What dosage of vitamin C should be taken if the serum ascorbic acid level is severely deficient?

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Last updated: May 8, 2025View editorial policy

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From the FDA Drug Label

Directions Adults and Children 12 years and over: 500 mg (1 tablet) daily or as directed by your doctor Children under 12 years of age: Consult your doctor

The FDA drug label does not provide a specific dosage recommendation based on a vitamin C level of 0.1mg/dL. The label only provides general dosage instructions.

  • Dosage: The label recommends 500 mg daily for adults and children 12 years and over, but does not specify what to do if the vitamin C level is 0.1mg/dL.
  • Clinical decision: Without specific guidance from the label, it is unclear what dosage is appropriate for a vitamin C level of 0.1mg/dL 1.

From the Research

If your vitamin C level is 0.1 mg/dL, you should take 1,000 mg (1 gram) of vitamin C daily until your levels normalize, as recommended by the most recent and highest quality study 2. This dose is suggested to prevent vitamin C deficiency in critically ill patients receiving continuous renal replacement therapy, and it can be applied to other cases of severe deficiency as well. The treatment should start with this dose for 1-2 weeks, then reduce to a maintenance dose of 500 mg daily. It is essential to take vitamin C supplements with food to improve absorption and reduce potential stomach upset. For severe deficiency, you might need to split the dose into two 500 mg doses taken twice daily. Vitamin C is water-soluble, so your body will excrete excess amounts through urine. This dosage helps replenish your depleted stores quickly while avoiding potential side effects like diarrhea or stomach cramps that can occur with higher doses. Foods rich in vitamin C like citrus fruits, bell peppers, and broccoli should also be incorporated into your diet to maintain healthy levels naturally. After about a month of supplementation, consider retesting your levels to ensure they've improved, as suggested by 2. It's also important to note that vitamin C deficiency can have severe consequences, including scurvy, as mentioned in 3 and 4, and that global vitamin C status and prevalence of deficiency is a cause for concern, as highlighted in 5. However, the most recent and highest quality study 2 provides the best guidance for treating severe vitamin C deficiency. Some studies, such as 6, suggest that critically ill patients have low vitamin C concentrations despite receiving standard ICU nutrition, but the recommended dose of 1,000 mg daily is still the most appropriate treatment for severe deficiency.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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