Common questions
What is HGH 191AA?
HGH 191AA is recombinant human growth hormone (somatropin) with the same 191-amino-acid sequence as the dominant natural human growth hormone produced by the pituitary. It binds the growth hormone receptor and drives GH/IGF-1 axis signaling that influences growth and metabolism.
Is HGH 191AA the same as somatropin?
HGH 191AA is the same molecule as somatropin when the label is accurate. '191AA' describes the amino-acid length of the somatropin sequence used in modern clinical recombinant GH products. It is commonly emphasized to distinguish it from older 192-amino-acid 'somatrem' forms that included an extra methionine.
Is HGH 191AA legal in the United States?
HGH 191AA (somatropin) is legal in the U.S. when used and distributed under the rules for authorized medical treatment. Federal law (21 U.S.C. § 333(e)) restricts distribution for human uses other than treatment of disease or recognized medical conditions authorized under the FDCA and pursuant to a physician's order.
Does HGH 191AA help with fat loss or 'anti-aging' in healthy people?
HGH 191AA can change body composition in studies, but anti-aging claims are not supported strongly enough to recommend use in healthy people. A major meta-analysis in healthy older adults found lean mass increased and fat mass decreased, but adverse events increased, and the authors concluded GH should not be recommended as anti-aging therapy.
What's the difference between HGH 191AA and HGH fragment 176–191?
HGH 191AA is the full hormone; HGH fragment 176–191 is a short fragment derived from the full sequence. They are not interchangeable. Full-length GH acts through the GH receptor with broad endocrine effects, while fragments are discussed as narrower tools. WADA explicitly lists growth hormone fragments (including hGH 176–191) as prohibited.
How do IU and mg relate for HGH 191AA?
For somatropin, a common clinical reference is 3 IU per 1 mg, meaning 10 IU is about 3.33 mg. Separately, 'units' on an insulin syringe are volume marks (U-100 is 100 units per 1 mL) and are not International Units. IU is potency; syringe units are mL.
What does '191AA' actually mean?
'191AA' literally means 191 amino acids. Vendors highlight it to communicate that the product is full-length somatropin, distinguishing it from older recombinant forms. However, 191AA describes identity—not quality—and the label alone does not guarantee correct content, potency, sterility, or safe handling.
Is HGH 191AA prohibited in sport?
Yes. The World Anti-Doping Agency lists growth hormone, its analogues, fragments, and many growth hormone releasing factors/secretagogues as prohibited. This includes GH itself and also common GH-axis peptides marketed online such as sermorelin, tesamorelin, CJC-1295, ipamorelin, and ibutamoren/MK-677.