses than older men to reach the same IGF-1 target. This individualized titration approach replaced the older method of dosing strictly by body weight, which caused more side effects.
Common Side Effects
The most frequent side effects come from fluid retention. You might notice swollen hands or ankles, joint stiffness or aching, muscle soreness, tingling or numbness in the hands (sometimes progressing to carpal tunnel syndrome symptoms), or mildly worsened blood sugar control. These effects are dose-dependent, meaning they’re more likely at higher doses and were much more common in the early days of growth hormone therapy when doses were higher across the board.
The good news is that these side effects typically resolve quickly with a dose reduction. If you develop joint pain or noticeable swelling in the first weeks of treatment, your prescriber will likely lower the dose and then increase it more slowly. Most people find a dose that works without significant side effects.
Storage and Handling
All growth hormone products should be stored in the refrigerator at 36 to 46°F (2 to 8°C), both before and after mixing. Once reconstituted, most products last 14 to 28 days in the refrigerator. If you mix a preservative-free vial with plain sterile water, use it within 24 hours.
Some pre-filled pen devices have more flexible storage. Certain formulations can be kept at room temperature (up to 77°F / 25°C) for as long as three weeks, which is useful for travel. Some single-dose devices can be stored unrefrigerated for up to three months before mixing. Always check the specific instructions for your product, since storage rules vary between brands. Never freeze growth hormone, and discard any solution that looks cloudy or contains particles after gentle swirling.
What Ongoing Monitoring Looks Like
Growth hormone therapy isn’t a set-it-and-forget-it treatment. In the first few months, you’ll have blood drawn every six to eight weeks so your prescriber can check IGF-1 levels and adjust your dose. Once your dose stabilizes, monitoring visits typically become less frequent, often every six to twelve months.
Beyond IGF-1, your prescriber will keep an eye on blood sugar, cholesterol, and general metabolic markers, since growth hormone influences all of these. The goal is to find the dose that improves your symptoms and quality of life while keeping IGF-1 in a safe range and avoiding side effects. Pushing IGF-1 to the very top of the normal range can improve certain markers like waist circumference and well-being scores, but it may also raise concerns around cholesterol changes and muscle pain, so the target is always a balance.