Holly Hagan branded Gemma Collins' weight loss journey as "irresponsible".
The Geordie Shore star, 27, insisted the GC's decision to use injections to lose weight sets a bad example to her legion of young fans.
Former TOWIE star Gemma, 39, has credited Skinny Jab injections for losing three stone in recent months.
The controversial injections cost up to £350 for a four week programme.
They work to suppress appetitie, regulate blood sugar levels and help the body to turn fat into energy.
Holly made her feelings known about the controversial jabs on Instagram.
In a candid quarantine question and answer session, one fan queried: "Thoughts on people such as Gemma Collins promotion injections for weight loss?".
The reality star didn't hold back her thoughts when she blasted Gemma's weight loss decision as irresponsible.
"I think it's quite irresponsible," she wrote.
"I've taken something similar years ago and she begged me to post it and give me the product for free.
"I declined and payed full price because even at 23 I knew I couldn't promote a slimming injection! I'll so a full video on my experience of it at some point.
In a tirade, Holly insisted Gemma's followers should be aware of the repercussions after using Skinny Jab injections.
She added: "I just hope Gemma's followers are a little older and would full research these things before jumping into them.
"I've actually tried something similar years ago I still have the full pens here!"
Gemma's representatives have declined the opportunity to comment on the matter.
However, a spokesman for Skinny Jab defended the slimming tool.
A statement read: "Skinnyjab is a prescription drug licenced for weight loss.
"Thousands of women like Gemma have found the Skinnyjab programme the perfect kick start. All our patients enjoy a comprehensive programme of support including diet, exercise and mental well being."
