Vitamin C (Ascorbic Acid)

What is Vitamin C?

Vitamin C, also known as ascorbic acid, is a powerful antioxidant and essential nutrient required for numerous physiological processes, including the synthesis of collagen, absorption of iron, immune function, and protection against oxidative stress (1). It’s water soluble so we need to consume it daily through food or supplements (2,9).

It’s most famously associated with preventing scurvy – the severe deficiency disease historically suffered by sailors – but its roles in everyday health (and adventure endurance) go well beyond that (15).

Why Do Outdoor Adventurers Need Vitamin C?

When you’re adventuring hard, especially over multiple days, your body churns through energy, generates oxidative stress, and experiences higher levels of inflammation and tissue wear (3). Vitamin C comes in handy here, as it reduces oxidative damage caused by free radicals and supports tissue repair (4). Essentially, it’s a great nutrient to help your joints, ligaments, and skin heal after long days of intense exercise (15).

It’s also proven useful for immune function, helping to keep coughs and colds at bay when your body is physically stressed (5). While some studies have found minimal effect (4), the general consensus is that it can’t hurt, and significantly more studies have found it is beneficial in this way (4,5). Since multiday hikes can compromise immune resilience due to physical strain, cold exposure, and insufficient nutrition, vitamin C becomes a key nutrient to maintain optimal performance and recovery, especially in combination with vitamins A & D (5). 

Plus, it boosts iron absorption, both from Optiventure Core’s iron bisglycinate and from plant-based meals, especially handy for hikers relying on vegan trail foods (6).

Dietary Sources of Vitamin C?

Off-trail, vitamin C is abundant in citrus fruits, strawberries, tomatoes, kiwifruit, and capsicum. This is convenient at home but a lot harder to find on trail. Most vitamin C-rich foods are fresh, heavy, or perishable, not ideal for multi-day hiking or adventures. Dehydrated fruits and freeze-dried veggies can help, but storage losses and trail-time degradation of vitamin C are common (7).

This makes it easy for active hikers to fall short, especially on longer trips.

What’s the Best Form of Vitamin C For Hikers?

Ascorbic acid is the most common and well-researched form of vitamin C. It’s water-soluble, fast-absorbing, and extremely bioavailable (8,10). Buffered forms like sodium ascorbate or calcium ascorbate can be gentler on the stomach for some, but for most people, standard ascorbic acid is perfectly tolerated and effective (9).

Key Information About Vitamin C

Deficiency Stats

While vitamin C deficiency is rare in the general Australian population, and 8% of Americans supplement it daily (8), it does occur, particularly in individuals with low fruit and vegetable intake. 

Research shows that even marginal deficiencies can impair immunity, slow wound healing, and increase fatigue (14,15).

Why Optiventure Has 250mg amount of Vitamin C

We’ve included 250mg of vitamin C in Optiventure – over 270% of the American RDI and 550% of the Australian RDI – because hikers and active individuals have unique physiological demands.

Supplemental doses of 200-400mg/day have been safely shown to:

• Reduce the severity and duration of colds, especially in those under physical stress (4,17)
• Improve iron absorption from meals and supplements
• Act as a potent antioxidant, protecting cells from damage during exercise (3)

Crucially, 250mg is well below the established upper limit of 2000mg/day (2,19), meaning it’s safe for daily use with no adverse effects in healthy adults. It also gives a buffer to account for lower intake from trail foods, increased needs during physically demanding trips, and the average absorption rate of 70-90% between dosages of 30-180mg (11). 

Doses above 400mg have been shown to have no benefit, as your body simply can’t absorb it, and above 1g per day, absorption drops to less than 50% anyway (11). The 250mg daily dose accounts for some intake from food, without exceeding an amount that would be wasteful (2,11).

Vitamin C is rapidly depleted during prolonged physical activity, cold exposure, or infections (1, 15,16,17). That’s why we’ve packed in more than enough to support your immunity, energy, and recovery – so you can hike harder, feel better, and recover faster.

References

1. Carr, A. C., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211.https://doi.org/10.3390/nu9111211
2. Levine, M., Dhariwal, K. R., Welch, R. W., Wang, Y., Park, J. B., & Cantilena, L. R. (1996). Vitamin C pharmacokinetics in healthy volunteers. Proceedings of the National Academy of Sciences, 93(8), 3704–3709. https://doi.org/10.1073/pnas.93.8.3704
3. Powers, S. K., & Jackson, M. J. (2008). Exercise-induced oxidative stress: Cellular mechanisms and impact on muscle force production. Physiological Reviews, 88(4), 1243–1276. https://doi.org/10.1152/physrev.00031.2007
4. Hemilä, H., & Chalker, E. (2013). Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, 2013(1), CD000980. https://doi.org/10.1002/14651858.CD000980.pub4
5. Wintergerst, E. S., Maggini, S., & Hornig, D. H. (2006). Contribution of selected vitamins and trace elements to immune function. British Journal of Nutrition, 98(S1), S29–S35. https://doi.org/10.1017/S0007114507832971
6. Lynch, S. R., & Cook, J. D. (1980). Interaction of vitamin C and iron. Annals of the New York Academy of Sciences, 355(1), 32–44. https://doi.org/10.1111/j.1749-6632.1980.tb21325.x
7. Rickman, J. C., Barrett, D. M., & Bruhn, C. M. (2007). Nutritional comparison of fresh, frozen and canned fruits and vegetables. Journal of the Science of Food and Agriculture, 87(6), 930–944. https://doi.org/10.1002/jsfa.2825
8. Johnston, C. S., & Luo, B. (1994). Comparison of the absorption and excretion of three commercially available sources of vitamin C. Journal of the American Dietetic Association, 94(7), 779–781. https://doi.org/10.1016/0002-8223(94)91953-4
9. Padayatty, S. J., & Levine, M. (2016). Vitamin C: The known and the unknown and Goldilocks. Oral Diseases, 22(6), 463–493. https://doi.org/10.1111/odi.12446
10. National Institutes of Health. (n.d.). Vitamin C – Health professional fact sheet. Retrieved February 25, 2025, fromhttps://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
11. National Health and Medical Research Council (NHMRC). (n.d.). Nutrient reference values for Australia and New Zealand – Vitamin C.https://www.nrv.gov.au/nutrients/vitamin-c
12. Food Standards Australia New Zealand. (2021). NUTTAB 2021 online searchable database. https://www.foodstandards.gov.au/science/monitoringnutrients/nutrientables/nuttab/Pages/default.aspx
13. Institute of Medicine. (2000). Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids. National Academies Press. https://doi.org/10.17226/9810
14. Jacob, R. A., & Sotoudeh, G. (2002). Vitamin C function and status in chronic disease. Nutrition in Clinical Care, 5(2), 66–74. https://doi.org/10.1046/j.1523-5408.2002.00005.x
15. Institute of Medicine. (2000). Tolerable upper intake levels: Vitamin C.https://www.ncbi.nlm.nih.gov/books/NBK225480/
16. Evans, W. J., & Cannon, J. G. (1991). The metabolic effects of exercise-induced muscle damage. Exercise and Sport Sciences Reviews, 19(1), 99–125. https://doi.org/10.1249/00003677-199100190-00008
17. Hemilä, H. (2013). Vitamin C supplementation and respiratory infections: A systematic review. Military Medicine, 178(7), 735–742. https://doi.org/10.7205/MILMED-D-13-0002