Fursultiamine IV is a nutrient IV drip that delivers a vitamin B1 derivative to manage fatigue. It is involved in converting carbohydrate into energy and in nerve signalling, so a shortage brings easy tiredness and tingling. Its original purpose is to correct a deficiency of this vitamin.

It is given once a week. Fatigue eases between immediately and a week later, because when a deficient nutrient is replaced the response comes relatively fast. Conversely, if you were not deficient to begin with, you may not feel much.

The effect is clear when a blood test confirms a vitamin B1 deficiency first. Repeating it without a deficiency simply means the surplus leaves in your urine. The garlic-like smell you notice during the infusion is a normal property of the ingredient.