Increased vitamin uptake from supplements with Ester-C

Ester C is eight times more expensive per mg than ordinary vitamin C, but also works considerably better than the regular variety. That’s the message in the results of a human study published in SpringerPlus.

The researchers gave 36 participants 1000 mg vitamin C on two separate occasions. On one occasion the participants got regular vitamin C; on the other they got Ester-C. Ester C is the calcium salt of vitamin C. The researchers then monitored the participants for 24 hours.

The study was financed by the supplements brand NBTY, which markets Ester-C. The researchers also worked for the company.

Supplementation with Ester-C increased the vitamin C concentration in the participants’ blood in much the same way as supplementation with regular vitamin C did.

When the researchers measured the concentration of vitamin C in the participants’ blood cells, they observed that supplementation with Ester-C resulted in a bigger rise than supplementation with regular vitamin C did.

“In conclusion, Ester-C significantly increased leukocyte vitamin C levels compared to ascorbic acid,” the researchers summarised. “This may be due to Ester-C’s metabolites, which have been shown to facilitate absorption and enhance retention.”

“The superior bioavailability of Ester-C in leukocytes may be beneficial to overall immune function since intracellular vitamin C levels are vital to the fundamental process of leukocytes. More studies are needed to better understand how Ester-C is associated with disease prevention and treatment.”

Determination of plasma and leukocyte vitamin C concentrations in a randomized, double-blind, placebo-controlled trial with Ester-C®


Rapid uptake of vitamin C into blood and retention in tissues are important indicators of the efficacy of vitamin C supplementation and its immune-supporting role. The objective of this study was to evaluate the bioavailability of vitamin C in plasma (reflective of recent intake) and leukocytes (reflective of tissue stores and influences on immune function) from a novel vitamin C formulation, Ester-C®.

The study was a double-blind, placebo-controlled, crossover trial. Thirty-six subjects, 18–60 years of age, were randomized to receive placebo (PL, 0 mg vitamin C), ascorbic acid (AA, 1000 mg vitamin C), and Ester-C® (EC, 1000 mg vitamin C). Plasma and leukocyte vitamin C were measured baseline and at 2, 4, 8 and 24 h postdose.

The concentration and percent change from baseline in plasma were significantly higher with EC at all time points when compared to PL. No significant differences between EC and AA were observed in plasma concentration. Maximum plasma concentration was higher for EC compared to AA (P = 0.039) and PL (P < 0.001). Plasma area under the curve (AUC0–24h) was higher for EC (P < 0.001) compared to PL. The concentration change from baseline in leukocyte vitamin C was increased with EC at 24 h post-dose (P = 0.036) while no significant within-group changes were observed in AA or PL at any time point. The percent change in leukocyte vitamin C concentration was higher for EC at 8 and 24 h compared to AA (P = 0.028 and P = 0.034, respectively) and PL (P = 0.042 and P = 0.036, respectively). Conclusions A single dose of EC resulted in favorable percent change in leukocyte vitamin C concentration compared to AA and PL, indicating EC is retained longer within leukocytes. Source: