Rich Fogarty has tried peptides, but says they didn't do much for him.
"I jumped on the peptides - the 157s - for a little bit," said Mr Fogarty, owner of Bro Fit Newcastle.
"That was more for muscle recovery. I'm 52 and my body has been battered from holding boxing pads for the last 35 years."
He said the peptides "didn't make any significant changes to me".
Peptides - which are short chains of amino acids - occur naturally in the body.
Synthetic peptides are being promoted through social media as shortcuts to muscle growth, anti-ageing, recovery and fat loss.
But there is limited scientific evidence behind the claims and concerns about side effects.
Mr Fogarty, who spoke to the Newcastle Herald to mark Men's Health Week, recommended ice baths, saunas and remedial massage for recovery from intense exercise.
He said men trying peptides were often "searching for other things to enhance their life".
"The best advice is go to a doctor or physician to put your mind at ease, rather than taking guesses," he said.
"A lot go to social media, but it's a forum of fakeness with AI.
"If you're going to be serious about your health, get a blood test to see where you're at."
Healthy Male chief executive Simon von Saldern said peptides were linked to the "looksmaxxing" trend.
"There will be young blokes in Newcastle going to the gym who are being told, you'll get bigger quicker if you take this and that," Mr von Saldern said.
"Guys are worried about their looks. They want the six-pack, square jaw and defined arms.
"It's a psychological thing. At the extreme end it's a type of body dysmorphia."
He prepared a briefing paper for the government on peptides and has discussed the issue with federal men's health special envoy Dan Repacholi.
Mr Repacholi, the Hunter MP, said Men's Health Week was about "having honest conversations with men about the choices we're making".
He was concerned about the "growing availability of peptides and other performance-enhancing substances".
"I've heard too many stories about peptides being passed around like they're no different to a protein shake," Mr Repacholi said.
"If you're buying peptides online or from a random at the gym, you've got no idea what's actually in that vial, where it came from or what it's doing to your body.
"That's a pretty big gamble to take with your health."
Mr Repacholi said there "simply isn't strong evidence that peptides improve sporting performance".
"But there is evidence they can cause serious health problems including heart disease, high blood pressure, diabetes and other long-term complications," he said.
Mr von Saldern said peptides were often promoted as "making you big and improving your recovery".
"None of them have been tested for human use," he said.
"They're unregulated and fall into this category called research drugs.
"They can be prescribed, but most men pick them up through the gym and mates. They buy them online."
Last week, the Therapeutic Goods Administration (TGA) expanded its focus to include unapproved peptide products.
This followed increased detection of "unlawful importation, supply and advertising of peptides".
A TGA statement said this posed "potential risks to consumer safety".
Mr Repacholi said there was "no shortcut to good health".
"No injection is going to replace hard work, good habits, decent sleep and proper nutrition," he said.
Mr von Saldern urged men to find a GP with whom they could build a rapport.
"Find someone you trust that knows your baselines," he said.
