What did @jennas_kitchen actually say?
She injected GHK-Cu subcutaneously into her stomach based on a friend's recommendation, then spent the night in what she described as "burning fire pain" that was "insufferable." She woke up still burning, called it "discouraging," and asked if anyone else had experienced this. She framed GHK-Cu as a skin peptide and mentioned she's new to peptides beyond NAD. That's essentially the whole story, and there's a lot to unpack here.
The first thing worth noting: she didn't say who "Andrew" is, what source she got the peptide from, what dose she used, or how she prepared the injection. She also didn't mention whether she reconstituted it correctly, used bacteriostatic water, or had any guidance from a clinician. Every one of those missing details matters enormously when evaluating why she had the reaction she had.
Does the science back this up?
GHK-Cu does have real research behind it, but almost none of that research involves subcutaneous injection for skin benefits in humans. The published literature is largely in vitro or animal-based, which is a significant gap between the hype and the evidence.
GHK-Cu (glycyl-L-histidyl-L-lysine copper complex) has been studied as a topical compound for wound healing and skin remodeling. Pickart et al. (2015, Journal of Aging Science) documented its effects on collagen synthesis and skin barrier function in cell models. Finkley et al. (1989, Journal of Investigative Dermatology) found topical GHK-Cu accelerated wound healing in animal models. Human injectable data is sparse. A 2018 review by Pickart and Margolina in Biomolecules summarized GHK-Cu's broader biological effects but still leaned heavily on in vitro data. Injecting a peptide carries different pharmacokinetics, sterility requirements, and local tissue responses than applying it topically. That's not a minor distinction.
What did they get wrong (or right)?
She got one thing right: GHK-Cu is indeed associated with skin-related research. That's accurate. The peptide has documented activity in fibroblast stimulation and antioxidant gene expression pathways. Credit where it's due.
But several things here are genuinely concerning. Subcutaneous injection of GHK-Cu for cosmetic skin benefit is not a validated clinical protocol. More importantly, "burning fire pain" lasting through the night after a stomach injection is not a normal expected response, and she doesn't seem to have sought medical guidance when it happened. That's a red flag. Injection site reactions can result from improper reconstitution, contamination, incorrect pH, or simply injecting into tissue that doesn't tolerate that compound well at whatever concentration she used. Without knowing her source, dose, or prep method, we can't pinpoint the cause, but none of the explanations are reassuring. She also describes starting this based solely on a friend's suggestion with no mention of any clinical oversight. That's the part that should concern viewers the most.
What should you actually know?
GHK-Cu is not approved by the FDA as an injectable therapeutic. It exists in a gray zone where compounded versions are sold through research chemical or peptide supplier markets with highly variable quality control. A 2021 analysis by Cohen et al. (JAMA Internal Medicine) found significant purity and labeling inconsistencies across compounded peptide products purchased online. If the compound itself is impure, or was reconstituted incorrectly, or was injected in too high a concentration, burning pain is a predictable outcome, not a detox response or "the peptide working."
The topical route for GHK-Cu actually has more published support for skin outcomes than injection does. If skin is genuinely the goal, the evidence points toward topical serums, not stomach injections. Anyone experiencing persistent burning pain after any injection should contact a clinician, not post a TikTok asking for crowd-sourced diagnosis. That's not a criticism of her as a person. It's just the correct order of operations.
- GHK-Cu is not FDA-approved as an injectable drug
- Published human injection data for skin benefits is essentially nonexistent
- Burning pain after subcutaneous injection warrants clinical evaluation, not internet crowdsourcing
- Peptide sourcing and reconstitution quality directly affect safety outcomes
- Topical GHK-Cu has more evidence for skin applications than injectable forms