The only way of getting Human Growth Hormone (HGH) till the mid 1980s was by extracting the pituitary glands from the cadavers that came mostly from Africa. But later in 1980s it was discovered that the human growth hormone extracted from the cadavers was the reason for causing Creutzfeld-Jacob disease (CJD) which was a rare condition that occurred mostly in the children that had been administered with the cadaver extracted HGH. Thus this form of HGH was pulled off from the market. In 1985, the exact copy of the DNA of the human growth hormone was produced synthetically by the Eli Lily pharmaceutical company in their lab. This leads to the production of the recombinant human growth hormone. But it is a very difficult process to exactly copy the 3D structure of the HGH having 191 amino acids.
But due to advancement in the medicine field, the rHGH is being produced artificially for use as a drug to treat people having a deficiency of the human growth hormone and several other artificial HGH supplements are present as health and fitness supplements. Only the injection form of the HGH is legal and tested but there is a big question on the safety and effectiveness of the other supplements.