Science doesn't back Lovett-Murray: expert

Medical experts say it's unlikely the use of growth hormone peptides can impact the health of a user's offspring, but can't rule in out.

Former Essendon AFL player Nathan Lovett-Murray believes injections he received during the club's infamous supplement program have harmed the health of his three-year-old daughter.

His daughter Harmony has a mysterious growth on her chest and behavioural issues.

Lovett-Murray, one of 34 past and present players banned for their involvement in the program, is now suing his former club over those health fears.

"There's no doubt in my mind that the injection program we were put through has had some impact on my daughter," Lovett-Murray told News Corp Australia on Friday.

However, experts have raised doubt.

While the supplements used in the Essendon scandal are not known, a number of growth hormone releasing peptides, including Thymosin, have been implicated.

Sydney University exercise and sports scientist Rhonda Orr says there's no conclusive evidence peptides can harm the health of a users' offspring.

"It could have an affect on offspring," Dr Orr told AAP.

"From what we know it's more unlikely, but definitely can't say no."

Another leading endocrinologist, who wanted to remain anonymous, said it was an "extremely long bow" to draw.

The professor of medicine told AAP issues related to sperm can affect offspring but they are very few and usually occur later in life.

He also noted that most defects in babies occur during pregnancy.

Dr Orr, who has an interest in anti-doping issues, says peptides increase the amount of amino acids - the building blocks of protein - in the body to induce growth.

They also help with the delivery of fat and glucose to cells.

Thymosin is "still under investigation" but it can be used to regenerate tissue.