Effect of L-carnitine on pH and Ingredient Stability in Formulation

It's understandable that you were concerned about the significant drop in pH after adding L-carnitine. A pH of 2.9-3 is quite acidic for many cosmetic ingredients.

However, it is unlikely that all the ingredients you added beforehand (allantoin, Trehalose, Green tea Extract, Calendula, Vitamin B5, Snail Secretion) instantly lost all their function the moment the pH dropped.

Here's a breakdown of potential effects:

• Allantoin & Trehalose: Generally quite stable, although prolonged exposure to very low pH might cause some slow degradation over time.
• Green Tea & Calendula Extracts: These contain complex mixtures of compounds. Some components might be more sensitive to low pH than others, but instant complete degradation is improbable.
• Vitamin B5 (Panthenol): Panthenol is more stable in a slightly acidic to neutral range (pH 4-7). At pH 2.9-3, some hydrolysis (breakdown) could occur, especially over time or with heat, but likely not instantly.
• Snail Secretion Filtrate: This is a complex biological material containing proteins, enzymes, etc. Biological components are generally more sensitive to pH extremes. A pH of 2.9-3 is significantly outside their optimal stability range, and some denaturation or loss of activity is possible, making this ingredient potentially the most affected.

The degree of degradation depends on the specific ingredient, the exact pH, the temperature, and the duration of exposure to the low pH before you adjusted it.

The advice you received to adjust the pH back up is correct. While some potential loss of efficacy might have occurred, particularly for the more sensitive ingredients like Snail Secretion and Vitamin B5, it's highly unlikely that everything is completely inactive if the exposure to the very low pH was brief before you corrected it. The product might not be optimally effective compared to one maintained at a stable pH throughout, but it's probably not entirely useless.