As people age, the cells that make the human body lose their ability to repair themselves make people vulnerable to disease and other conditions directly linked to aging. These changes, called somatopause in medical jargon, are associated with loss of vitality, muscle mass and physical function, and are often accompanied by belly fat (central adiposity), cardiovascular complications, physical frailty and deterioration of mental function.
The pituitary gland, a pea-sized organ located near the base of the brain, is responsible for encouraging childhood growth and maintaining tissues and organs throughout life. By the time adults reach middle age, however, the pituitary gland slowly reduces the amount of growth hormone it produces.
In the past decade, there has been a notable increase in the use of hormone replacement therapies, including the administration of synthetic human growth hormone or HGH, which was initially developed to help children grow. The term synthetic is used here to denote that the hormone was created from non-human materials, such as yams, soy and even horse urine. That means that the synthetic’s origin is still nature.
The interest for more “natural solutions” has given rise to “bioidentical hormones” — hormones that are identical in molecular structure to the hormones produced in the human body. The differences between HRT and Bio-Identical Hormone Replacement Therapy (BHRT) is shown in the table (left). Keep in mind that this comparison is provided by parties that mix and match drugs, called “compounding” to tailor-make solutions for specific therapies. Compounding labs have gained a lot of currency due to the popularity of BHRT.
In 1958, HGH was extracted for the first time from cadavers. By the early 1980s, genetic engineering enabled mass-production of synthetic HGH, which eliminated the need for cadavers. The HGH hormone increases the height of hormone-deficient children, although they still typically remain shorter than average.
In 1989, National Institutes of Health researchers began to test HGH in children who were not deficient in growth hormone but were simply short. An FDA report found that non-hormone-deficient children gained an average of 2.8 to 5 cm (1 to 2 inches) beyond their predicted height at 19, after 4.4 years of treatment. In another study, a higher dose of six injections per week for an average duration of 5.3 years, resulted in a mean gain in adult height of 7 cm, or about 2.7 inches, according to a report in The Physicians Committee.
In 2003, the FDA approved the use of HGH in non-hormone-deficient short children. The long-term risks of HGH injections in children who already produce adequate growth hormone are not known. Possible risks of such treatment relate both to the multiple injections the children receive and to the drug itself.
The good news is that Pfizer is in phase 3 trials of a new drug, currently called HGH-CTP, which would revolutionize patient treatment by reducing injections to once per week.
While most HGH prescriptions were initially written for children, by 2004 74% went to people ages 20 and older. That year, sales of HGH totaled $622 million for legitimate and non-legitimate uses, according to BusinessWeek. Ten years later, global sales for the two top players alone, Pfizer Genotropin and Novo Nordisk, reached $1.7 billion in 2014. That year, Novo Nordisk generated more than 30% of market revenues ($973 million) followed by Pfizer ($723 million).
Pfizer’s Genotropin was one of the HGH drugs reportedly used by baseball’s Barry Bonds, who morphed from a skinny Pittsburgh Pirates player into a muscular San Francisco Giants slugger, and who, at age 37, hit a record-setting 73 home runs in 2001. While Bonds’ brawny physique was partially gained through intense physical training, BHRT is known to help shed fat and gain lean muscle mass. As with any medical treatment involving humans, some study subjects experience side effects including diabetes and glucose intolerance, which is why some experts hesitate to recommend using HGH to treat aging or age-related conditions.
Dr. Fred Sattler, Professor of Medicine and Biokinesiology at the Keck School of Medicine, University of Southern California, reports that “a limited number of controlled studies suggest that GH [growth hormone] supplementation in older men increases lean mass by ~2 kg (4.4 lb.) with similar reductions in fat mass.”
In 2010, researchers at Garvan Institute of Medical Research in Sydney, Australia found that the use of HGH can provide as much as a 0.4-second improvement in a 10-second sprint, enough to turn a last-place Olympic athlete in either a running or swimming event into a gold medal winner.
Professor Ken Ho, head of pituitary research at Garvan Institute and Chairman of the Department of Endocrinology at St. Vincent’s Hospital in Sydney, conducted the research study in concert with Dr. Udo Meinhardt and Dr. Anne Nelson. Their findings were published in the journal Annals of Internal Medicine. Observes Ho, “Athletes given growth hormone improved their sprint capacity by 4 to 5%.” Another key finding: Sprint capacity nearly doubled in men who received testosterone injections in addition to growth hormones.
Testosterone is an androgenic anabolic steroid — a synthetic substance that produces such anabolic effects as the growth of skeletal muscle, and androgenic effects, like the development of male sexual characteristics in both males and females. Testosterone is a widely used hormone in both age management and sports and comes in a variety of form factors, including injectable fluids, gels, patches, creams, oral pills or pellets and powders.
Testosterone replacement is often used by geriatric male patients suffering from hypogonadism — defined as the diminished functional activity of the gonads, the testes in males or ovaries in females, that may result in diminished sex hormone biosynthesis. Like HGH, testosterone treatment can have undesirable side effects, including acne or oily skin, fluid retention, increased risk of prostate cancer and breast enlargement.
U.S. sales of testosterone drugs reached $2.4 billion in 2013, and are forecast to reach $3.8 billion by 2018, driven by the availability of new gel-based formulations and the aggressive direct-marketing techniques used by pharmaceutical companies.
But it’s menopausal women that are at the forefront of the hormone replacement trend. The loss of female hormones in aging women lead to the first estrogen drug in 1942 when Ayerst launched Premarin, an estrogen synthesized from the urine of pregnant mares, explaining its creative branding, according to “A Woman’s Complete Guide to Natural Health,” authored by Lynne Paige Walker and Ellen Hodgson Brown.
Hormone Replacement Therapy (HRT) began catching on in the mid-1970s when a mixture of estrogen and progesterone became the preferred treatment. The interest in a more natural approach to hormone therapy led to the creation of bioidentical hormones — hormones that are identical in molecular structure to those made in women’s bodies. Bioidentical estrogens are 17 beta-estradiol, estrone, and estriol.
A growing female population ages 45 to 59, plus a median menopausal window of 7.4 years is propelling growth. According to the American Congress of Obstetricians and Gynecologists, an estimated 6,000 U.S. women reach menopause every day, or more than 2 million each year in the U.S. alone, according to a 2012 report, “Overview of Menopause,” by the North American Menopause Society. And their ranks are growing. In 1998, about 477 million women worldwide were post-menopausal, a figure that will more than double to 1.1 billion by 2025.
In a product segment that includes human growth hormone, estrogen, testosterone and thyroid hormones, estrogen-based products, including both combination drug therapies and single doses of estrogen or progestin, contributed more than half of the revenue in 2014 while generating the largest number of doctor prescriptions, according to Grand View Research. Estrogen drugs such as Premarin, Menest and Combipatch lead the category. Pfizer reports that Premarin was its seventh best-selling drug, generating sales of $1 billion in 2015.
Still, some believe human growth hormone therapy will be the fastest growing segment due to the growing number of premature births globally. That, plus the market launch of such innovations as Pfizer’s HGH-CTP, which requires only a weekly injection in children, will further stimulate growth.