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The lives of all hospitalised COVID patients given spirulina were saved; but 19% of COVID patients died in the control group not given this supplement


Senior Member
An Iranian study randomly assigned hospitalised COVID patients to either receiving standard care alone, or receiving standard care along with spirulina for 6 days.

The group of 91 hospitalised COVID patients who were given 15.2 grams of spirulina daily as well as standard care had no deaths; whereas the control group of 98 patients given only standard care had 19 deaths overall (19.4% death rate).

The study says:
Overall, death in the control group was four patients in non-ICU and 15 in the ICU; on the other hand, there was no death in the Spirulina group.

This study almost seems too good to be true! 19.4% patients died of COVID in the control group not given spirulina; whereas no patients died in the spirulina group!

Spirulina does actually contain a number of antivirals:

C-phycocyaninone study suggested C-phycocyanin might be antiviral for SARS-CoV-2. C-phycocyanin is also antiviral for poliovirus, Newcastle virus, avian adenovirus and hepatitis A virus.

Cyanovirin-None study suggested Cyanovirin-N might be antiviral for SARS-CoV-2. Cyanovirin-N shows no antiviral effects against coxsackievirus A, coxsackievirus B, echovirus, enterovirus 71, rhinovirus, adenovirus, cytomegalovirus, HSV-2, hepatitis B virus (in this study see table 1), but is a highly potent antiviral for influenzavirus (see here), and has modest antiviral effects for HSV-1, EBV, HHV-6 (see table 2).

Allophycocyanin — inhibits enterovirus 71 probably by inhibiting virus adsorption and penetration (see here). It's EC50 is 0.045 μM.

Calcium spirulan — inhibits HSV-1 (see here), and inhibits enveloped viruses such as cytomegalovirus, measles virus, mumps virus, influenza A virus, and HIV-1.

However, the above antiviral compounds are very large molecules, with molecular weights in the 10 to 100 kilodalton range. So I don't think any will be systemically absorbed from the intestines into the bloodstream. Thus they will likely not have a systemic antiviral effects.

However, possibly these compounds may exert antiviral effects on the intestinal lining as the spirulina passes through the digestive tract. SARS-CoV-2 is able to infect the epithelial cells of the intestinal lining, and maybe if the intestines are infected, it makes hospitalised COVID patients worse, and increases the chances of death.

The authors point out several possibly beneficial effects of spirulina:
Previous studies have confirmed the anti-inflammatory properties of Spirulina platensis, demonstrating its ability to prevent and reduce inflammation by inhibiting histamine release from mast cells

[Spirulina] increases immunoglobulin A levels in saliva, thereby enhancing mucosal immunity

Spirulina platensis boosts the function of natural killer (NK) cells and increases the secretion of interferon-γ (IFN-γ), thereby improving the innate immune system

Spirulina also contains an effective substance called calcium spirulan (Ca-Sp), which, according to in vitro studies, can inhibit the proliferation of various enveloped viruses, including mumps virus, measles virus, influenza A virus (IAV), human immunodeficiency virus type 1 (HIV-1), human cytomegalovirus (CMV), and herpes simplex type 1 (HSV-1)

Spirulina has been shown to inhibit the NF-κB pathway and induce Nrf2 (nuclear factor erythroid 2–related factor 2) activation ... NF-κB activation in various cell types leads to pro-inflammatory cytokines production
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Senior Member
I do like chlorella and spirulina and such - but yeah, it does sound too good to be true. Wish it weren't Iran, as some of their research on saffron and such seems a bit questionable to me as well. I've seen a few in vitro studies of spirulina and chlorella, but this study's results are remarkable.


Senior Member
But it does look a bit to good to be true.

It does sound too good to be true. It will be interesting to see if there is any response or follow-up from the wider scientific community.

I am wondering though if high dose spirulina might help with long COVID: if spirulina helps with an acute COVID infection, it might also have some benefits for long COVID, if we assume LC is driven by a persistent lingering chronic SARS-CoV-2 infection.


Senior Member
I wonder if they tested people for Phenylketonuria (PKU).
Spirulina is a very good supplement but is not suitable for people with phenylketonuria.