Since I live in cloudy northern NY, I can't get enough vitamin D from the sun. When I used a standard Vitamin D supplement, my blood test showed my serum level of 25 Hydroxy Vitamin D was 32 ng/ml. My doctor recommended that I increase my intake of Vitamin D to 10,000 IU per day to get my blood level closer to 50. I immediately switched to these drops. They are an easy, relatively inexpensive way to get such a large dose of Vitamin D. I learned from naturopaths that Carlson can be trusted for purity and potency. I take the 10,000 IU (5 drops) every other day, on average.
A year later my blood level was 67! Success!
These drops are easy to use. I tilt my head back and let the drops fall on my tongue. If I had trouble doing this, I would use a stainless steel spoon. I don't notice that the drops have any taste.
I also like the long shelf life of this supplement. The bottle I'm finishing up expires in 4 years.
Warning: this Vitamin D3 is in fractionated coconut oil. Avoid this supplement if you are sensitive to coconut products.