What did @justsaracherry actually say?
She's on cycle two of subcutaneous GHK-Cu peptide injections and says her skin is going through a visible purge: active blemishes, dryness, sensitivity. Her claim is that this is what the process looks like in real time, especially for someone with rosacea, hormonal acne, and possible perimenopause. She credits GHK-Cu with clearing "a lot of the discoloration" and says Differin is the only topical helping her get through it. She also mentions improved crow's feet and overall skin quality after one month, without Botox or fillers.
To her credit, she's not selling anything here. She's documenting a rough stretch and warning viewers this is what it actually looks like. That kind of transparency is genuinely rare in this corner of TikTok. But several of her framing choices, especially around the word "purge," deserve a closer look.
Does the science back this up?
GHK-Cu (copper peptide GHK-Cu) does have legitimate research behind it for skin remodeling, but the "purging" framing is where things get scientifically murky. The peptide's documented mechanisms include stimulating collagen and elastin synthesis, modulating inflammation, and promoting wound healing. None of that explains a classic purge the way retinoids do.
Pickart and Margolina (2018, Cosmetics) reviewed decades of GHK-Cu data and confirmed its role in upregulating genes associated with tissue repair and anti-inflammatory pathways. A separate study by Gorouhi and Maibach (2009, Skin Pharmacology and Physiology) found copper peptides improved skin laxity and fine lines in controlled trials. What neither paper describes is a mechanism that would cause subcutaneous administration to accelerate blemish turnover the way tretinoin or adapalene does. The retinoid-style purge is driven by increased cell turnover in the follicle. GHK-Cu doesn't work that way.
Her skin reaction is real. The reason she's calling it a purge may not be accurate.
What did they get wrong (or right)?
She got the general skin benefits of GHK-Cu roughly right. The collagen and anti-inflammatory properties are documented, and her observation that discoloration improved before active blemishes resolved is actually consistent with how copper peptides affect pigmentation pathways, specifically through antioxidant activity involving superoxide dismutase, as noted by Pickart et al.
Where she goes wrong is using the word "purge" as if it's an established, expected side effect of subcutaneous GHK-Cu. It isn't. What she's likely experiencing is an inflammatory response from the injection itself, hormonal acne flaring during her period (which she acknowledges), and possibly rosacea sensitivity to any systemic change. Calling all of that a "purge" implies GHK-Cu is flushing impurities or accelerating skin cell turnover subcutaneously, which is not a supported mechanism.
She also combines GHK-Cu with Differin (adapalene) and seems to credit the combo for her progress. Differin absolutely does cause purging. It's a retinoid. Separating those effects on camera without clarifying that is genuinely misleading to viewers who may not be using adapalene.
What should you actually know?
GHK-Cu is one of the more studied peptides in cosmetic and regenerative research, but the subcutaneous route for skin benefits is not the same as topical application, and the evidence base for injectable GHK-Cu specifically is thinner than what she implies. Most robust skin data comes from topical formulations. The jump to subcutaneous dosing is something researchers haven't fully characterized yet in controlled human trials.
Anyone with rosacea considering GHK-Cu should know that inflammatory skin conditions can be unpredictable with any new compound, injectable or otherwise. Her rosacea flare during this period could have multiple triggers, including the injection site inflammation, hormonal shifts, or the Differin itself.
Also worth flagging: she mentions a cold sore during this cycle. GHK-Cu has shown some immune-modulating effects in vitro. Whether that interacts with HSV-1 reactivation in any meaningful way is unknown. That's not a reason to panic, but it's a reason to talk to a clinician before starting, not after a flare is already happening.
Bottom line on this video
She's honest about her experience and not pretending it's glamorous. That matters. But her framing conflates a retinoid purge from Differin with a GHK-Cu purge, and those are different things with different mechanisms. Viewers watching this and considering subcutaneous GHK-Cu without Differin may expect a similar process and be confused when it doesn't happen, or alarmed when something else happens instead. The video is a personal document, not a clinical guide. Treat it like one.