Last updated March 2026
Vitamin C
Fireblood includes 500 mg of ascorbic acid per serving, well above the 90 mg RDA. This dose keeps tissues saturated to support immune function, collagen synthesis, and iron absorption, based on research showing tissue saturation occurs around 200-400 mg daily (Levine et al., PNAS, 1996).
What Vitamin C Does
Collagen is the most abundant protein in your body. It holds together your skin, tendons, ligaments, blood vessels, and bones. Your body cannot make collagen without vitamin C. When C runs low, collagen production stalls. Historically and literally, that is scurvy.
Vitamin C also supports both innate and adaptive immune function. It helps white blood cells do their job and acts as an antioxidant against oxidative stress. Carr and Maggini (Nutrients, 2017) reviewed the evidence and found that vitamin C contributes to immune defense at multiple levels, from barrier function to antibody production.
There is a practical bonus too. Vitamin C significantly improves absorption of non-heme iron, the type found in plant foods and supplements. If you eat iron-rich foods alongside adequate vitamin C, you absorb substantially more of that iron.
Why the Dose Matters
With vitamin C, the story is not about the form. Ascorbic acid is vitamin C. It absorbs well, it is well studied, and it does not require conversion. The real issue is dose. Most supplements are stingy with it.
Plenty of multivitamins include just 60-90 mg. That is the RDA and nothing more. Enough to prevent scurvy, but the research on immune function and recovery points to higher intakes being more useful.
Hemila and Chalker (Cochrane Database of Systematic Reviews, 2013) found that regular supplementation of 200 mg or more reduced cold duration by 8% in adults and 14% in children. Consistent across multiple trials. For people under physical stress, like soldiers and marathon runners, the effect was larger: a 50% reduction in cold incidence.
The tolerable upper limit is 2,000 mg per day. Fireblood includes 500 mg. Enough to do real work, with a wide safety margin above.
Signs You Might Not Be Getting Enough
- Slow wound healing
- Getting sick frequently
- Bleeding or swollen gums
- Dry, rough, or bumpy skin
- Fatigue and low mood
- Easy bruising
- Joint pain or swelling
Full-blown scurvy is rare in developed countries. But subclinical deficiency, low enough to affect immune function and recovery without obvious symptoms, is more common than you would expect. Smokers, people who eat few fruits and vegetables, and those under chronic stress tend to run low.
How Much You Actually Need
The RDA is 90 mg for men and 75 mg for women (add 35 mg if you smoke). That is the floor, not the target.
Vitamin C is water-soluble, so your body excretes what it cannot use. Tissue saturation, the point where your cells are fully topped up, occurs around 200-400 mg per day according to Levine et al. (Proceedings of the National Academy of Sciences, 1996).
Fireblood includes 500 mg. That keeps tissues saturated with a buffer for the days when your body burns through more: hard training, illness, poor sleep.
What Fireblood Includes
500 mg of ascorbic acid per serving. A straightforward form at a dose well beyond the RDA. Your tissues stay saturated, your immune system has what it needs, and you are nowhere near the 2,000 mg upper limit.
Try Fireblood