Why stress depletes your vitamin C and B vitamins & what to do about it

Article by Olivier Sanchez ND, NT Dip, Ir

Most nutrition content tells you which vitamins may help your body manage stress. Sure, supplementation can help, but it overlooks something more important: stress actively depletes key nutrients, creating a cycle in which stress makes you more depleted, and depletion makes you less able to handle stress. This is a direct physiological consequence of how your body responds to pressure. 

The adrenal glands, which produce cortisol, contain the highest concentration of vitamin C in the body. Several B vitamins and magnesium are consumed at higher rates during the stress response. When stress is chronic, requirements increase faster than most people realise. Stress also suppresses digestive capabilities and disturbs the gut microbiome, leading to deficiencies and further compounding the problem. 

Understanding these mechanisms is what turns “I should take my vitamins” into “I actually need to do something about this.”

Vitamin C and the adrenal glands

The adrenal glands sit on top of your kidneys and are central to your stress response. When activated during acute and chronic stress, infection or illness, vitamin C is used at an accelerated rate to support cortisol production and protect adrenal tissue from oxidative damage. 

What vitamin C depletion looks like

Vitamin C depletion doesn’t always manifest as scurvy. More often, it shows up as: 

• Persistent fatigue that doesn’t match your activity level
• Increased susceptibility to colds and infections
• Slower wound healing and easy bruising
• Lower mood and irritability 

These are symptoms many stressed people already experience, yet they rarely attribute these to vitamin C depletion.

How much more vitamin C do you need under stress?

The standard reference nutrient intake (around 40 mg/day for both men and women in the UK) was set for a healthy, non‑stressed adult in 1953. This is less than half the recommended intake in the U.S. Under chronic stress, the demand is multiple times higher. While the required intake varies by individual and stress load, it may be essential to increase the body’s pool of vitamin C, especially for those with limited fruit and vegetable intake. 

This may be relevant for anyone, because during sustained stress, food alone may not be enough, and the doses used in studies are often 1,000–2,000 mg. However, higher doses can cause gastrointestinal upset in some people, so it is generally best to split the dose into 3–4 smaller amounts throughout the day.

The B vitamin drain

Vitamin B5, B6, B12 and folate play direct roles in stress metabolism, neurotransmitter production and nervous system function, and chronic stress sequesters stores through several mechanisms.

Vitamin B5 (pantothenic acid)

Vitamin B5 is required for cortisol synthesis and energy metabolism in the adrenal glands. Demands increase under chronic stress. Low B5 status has been linked to fatigue, poor stress tolerance and impaired adrenal function, creating a vicious cycle: low reserves make it harder to mount an effective stress response, which in turn increases strain on the adrenals.

Vitamin B6

Vitamin B6 is a cofactor for the synthesis of serotonin and GABA; two neurotransmitters essential for mood regulation and stress resilience. Deficiency, high cortisol, and accelerated production of these calming and balancing neurochemicals heavily draw down available B6 reserves, potentially worsening anxiety, low mood and irritability.

Vitamin B12 and folate

Stress also depletes B12 and folate through increased metabolic demand and methylation, making it more difficult for the body to clear homocysteine, a compound that, when elevated, is associated with increased anxiety, low mood and cognitive decline, as well as cardiovascular complications. This is particularly relevant for vegans and vegetarians, who may already have lower B12 reserves and higher homocysteine risk. 

The depletion cycle - and how to break it

Chronic stress depletes nutrients, which reduces resilience. In turn, this increases cortisol output and further nutrient depletion. A self-feeding loop, also known as the depletion cycle. Breaking it requires interrupting the loop at a few key nutrients so your body can catch up:

• Vitamin C-rich foods: Bell peppers (especially red), kiwi, broccoli, citrus fruits, berries and leafy greens are among the richest sources. A large red pepper or a couple of kiwis can cover a full day’s baseline needs for many people.
• B vitamin-rich foods: Nutritional yeast, whole grains, legumes, leafy greens, eggs, meat and fish. Most B vitamins, including B5, are mostly absent in highly processed diets. 

Under significant chronic stress, food alone may not replenish fast enough, especially if appetite is poor or digestion is suppressed by the stress response.

When to supplement - and what to look for

During periods of sustained stress, targeted supplementation can help interrupt the depletion cycle. 

• Vitamin C: Look for well‑tolerated forms such as buffered ascorbate or 'food‑state' vitamin C if you have a sensitive stomach. Split doses to prevent gastrointestinal discomfort. 
• B vitamin-rich foods: A balanced B complex can help cover increased demand.

Key features to look for include:

• Methylated forms of B12 (methylcobalamin) and folate (methylfolate), especially if you have a known MTHFR variant or elevated homocysteine.
• Adequate B5 and B6. While the respective recommended intake is around 5-7mg, and 1.2 to 1.8mg per day, B5 is water soluble, meaning excess amounts are generally excreted in the urine.

A good multivitamin such as DR.VEGAN^® Women’s ProMulti or Men’s ProMulti can serve as a foundational layer, with additional vitamin C or B complex added during particularly demanding periods.

Important Facts to Remember

Stress exhausts you and changes your nutrient requirements. Vitamin C and several B vitamins are used up faster when cortisol is high, and depletion in turn makes it harder to cope with stress. It is necessary to recognise that during periods of stress, your minimum requirements are higher, and that diet, sleep and targeted supplementation are all legitimate tools to break the 'depletion cycle.'

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