SECTION 03 / WHAT THE STUDIES USED
GHK-Cu amounts used in skin, animal, and cell tests
This page names amounts from human, animal, and dish work. They tell you what researchers tried, not what dose to use.
What amounts GHK-Cu studies used
Researchers first asked how little GHK-Cu could make skin cells respond. This page reports what their tests used, not a dose for you. Copper Tripeptide-1 is the name often found on skin labels. GHK-Cu is the same copper-bound form used in much lab work.
Collagen rose between one part among 10 multiplied by itself 12 times and one among 10 multiplied 11 times [1]. The best dish result came near one part among 10 multiplied 9 times. Cell numbers stayed level. These tiny shares can't be turned into an amount for your body or skin.
At age 20, blood held about 200 nanograms of GHK per milliliter. That was near one part among 10 multiplied by itself 7 times. At age 60, blood held about 80 nanograms per milliliter [3]. Blood levels don't reveal the share of a cream that reaches live, deeper skin.
Skin products ranged from 0.05% to 2% by weight. Mouse belly shots used 0.2 to 260 micrograms; other tests used 2, 20, 20, or 15 milligrams for each kilogram [11]. A hair trial used 50 to 100 milligrams per milliliter of mixed GHK cream [4]. These test amounts don't form a safe-use guide for you.
What attaching copper changes in GHK-Cu
Reading GHK-Cu dose data requires tracking which molecule a study used, because the literature mixes two. GHK is the free tripeptide (340.38 Da); GHK-Cu is the copper(II) chelate (402.92 Da) [6]. Copper coordination is required for most documented matrix activity — free GHK does not reproduce the copper form's matrix-metalloproteinase stimulation in fibroblast cultures [6]. Several systemic rodent and gene-expression studies dose the free peptide, while the skin and wound work generally uses the copper complex.
The difference matters for concentration too. The picomolar collagen onset was measured for the copper complex in fibroblasts [1], whereas the broad gene-modulation signature derives largely from free-GHK database analysis [2]. When this review reports a dose, the body text names the form and the model so the number is read against the right molecule. The blue-violet color of a reconstituted GHK-Cu solution is the expected Cu(II) signature of an intact 1:1 complex; a color shift signals that the copper has been reduced or the complex has precipitated [11].
The literature's two molecules are not the only forms in circulation. GHK-Cu prescribing at Promise Peptides (mypromise.com) starts with a licensed U.S. clinician considering an individual request, which can end without a prescription; the injectable product needs that prescription. The practice is restricted to U.S. patients, with the range of options determined separately for each state and treatment. A compounded preparation does not carry FDA approval. That channel is noted for completeness — this review reads the studies, and the studies alone.
What tests say about how long GHK-Cu stays
Researchers wanted to learn how long GHK-Cu stays after entering tissue. No sound human study has measured the time for half of it to leave [11]. In a rat blood test, GHK without copper broke down fast after a vein dose. That result doesn't tell us how long GHK-Cu lasts in you.
The rat test could find 50 nanograms of GHK per milliliter and 15 nanograms of a broken piece per milliliter [15]. Those numbers describe the blood test, not safety. Other reviews say half may leave in 1 to 2 hours [11]. Rat blood still can't give a sure time for people.
After 48 hours, or 2 days, 97 micrograms stayed in each square centimeter of removed skin [5]. The 2 useful findings were that some copper crossed and some stayed. The paper wrote a slow rate as 2.43 x 10^-4 centimeters per hour, or about two ten-thousandths. That lab pace can't tell you what daily use does.
How researchers gave GHK-Cu
Most human skin work put GHK-Cu on the skin [5]. Animal tests also used belly shots, nose drops, pills, skin needles, and vein shots [11]. Cell work used tiny dish amounts [1], while a scalp cream used far more [4]. You can't compare those amounts without knowing who received them and how.
What keeps GHK-Cu together or breaks it
Chemists wanted GHK-Cu to hold copper without letting much break free. Their tests found a strong copper bond [11]. The bond stayed firm near 5 on the acid scale, with a 1:1 match of copper and GHK. Blue-violet color meant the mix held together; brown or green could mean damage.
Getting GHK through the outer skin was harder. A 2025 review found that watery GHK crossed poorly [11]. A changed form crossed better. Tiny needles moved 134 nanomoles through test skin [11]; a nanomole is one billionth of a mole.
Researchers also packed GHK-Cu inside fat-like bubbles about 100 nanometers wide. The bubbles held some GHK-Cu for 4 weeks and cut a skin-damaging enzyme by 48.9% in human skin cells [8]. The cells lived, but no whole person was tested. Those bubbles may help a serum reach deeper skin.
Very sour vitamin C and strong peeling acids can pull copper away from GHK-Cu. These include glycolic, lactic, or salicylic acid products. If the bond breaks, the mix isn't the form used in studies. A pharmacist can help you check products you plan to use together.