What Does Vitamin C Actually Do for Women Under Stress?

Vitamin C is not just an immune nutrient. It is one of the most important cofactors in your adrenal glands, which are the organs responsible for producing cortisol. Research published in the American Journal of Clinical Nutrition and accessible via PubMed was the first to demonstrate in humans that adrenocorticotrophic hormone (ACTH) stimulation causes adrenal vitamin C to be secreted alongside cortisol, confirming that adrenal vitamin C release is a direct part of the stress response. The adrenal glands contain among the highest concentrations of vitamin C in the body precisely because cortisol synthesis depends on it. When you are under chronic stress, that reserve is being depleted faster than most women realize, and the consequences show up in immunity, skin, and energy long before the shortage becomes obvious.

Why the adrenal glands have such a high concentration of vitamin C

Vitamin C acts as a cofactor for enzymes involved in glucocorticoid biosynthesis in the adrenal cortex. In plain terms, your adrenal glands use vitamin C as a raw material to make cortisol. Research published in Frontiers in Endocrinology confirmed that vitamin C modulates the HPA axis by acting as a cofactor for 11-beta-hydroxylase, the enzyme that converts a cortisol precursor into cortisol itself, and that ascorbate helps maintain cortisol levels within physiological ranges. The adrenal glands concentrate vitamin C at levels far above most other body tissues so that this supply is available on demand during stress activation.

The problem is that each stress event draws on that reserve. Acute stress depletes adrenal vitamin C rapidly as the glands respond to ACTH signaling. Under chronic stress, the rate of depletion can outpace the rate of replenishment from diet and supplementation, especially in women whose vitamin C intake is already insufficient.

According to the nationally representative NHANES data cited in PubMed Central, approximately 46% of US adults fall below the estimated average requirement for vitamin C. Nearly half the adult population is not meeting even the minimum threshold for this nutrient, and that is before accounting for the elevated demand that chronic stress creates.

The stress-immunity-skin connection

Vitamin C's role in immunity is well established, but it connects to stress in a way that most women have not been told. Chronic cortisol elevation suppresses immune function by design, because running a full immune response is metabolically expensive and the stress system deprioritizes it during threat mode. Vitamin C is a key nutrient for both arms of this system: it supports cortisol synthesis in the adrenal glands, and it directly supports immune cell function, particularly natural killer cells and neutrophils.

For women cycling through chronic stress, this creates a compounding shortfall: stress depletes adrenal vitamin C, immune function is already cortisol-suppressed, and the vitamin C needed to support both systems is being drawn down simultaneously. The result is a woman who gets sick more often, heals more slowly, and feels chronically run-down in ways that do not fully resolve with rest.

Skin is the third system in this triad. Vitamin C is the primary cofactor for collagen synthesis. Collagen is the structural protein in skin, tendons, blood vessel walls, and connective tissue throughout the body. Under chronic stress, when vitamin C is being redirected to adrenal function, collagen synthesis is deprioritized. Women who notice their skin becoming dull, thinner, or less resilient during periods of high stress are often observing this mechanism in action.

"If we teach women about their bodies and teach them what is actually normal versus what is abnormal, that education can make a real difference earlier on."

— Dr. Samantha Ess, ND, Naturopathic Doctor specializing in hormone health and fertility

Iron absorption: the third reason vitamin C matters more than you think

Vitamin C significantly enhances the absorption of non-heme iron, the form of iron found in plant foods and most iron supplements. This is a nutrient interaction that matters practically for every woman who is trying to maintain healthy iron status. According to the NIH Office of Dietary Supplements, consuming vitamin C alongside non-heme iron sources significantly increases total iron absorption, and dietary components like ascorbic acid are among the most important enhancers of non-heme iron bioavailability.

For women who are iron-depleted, borderline anemic, or simply trying to maintain healthy iron status through a diet that is not high in red meat, the vitamin C in their supplement is not a nice-to-have. It is doing functional work on iron absorption every time they take it.

Why prenatal-grade vitamin C formulation matters

Most standard multivitamins include a token amount of vitamin C, often 60 to 100 mg, at or just above the RDA. That is a minimum floor, not an amount calibrated to the adrenal demands of a woman under chronic stress or the iron absorption needs of a woman with heavy cycles.

Prenatal vitamins are formulated to a higher standard partly because the demands of pregnancy and preconception create elevated vitamin C requirements alongside elevated iron requirements. The ACOG-recommended nutrient profile for pregnancy includes vitamin C specifically as part of its recommended daily nutrient framework for pregnant women.

Pink Stork's our clean-label prenatal with 5-MTHF and iron bisglycinate includes vitamin C alongside iron bisglycinate chelate (Ferrochel), which means the iron and the vitamin C that enhances its absorption are both present in a single daily supplement.† It is formulated for preconception through breastfeeding, third-party tested at ISO 17025 accredited labs, non-GMO, gluten-free, and cGMP-certified. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition.

"I think so many things can be avoided if there's just prevention."

— Dr. Samantha Ess, ND, Naturopathic Doctor specializing in hormone health and fertility

Practical ways to support vitamin C status under stress

The RDA for vitamin C is 75 mg for adult women and 85 mg during pregnancy. These are baseline prevention thresholds. Women under chronic stress may benefit from higher dietary intake, and consuming vitamin C consistently across the day is more effective than a single large dose because the body does not store vitamin C and excess is excreted. Food sources include citrus, bell peppers, kiwi, strawberries, and broccoli. Supplementation fills the gap when diet is insufficient or stress demands are elevated.

For women also navigating iron depletion alongside stress, pairing vitamin C with iron-containing meals or iron supplements is a practical strategy that meaningfully increases absorption without requiring any change to the iron source.

"Empowering women at every stage of their journey."

— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

For the full picture of how the HPA axis and cortisol biology work in women, read why stress hits women differently than men. For how women's supplements should be formulated to address the full range of female nutritional demands, read whether women's supplements are actually formulated for women.

Frequently asked questions

Why do the adrenal glands need so much vitamin C?

The adrenal glands concentrate vitamin C at higher levels than most body tissues because vitamin C is a cofactor for the enzymes that synthesize cortisol. Every time the adrenal glands respond to ACTH and produce cortisol, vitamin C is used and secreted as part of that process. Chronic stress creates a persistent draw on this reserve.

Does stress deplete vitamin C?

Yes, in a measurable way. Research has shown that adrenal vitamin C is secreted alongside cortisol in response to ACTH stimulation, meaning each stress activation draws on the adrenal vitamin C reserve. Under chronic stress, the depletion rate can exceed replenishment from diet alone for women who are not consistently meeting their vitamin C requirements.

How much vitamin C do women need under stress?

The RDA of 75 mg is a minimum prevention threshold, not an optimal intake for women under chronic stress. Many researchers suggest that higher intakes may better support adrenal function and immune resilience under sustained stress conditions, though specific therapeutic doses should be discussed with a healthcare provider.

Does vitamin C help with iron absorption?

Yes. Vitamin C is one of the most potent enhancers of non-heme iron absorption. Consuming vitamin C alongside iron-containing foods or iron supplements increases the amount of iron absorbed. This interaction is particularly relevant for women who are iron-depleted or who rely primarily on plant-based iron sources.

Can vitamin C support skin health during stress?

Vitamin C is the primary cofactor for collagen synthesis. During periods of chronic stress, when vitamin C is being used heavily by the adrenal glands, collagen synthesis can be compromised. Maintaining adequate vitamin C intake supports both adrenal function and skin structural integrity.†

Is the vitamin C in a prenatal vitamin enough to support adrenal function?

The vitamin C in a quality prenatal provides a consistent daily baseline that covers both the iron absorption and baseline adrenal support functions. Whether additional supplementation is warranted depends on individual stress levels, dietary intake, and other health factors. A conversation with your healthcare provider can help calibrate the right approach for your situation.

† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.