AOD-9604

AOD-9604 is a piece cut from human growth hormone and built in the lab; it uses only the final stretch of the hGH chain with one extra amino acid attached, and it was made to trigger fat breakdown while skipping the wider growth-promoting effects that come with the full-length hormone. It went through six human trials in roughly 900 people and came out of them with a solid safety record, yet the largest of those trials found no meaningful weight-loss benefit over placebo, and the program was stopped in 2007.

What it is

AOD-9604 is built from amino acids 177 to 191 of human growth hormone, the very end of the hormone's chain, with an extra tyrosine amino acid attached. Full-length growth hormone affects many tissues and can raise blood sugar and a hormone called IGF-1, effects tied to some of its known risks. AOD-9604 was designed to keep the fragment of hGH linked to fat breakdown while leaving out the rest of the molecule responsible for those broader effects.

It was developed by researchers at Monash University working with an Australian pharmaceutical company. Early studies described it as speeding up lipolysis, the process by which stored fat gets broken down, and slowing how quickly the body builds new fat, all without acting through the same receptor full growth hormone uses [1]. That distinct mechanism is why researchers were interested in it as a possible weight-management compound distinct from hGH itself.

How it is studied

AOD-9604 went through six randomized, placebo-controlled human trials between roughly 2001 and 2006, given by mouth or by injection to obese adults, with the largest studies enrolling several hundred participants over periods from several weeks up to 24 weeks [1]. Researchers tracked body weight, blood glucose, insulin, and IGF-1 levels, along with tests for immune antibodies against the compound, comparing treated groups with placebo groups throughout.

What studies report

Across six human trials in about 900 obese adults, no serious side effects were tied to AOD-9604, no one stopped treatment because of a reaction, and no meaningful changes appeared in blood sugar, insulin, or IGF-1, unlike what is seen with full growth hormone. [1]
In a twelve-week trial, adults taking the compound by mouth lost more weight on average than those taking a placebo, though the difference was modest in absolute terms. [2]
In a larger, 24-week follow-up trial with several hundred participants, weight loss with the compound was not meaningfully different from placebo, and the drug's development program was ended shortly after. [3]

What is not known

Because the larger, longer follow-up trial did not confirm the smaller trial's weight-loss result, it remains unclear whether AOD-9604 has a real, reliable effect on body weight in people, or whether the earlier positive finding was a chance result in a smaller sample. No further human efficacy trials have been conducted since development stopped in 2007, so this question has not been revisited with newer trial designs.

Reported adverse findings

Across the full six-trial human safety record, no serious adverse events were attributed to the compound, though a 2024 US regulatory review flagged unresolved questions about the immune response it can trigger before recommending against including it on a bulk drug substance list. [1]

Regulatory status

The FDA has not approved AOD-9604 for any use, and in December 2024 it recommended against including the compound on the list of substances allowed in compounded preparations, citing immune-response concerns. Australia's therapeutic goods regulator has approved a related formulation, marketed as iTRAM, for injection directly into the knee joint in osteoarthritis, a narrower use than the weight-loss research described here.