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ingestible · for adrenal fatigue

Vitamin C (High-Dose)

Reviewed by the Nimbera editorial team · Last updated May 2026

A placebo-controlled trial found that ultramarathon runners supplementing 1,500 mg/day vitamin C had cortisol concentrations 30% lower post-race than placebo, demonstrating significant attenuation of stress-induced HPA activation.$10-$30 per month

How to use

Take 1,000-2,000 mg of ascorbic acid or buffered vitamin C (sodium ascorbate) daily in 2 divided doses with meals. Liposomal forms improve absorption at higher doses.

How it works

The adrenal cortex has the highest concentration of vitamin C in the body - it is co-released with cortisol during ACTH stimulation and is required for steroidogenesis enzyme function. Adequate levels buffer cortisol overshoot and speed recovery of adrenal tissue after stress bursts.

Where to buy

Thorne, Pure Encapsulations (buffered C), LivOn Labs (liposomal), or bulk ascorbic acid from supplement retailers.

Typical cost: $10-$30 per month

Safety notes

Doses above 2,000 mg/day may cause digestive upset or diarrhea (use buffered form to reduce GI irritation). Can interfere with some cancer therapies. Consult a doctor if you have a history of kidney stones, as high oxalate excretion is possible at very high doses.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

PubMed - Peters et al. 2001

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.