|Natural Product Number|
Vitamin C is an antioxidant required for tissue growth and repair, as it is essential in the formation of collagen. It is well-known as a stimulator of the immune system, especially in the prevention and treatment of the common cold.
Although vitamin C has been shown to be antiviral and antibacterial, its main effect is via improvement in host resistance.
Adults: Take 1 tablet daily or as directed by your health-care practitioner.
Duration of use: Consult a health-care practitioner for use beyond 2 months.
Cautions and warnings:
Warning: Consult a health-care practitioner prior to use if you are pregnant or breast-feeding, or if you are taking any prescription medications.
Known adverse reactions: Allergy/hypersensitivity to Rosa canina, rose hip dust, its constituents, or members of the Rosacea family has been known to occur; in which case, discontinue use.
|Each tablet contains:|
|Vitamin C (ascorbic acid)||1000 mg|
|Citrus bioflavonoids||150 mg|
|Rose hips (Rosa canina)||50 mg|
|Other ingredients: Hyprolose, microcrystalline cellulose, dicalcium phosphate, vegetable stearic acid, vegetable magnesium stearate, and silicon dioxide, with a coating of polyvinyl alcohol, talc, polyethylene glycol, and polysorbate 80.|
Evidence supporting the use of vitamin C
Prevention of Cold and Flu
|Vitamin C||1 g/d during winter||Taking 1 g/d of vitamin C all winter reduced the length (by 22% overall, 47% in men) and severity of URTI in athletes.|
|500 mg daily for 5 years||Taking 500 mg of vitamin C reduced the frequency of colds among older Japanese adults; the risk of developing three or more colds over 5 years decreased by 66%, RR 0.34 (0.12–0.97), compared to taking only 50 mg/d.|
|2 tablets per day during winter||Taking 2 tablets of vitamin C daily from November to February significantly reduced the number (37 v. 50, p < .05) and duration (severe symptoms for 1.8 v. 3.1 days, p < .03) of the cold.|
|Zinc||15 mg/d preventively; increased to 30 mg acutely||Supplementation reduced the number of colds in children compared to placebo (1.2 v. 1.7 colds per child; p = 0.003). There was a decrease in cold-related school absence and a reduced duration and severity of cold symptoms.|
|Green tea extract||378 mg/d catechins + 210 mg/d theanine during the winter||Among health-care workers supplemented, the incidence of clinically defined influenza was reduced by 75%: 4 participants (4.1%) compared with the placebo group, 13 participants (13.1%) (adjusted OR, 0.25; 95% CI, 0.07 to 0.76, p = 0.022).|
|Taken twice daily for 3 months||Green tea significantly decreased the frequency of cold and flu symptoms (32.1% fewer subjects with symptoms), number of illnesses (22.9% fewer illnesses of at least 2 days duration), and reduced the number of days with symptoms by 35.6%.|
GTE also increased T‑cell proliferation and IFN‑gamma secretion.
Treatment of Cold and Flu
|Vitamin C||1000 mg every hour for 6 hours, then three times daily||Study of 463 control students and 252 in the treatment group recorded their cold and flu symptoms. When subjects fell ill, they took either decongestants (control) or megadose vitamin C (treatment). Flu and cold symptoms in the test group decreased 85% compared with the control group after the administration of mega-dose vitamin C.|
|Zinc||N/A||A double-blind, randomized, placebo-controlled trial in 108 COPD patients with acute URTI on antibiotics found that the addition of echinacea, zinc, selenium, and vitamin C significantly reduced the length and severity of exacerbation episodes following URTI compared to placebo.|
|30 mg/d acutely||See above for prevention of cold and flu.|
|Vitamin C||250 mg/d||Chlamydial cervicitis. Adding vitamin C to doxycycline and triple sulfa was more efficient than standard regimen without vitamin C in treating chlamydial cervicitis; significantly greater decrease in discharge and dyspareunia (p = 0.005, p < 0.001).|
|500 mg twice daily||H. pylori infection. The addition of vitamin C to drug therapy for H. pylori increased the eradication rate to 91.25%, which is higher than both the ideal 80% eradication rate and the 60% eradication rate achieved in the control group (drugs only).|
|100 mg/d for 3 months||Prevention of UTI in pregnancy. The incidence of UTI was significantly lower in the vitamin C–supplemented group (12.7%) compared to nonsupplemented (29.1%), (p = 0.03).|
Allergy and Asthma
|Vitamin C||1500 mg/d for 2 weeks||Supplementation with vitamin C reduced exercise induced bronchoconstriction in asthmatic patients compared to placebo.|
|1 g/d for 4 months||Vitamin C modestly reduced corticosteroid requirements compared to placebo in asthmatics.|
|2 g acute dose||Acute oral administration of 2 g vitamin C decreased bronchial responsiveness to inhaled histamine in 16 patients with allergic rhinitis compared with placebo. Lung function testing was significantly improved one hour after treatment with vitamin C but not with placebo.|
|Bioflavonoids||100–500 mg per day||Various mixtures of bioflavonoids have been shown to reduce symptoms of wheezing and seasonal allergy.|