I started using Spring Valley High Potency Vitamin D a few years ago when I had been going through a seasonal depression, due to lack of sunlight. I was having trouble getting up in the morning. Then, when I got to work, I was irritable and completely unmotivated. I also had trouble sleeping at night. Within a few days of taking Spring Valley High Potency Vitamin D, I noticed a remarkable difference. I went from unstable mood swings, to more consistent peaceful, patient moods. In addition to this added stability, my energy had come back. I could now keep up with my work load, and I had a new sense of drive that helped me to excel at my work. After a few weeks of taking it, my legs felt stronger. I could start hiking again. Then, after about six weeks of taking Spring Valley High Potency Vitamin D 1000 IU, my chronic neck and back pain had diminished immensely. I believe that the results of taking Spring Valley High Potency Vitamin D, were so amazing, at least partially due to the fact that it is highly absorbent. Thumbs Up!