You may have seen the claim that GHK-Cu beat retinol for collagen, 70% to 40%. We have quoted those numbers ourselves. So we went back to the original study. It is real, but it is smaller than the headline suggests, and it did not test retinol.
Here is what it did test, what retinol’s own evidence looks like, and how to choose between them or use both.
The short answer
- Retinol belongs to the retinoids, which have a much larger body of clinical research than GHK-Cu. It can irritate, especially at the start, and it calls for care with sun and pregnancy.
- GHK-Cu has a handful of human studies, all small, but a long tolerability record and no adjustment period, so it fits morning and night.
- You do not have to choose. GHK-Cu in the morning and retinol at night works well.
Where “70% vs 40%” comes from
The figure traces back to a 1998 pilot study by Abdulghani and colleagues. Twenty healthy volunteers took part for one month, in two groups of ten. In one group, each person put tretinoin on one thigh and vitamin C cream on the other. In the other group, each person used melatonin cream on one thigh and a copper-binding peptide cream on the other. The study calls it a copper-binding peptide; the GHK-Cu reviews identify it as GHK-Cu.
Skin biopsies were taken before and after. The researchers then counted how many people showed a significant rise in procollagen, the precursor of collagen: 7 of 10 with the copper peptide cream, 5 of 10 with vitamin C, 5 of 10 with melatonin and 4 of 10 with tretinoin. Their own conclusion was that all four creams enhanced collagen synthesis, “although not in all individuals”.
That is where 70% and 40% come from. Four things are worth knowing about it:
- It was tretinoin, not retinol. Tretinoin is prescription retinoic acid. Retinol is the over-the-counter form, and a review of retinoid research describes it as 20 times less potent.
- Different people used each cream. The copper peptide cream and tretinoin were never on the same person’s skin, and with ten people per cream, one person changes the result by ten points.
- It measured collagen in biopsies, not how skin looks. The samples came from healthy thigh skin, not faces, and the results were counts of people, not wrinkle measurements.
- It ran for one month. Some later summaries, including a review we relied on ourselves, give it as twelve weeks. The study itself says one month.
So it is a small, early signal in GHK-Cu’s favour, and a fair reason to be interested in it. It is not evidence that GHK-Cu outperforms the retinol in your bathroom cabinet.
What retinol’s evidence looks like
Retinol is a form of vitamin A that skin converts into retinoic acid. Retinoids, the family it belongs to, have been studied for skin ageing for decades; Mukherjee and colleagues’ 2006 review is a good overview.
One well-designed retinol study is Kafi et al., 2007: randomised, double-blind and vehicle-controlled, with 36 people whose average age was 87. Study staff applied a 0.4% retinol lotion to one arm and a plain lotion to the other, up to three times a week for 24 weeks. Fine wrinkling improved significantly on the retinol arm compared with the plain one, and biopsies from a small subgroup showed more glycosaminoglycans and procollagen.
The trade-off is comfort. The same review lists itching, burning, redness and peeling as the most common reaction to topical retinoids. It is less common with retinol than with tretinoin, but it happens. Retinoids can also make skin more sensitive to sun early on, and the review advises caution in pregnancy.
GHK-Cu vs retinol at a glance
| GHK-Cu | Retinol | |
|---|---|---|
| What it is | A copper-bound peptide (Copper Tripeptide-1 on labels) | A form of vitamin A, converted in skin to retinoic acid |
| Best-known controlled study | 40 women aged 40 to 65, 8 weeks, against Matrixyl 3000 and a control serum | 36 people averaging 87, 24 weeks, against a plain lotion |
| Getting used to it | A long tolerability record, no adjustment period | Itching, redness or peeling are common at first |
| When to use it | Morning and night | Usually at night |
| Pregnant or trying | Ask your doctor before starting any new active | Use with caution and ask your doctor |
The GHK-Cu study is Badenhorst et al., 2016, which we cover in How much GHK-Cu should a serum contain?
Can you use GHK-Cu and retinol together?
Yes. The simplest way is GHK-Cu in the morning and retinol at night, or alternate nights. Keep strong acids such as L-ascorbic acid or glycolic acid out of the same routine as GHK-Cu.
If you are new to retinol, a few nights a week is a gentle start; the 24-week study above used it up to three times a week. Use sunscreen during the day either way.
Which should you choose?
- You want the ingredient family with the most research and your skin tolerates it: retinol.
- Retinol has irritated you, or you want something for morning and night: GHK-Cu.
- You want both: GHK-Cu in the morning, retinol at night.
- You are pregnant or trying: talk to your doctor first.
Our serum is GHK-Cu at a disclosed 1% with Pal-150, and no retinol, so it sits alongside one. Every study we cite is on The studies.
Common questions
Is GHK-Cu better than retinol?
The research does not show that. The study behind the claim compared a copper peptide cream with tretinoin, not retinol, in ten people per cream for one month, and measured collagen in biopsies rather than how skin looked.
Is GHK-Cu a good retinol alternative?
It is a gentler option with a smaller body of evidence. If retinol does not suit your skin, it is worth trying; if retinol works for you, there is no need to give it up.
What is the difference between retinol and tretinoin?
Tretinoin is retinoic acid, available on prescription. Retinol is sold over the counter and has to be converted in the skin before it acts, which makes it milder and, per the review above, about 20 times less potent.
Sources
- Abdulghani A.A., Sherr A., Shirin S. et al. Effects of topical creams containing vitamin C, a copper-binding peptide cream and melatonin compared with tretinoin on the ultrastructure of normal skin. Disease Management and Clinical Outcomes, 1998.
- Kafi R. et al. Improvement of naturally aged skin with vitamin A (retinol). Archives of Dermatology, 2007.
- Mukherjee S. et al. Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clinical Interventions in Aging, 2006.
- Badenhorst T., Svirskis D., Merrilees M., Bolke L., Wu Z. Effects of GHK-Cu on MMP and TIMP Expression, Collagen and Elastin Production, and Facial Wrinkle Parameters. Journal of Aging Science, 2016.
These are published studies of ingredients and of other brands’ formulas, not studies of Mystifi’s formula. This article is general information, not medical advice.
