Forget about it, its not useful, it is most probably harmful because of opportunistic bacterial infections and overactive immune system. Most probably you have enough w-6 and not enough w-3 since those are rare in food (walnuts, fish, flax). W-3 is also not helpfull, it needs to be taken weeks before for COX inhibition (the same is true for w-6, process of membrane integration doesn't happen over night). You need rapid acting solution.
For cold, this is what you should do:
Do not eat. Viruses are intracellular intruders, you need to promote xenophagy.
Ascorbate Acid Powder, every 1 hour 1 teaspoon freshly made in carbonated water with magnesium with some limunade or kiwi gel. You can add ehinacea and/or propolis. You need to take from 30-100g per day of Ascorbate, and this depends on your level of body stress. If you get flatulence, lower the dose by half but still continue until you are sympthom free. If you can't tolerate flatulence, order liposome encapsulated ascorbate.
NAC, 600mg per day, to boost glutathion.
Vitamin D3, 10K IU.
1 multivitamin
Lots of water, tea, chicken soup.
Rest
To prevent it, regular cold showers, ascorbate, Vitamin D, Alkylglicerides (Shark liver oil) and
low carb diet are enough.
I didn't have cold in years.