Stearic Acid is one of most common candle additives.

It is generally used for increasing the hardness level of wax while making Pillar candles. Stearic also helps making the candle shrinks which helps in easy mould release.

It also improves the performance for the candle by making it drip less.(compared to the candle without stearic) .

stearic acid for making candles
Stearic Acid For Candle Making