Bootleg Peptides Linked to Severe Allergic Reactions in Fitness Users

People using gray market peptides marketed for muscle building, fat loss and recovery have reported severe allergic reactions, according to a Forbes report that examined several cases.

Peptide products marketed through gray market channels can carry safety risks when their contents, purity and manufacturing conditions have not been independently verified.

One user, Sarah Keese, said she experienced a severe allergic reaction after injecting the peptide sermorelin and required emergency treatment.

She told Forbes that she believed the reaction could have been fatal without medical attention.

Sermorelin and related compounds known as growth-hormone secretagogues are promoted in some fitness communities for their purported effects on muscle development, fat loss and recovery.

However, products obtained through gray-market channels may not have the same quality controls, manufacturing oversight or verified ingredients as approved medicines.

Forbes interviewed five people who reported severe allergic reactions after using secretagogues.

However, the report also noted an important limitation: without laboratory testing of the substances used by those individuals, it is impossible to determine whether the reactions were caused by the peptide itself, another ingredient or contamination.

That distinction is important when reporting adverse reactions involving gray-market products.

A reported reaction establishes that the person experienced an adverse event after using a product, but it does not by itself establish that the named peptide was the cause.