Salicylic acid doesn't dissolve well in water and many other common solvents. Here is a list of its solubility:
- Water: about 0.2% at 20oC, about 1.7% at 75oC (by adding about 5% of sodium phosphate or another neutral salt, solubility of salicylic acid in water is increased to about 1.8%)
- Alcohol (ethanol): about 14% in pure ethanol, about 0.5% in 20% ethanol
- Glycerin: about 1.6%
- Octyldodecanol: about 15-20%
If you want to make a 2% solution you'd have to use alcohol or a water/alcohol mixture or maybe just glycerin. A better solvent would be octyldodecanol. If you don't want to go that route you could also buy our salicylic acid solution which can be easily incorporated into formulas and diluted further with water if necessary. Make sure that you check the pH value after adding salicylic acid to your formula as salicylic acid lowers the pH. A very low pH may destabilize an emulsion and may even separate it. To increase the pH again you can add triethanolamine. Typically, the pH should not be below 3.5 for most cosmetic products.

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