Tl;dr I tried to run an n of 1 study on niacin and covid, and it failed to confirm or disprove anything at all.

You may remember that back in October I published a very long post investigating a niacin-based treatment protocol for long covid. My overall conclusion was “seems promising but not a slam dunk; I expect more rigorous investigation to show nothing but we should definitely check”. 

Well recently I got covid and had run out of more productive things I was capable of doing, so decided to test the niacin theory. I learned nothing but it was a lot of effort and I deserve a blog post out of it null results are still results so I’m sharing anyway.

Background On Niacin

Niacin is a B-vitamin used in a ton of metabolic processes. If you’re really curious, I describe it in excruciating detail in the original post.

All B vitamins are water-soluble, and it is generaly believed that unless you take unbelievably stupid doses you will pee out any excess intake without noticing. It’s much harder to build up stores of water-soluble vitamins than fat vitamins, so you need a more regular supply.  Niacin is a little weird among the water-solubles in that it gives very obvious signs of overdose: called flush, the symptoms consist of itchy skin and feeling overheated. Large doses can lead to uncontrolled shaking, but why would you ever take that much, when it’s so easy to avoid?

People regularly report response patterns that sure look like their body has a store of niacin that can be depleted and refilled over time. A dose someone has been taking for weeks or months will suddenly start giving them flush, and if they don’t lower it the flush symptoms will get worse and worse. 

Some forms of niacin don’t produce flush. Open question if those offer the same benefits with no side effects, offer fewer benefits, or are completely useless.

Niacin And Long Covid

There’s an elaborate hypothesis about how covid depletes niacin (and downstream products), and this is a contributor to long covid. My full analysis is here. As of last year I hadn’t had covid (this is antibody test confirmed, I definitely didn’t have an asymptomatic case) but I did have lingering symptoms from my vaccine and not a lot else to try, so I gave the protocol a shot.

My experience was pretty consistent with the niacin-storage theory. I spent a long time at quite a high dose of the form of niacin the protocol recommends, nictonic acid. My peak dose without flush was at  least 250mg (1563% RDA) and maybe even 375mg (2345% RDA). When I hit my limit I lowered my dose until I started getting flush at the new dose, and eventually went off nicotnic acid entirely (although I restarted a B-vitamin that included 313% RDA of a different form). That ended in September or early October 2021. It made no difference in my lingering vaccine symptoms.

In early 2022 I tried nicotinic acid again. Even ¼ tablet (62.5mg, 390% RDA) gave me flush.

I Get Covid

Once I developed symptoms and had done all the more obviously useful things like getting Paxlovid, I decided it would be fun to test myself with niacin (and the rest of the supplement stack discussed in my post) and see if covid had any effect. So during my two weeks of illness and week of recovery I occasionally took nicotinic acid and recorded my results. Here’s the overall timeline:

1. Day -2: am exposed to covid.
2. Day 0: test positive on a cue test (a home test that uses genetic amplification).
   1. Lung capacity test: 470 (over 400 is considered health).
   2. Start Fluvamoxine and the vitamin cocktail, although I’m inconsistent with both the new and existing vitamins during the worst of the illness. Vitamin cocktail includes 313% RDA of no-flush niacin, but not nicotinic acid. 
3. Day 1: symptomatic AF. 102.3 degree fever, awake only long enough to pee, refill my water, and make sure my O2 saturation isn’t going to kill me. I eat nothing the entire day.
   1. I monitored my O2 throughout this adventure but it never went into a dangerous zone so I’m leaving it out of the rest of the story.
4. Day 2: start with 99 degree fever, end day with no fever. Start Paxlovid.
   1. Every day after this I am awake a little bit longer, eat a little bit more, and have a little more cognitive energy, although it takes a while to get back to normal. 
   2. Try ¼ tab nicotinic acid (62.5 mg/ 375% RDA), no flush.
   3. Lung capacity troughs at 350 (considered orange zone).
5. Day 4: ½ tablet nictonic acid, mild flush.
6. Day 7: lung capacity up to 450, it will continue to vary from 430-450 for the next two weeks before occasionally going higher.
7. Day 9: ½ tablet nictonic acid, mild flush
8. Day 10-17: ⅓ tablet nictonic acid, no flush
   1. Where by “⅓” tablet I mean “I bit off an amount of pill that was definitely >¼ and <½ and probably averaged to ~⅓ over time”
9. Day 12: I test positive on a home antigen test
10. Day 15: I test negative on a home antigen test (no tests in between) 
11. Day 17: ⅓ tablet produces flush (and a second negative antigen test)
    1. This was also the first day I left my house. I had thought of myself as still prone to fatigue but ended up having a lot of energy once I got out of my house and have been pretty okay since.

Conclusions

My case of covid was about as bad as you get while still technically counting as mild. Assuming I went into it with niacin stores such that 62.5mg nicotinic acid would generate flush, it looks like covid immediately took a small bite out of them. Or it reduced my absorption of vitamins, such that the same oral dosage resulted in less niacin being taken in. There’s no way to know covid had a larger effect on niacin than other illnesses, because I don’t have any to compare it to. Or maybe the whole thing was an artifact of “not eating for two days, and then only barely, and being inconsistent with my vitamins for a week”.