I only use 2 ingredients.... pharmaceutical grade vitamin C powder (L-ascorbic acid) and Life brand distilled drinking water from ntuc....
some pple add in extra ingredients like vegetable glycerin, essential oils, rose water, etc....
buy small 30ml or 50ml dark color(usually amber or blue) glass bottle with either dropper cap, mist spray or treatment pump....
start out low... 5% vitamin C (1/4 teaspoon) with 95% water for about 1 or 2 week too....
if not much stinging feeling, then increase to 10% for 1 or 2 weeks too.....
later 15% and finally 20% max....
the serum is colorless one but when it oxidize, it will become yellowish or orange color, time to make fresh ones....
so usually make enough for 1 week can already..... store in fridge....
cheap and effective....
Any recommendations on where to get vitamins C powder from ? Thanks!