The human body has two primary mechanisms for helping us determine our current need for vitamin C. Although far from perfect, these mechanisms are a good starting point for anyone looking to find their optimal dosage of vitamin C.

Bowel Tolerance

People who have used high doses of traditional vitamin C often experience a watery diarrhea, called a C-flush. This phenomenon happens whenever a large amount of vitamin C is not absorbed in the small intestine. The unabsorbed vitamin C reaches the colon where it draws water into the bowels. At the point of bowel tolerance, a watery diarrhea naturally ensues. This is not an adverse side effect, it simply happens because the intestines cannot handle the volume of water the vitamin C draws into the large bowel. The vitamin C dosage that initiates a C-flush is referred to as a “bowel tolerance” dosage.

Daily bowel tolerance dosing to determine your current need for vitamin C can be inconvenient and unpleasant, but a good strategy includes periodic utilization of this type of vitamin C supplementation. Once a month, or even once a week, take spaced doses of vitamin C powder dissolved in water until the onset of diarrhea. At this point a baseline dose can be determined, and the bowels will benefit from a healthy cleanse. Please note: Since the liposome formulation enjoys superior absorption, it will not cause a diarrheal flush.

When the baseline requirement is established, supple¬mentation on subsequent days could include a combination of a liposomal formulation and sodium ascorbate powder or either type alone. Because liposome-encapsulated vitamin C is more bioavailable than other oral forms, especially as dose sizes increase, the following substitution schedule provides approximate values:

  • 1,000 mg liposomal = 3,000 – 4,000 mg powder
  • 2,000 mg liposomal = 8,000 – 10,000 mg powder
  • 3,000 mg liposomal = 12,000 – 18,000 mg powder

You will also need to keep in mind that the presence of a toxic or pathogenic challenge often increases bowel tolerance for vitamin C, most often in proportion to the severity of the challenge. In fact, Robert Cathcart, MD noted that with certain patients, bowel tolerance frequently rose to 75-100 grams per day.

The total daily dosage should be at least as much as determined by the last bowel tolerance result. Additional amounts often provide increased benefit.

To help you choose a form of vitamin C that will induce a C-flush, here are some considerations. These forms are all water-soluble:

  • Ascorbic acid powder is the least expensive form of vitamin C — because it is an acid, it is more likely to cause digestive stress.
  • Sodium ascorbate powder is safe and easy to use — preferred over all other non-liposomal forms.
  • Ascorbyl palmitate is a fat-soluble form of vitamin C which gives a different absorption characteristic.
  • Bioflavonoids are good antioxidant nutrients — although they can help vitamin C improve the antioxidant capacity of the body, they are not necessary for this.
  • Calcium ascorbate may slightly improve absorption, but high doses can introduce excessive amounts of calcium into the body.
  • Mineral forms: chromium ascorbate, magnesium ascorbate, manganese ascorbate, molybdenum ascorbate, potassium ascorbate, and zinc ascorbate present a problem because the associated minerals bring toxicities of their own to the table when used in the high dosages that you want to reach with your vitamin C supplementation. Avoid them except in lower doses.
  • Pills and capsules often contain non-nutritive fillers and ingredients that can add expense and adversely affect absorption. Also, liquid and chewable formulations may contain sugar — avoid them if possible.

Experimental Dosage

Another way to determine an optimum dose is simply by evaluation of bodily signals. When one doesn’t “feel quite right,” an increase in dose will usually be in order. If one reaches a sense of well-being and additional vitamin C does not produce any further improvement, the body’s need has most likely been met.