GHK-Cu with zinc thymulin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
GHK-Cu with zinc thymulin is a pharmacy-made scalp serum in a dropper bottle.
Evidence grade for GHK-Cu with zinc thymulin: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 1 completed trial, 13 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 13
- Human studies
- 1
- Found nothing
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 13 people given it
7 effects reported, 4 unwanted, 3 wanted, by people using it, not a trial
Goal pages: Skin, hair and appearance
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
A scalp serum you drip on and leave. A common mix is 5 mg per mL of copper peptide with 10 micrograms per mL of zinc thymulin. Do that division. The copper peptide outweighs the other one 500 to 1. Neither has a real trial for hair in people.
What people take it for
- Less shedding.
- Thicker looking hair.
- A calmer scalp.
- Something to add on top of minoxidil.
What studies in people showed
Nobody has tested the mix. The zinc thymulin hair claim comes from one short research letter. Scientists took human scalp hair follicles, kept them alive in a dish, and found thymus peptides changed how they grew. Human tissue, in a dish, not on a head. The copper peptide has human data, but it is about skin, not hair, and it did not go well. Thirteen people used it after laser skin work. Raters who did not know who got what saw no real change in redness, wrinkles or skin quality. One trial is running now and it is a gel on small wounds in 60 healthy adults. It has not reported. Now the math. A 1 mL squirt gives you 5 mg of copper peptide and 10 micrograms of the thymus peptide. Copper metal is about 16 percent of the copper peptide by weight, so that squirt puts roughly 0.8 mg of copper on your scalp.
What people report
Reports, not study results
The good
- Less shedding in the first couple of months. This is the main report.
- Scalp feels less irritated.
- Hair looks thicker, usually judged by the person in a mirror.
The bad
- Blue or green stains on pillowcases and light hair.
- Scalp itch or irritation in some people.
- Nothing at all, and disappointment next to minoxidil.
- Hair sheds more in some seasons on its own, so a new serum gets credit or blame it did not earn.
Where these come from: Hair loss forums, clinic write-ups and seller review pages. People talking, in a condition that moves around by itself and where almost nobody changes only one thing.
My bottom line
If the thymus peptide is what you came for, you are buying it at one five hundredth the weight of the ingredient you are mostly paying for. Minoxidil has the trials.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
What people using it report
Real people telling you what happened to them. Nobody checked it, and the people who post are not a fair sample, so it cannot prove anything works. It is still the best guide on this page to what people actually do with GHK-Cu with zinc thymulin, what they expect, and what goes wrong. The full account, including the negative reports, is below.
Nothing indexed yet
The 5 citations on this page do not report a result for any of the 36 goals indexed here. Most of what sits here is something else: a listing of a planned study, a study of how the body handles the drug, a safety report or a government record. None of those tests whether it works.
Show full evidence
What is GHK-Cu with zinc thymulin?
GHK-Cu with zinc thymulin is a pharmacy-made scalp serum in a dropper bottle. It usually has 5 mg/mL of copper peptide with 10 micrograms/mL of zinc thymulin. So there is 500 times more copper peptide than thymulin. Neither ingredient has a proper study for hair growth in people. The mix has never been tested. The hair evidence for thymulin is human hair roots in a dish.
Hair loss clinics and pharmacies sell this as a leave-on scalp serum, usually in a 25 mL dropper bottle. The usual strengths are GHK-Cu 5 mg/mL with zinc thymulin 10 micrograms/mL. That mix is the fact this page exists to point at.
At those strengths, there is 500 times more copper peptide than thymulin by weight. A 1 mL dose gives 5 mg of GHK-Cu and 10 micrograms of zinc thymulin. Whatever you bought it for, almost everything that lands on your scalp is copper peptide. Copper is about 16% of the GHK-Cu by weight. So that 1 mL dose puts roughly 0.8 mg of copper on the skin. On the skin that number means something different from a shot. The skin's outer layer limits how much gets in, and the gut is not involved either way. But it is the size worth knowing.
On the evidence. Every study of GHK-Cu in people used it on the skin. That is at least the right way in here. But the evidence is weak. In 13 patients after a laser skin treatment, checkers who did not know who got what found no difference in redness, wrinkles or overall skin. Only the patients' own survey liked it better. The one listed GHK-Cu trial is a gel on small cut wounds in an expected 60 healthy adults. It has not reported. Neither study is about hair.
The hair evidence for zinc thymulin is one short research letter. Researchers put thymus peptides, including thymulin, on human scalp hair roots kept alive in a dish. Different peptides changed hair root growth in different ways. Human tissue is better than mouse. But it was in a dish, not a person, and in a letter, not a proper study.
So both ingredients have a believable story for how they might work. One has skin data in people, for a different goal. One has human tissue data in a dish, for the right goal. Neither has a proper study for hair. The pooled research on peptides for skin found the overall cream effect to be modest. Hair has even less research than skin.
How does GHK-Cu with zinc thymulin work?
GHK-Cu carries copper into tissue. In a dish and in rat wounds it pushes cells to make collagen and other building materials. It is also claimed to enlarge hair roots and improve blood flow around them. Thymulin is a small peptide from the thymus, nine building blocks long. It needs zinc to work, and the zinc-bound form is the one in these serums. The hair idea comes from dish work showing thymus peptides change how human hair roots grow. No published work looks at the two together, on a scalp or anywhere else.
What have studies in people found about GHK-Cu with zinc thymulin?
No proper study of either ingredient for hair growth in people, and none of the mix.
- GHK-Cu: every study in people used it on the skin, and was about skin, not hair. In 13 patients after a laser skin treatment, checkers who did not know who got what found no difference in redness, wrinkles or skin quality.
- The one listed GHK-Cu trial is a gel on small cut wounds, and it has not reported.
- Zinc thymulin for hair: human scalp hair roots in a dish, in a short research letter. No study in people.
- The serum: no published study and no listed trial.
What this does not tell you: A dish test tells you a hair root reacted to a molecule. It does not tell you whether a serum gets through the scalp to the hair root in a useful amount. It does not tell you whether the effect lasts, or whether the hair on a head gets thicker.
What do people who took GHK-Cu with zinc thymulin report?
This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.
- Less shedding in the first two months. This is the most common single report.
- Scalp feeling less irritated.
- Hair looking thicker, usually judged by the person in a mirror.
- Blue or green stains on pillowcases and light hair from the copper.
- Nothing at all, and disappointment when compared with minoxidil.
- Scalp irritation or itch in a few people.
Sources: Hair loss forums including the tressless community, clinic write-ups and vendor testimonial pages. Uncontrolled self-reports, in a condition that fluctuates seasonally and where almost nobody changes only one variable.
The state of the research
With hair loss, stories from users are close to worthless, for a reason special to hair. Hair loss comes and goes. Shedding changes with the seasons. And people who start a new serum almost always start or stop something else at the same time. A product with no study in a field like that will collect glowing reviews whether or not it works.
The mix is the point to remember. At 5 mg/mL against 10 micrograms/mL, this is a copper peptide serum with a trace of thymus peptide in it. And the thymus peptide is the one with the hair root evidence, thin as it is. If thymulin is what you came for, you get it at one five-hundredth of the weight of the ingredient you are mostly paying for.
The evidence, in charts
Fig. 1a · how many people
13people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Archives of Facial Plastic Surgery 2006 | 13 | 100% |
The whole total is one study of 13. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 1 more study in people gives no headcount and is not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 5 sources here are studies in people. The rest are not.
- Study in people · done in people240%
- Lab (cells in a dish) · cells or tissue120%
- Review of studies · sums up other studies240%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2006 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Blend
- Molecule weight
- Not on file
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Not applicable to a serum left on the scalp, and no absorption or clearance study of either component has been published.
No amino acid sequence is on file for GHK-Cu with zinc thymulin, which is expected: a blend is not built from amino acids.
Fig. 6 · what is in the vial
We cannot show how much of each is in this blend
Sellers do not agree on a vial size for GHK-Cu with zinc thymulin, so nobody outside can know how much of each ingredient is in it. Splitting the bar evenly would make up the very number this page is here to question.
- GHK-CuLimited. People have taken it in a published study, but fewer than 100 of them. 2 completed trials, 99 people given it.amount not stated
- Zinc thymulinAnimal or lab only. Only animal or lab studies on this page. No study in people yet. 1 animal study, no human study.amount not stated
Ingredient list from the product labels we have. Amounts are what the label says is in the vial, never a dose.
The studies we cite
- Study in people2006Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin
Thirteen people put a copper peptide skin cream on after a laser skin treatment, and it did not beat the routine without it. Each person got one routine or the other by chance. A computer and checkers who did not know which face was which found no difference in redness, wrinkles or overall skin. Only the patients' own survey liked the copper peptide better. Thirteen people is a very small group. This was a cream, not a shot.
Thirteen patients randomised after circumoral CO2 laser resurfacing to a regimen with or without GHK-Cu skin care. Computer analysis and blinded evaluators found no significant difference in resolution of redness, and objective evaluation found no significant improvement in wrinkles or overall skin quality. Only the patients' own questionnaire favoured GHK-Cu, at P = 0.04.
- Study in people2026Topical GHK-Cu Gel for Acute Skin Wound Healing
Nobody knows yet. This is the only listed trial of GHK-Cu anywhere. It started in February 2026 and has not reported anything. The plan is 60 healthy adults with two small cut wounds each. Each wound gets the copper peptide gel or the same gel with nothing in it, by chance. It is a gel on skin. It says nothing about injecting the peptide.
A recruiting phase 2 trial, estimated 60 healthy adults, two punch-biopsy wounds each, every wound randomised to GHK-Cu gel or matching vehicle. Started February 2026 and has not reported. It is the only registered interventional trial of GHK-Cu and it is a gel on skin.
- Review of studies2026Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials
This review pooled 19 studies with 1,341 people. Peptides helped skin moisture and brightness. The effect on wrinkles was small, and most of it came from peptides taken by mouth, not creams. Effects on firmness and thickness were mixed. That is how big the peptide cream effect is on skin, where the research is much further along than for hair.
Nineteen randomised trials in 1,341 participants found peptides improved hydration and brightness with a modest pooled wrinkle effect of mean difference 0.27, largely driven by oral polypeptides rather than topicals, and inconsistent effects on elasticity and density. This is the size of the topical peptide effect in skin, where the evidence is considerably better developed than it is in hair.
- Review of studies2024Is Copper Still Safe for Us? What Do We Know and What Are the Latest Literature Statements?
This review sums up what we know about copper safety. The whole body holds 50 to 120 mg of copper. The safe upper limit from food is 10 to 12 mg a day, against a daily target of 0.9 mg. Copper from food takes 13 to 33 days to fall by half. The review warns that even small shifts in copper levels can be harmful. It is about copper in food and the world around you, not a copper peptide shot.
Total body copper is 50 to 120 mg, the safe upper limit of average intake is put at 10 to 12 mg a day against a reference limit of 0.9 mg a day, and the biological half-life from diet runs 13 to 33 days. The review notes that even small changes in copper concentration can carry significant toxicity. It covers dietary and environmental copper, not an injected peptide complex.
- Lab (cells in a dish)2012Thymic peptides differentially modulate human hair follicle growth
This is a short research letter, not a study in people. Researchers put thymus peptides, including thymulin, on human scalp hair roots kept alive in a dish. Different peptides changed hair root growth in different ways. This is where the zinc thymulin hair claim comes from. It was human tissue in a dish, not a test in people.
A research letter reporting that thymic peptides, including thymulin, thymosin beta 4 and prothymosin alpha, differentially modulate the growth of human scalp hair follicles in organ culture. Human tissue in a dish, with different peptides producing different effects. It is the origin of the zinc thymulin hair claim and it is not a trial in people.
Where to buy GHK-Cu with zinc thymulin
No seller we track lists GHK-Cu with zinc thymulin yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has GHK-Cu with zinc thymulin been tested in people?
Yes. 13 people given it across 1 completed trial cited here, 1 of which found nothing. GHK-Cu with zinc thymulin is a pharmacy-made scalp serum in a dropper bottle.
What is the GHK-Cu with zinc thymulin dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 1 completed trial, 13 people given it
Is GHK-Cu with zinc thymulin FDA-approved?
Sold as a cosmetic, or as a skin product mixed by a pharmacy. Neither part is an approved drug for hair loss. The approved drug you put on the scalp for pattern hair loss is minoxidil.
How much of each is in an application?
At the common 5 mg/mL copper peptide with 10 micrograms/mL zinc thymulin, a 1 mL dose gives 5 mg of GHK-Cu and 10 micrograms of zinc thymulin. There is 500 times more copper peptide than thymus peptide.
Is there a trial for zinc thymulin and hair?
No study in people. The evidence is a short research letter. It found thymus peptides change how human scalp hair roots grow in a dish. That is human tissue in a dish.
Is the copper a problem on skin?
A 1 mL dose carries roughly 0.8 mg of copper. It goes on unbroken skin instead of being injected, so the skin limits how much gets in, in a way a shot does not. The stains on pillowcases are the visible reminder of how much copper is in the bottle.
How does it compare to minoxidil?
Minoxidil is an approved scalp treatment for common male and female pattern hair loss. It has a large body of proper studies. Neither ingredient in this serum has a proper study for hair in people.
Has the combination been tested?
No. There is no study of GHK-Cu with zinc thymulin together, on a scalp or anywhere else.