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Updated: Mar 30, 2026

Preparation of Herbal Medicine: Er-Xian Decoction and Er-Xian-containing Serum for In Vivo and In Vitro Experiments
Published on: May 31, 2017
Study of the Safe Dosage of Ergocalciferol
Abstract:
Vitamin D2 or ergocalciferol can replace vitamin D3, but its dosage must be a higher international unit: one unit of vitamin D3 is equal to 4 units ofvitamin D2. A proper interval of administration should take 200,000 IUper day. The 123 cases enrolled for study, every case had blood levels of 25 (OH) D and blood calcium checked before intake of vitamin D2 followed by a second check after 2 months. The means of before-intake group was 31.92 ng/ml and after-intake group was 48.62 ng/ml; the pair sample mean was 0.001. We found the level of 25 (OH) D was greater than 70 ng/ml (max = 90), 3.2 percent. Twelve cases showed no response, 9.6 percent. No cases of hypercalcemia or allergic phenomenon were noted. Before the study, we tried a random dosage of 200,000 IU per week and found the pair mean showed nothing significant (p = 0.052). In practice, the dosage of 200,000 IU of vitamin D2 is suitable for treatment of vitamin D deficiency, but for long-term treatment, dosage should be adjusted by monitoring the levels of 25 (OH) D from time to time.
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