What GHK-Cu amounts did researchers test?
A dish, a skin cream, and a mouse need different amounts. None of those tests gives you a safe personal dose.
What GHK-Cu dosage figures really mean
They show what each test used, and nothing more. They can't guide your use.
Skin cells in dishes got the smallest amounts. The paper's full range runs from 10 to the minus 12 up to 10 to the minus 9. Collagen started rising between 10 to the minus 12 and 10 to the minus 11. It peaked near 10 to the minus 9 [1]. That's a trillionth to a billionth of the usual lab measure. Skin creams and serums held far more: about 0.05% to 2% of the product's weight [13].
Animals got more again. Mice with scarred lungs got shots into the belly on alternate days. The liquid held 2.6, 26 or 260 micrograms per milliliter [8]. Mice with sore colons got 20 milligrams for every kilogram of a mouse's weight, by mouth [14]. Rats got about 0.5 micrograms to 0.5 milligrams per kilogram, as belly shots [10][11]. The one human hair study used a scalp liquid holding 50-100 milligrams per milliliter [4].
An animal amount can't be scaled to a person. None of these tests gives a human dose.
How the way GHK-Cu goes in changes where it ends up
A great deal. Researchers have put GHK-Cu on skin, in wounds and up the nose. In animals they've also given it by mouth and by shot [13]. Skin creams are sold under cosmetic rules and have most of the human data; prescription access to injectable GHK-Cu rests on a licensed clinician's decision. Each way sends it to different places for different lengths of time.
Nobody has properly measured how long GHK-Cu lasts in a person's blood. In rats given GHK into a vein, blood enzymes broke it down quickly. Other reviews guess that half of it is gone in 1-2 hours. The copper form holds up longer than plain GHK [6]. That's part of why claims about shots are hard to back. Something gone in hours acts nothing like a store in the skin.
On skin it's the reverse. Over 48 hours, 136.2 micrograms per cm^2 passed through. That's a patch about the size of a fingernail. About 97 micrograms per cm^2 stayed inside the skin [5]. That leftover copper stays on hand in that patch of skin for longer, instead of rushing through the body. Researchers see it as how a cream keeps working, not as a danger.
Skin data can't settle the question about shots. Your blood may handle GHK-Cu another way.
What keeps the copper attached to GHK
A mild product that isn't too acidic. GHK-Cu holds its copper very tightly. That grip keeps copper from getting loose and harming cells [7].
It stays together best between pH 5-6.5, which is only mildly acidic. Each GHK holds one copper, a 1:1 pairing. Mixed into water, fresh GHK-Cu is blue-violet. Brown or green spells trouble: the copper may have come loose or begun to settle out [6].
Harsh products pull it apart. Vitamin C below about pH 3.5 knocks the copper loose. Skin-peeling acids and other very acidic products can do the same [13]. So researchers keep GHK-Cu mildly acidic and away from strong vitamin C if the copper is to stay put [6][13].
What researchers tried to get more GHK-Cu into skin
Plain GHK dissolves in water, not oil. The skin's outer layer is oily, so GHK mostly stays on top [13]. One fix was to attach a small fatty tail to the GHK. That made it mix far better with oil and slip in more easily [13].
Others wrapped GHK in tiny fat bubbles or in oil-and-water mixes. Another way skipped the barrier: pricking the skin with very fine needles first. In one study, about 134 nanomoles of GHK went through the pricked skin. That's well under a thousandth of a gram. None went through unbroken skin [13]. Hair studies have used fine needles, and even tattoo machines, to put GHK deeper [13].
A 2025 review called all these ideas promising but early [13]. What's rubbed on and what gets in can differ by a huge amount. Your skin may take in more or less.
What no human study has settled yet
A safe dose for shots or any whole-body use. Studies in people have been about skin products. Small face-cream and serum studies reported denser, firmer skin with finer lines. One 6-month hair study used ALAVAX, a scalp liquid holding 50-100 milligrams per milliliter [3][4][13].
No finished Phase 2/3 trial has tested GHK-Cu shots or whole-body use. Those are the larger trials that check whether a drug works and what harm it does. One skin-wound trial, CuHeal, has been entered on the public list of planned trials [6]. Being listed shows it was planned. The source doesn't say whether it started or finished.
Nobody knows how fast a shot reaches the blood, how high the level climbs, or where it goes [6]. Dosing plans that circulate online have nothing solid behind them. The figures on this page describe set tests only.
For a whole person, no dose has been proven, and a safe amount isn't known.