What depletes vitamin C?

Your body cannot store vitamin C, so anything that speeds up the losses shows up quickly.

Smoking, heavy drinking, infection, surgery and a handful of everyday medications all push those losses higher. Cooking takes its own share before the food reaches your plate.

The result is visible in national data: 41.8% of US adults have insufficient plasma vitamin C. Here is what drains it, how much, and what actually helps.

Table of Contents

• 1. Why vitamin C empties out so fast
• 2. Smoking, secondhand smoke and polluted air
• 3. Alcohol
• 4. Infection, injury and surgery
• 5. Medications that quietly lower it
• 6. What cooking and storage take first
• 7. When losses are high, absorption matters more
• Frequently asked questions
• Conclusion
• Research references

1. Why Vitamin C Empties Out So Fast

Vitamin C is water-soluble, which means your body holds no useful reserve of it. The whole-body pool in a healthy adult is roughly 1,500mg, and it can be depleted within 1 to 3 months if intake stops. Scurvy appears once that pool drops below about 350mg.

The threshold is lower than most people expect. Getting below roughly 10mg a day for several weeks is enough to produce scurvy, against an RDA of 90mg for men and 75mg for women.

That leaves two ways to end up short, and they work independently. You can take in less than you need. Or you can take in a normal amount while something increases how fast you burn through it or excrete it. Most of the causes below belong to the second group, which is why people eating a reasonable diet can still show low vitamin C status without any obvious deficiency symptoms.

2. Smoking, Secondhand Smoke and Polluted Air

Smoking is the best-documented depleter, and the effect is large enough that official intake targets account for it. The Food and Nutrition Board sets an extra 35mg per day for people who smoke, specifically because smoking raises both oxidative stress and the metabolic turnover of vitamin C. That brings the target to 125mg for men and 110mg for women.

Two mechanisms are working at once. Smoke delivers oxidants that vitamin C is spent neutralising, and the body clears the vitamin faster. Studies consistently find that people who smoke carry lower plasma and leukocyte vitamin C than non-smokers, and secondhand smoke exposure lowers levels too, though no separate intake figure has been set for it.

Air pollution appears to work along similar lines. A 2020 review of global vitamin C status identified pollution as an environmental factor affecting status, partly through enhanced oxidative stress, alongside season, geography and climate. The evidence here is weaker than for smoking, and no intake adjustment exists for it. If you smoke, the more detailed picture is in our article on why vitamin C requirements are higher for smokers.

3. Alcohol

Alcohol depletes vitamin C through two routes at once, and the combined effect is striking in heavy drinkers. In a study of 69 patients with alcohol use disorder admitted to a medical intensive care unit, mean admission vitamin C was 17.0 μmol/L against a normal range of 40–60, with 88% below 40 and 75% meeting the threshold for hypovitaminosis C.

The mechanisms behind those numbers are reasonably well described. Ethanol has a direct toxic effect on the cells lining the gut, which interferes with absorption of several nutrients including vitamin C. Alcohol also significantly increases urinary loss, so intake and excretion move in the wrong direction at the same time.

One honest limitation: this research sits almost entirely in heavy or dependent drinkers, usually hospitalised, and diet is a confounder throughout. A cohort with a mean level of 17.0 μmol/L tells you nothing about what two glasses of wine on a Friday does to your vitamin C status, and nobody should read these figures as applying to moderate drinking.

4. Infection, Injury and Surgery

Inflammation consumes vitamin C quickly, which is why hospital populations show far higher deficiency rates than the general public. A retrospective study of 1,791 adult inpatients across five Australian hospitals found vitamin C deficiency in 23.2% of acute admissions, rising to 30% in patients with malnutrition and 37.3% in those admitted to intensive care.

Surgery produces the same pattern on a shorter timeline. Plasma ascorbic acid falls after cardiac surgery through the generation of reactive oxygen species, and from an already low baseline it drops further as inflammation continues. Our article on vitamin C and wound healing after surgery covers the recovery data in more detail.

Two caveats matter, and the same Australian study supplies one of them. Deficiency in that cohort was not associated with in-hospital death, length of stay, or hospital-acquired complications — levels fell, but the fall did not predict outcomes. Several high-quality randomised trials of vitamin C in sepsis have likewise found no reduction in organ dysfunction or mortality. Depletion during serious illness is well established. The treatment case is not, and an ordinary winter cold is not equivalent to any of this.

5. Medications That Quietly Lower It

Several common medicines lower vitamin C levels, generally by increasing urinary loss or interfering with uptake. The effects are modest individually, and none of them is a reason to stop a prescribed drug.

• Proton pump inhibitors. In 29 volunteers taking omeprazole 40mg a day for 28 days, mean plasma vitamin C fell by 12.3%. Stomach acid stabilises the vitamin, so raising gastric pH reduces its bioavailability.
• Estrogen-containing oral contraceptives. Plasma, leukocyte and platelet ascorbic acid are lower in women taking them, with the estrogen component identified as the driver rather than the progestin.
• Aspirin and NSAIDs. A 2024 review of 45 drug–nutrient interactions found that aspirin affects both the absorption and the excretion of vitamin C.

The clinical importance of these losses is genuinely unclear, and the researchers reporting them say so directly. A 12.3% drop in someone whose intake sits comfortably above 90mg a day is unlikely to matter. The same drop in someone who smokes, drinks, and eats little fresh produce is a different proposition. If you take any of these long term, the fuller picture is in our guide to vitamin C interactions with medications and supplements — and speak to your physician rather than adjusting anything yourself.

6. What Cooking and Storage Take First

A meaningful share of the vitamin C in fresh produce never reaches you. Vitamin C is destroyed by heat and dissolves into cooking water, so losses depend heavily on method and holding time. A systematic review of food prepared in hospitals and care facilities recorded losses from 36.4% in boiled carrots up to 88.6% in steamed green beans that were then hot-held.

Chilling and reheating add more. The same review found blast chilling removed 63% of the vitamin C in cabbage and 73% in peas. Home cooking is gentler but not trivial — a 2023 analysis of six commonly eaten vegetables found boiling losses from 9.83% to 70.88%, with spinach worst affected, while microwaving preserved over 90% because of the minimal water contact.

Storage matters before cooking even starts. The NIH notes that vitamin C in food is reduced by prolonged storage as well as by cooking, which is one reason frozen produce sometimes tests higher than fresh. If you are trying to cover your intake through food, our article on foods high in vitamin C works through what survives to the plate.

7. When Losses Are High, Absorption Matters More

If something in your life is raising your losses, the practical question becomes how much of what you take in actually gets absorbed. That is where delivery format enters the conversation, because absorption efficiency falls as the dose climbs — a point worked through in our article on why most of a vitamin C dose is wasted.

Bio Absorb Nutraceuticals makes Liposomal Vitamin C in two formats: Liposomal Vitamin C Liquid 1000mg (Corn-Free), which mixes with water or juice and carries a natural orange flavour, and Liposomal Vitamin C Capsules 1000mg (Corn-Free), which need no refrigeration and travel without fuss. Both use phospholipid encapsulation, and both are verified corn-free — worth knowing, since nearly all commercial ascorbic acid starts as corn and most brands do not address it.

Both formats share the same standards: non-GMO, gluten-free, nut-free, dairy-free and vegan, made in a GMP-certified Canadian facility, non-irradiated, and third-party tested every batch. Both are backed by a money-back guarantee with no need to return empty bottles. See the product pages above for current pricing and serving details.

One thing worth stating plainly: the absorption advantage of liposomal delivery is well supported, but whether it changes health outcomes in someone whose vitamin C status is already adequate has not been established. Better absorption is a real benefit when your losses are genuinely elevated. It is not a benefit in search of a problem.

Frequently Asked Questions

Does stress deplete vitamin C?

Your adrenal glands hold some of the highest vitamin C concentrations in the body, which is where this idea comes from, and physical stressors like surgery and infection clearly drive levels down — deficiency reached 37.3% in patients who spent time in intensive care. Whether ordinary psychological stress does the same is far less certain, and the human evidence is thin. Treat it as plausible rather than established.

How long does it take to become deficient?

Faster than most people assume. The whole-body pool of roughly 1,500mg can be depleted in 1 to 3 months without intake, and scurvy develops once the pool falls below about 350mg. Low-level insufficiency arrives much sooner than that, and usually without symptoms you would notice.

Does exercise deplete vitamin C?

Hard training raises oxidative stress, and vitamin C is spent dealing with it. The complication is that high sustained doses have been shown to blunt some training adaptations, so more is not automatically better for athletes. Our article on vitamin C for athletes covers where that line sits.

Do coffee and tea deplete vitamin C?

There is no good evidence that either drains vitamin C directly. The more realistic issue is what they displace — if a morning coffee replaces fruit or juice, intake falls for straightforward reasons rather than any effect of the drink itself.

Can I cover the losses with food alone?

Often yes, but the margin is thinner than it looks once cooking losses of 36.4% to 88.6% are accounted for. National data show 41.8% of US adults already sit at insufficient plasma levels, and that figure has barely moved between 2003–2006 and 2017–2018 despite smoking rates falling.

Should I take more than the RDA if I smoke or drink?

For smoking, the official answer is yes — an additional 35mg a day, which one orange roughly covers. For alcohol, no formal adjustment exists, because the research sits in heavy drinkers rather than the general population. The tolerable upper intake level of 2,000mg a day applies either way. Anyone with kidney disease, a history of kidney stones, haemochromatosis or another iron-overload condition, or a regular medication routine should speak with a physician before supplementing at meaningful doses.

Conclusion

Vitamin C depletion is rarely one dramatic cause. It is usually a few ordinary things stacking up — a pack a day, a course of omeprazole, boiled vegetables, a rough month — against a body pool that holds no reserve. With 41.8% of US adults already at insufficient levels, the margin for those losses is smaller than it looks. If you want to understand the absorption side of the problem, start with our complete guide to liposomal vitamin C.

Research References

1. Insufficient Vitamin C Levels among Adults in the United States: Results from the NHANES Surveys, 2003–2006. Nutrients, Vol. 13, Issue 11 (2021). Found that 41.8% of US adults had insufficient plasma vitamin C, with smokers, higher BMI and food insecurity significantly associated — the baseline prevalence figure used throughout this article.
2. The Prevalence, Risk Factors, and Clinical Outcomes of Vitamin C Deficiency in Adult Hospitalised Patients: A Retrospective Observational Study. Nutrients, Vol. 17, Issue 7 (2025). Retrospective study of 1,791 inpatients across five Australian hospitals; found deficiency in 23.2% of acute admissions, 30% of malnourished patients and 37.3% of ICU patients, and reported no association with clinical outcomes.
3. Adding an orange to the banana bag: vitamin C deficiency is common in alcohol use disorders. Critical Care, Vol. 23 (2019). Reported mean admission vitamin C of 17.0 μmol/L in 69 intensive care patients with alcohol use disorder, with 88% subnormal and 75% meeting the hypovitaminosis C threshold.
4. Proton pump inhibitors reduce the bioavailability of dietary vitamin C. Alimentary Pharmacology & Therapeutics, Vol. 22, Issue 6 (2005). Measured plasma vitamin C before and after omeprazole 40mg daily for four weeks in 29 subjects; mean level fell 12.3% (P = 0.04), independently of dietary intake.
5. Potential Drug–Nutrient Interactions of 45 Vitamins, Minerals, Trace Elements, and Associated Dietary Compounds with Acetylsalicylic Acid and Warfarin — A Review of the Literature. Nutrients, Vol. 16, Issue 7 (2024). Review identifying effects of acetylsalicylic acid on vitamin C absorption and excretion.
6. Oral contraceptives and ascorbic acid. American Journal of Clinical Nutrition, Vol. 28, Issue 5 (1975). Found reduced plasma, leukocyte and platelet ascorbic acid in women taking estrogen-containing oral contraceptives, with the estrogenic component identified as the driver.
7. Food cooking methods contribute to the reduced vitamin C content of foods prepared in hospitals and care facilities: a systematic review. International Journal of Food Science and Technology, Vol. 54, Issue 1 (2019). Documented vitamin C losses from 36.4% to 88.6% across cooking, holding and chilling processes.
8. Effect of cooking methods on the nutritional quality of selected vegetables at Sylhet City. Heliyon, Vol. 9, Issue 11 (2023), article e21709. Found boiling losses of 9.83% to 70.88% across six vegetables, with spinach worst affected, and over 90% retention with microwaving.
9. Factors Affecting Vitamin C Status and Prevalence of Deficiency: A Global Health Perspective. Nutrients, Vol. 12, Issue 7 (2020). Narrative review identifying dietary, cultural and environmental influences on vitamin C status, including pollution acting partly through oxidative stress.
10. Vitamin C Status of US Adults Assessed as Part of the National Health and Nutrition Examination Survey Remained Unchanged between 2003–2006 and 2017–2018. The Journal of Applied Laboratory Medicine, Vol. 8, Issue 2 (2023). Showed US vitamin C status essentially unchanged across fifteen years despite falling smoking rates.
11. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Institute of Medicine, Food and Nutrition Board (2000). The primary source for the additional 35mg per day recommended for people who smoke, based on increased oxidative stress and metabolic turnover.
12. Vitamin C Fact Sheet for Health Professionals. National Institutes of Health, Office of Dietary Supplements. Establishes the RDA, the additional smoker requirement, the 2,000mg tolerable upper intake level, and the finding that secondhand smoke exposure also lowers vitamin C levels.
13. Vitamin C Fact Sheet for Consumers. National Institutes of Health, Office of Dietary Supplements. Source for the reduction of food vitamin C through prolonged storage and cooking, and for the approximately 10mg per day threshold below which scurvy develops.
14. Scurvy (Vitamin C Deficiency): Practice Essentials, Pathophysiology, Etiology. Medscape eMedicine. Source for the approximately 1,500mg whole-body vitamin C pool, its depletion within 1 to 3 months, and the 350mg threshold at which scurvy appears.

About the Author

David Kimbell is a health writer, digital entrepreneur and former aerospace engineer, based in Ottawa, Canada. He loves translating complex science into clear, actionable guidance for consumers seeking evidence-based solutions.

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Important Disclaimers

Medical Disclaimer: This article provides educational information only and is not intended as medical advice. Always consult with a qualified healthcare provider before starting any new supplement, especially if you have existing health conditions, take medications, or are pregnant or nursing.

FDA/Health Canada Statement: These statements have not been evaluated by the Food and Drug Administration or Health Canada. This product is not intended to diagnose, treat, cure, or prevent any disease.