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Take Poly C® to increase your immunity

As you know, Vitamin C would be the best way to enhance your immune system.

Poly C is USANA’s proprietary vitamin C blend. It’s a unique combination of calcium, potassium, magnesium, and zinc mineral ascorbates (mineral salts). This mixture has been shown to increase and maintain higher levels of vitamin C in the blood than equal amounts of ascorbic acid alone. *

Plasma of Vitamin C
Plasma of Vitamin C

Pharmacokinetics of Poly C versus Ascorbic Acid


V itamin C, also known as ascorbic acid, is an essen-tial nutrient for humans. It plays several roles in the body: as a cofactor or co-substrate for sev-eral enzyme systems—including three involved in collagen biosyn-thesis—as an electron donor or reducing agent for many bio-chemical reactions, and as a gen-eral antioxidant in protecting cells and tissues against free-radical damage.1 Acute vitamin C defi-ciencies result in scurvy.

Because of its essential role in human nutrition, vitamin C is a common and often high-dose constituent of nutritional sup-plements. As such, many chemi-cal forms of the compound have been developed, in part as a means of improving product per-formance and as a way to differen-tiate one supplement brand from another. USANA’s proprietary vi-tamin C blend, Poly C, is a mix-ture of calcium, potassium, mag-nesium, and zinc ascorbates. This blend was developed to promote bioavailability and help reduce stomach upset that often accom-panies high doses of pure ascorbic acid. The clinical study reported here was undertaken to compare the pharmacokinetics of Poly C and ascorbic acid, and to substan-tiate claims of improved bioavai-lability.


This study was a prospective, double-blind pharmacokinetic study involving 19 healthy volun-teers. Subjects were randomly as-signed to two treatment groups – Poly C (nine individuals), and as-corbic acid (ten individuals).

Subjects reported at 7:30 a.m. on the test day for their first blood draw. Immediately follow-ing the draw, they consumed ei-ther 1,200 mg of vitamin C as Poly C or 1,200 mg of pure ascorbic ac-id. Subjects reported to the lab again for blood draws at 1, 2, 3, 4, 7, and 10 hours following sup-plementation. In the interim, subjects received given low-vitamin C meals and snacks. Treatments were run in parallel.

Following the last blood collec-tion, samples were processed and analyzed for plasma vitamin C content by HPLC, using an inter-nal standard and an electrochem-ical detector. Results were tabu-lated, and differences between treatments were assessed using a Profile Repeated Measures Analy-sis performed by an independent statistician.

Analyses were conducted on three sets of variables: raw plas-ma concentration of ascorbic acid, percent increase (from baseline) in plasma ascorbic acid, and per-cent increase in plasma ascorbic acid per kilogram of body weight. Differences associated with a p-value below 0.05 were considered statistically significant.


Results showed that Poly C, USANA’s proprietary blend of four mineral ascorbates, deli-vered more vitamin C to the bloodstream than did an equiva-lent dose of pure ascorbic acid (Figure 1). Plasma vitamin C con-centrations were consistently higher in the Poly C group than in the ascorbic acid group across the 10-hour study period. Differ-ences were most pronounced be-tween two and four hours follow-ing supplementation. During this time, vitamin C levels in the Poly C group averaged 10–15% higher than in the ascorbic acid group. Similarly, increases in plasma vi-tamin C per kilogram of body weight were 8% higher in the Poly C group than in the ascorbic acid group (results not shown). This difference was statistically significant (p<0.01) and, as before, was largest between two and four hours after treatment. When per-cent increases in plasma ascorbic acid were not normalized for body weight, differences between groups were not statistically sig-nificant.


These results show that Poly C delivers more vitamin C to the bloodstream than pure ascorbic acid. Subjects who were given the equivalent of 1,200 mg of ascorbic acid as Poly C had significantly higher concentrations of plasma ascorbic acid over a 10-hour pe-riod than did subjects given 1,200 mg of pure ascorbic acid. Differ-ences were most prominent be-tween two and four hours after supplementation.

We conclude that, from the standpoint of bioavailability, Poly C is superior to pure ascorbic acid as a supplemental source of vita-min C.

Vitamin C is an essential nutrient that must be provided by the diet, because your body can’t make it naturally. As a source of vitamin C, Poly C offers a number of important benefits:

  • Antioxidant activity neutralizes damage caused by free radicals to maintain cellular health*
  • Helps your body use iron*
  • Supports collagen synthesis (a major structural protein in the body) to help maintain healthy skin, gums, cartilage, blood vessels, muscle, and bones*
  • Supports immune function*
  • Supports eye health*

Your body can absorb approximately 500 mg of vitamin C at one time. And, levels of vitamin C in your blood begin to decline after about five hours (as you can see in the chart above). So, spread your Poly C across two or more supplement doses during the day to optimize absorption and maintain protective levels.*

USANA Nutritionals with Poly C

USANA booster C 600
USANA booster C 600

Poly C is included in a number of USANA supplement formulas, including the CellSentials™, Proflavanol®, and Booster C 600™.

Some USANA markets also offer a stand-alone Poly C supplement, which features the proprietary vitamin C blend plus citrus bioflavonoids, rutin, and quercetin. Together, these antioxidants provide powerful defense against oxidative damage to support overall health and wellness.*

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