pH and Stability 

Sodium Hydroxide (NaOH)

This ended up being unnecessary once I realized that L-Arginine has a pH above 12.00. Unfortunately, I had to learn the hard way, and it cost me an entire 1000 mL batch.

The mistake happened after I poured in enough stock solution to include L-Arginine at 1% of the total formula. That was still too much. The pH skyrocketed, and I didn’t notice until I had stopped counting the drops of the citric acid, desperately trying to bring the pH back down. By then, the formula was ruined and there was no turning back. Sensitive botanicals had already begun to denature, and even if I could have lowered the pH, I don’t think it would’ve been wise to use something with that much citric acid mixed in.

Round two I was more patient. I used a smaller, premade L-Arginine stock solution and added it drop by drop, carefully monitoring the pH each time.