Vitamin C

Vitamin C (ascorbic acid) is a water-soluble essential vitamin that humans cannot produce internally and must obtain through diet or supplements. It's crucial for numerous bodily functions including immune support, collagen synthesis, wound healing, and antioxidant protection. While vitamin C won't prevent colds in most people (contrary to popular belief), it can reduce cold duration and severity, particularly in people under physical stress. The vitamin supports white blood cell function and is depleted during illness. Vitamin C is also essential for producing collagen (the protein that forms skin, tendons, ligaments, and blood vessels), supports iron absorption, and protects cells from oxidative damage. Deficiency causes scurvy, though severe deficiency is rare in developed countries. However, subclinical deficiency is more common and can affect immune function and healing. Most people can get adequate vitamin C from diet (citrus fruits, berries, peppers, broccoli), but supplementation may benefit those with inadequate intake, during illness, or under stress.

Vitamin C supports immune function through multiple mechanisms. It accumulates in white blood cells (neutrophils and lymphocytes) and enhances their ability to fight infections. It protects immune cells from oxidative damage caused by fighting pathogens. Vitamin C supports the production and function of antibodies and interferon. As an antioxidant, it donates electrons to neutralize free radicals, protecting cells and tissues from oxidative stress. It's essential for collagen synthesis through its role in hydroxylating proline and lysine residues. Vitamin C enhances iron absorption from plant sources by converting iron to its more absorbable form. It regenerates other antioxidants like vitamin E. Being water-soluble, excess is excreted in urine rather than stored, requiring regular intake.

Extensive evidence base - one of the most studied vitamins. Large body of research on immune function. Meta-analyses show vitamin C reduces cold duration (8% adults, 14% children) when taken regularly, but doesn't prevent colds in general population. Does reduce cold incidence in people under extreme physical stress (marathon runners, soldiers in extreme cold). Role in collagen synthesis and wound healing well-established. Antioxidant effects extensively documented. Safety profile extremely well-characterized. Requirements during illness higher than baseline. Overall: strong evidence for immune support and other functions, though doesn't prevent colds in most people as once believed.

Vitamin C is vitamin C - synthetic ascorbic acid identical to natural. Choose: Pure ascorbic acid or calcium/sodium ascorbate (buffered forms easier on stomach), Third-party tested (USP, NSF), Time-release formulas for sustained levels, Liposomal vitamin C for enhanced absorption (premium option), Powder form economical for high doses. Avoid: Products with unnecessary additives, Very expensive 'natural' vitamin C (synthetic is identical molecularly and cheaper), Products making exaggerated claims. Store in cool, dry place away from light. Shelf life 2-3 years.