What are the signs of vitamin C deficiency?

Signs of scurvy can appear within about a month of intake below roughly 10 mg a day.

Who is most likely to run low

People who smoke or are exposed to second-hand smoke are at higher risk of vitamin C inadequacy.

What this means for you

Real vitamin C deficiency is rarer than the internet suggests and more dramatic than people expect. Below roughly 10 mg a day, signs of scurvy can appear within about a month. That means a diet with essentially no fruit and no vegetables in any form, for weeks.

The early picture is tiredness, irritability and aching legs. Then the specific signs arrive, and they come from collagen failing. Gums swell and bleed when you brush. Small red dots appear around hair follicles, often on the thighs and shins, and body hairs grow in coiled and corkscrewed. Bruises appear from nothing. Old wounds and scars reopen.

Established. Those follicle signs are the ones doctors look for, because bleeding gums alone have many causes. Scurvy responds to vitamin C within days, and the recovery is one of the fastest in nutritional medicine.

Who actually gets it

People whose diets have no variety at all: long-term heavy drinkers, people living alone in poverty, people with severe eating disorders or restrictive autism-related diets, people in institutions. It also shows up after months of a diet built entirely on refined food. Smoking raises the requirement, and people who smoke or live with smokers are at higher risk of running inadequate.

Bleeding gums arrive before scurvy does

Everything above describes a diet with almost nothing in it. There is a milder state below that, and it has been measured.

Established. Across 15 trials in 1,140 people, vitamin C supplements cut how readily gums bleed, and the size of the effect depended entirely on where people started. Below 28 micromoles per litre of plasma the reduction was large. Above 48 it was small and barely cleared zero. In someone who is genuinely low, bleeding gums are a sign that reverses.

Unsettled. What that says about the target is awkward. In a survey of 8,210 Americans, people whose plasma sat between 11 and 28 micromoles per litre, the range that keeps scurvy away, had about half again as much gum bleeding and retinal bleeding as people above it. Survey data shows association rather than cause. It points the same way as the trials in the same paper, and together they suggest the level that prevents the disease sits below the level that stops the bleeding. Nobody has settled where the second one is.

Not for everyone. Severe deficiency can reach the lungs, which is on nobody's list of vitamin C signs. In 32 published cases where deficiency was judged to be the cause, pressure in the lung arteries ran at a median of 48 mmHg while people were deficient and 20 mmHg after vitamin C was started. Breathlessness was reported in about seven cases in ten and swelling in half. These are individual case reports with no control group, the cases that did not improve are less likely to have been written up, and other treatments were running at the same time.

Myth. Low mood is not a sign of running short of vitamin C, whatever the supplement aisle implies. Ten trials in 836 people measured it and found nothing. A subgroup of five trials in people not taking antidepressants showed a small effect that only just cleared significance, and the researchers who found it call it tentative and ask for more work before anyone leans on it.

If you eat produce at all, this is not your problem. Five varied servings of fruit and vegetables a day can supply more than 200 mg, twice the requirement. Cooking does take a toll, since vitamin C dissolves in water and breaks down in heat, so keep some of what you eat raw or steamed rather than boiled.

One thing worth separating from the deficiency question, since it is why most people buy vitamin C at all. Taking it regularly does not reduce the chance of catching a cold in the general population, and it shortens one slightly, by about 8 per cent in adults and 14 per cent in children. Scurvy is a different matter entirely, and it responds to ordinary amounts of vitamin C rather than to the doses sold for colds.

One population is a genuine exception to everything above about colds and vitamin C. In five trials in 598 marathon runners, skiers and soldiers on subarctic exercises, daily vitamin C halved the chance of catching a cold. Severe physical stress in the cold is a different situation from ordinary life, and it is the one place the prevention claim holds up. the review of both is here.

If most of your vitamin C arrives in a glass

A third of the vitamin C Americans take in comes from drinks rather than from anything on a plate. That is worth knowing if you are wondering whether you are drifting low, because a drink is the form that loses it quietly. Orange juice made up from frozen concentrate held 117 mg per 8 fl oz when it was opened and 89 mg a week later in the fridge. Chilled juice hardly changed, 69 to 64. The carton is not misleading you. The number on it belongs to the day it was filled, and a week of fridge door counts against it.

Written from the evidence cards and the data on this page, then checked back against the sources. Bioma Learn has no human medical reviewer at this time and we say so rather than invent one. Information, not medical advice. How we verify.

Where to get it from food

• Guavas, common, raw — 376.7 mg per 1 cup (419% DV)
• Guava sauce, cooked — 348.4 mg per 1 cup (387% DV)
• Grapefruit juice, white, frozen concentrate, unsweetened — 248 mg per 1 can (6 fl oz) (276% DV)
• Apple juice, grape and pear blend, and calcium — 126.8 mg per 8 fl oz (141% DV)
• Lemons, raw, without peel — 112.4 mg per 1 cup, sections (125% DV)

All vitamin C sources ranked →

Full guide: Vitamin C: what it does, how much you need, and what it will not do