A possible clue to their mechanism is provided by a trial with flumazenil (Anexate, Romazicon) a benzodiazepine receptor antagonist, published by Lader and Morton (Journal of Psychopharmacology 1992, 6, 357-63)
Both glutathione groups experienced improvements in skin elasticity, but these improvements did not reach statistical significance, compared with placebo
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Injectable GHK-Cu was in Category 2 the more restrictive category for substances with "significant safety concerns." Its removal from Category 2 is the more positive development, as it signals the FDA no longer considers injectable GHK-Cu to carry the safety risk level that warranted Category 2 placement
The free radical scavenging effect of glutathione blocks the induction of tyrosinase activity caused by peroxides
Foundations of Athletic Training: Prevention, Assessment, and Management