TB-500 vs GHK-Cu: A Covered Injection and an Uncovered Copper Peptide

TB-500 and GHK-Cu are both sold for repair, and they often share a vial in blends called “Glow”. They are very different products. TB-500 is a lab-made seven-amino-acid fragment of thymosin beta-4, and FDA found no study that gave it to a person.^[1] GHK-Cu is a three-amino-acid peptide bound to copper, first found in human blood, used for decades in skin creams and tested in a few small wound trials.^[5][6][8] Since October 28, 2026, compounded TB-500 injections are covered by an HHS enforcement-discretion policy; GHK-Cu is not, and FDA flags injectable GHK-Cu as a possible immune risk.^[2][3]

TB-500 vs GHK-Cu at a glance

What each peptide is

TB-500 copies seven amino acids (positions 17 to 23) of thymosin beta-4, a 43-amino-acid protein, with an acetyl group added at one end.^[1] It is often treated online as if it were the full protein, which orthopedic reviewers call a mistake: the two have not been shown to act the same way.^[14]

GHK is a tripeptide, glycine-histidine-lysine, identified in human serum in 1973.^[5] In 1980 its discoverer reported that it readily binds copper and helps cells take up the metal, which is why it is usually sold as the copper complex, GHK-Cu.^[6] It is a common cosmetic ingredient. Whether a cream counts as a cosmetic or a drug depends on its intended use and the claims made for it, and cosmetics do not need FDA approval before sale.^[16]

The human evidence for each

TB-500: none, and a parent protein with its own record

FDA searched the literature and did not identify any clinical study of TB-500 in humans; the references submitted to support it were studies of full thymosin beta-4.^[1] The full protein has human data. In a phase 1 trial, 40 healthy volunteers received IV thymosin beta-4 or placebo, with doses up to 1,260 mg a day for 14 days, and adverse events were infrequent and mild or moderate.^[12] In two phase 2 trials, thymosin beta-4 sped healing of venous stasis and pressure ulcers by almost a month in the patients whose ulcers healed.^[13] None of that tested TB-500, and none tested injection under the skin or into muscle.

GHK-Cu: small wound trials, one of them negative

• Venous ulcers (1992). In a randomized, evaluator-blinded trial with 86 evaluable patients, a 0.4% copper tripeptide cream did no better than placebo, and both did worse than silver sulfadiazine.^[7]
• Diabetic foot ulcers (1994). In a randomized, placebo-controlled trial, topical GHK-Cu closed a median 98.5% of plantar ulcer area against 60.8% with the vehicle, and infections were less common (7% vs 34%).^[8]
• Skin and hair. A 2026 review of GHK-Cu across uses found the clinical evidence “remains sparse” and called GHK-Cu “promising but unproven.”^[9] In a lab test on human skin, almost no peptide or copper passed through intact skin without microneedles,^[11] a delivery problem shared by most skincare peptides.
• Injury and recovery. A 2026 review for orthopedic and sports physicians found no clinical data supporting GHK-Cu for musculoskeletal conditions.^[10]

We found no published trial of injected GHK-Cu for any purpose. FDA’s note on injectable GHK-Cu says there are limited data in humans.^[3]

GHK-Cu has a few small topical trials. TB-500 has none. Neither has a human trial of the injection sold for recovery.

Regulatory status side by side

TB-500. From September 29, 2023 to April 22, 2026, TB-500 sat in FDA’s Category 2. FDA staff recommended against listing it for 503A compounding, and the advisory committee voted in favor. On October 28, 2026, HHS said it does not intend to take enforcement action against 503A pharmacies and physicians compounding TB-500 acetate for injection under the skin or into muscle, if every condition of its interim policy is met, among them a prescription for a named patient and one active ingredient per product. HHS called the safety concerns raised by FDA staff “inferential rather than observed.” The policy is not an approval and lasts until a final rule settles the listing.^[2]

GHK-Cu. GHK-Cu is not in the HHS policy.^[2] Its status depends on the route. FDA’s May 2026 list puts “GHK-Cu (except for injectable routes of administration)” back in Category 1, substances under evaluation, after a nominator clarified in May 2026 that it was withdrawing only the injectable nomination. FDA plans to consult its advisory committee on GHK-Cu before the end of February 2027.^[4] Injectable GHK-Cu is outside Category 1 and appears on FDA’s safety-risk page among withdrawn nominations, where FDA warns that compounded injections could provoke an immune response because the peptide can clump and can carry impurities.^[3]

In sport. WADA names TB-500 under S2.3, prohibited at all times.^[15] GHK-Cu is not named on the Prohibited List. WADA’s S0 section bans substances with no current government approval for human therapeutic use, so an athlete considering an injectable GHK-Cu product should check with their anti-doping body first.^[15]

Research-use-only vials of either peptide are outside the HHS policy and any compounding framework. The difference is set out in research-use-only vs compounded peptides.

Safety: what is known and what is not

• TB-500. No human safety data exist for the fragment. FDA notes possible immune reactions from aggregation and impurities.^[3] Reported side effects in people come from the full protein, given by other routes; see TB-500 side effects and dosing.
• GHK-Cu on the skin. Topical use has a long cosmetic history and little passes through intact skin.^[11] The wound trials were small.^[7][8]
• GHK-Cu by injection. FDA flags possible immune reactions and says human data are limited.^[3] We found no published trial of the injection, so its side effects in people are unknown.

Why people combine them

The “Glow” blend usually puts GHK-Cu, BPC-157 and TB-500 in one vial, on the idea that skin and tissue repair add up. No human or animal study we found has tested TB-500 with GHK-Cu. A combined vial is outside the HHS policy twice: condition 7 requires one active ingredient per product, and GHK-Cu is not on the policy’s list at all.^[2] The injectable form of GHK-Cu in such a vial is the form FDA has flagged.^[3] The blends, and an adverse event FDA could not pin on either ingredient of a two-peptide vial, are covered in peptide blends and stacks. For how TB-500 compares with BPC-157, see BPC-157 vs TB-500.

To check where any other peptide stands, use our peptide status checker.