What Is Recombinant Human Growth Hormone?

Human Growth Hormone (HGH) is a protein produced by the pituitary gland that stimulates growth, cell reproduction, and regeneration. It also aids the metabolism of proteins, carbohydrates, and lipids. Recombinant Human Growth Hormone (rhGH) is a synthetic version of HGH created through laboratory methods. It is used for medical treatment when the body does not produce enough of its own or when certain medical conditions cause growth problems.

The Science: How Recombinant HGH is Made

The creation of rhGH uses recombinant DNA technology. The process begins with isolating the human gene that instructs cells to produce HGH. Scientists insert this gene into the genetic material of a host organism, such as the bacterium Escherichia coli (E. coli), yeast, or Chinese Hamster Ovary (CHO) cells.

Once the HGH gene is integrated into the host’s DNA, the cells are cultured in a controlled environment. During this fermentation process, the host cells follow the instructions from the inserted human gene and produce large quantities of HGH.

The HGH produced by these host cells is structurally identical to the hormone made by the human pituitary gland. After production, the hormone is harvested from the host cells. A multi-step purification process then separates the rhGH from other cellular components, resulting in a pure therapeutic product.

Medical Uses of Recombinant HGH

Medical professionals prescribe rhGH for approved conditions in children and adults. For children, rhGH is used to treat short stature caused by several conditions, including:

• Growth Hormone Deficiency (GHD)
• Turner syndrome
• Prader-Willi syndrome
• Being born small for gestational age (SGA) without catch-up growth
• Idiopathic short stature (ISS), which is short stature without a known cause

For adults, rhGH therapy is approved to treat GHD that either begins in adulthood or persists from childhood. The therapy can help address reduced muscle mass, increased fat mass, and decreased bone density. Another approved use in adults is for muscle wasting syndrome associated with HIV/AIDS, where rhGH helps maintain muscle mass.

The U.S. Food and Drug Administration (FDA) has approved several rhGH products, though not all are approved for every indication.

Administering rhGH and Medical Follow-Up

The standard method for administering rhGH is through subcutaneous injection into the fatty tissue just under the skin. It is usually injected daily, though some long-acting formulations allow for weekly injections. Healthcare professionals train patients or their caregivers on proper injection techniques, including dose preparation and rotating injection sites.

Regular medical supervision is required during rhGH therapy. Physicians monitor the patient’s response through periodic check-ups. For children, this involves tracking growth to ensure the therapy is effective.

Blood tests are a routine part of monitoring. These tests assess levels of hormones like insulin-like growth factor 1 (IGF-1), a marker for GH activity, to ensure the dosage is appropriate. Blood glucose levels are also monitored, as GH can affect insulin sensitivity, allowing for adjustments to the treatment plan.

Recognizing Potential Side Effects

While rhGH therapy is safe when used as prescribed, it can have side effects. Common effects include:

• Reactions at the injection site, such as pain or a rash
• Joint or muscle pain
• Fluid retention leading to swelling (edema)
• Headaches
• Carpal tunnel syndrome

Less common but more serious side effects require immediate medical attention. These can include glucose intolerance or an increased risk of type 2 diabetes. Other risks are increased pressure inside the skull (intracranial hypertension), a hip condition in children known as slipped capital femoral epiphysis, and the progression of scoliosis.

The therapy is contraindicated, meaning it should not be used, in individuals with active cancer, as GH can stimulate cell growth. A physician’s careful monitoring helps manage and mitigate these risks.

Prescription Status and Unapproved Uses

Recombinant Human Growth Hormone is a controlled substance only legally available with a prescription from a licensed physician. Its distribution and use are regulated due to the potential for adverse effects and misuse.

Despite these regulations, rhGH is sometimes used for unapproved, or “off-label,” purposes like anti-aging, athletic performance enhancement, or bodybuilding. Scientific evidence does not support the safety and effectiveness of rhGH for these uses. The use of rhGH for performance enhancement is banned by most major sports organizations.

Illicit use carries significant health risks, as products obtained without medical supervision may have unknown dosage and purity. Physicians who prescribe rhGH for non-approved indications can face legal and professional consequences. The high cost of legitimate therapy also fuels a black market, increasing risks for users.