At a glance

What is somatropin?

Somatropin is recombinant human growth hormone, made by inserting the human growth hormone gene into cells so they produce a protein identical to the body's own 191-amino-acid hormone. It is sold under brand names including Genotropin, Norditropin, Omnitrope, and Zomacton. Nutropin was discontinued¹ in the U.S. at the end of 2024, and Humatrope is being withdrawn² at the end of 2026. (Some newer long-acting products, such as lonapegsomatropin and somatrogon, are distinct engineered molecules rather than plain somatropin.)

The history of somatropin

Growth hormone therapy has a sobering history that shaped modern practice. Before recombinant technology, growth hormone could only be extracted from the pituitary glands of human cadavers, and supply was scarce. In 1985 that program was halted after cadaver-derived growth hormone was linked to cases of Creutzfeldt-Jakob disease, a fatal neurodegenerative illness transmitted through contaminated pituitary material. Recombinant human growth hormone, first approved shortly afterward, removed that risk by producing the hormone in the laboratory, and it has been the standard ever since.

How does somatropin work?

Somatropin binds growth hormone receptors on cells throughout the body and stimulates the liver and peripheral tissues to produce insulin-like growth factor 1 (IGF-1). IGF-1 and growth hormone together drive linear bone growth at the growth plates in children, promote protein building, encourage the breakdown of fat, and influence carbohydrate metabolism. Because it is identical to the natural hormone, it reproduces the full range of growth hormone's effects.

In children who do not make enough growth hormone, or who have conditions such as Turner or Prader-Willi syndrome, replacement increases growth velocity and adult height; in adults with deficiency, it improves body composition and metabolic measures. The hormone is cleared quickly, which is why standard somatropin is injected daily, and dosing is adjusted to growth response and IGF-1 levels.

Is it FDA-approved?

Yes. Recombinant human growth hormone products have been FDA-approved³ since the late 1980s, beginning with Humatrope in 1987, and many brands have followed. The approved indications vary by product but are extensive, covering pediatric and adult growth hormone deficiency and several specific syndromes.

What is somatropin prescribed for?

Somatropin is prescribed for growth hormone deficiency in children and adults, and for short stature associated with:

• Turner syndrome
• Prader-Willi syndrome
• Chronic kidney disease
• Noonan syndrome
• SHOX deficiency
• Being born small for gestational age
• Idiopathic short stature

Some products are also approved for HIV-associated wasting.

What are the side effects?

Common side effects vary by product and include:

• Injection-site reactions
• Joint and muscle aches
• Swelling from fluid retention
• Headache

More serious considerations include:

• Reduced insulin sensitivity and higher blood sugar
• A specific caution against use in people who are acutely critically ill, where growth hormone increased mortality in studies
• In Prader-Willi syndrome with severe obesity or breathing problems, reports of sudden death, so breathing is assessed before and during treatment
• Increased pressure around the brain, slipped hip growth plate, and worsening scoliosis in children
• Growth of existing tumors, pancreatitis, and serious allergic reactions

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