Not all it lost! Over the years, I've saved some posts that I could refer back to later on. Some info was edited out when I did save it (names, etc) so I can not credit the original poster. In the next few days, I'll keep searching my documents, but here is a good start. Enjoy and post some that you may have saved!

Pandy's vitamin C serum

Here's the basic recipe -- Pandy also posted numerous options for additional ingredients, but I keep it super simple with just water and vitamin C (btw, I use Vitamin Shoppe C-1000 powder

For about 1/4 oz (7088 mg) of serum
What strength do you want? About 20% is the highest you should ever consider. Sensitives should start low. Get pure, unbuffered C crystals from the health food store.

Here are some guidelines. The measures are approximate.

for 22%, use 1/3 tsp C
for 16.6%, use 1/4 tsp C
for 8.3%, use 1/8 tsp C

You can add this amount to 1 1/2 teaspoons of water, or pure hyaluronic acid. Dissolve the C in water first, before making any additions. If you like, you can use an inexpensive premade serum as part of your 1 1/2 teaspoon liquid measure, but the C will probably not dissolve as easily in it. If this happens, you will have to use a little water to dissolve your C first, then add your premade serum to get a final measure of about 1 1/2 teaspoons.

The pH of the 16.6% solution will be about 2.5. This is very acidic. Test a little on a small area of your face. It will sting a little bit. If you can't tolerate this, dilute it before proceeding.