Kirkland Signature is the private label of Costco, the world's second-largest retailer, and in the U.S. market, Kirkland's image of high quality and low price has long been deeply rooted in the hearts of the people, and it is very competitive with other non-private label brands on Costco's shelves. In 2016, Costco's sales were $118.7 billion, a quarter of which came from Kirkland, and this proportion has continued to rise in recent years.
 
Kirkland Signature is also well-known in the calcium field due to its extremely low price. However, low price does not mean mediocre, the brand's two calcium supplements, Calcium 600mg with Vitamin D3 and Calcium Citrate Magnesium and Zinc, are certified by the United States Pharmacopeial Convention (USP) to ensure efficacy and safety. Since it is an economical brand, Kirkland's calcium tablets are all packaged in large capacity of 500 tablets, which is more suitable for families.
 
Kirkland's two calcium tablets have their own characteristics. The recommended intake of calcium in the United States is 1000mg/day for adults, 1200mg/day for seniors over 70 and women over 50 years old, while the recommended intake for calcium in China is about 200mg/day lower than that in the United States. Compared with the recommended intake, the product recommendation of taking two capsules (1200mg calcium) of Calcium 600mg with Vitamin D3 per day is not very appropriate for Chinese, after all, the daily diet also contains a certain amount of calcium. To take this calcium, one capsule per day is more appropriate.
 
The most attractive thing is that 500 tablets of Calcium 600mg with Vitamin D3 are only about 120 yuan, which is the most cost-effective calcium carbonate tablets, but it is not friendly to patients with stomach problems, especially those with insufficient gastric acid secretion.
 
Calcium Citrate Magnesium and Zinc are also a good choice for those with poor digestion, as calcium citrate is selected as the source of calcium, calcium tablets can be fully digested without relying on stomach acid, and do not need to be taken with meals. In addition, calcium tablets also contain a variety of nutrients such as vitamin D, B6, magnesium and zinc, and the recommended daily dosage of 500mg of calcium is also more suitable for the general Chinese population. Calcium Citrate Magnesium and Zinc 500 tablets are about 130 yuan, and the price is more than twice that of calcium carbonate tablets Calcium 600mg with Vitamin D3, but compared with other brands of calcium citrate tablets, this calcium supplement is undoubtedly the king of cost performance, and it is highly recommended.
 
ConsumerLab and Labdoor, authoritative third-party evaluations in the United States, have also given positive reviews to these two calcium supplements, but at present, Kirkland Signature's products can only be purchased on behalf of others or at costco supermarkets.