Tips for maximum absorption of vitamin C from food & supplements.

How much vitamin C can be absorbed? Do we need supplements? When should we take them?
Vitamin C supplements.

We can’t synthesize vitamin C. We must take vitamin C from food. Vegetables and fruits are the only foods that contain adequate amounts of vitamin C. This articles contain tips for maximum absorption of vitamin C.

How much vitamin C can be absorbed?

When consuming vitamin C, the body produces tissue and plasma concentrations. The vitamin C absorption depends on the dose (6).

  • moderate intakes of 30–180 mg/day are absorbed to 70% – 90%.
  • high doses more than 1000 mg/day are absorbed to less than 50%.

Excess vitamin C is excreted through urine.

Studies have shown that even relatively high doses of vitamin C won’t elevate the vitamin C plasma concentrations (6). For instance,

  • 200 – 300 mg/day vitamin C consumed by food, produced plasma vitamin C concentrations of 70 micromol/L,
  • 1250 mg/day produced plasma vitamin C concentrations of 135 micromol/L,
  • 18000 mg/day can produce peak plasma concentrations no more than 220 micromol/L.

Actually, excess vitamin C is excreted through urine. The recommended daily intake of vitamin C is 90 mg. We can take this dose from food.

You better split your daily dosage of vitamin C

You can improve absorption rates, decreasing the dose of vitamin C. So, you should take many lower doses of vitamin C throughout a day, than a huge dose in the morning! Moreover, you’ll have high plasma concentrations of vitamin C all day long.

When should I take vitamin C?

Vitamin C is a water-soluble vitamin. It means that it dissolves in water. Most importantly, water-soluble vitamins don’t store in the body in high concentrations. So, vitamin C supplements are considered pretty safe. Even a daily dose of 1000 mg of vitamin C is pretty safe. But, in most case, it’s a waste of money. Our body will absorb only a small percentage! Better cut vitamin C pills in half.

As vitamin C is a water-soluble vitamin it can easily be absorbed on an empty stomach. This may be a problem for some people upsetting digestion, or causing diarrhea. In this case, better take vitamin C supplements with a meal to avoid digestion problems.

Moreover, you better take the highest dose of vitamin C in the morning. You’ll boost your immune system and protect your body from free radicals. For instance, vitamin C, along with vitamin E protects your face, fighting oxidative stress from pollution and preventing damage from sunlight.

Also, vitamin C helps prevent eye-related diseases, such as macular degeneration, as it’s a strong antioxidant (7). Vitamin C is vital for good eyesight and weight loss.

Supplements or food for better vitamin C absorption?

Supplemental vitamin C typically takes about two hours to reach maximum plasma levels.

Additionally, ascorbic acid from food and supplements seems to be equally bioavailable (8). Synthetic and food-derived vitamin C is equally bioavailable in humans (2). According to a recent study, vitamin C from kiwi fruit is comparable to synthetic (5).

Certainly, vitamin C from food is a better source of vitamin C, compared to supplements. Food provides many other macronutrients, micronutrients, and phytochemicals which cooperatively provide additional health benefits (2).

Phytochemicals like flavonoids may affect the bioavailability of food-derived vitamin C. Flavonoids act as antioxidants, effectively fighting free radicals (5).

Can you absorb vitamin C through the skin?

If you’re deficient in vitamin C, creams with vitamin C can help you. Applying vitamin C topically is preferred for skin therapies (3). On the contrary, oral bioavailability of vitamin C is much lower. Only a percentage of vitamin C is absorbed.

But, there is no need for topical application of vitamin C, if the health of the patient is optimal. In this case, there the absorption of vitamin C through the skin is also minimum. A well-balanced nutrition can be more effective than topical application of vitamin C (4)!


  1. NCBI – PMC: Vitamins and Sleep: An Exploratory Study
  2. NCBI – PMC: Synthetic or Food-Derived Vitamin C—Are They Equally Bioavailable?
  3. NCBI – PMC: Vitamin C in dermatology
  4. NCBI – PMC: The Roles of Vitamin C in Skin Health
  5. NCBI – PMC: A Randomised Cross-Over Pharmacokinetic Bioavailability Study of Synthetic versus Kiwifruit-Derived Vitamin C
  6. National Institutes of Health – Vitamin C
  7. NCBI – PMC: Nutrients for Prevention of Macular Degeneration and Eye-Related Diseases
  8. NCBI – The bioavailability to humans of ascorbic acid from oranges, orange juice, and cooked broccoli is similar to that of synthetic ascorbic acid.