Both trade on a parent molecule's reputation. GHK-Cu is a naturally occurring plasma tripeptide with cosmetic-ingredient evidence; TB-500 is a fragment of a protein that has been trialed but was not itself the thing trialed.
Side by side
| TB-500 | GHK-Cu | |
|---|---|---|
| Class | Thymosin Beta-4 active fragment | Copper tripeptide |
| Status | Research compound | Research compound (cosmetic use of topical forms) |
| Route | Subcutaneous injection | Subcutaneous injection |
| Typical vials | 2 mg, 5 mg, 10 mg | 50 mg, 100 mg |
| Dose range | 2 mg to 5 mg | 1 mg to 3 mg |
| Frequency | 1 to 2 times weekly | Daily |
| Half-life | No human data | No human data |
| Dosing unit | milligrams | milligrams |
Pharmacokinetics
No curves are shown, on purpose.
No published human pharmacokinetics for TB-500 or GHK-Cu. Drawing one curve against an absent one would imply a comparison that cannot be made.
What the evidence supports
These grade how well each outcome has been studied in humans, never how well either compound works. A strong grade can sit on a negative result.
The strongest evidence for any claimed outcome is Human RCT for GHK-Cu and Human, observational for TB-500. That gap is the most important line on this page.
TB-500
| Outcome | Evidence |
|---|---|
| Tissue repair (full-length thymosin beta-4) | Human, observational |
| Tissue repair (TB-500 fragment) | Animal only |
| Any outcome in humans from the fragment | No data |
GHK-Cu
| Outcome | Evidence |
|---|---|
| Skin appearance, topical | Human RCT |
| Wound healing, topical | Human, observational |
| Gene expression changes | Mechanistic only |
| Any outcome from injection | No data |
How to choose
GHK-Cu is the more established of the two
Decades as a cosmetic ingredient, with human skin studies.
TB-500's human evidence belongs to thymosin beta-4
Not to the fragment being sold.
Neither supports the injury-repair use they are marketed for
GHK-Cu's evidence is skin appearance. TB-500's is animal.
At the syringe
At the default setup on each compound's own page, a 5 mg vial in 2 mL puts 25 mcg on every insulin unit, while a 50 mg vial in 5 mL puts 100 mcg on every unit. That is the number that decides whether a dose lands on a readable mark, and it is set by how much water goes in, not by the compound.