I was wondering if anyone could help me with this. I like to use diluted apple cider vinegar as a toner. Would the ph of the vinegar affect the activity of copper peptides or of retin-a?

The pH is about 5 to 7. This would not affect the copper peptides.

From http://www.homeremediesweb.com..._health_benefits.php


What is Apple Cider Vinegar?
Apple Cider Vinegar (ACV) is an effective natural bacteria-fighting agent that contains many vital minerals and trace elements such as potassium, calcium, magnesium, phosphorous, chlorine, sodium, sulfur, copper, iron, silicon and fluorine that are vital for a healthy body.

Natural Apple Cider Vinegar is made by crushing fresh, organically grown apples and allowing them to mature in wooden barrels. This boosts the natural fermentation qualities of the crushed apples, which differs from the refined and distilled vinegars found in supermarkets. When the vinegar is mature, it contains a dark, cloudy, web-like bacterial foam called mother, which becomes visible when the rich brownish liquid is held to the light. The mother can be used to add to other vinegar to hasten maturity for making more Apple Cider Vinegar. Natural vinegars that contain the mother have enzymes and minerals that other vinegars in grocery stores may not have due to over-processing, over-heating, and filtration. For this reason, it is recommended that you purchase only Natural Apple Cider Vinegar, with an ideal acidity (pH) level of 5 to 7.