Beware of companies that advertise vitamins, supplements and herbal remedies that can increase your CD4 count; these are all scams.
There is no such thing as an “immune booster” to raise your CD4 count or “cure” your HIV.
The only way to increase your CD4 is to use antiretroviral drugs (ARV) which stops HIV from replicating.
As your viral load goes down, your immune system will start to repair itself and your CD4 count will slowly go up to higher levels again.
The current South African recommendation for when to start treatment is when the CD4 count is below 500 cells/mm3.
Read more on preventing HIV infection.