Oh and will add that I also started Vitamin D supp along with low iron supp. Iron supp after noticing regular blood donations made my iron levels drop significantly and I felt awful. Confirmed with blood tests. Immediately after adding the iron I noticed I started feeling a lot better. As far as Vitamin D goes i can't say I noticed anything overnight but started feeling dang good about 2 months after and just low dose TRT so I think there was perhaps a difference. All feels reports really.