Product comparison
Kirkland Signature supplements at Costco: which ones are worth buying?
Kirkland Signature is Costco's store brand. It's low cost, one bottle often lasts more than a year, and many products carry the USP Verified mark. But some names, like "Fish Oil 1,000 mg," don't match the actual active amount, and some use basic, poorly absorbed forms. So we went through each one using the Supplement Facts panel on the back of the bottle.
| Product | Per serving | Rating |
|---|---|---|
| Kirkland Signature Daily Multi (multivitamin) | 1 tablet · 13 vitamins + minerals | Depends |
| Kirkland Signature Mature Multi 50+ (multivitamin) | 1 tablet · 13 vitamins + minerals, no iron | Recommended |
| Kirkland Signature Adult Multivitamin Gummies | 2 gummies · 10 vitamins | Not recommended |
| Kirkland Signature Organic Multivitamin | 1 tablet · 13 vitamins + whole-food blend | Depends |
| Kirkland Signature Vitamin D3 2,000 IU | 1 softgel · D3 2,000 IU (50 mcg) | Recommended |
| Kirkland Signature Fish Oil 1,000 mg | 1 softgel · fish oil 1,000 mg (EPA+DHA 250 mg) | Depends |
| Kirkland Signature Wild Alaskan Fish Oil 1,400 mg | 1 softgel · fish oil 1,400 mg (EPA+DHA 230 mg) | Not recommended |
| Kirkland Signature Krill Oil 500 mg | 1 softgel · krill oil 500 mg (EPA+DHA 90 mg) | Depends |
| Kirkland Signature Calcium 600 mg + D3 | 1 tablet · calcium 600 mg + D3 400 IU | Depends |
| Kirkland Signature Calcium Citrate Magnesium and Zinc | 2 tablets · calcium 500 mg + magnesium 80 mg + D3 800 IU | Depends |
| Kirkland Signature Calcium 500 mg + D3 & Zinc Gummies | 2 gummies · calcium 500 mg + D3 1,000 IU + zinc 7 mg | Depends |
| Kirkland Signature Vitamin C 1,000 mg | 1 tablet · vitamin C 1,000 mg | Recommended |
| Kirkland Signature Chewable Vitamin C 500 mg (orange flavor) | 1 tablet · vitamin C 500 mg | Depends |
| Kirkland Signature Super B-Complex | 1 tablet · B1 100 mg, B2 20 mg, B6 3 mg + vitamin C 200 mg | Depends |
| Kirkland Signature B12 5,000 mcg Quick Dissolve (cherry flavor) | 1 tablet · methylcobalamin 5,000 mcg | Depends |
| Kirkland Signature CoQ10 300 mg | 1 softgel · CoQ10 300 mg (ubiquinone) | Depends |
| Kirkland Signature Glucosamine 1,500 mg + Chondroitin 1,200 mg | 2 tablets · glucosamine 1,500 mg + chondroitin sulfate 1,200 mg | Recommended |
| Kirkland Signature Glucosamine + MSM | 2 tablets · glucosamine 1,500 mg + MSM 1,500 mg | Recommended |
| Kirkland Signature Turmeric 1,000 mg + Black Pepper | 2 capsules · 95% turmeric extract 1,000 mg (curcuminoids 950 mg) + piperine 9.5 mg | Depends |
| Kirkland Signature Vitamin E 400 IU | 1 softgel · vitamin E 180 mg (400 IU) | Depends |
Recommended 5
Kirkland Signature Mature Multi 50+ (multivitamin)
Tablet · 1 tablet · 13 vitamins + minerals, no iron · 400 count
- No iron
- B12 25 mcg, folate as standard folic acid 500 mcg
- Vitamin D 500 IU, on the low side
- Small amounts of calcium 220 mg and magnesium 50 mg (oxide)
- All 8 B vitamins and 6 trace minerals, with iron left out
- Sticks to the basics with no herb or fruit blends
- Only 500 IU of vitamin D, so adding about 1,000 IU separately is a good idea
Adults 50+, people looking for a good-value basic multivitamin
Kirkland Signature Vitamin D3 2,000 IU
Softgel · 1 softgel · D3 2,000 IU (50 mcg) · 600 count
- D3 (cholecalciferol) only
- Soybean oil softgel with almost nothing else added
- USP Verified mark
- 600 count: more than a year and a half at 1 a day
- D3 2,000 IU is just right for a daily maintenance dose
- Simple formula with almost no additives
- Add up the vitamin D in your multivitamin and calcium too, and keep the total at 4,000 IU a day or less
People who need a daily maintenance vitamin D
Kirkland Signature Vitamin C 1,000 mg
Tablet · 1 tablet · vitamin C 1,000 mg · 500 count
- Standard ascorbic acid 1,000 mg
- Also has citrus bioflavonoids 100 mg and rose hips
- USP Verified mark
- Label says 1 a day with a meal
- One 1,000 mg tablet of standard ascorbic acid, the best value form
- The bioflavonoids are a harmless extra
- The USP Verified mark means the amounts are checked by a third party
People who want a basic 1,000 mg a day
Kirkland Signature Glucosamine 1,500 mg + Chondroitin 1,200 mg
Tablet · 2 tablets · glucosamine 1,500 mg + chondroitin sulfate 1,200 mg · 220 count
- Glucosamine hydrochloride (HCl) 1,500 mg
- Sodium chondroitin sulfate 1,200 mg
- 115 mg sodium per 2 tablets
- USP Verified mark
- 2 tablets cover the standard daily amounts: glucosamine 1,500 mg and chondroitin 1,200 mg
- Chondroitin sulfate content is clearly listed
- The USP Verified mark means the amounts are checked by a third party
People who want steady, long-term joint support
Kirkland Signature Glucosamine + MSM
Tablet · 2 tablets · glucosamine 1,500 mg + MSM 1,500 mg · 375 count
- Glucosamine hydrochloride (HCl) 1,500 mg
- MSM 1,500 mg (no ingredient brand listed)
- No chondroitin
- USP Verified mark
- 2 tablets give the standard daily amount of glucosamine, 1,500 mg
- Includes 1,500 mg MSM. It's fine to start with 1 tablet
- MSM taken in the evening can disturb sleep, so after breakfast or lunch is best
People who want MSM along with their joint support
Depends on your needs 13
Kirkland Signature Daily Multi (multivitamin)
Tablet · 1 tablet · 13 vitamins + minerals · 500 count
- Vitamin D 400 IU: not enough as a daily maintenance dose
- Contains 18 mg iron
- Folate as standard folic acid 500 mcg, B12 6 mcg
- Magnesium and zinc in oxide form
- A basic formula with all 8 B vitamins and 6 trace minerals
- Only 400 IU of vitamin D, so add 1,000–2,000 IU separately
- 18 mg iron. Men and adults over 50 who don't need iron are better off with the 50+ multi
Adults who need iron, people who take vitamin D separately
Kirkland Signature Organic Multivitamin
Tablet · 1 tablet · 13 vitamins + whole-food blend · 80 count
- Vitamin D 1,200 IU, B6 11.3 mg
- Very small mineral amounts: calcium 4.5 mg, magnesium 1.1 mg, zinc 1.7 mg
- No copper, iodine or molybdenum
- A blend of more than 30 fruits, vegetables, herbs and mushrooms
- Good spread of vitamins, but almost no minerals
- Includes a blend of more than 30 herbs and mushrooms, such as holy basil and astragalus
- Organic certification is a plus; take minerals separately
People who want organic ingredients and take minerals separately
Kirkland Signature Fish Oil 1,000 mg
Softgel · 1 softgel · fish oil 1,000 mg (EPA+DHA 250 mg) · 400 count
- Of the 1,000 mg fish oil, actual EPA+DHA is 250 mg (other omega-3s 50 mg)
- Label suggests 2 a day = 500 mg EPA+DHA
- Made from anchovy and sardine; contains soy
- USP Verified mark
- EPA+DHA is 25% of the oil. It's low concentration, so you swallow more oil you don't need
- You need 4 a day to reach 1,000 mg EPA+DHA
- The USP Verified mark means the amounts are checked by a third party
People fine with taking more softgels who just want a basic amount
Kirkland Signature Krill Oil 500 mg
Softgel · 1 softgel · krill oil 500 mg (EPA+DHA 90 mg) · 180 count
- Per softgel: EPA 60 + DHA 30 = 90 mg
- Phospholipids 200 mg, astaxanthin 150 mcg
- Made from shellfish (krill). Avoid if you're allergic
- Small softgel, 1 a day
- EPA+DHA 90 mg is less than a third of a regular omega-3 softgel
- 1 a day falls short even of the krill benchmark (EPA+DHA 200 mg, phospholipids 400 mg or more)
- Small and easy to swallow, USP Verified mark
People whose stomach doesn't handle regular omega-3 and who want a small softgel
Kirkland Signature Calcium 600 mg + D3
Tablet · 1 tablet · calcium 600 mg + D3 400 IU · 500 count
- 600 mg calcium carbonate per tablet
- No magnesium
- Label says 2 a day (1,200 mg calcium)
- USP Verified mark
- One 600 mg tablet is more than your body absorbs at once, so split it in half
- It's calcium carbonate, so always take it after a meal, and get magnesium separately
- 2 a day per the label is 3 times the amount you need from supplements (200–400 mg)
People whose doctor recommended 1,000 mg+ of calcium a day, split up with meals
Kirkland Signature Calcium Citrate Magnesium and Zinc
Tablet · 2 tablets · calcium 500 mg + magnesium 80 mg + D3 800 IU · 500 count
- Calcium in citrate form
- The 80 mg magnesium is magnesium oxide; calcium to magnesium is about 6:1
- Also has zinc 10 mg, copper, manganese, boron and B6 10 mg
- USP Verified mark
- Calcium citrate is relatively easy on the stomach
- Magnesium is low and in the poorly absorbed oxide form, so it's better to take it separately
- 250 mg calcium per tablet makes it easy to adjust with 1–2 tablets
People who already take magnesium separately and want calcium citrate
Kirkland Signature Calcium 500 mg + D3 & Zinc Gummies
Gummy · 2 gummies · calcium 500 mg + D3 1,000 IU + zinc 7 mg · 240 count
- Calcium as tricalcium phosphate
- 5 g added sugar per 2 gummies
- No magnesium
- Zinc 7 mg overlaps with the zinc in your multivitamin
- Gummies are easy for people who struggle with pills
- 5 g added sugar per 2 gummies. Cutting to 1 gummy still gives 250 mg calcium
- No magnesium, so you end up taking only calcium + D3
Adults who have trouble swallowing pills
Kirkland Signature Chewable Vitamin C 500 mg (orange flavor)
Chewable tablet · 1 tablet · vitamin C 500 mg · 500 count
- Sodium ascorbate + ascorbic acid
- Sweetened with sorbitol and sucralose
- Uses artificial colors (Yellow 6, Red 40)
- Contains lactose
- Chewable, so easy for people who struggle with pills
- Contains artificial colors
- 2 tablets for 1,000 mg; the label also says 1–2 a day
People who have trouble swallowing pills, people who split their vitamin C through the day
Kirkland Signature Super B-Complex
Tablet · 1 tablet · B1 100 mg, B2 20 mg, B6 3 mg + vitamin C 200 mg · 500 count
- B1 100 mg and B2 20 mg are high; B6 is low at 3 mg
- B12 100 mcg in the standard form (cyanocobalamin); folate is also the standard form
- Vitamin C 200 mg, sodium 90 mg, potassium 30 mg
- USP Verified mark
- Has all 7 B vitamins, but B6 at 3 mg is only multivitamin level
- Built around B1, unlike a B-complex that's high across the board
- Low B6 means little worry about going over the upper limit when combined with other supplements
People who want a light B boost focused on B1
Kirkland Signature B12 5,000 mcg Quick Dissolve (cherry flavor)
Dissolving tablet · 1 tablet · methylcobalamin 5,000 mcg · 300 count
- Active form methylcobalamin
- Let it dissolve under your tongue for 30 seconds, then swallow
- Sweetened with mannitol and sucralose
- USP Verified mark
- Active methylcobalamin, a good form
- 5,000 mcg is a lot for daily use (though usually not a big problem)
- Dissolves in your mouth, so easy for people who struggle with pills
People who want high-dose B12, people who have trouble swallowing pills
Kirkland Signature CoQ10 300 mg
Softgel · 1 softgel · CoQ10 300 mg (ubiquinone) · 100 count
- Standard ubiquinone 300 mg
- Softgel dissolved in soybean oil
- No BioPerine (black pepper extract)
- USP Verified mark
- 300 mg per softgel is more than most goals need (100–200 mg a day) and can't be split
- Basic oil-based form with nothing else mixed in
- When you need a high dose, one a day covers it
People who were advised to take 300 mg a day
Kirkland Signature Turmeric 1,000 mg + Black Pepper
Vegetarian capsule · 2 capsules · 95% turmeric extract 1,000 mg (curcuminoids 950 mg) + piperine 9.5 mg · 320 count
- Uses only 95% extract, no turmeric powder
- Contains black pepper extract (piperine 9.5 mg)
- No patented enhanced-absorption ingredient listed
- Label warning: don't take if pregnant or breastfeeding, or if you have gallstones, liver problems or blood clotting problems
- Curcuminoid content is clearly listed (950 mg per 2 capsules)
- Contains piperine. Avoid it if you take medicines or are concerned about your liver
- 2 capsules (1,000 mg) a day is a lot. Start with 1
People who don't take medicines and have a healthy liver
Kirkland Signature Vitamin E 400 IU
Softgel · 1 softgel · vitamin E 180 mg (400 IU) · 500 count
- Synthetic dl-alpha tocopherol
- 400 IU per softgel, the same as the maximum suggested supplement amount
- Softgel with almost nothing else added
- USP Verified mark
- Synthetic (dl-alpha). Choosing the natural form (d-alpha) is usually the better pick
- Each softgel is 400 IU, so add up the vitamin E in your multivitamin too
- If you take blood thinners or have surgery coming up, talk to your doctor first
People fine with the synthetic form who want to take vitamin E separately
Not recommended 2
Kirkland Signature Adult Multivitamin Gummies
Gummy · 2 gummies · 10 vitamins · 320 count
- No B1 or B2 at all
- Only chromium and molybdenum for minerals (no zinc, selenium or magnesium)
- 2 g added sugar per 2 gummies; corn syrup and sugar are the main ingredients
- Vitamin D 800 IU, B12 50 mcg
- It's a multivitamin, but B1, B2 and key minerals are missing
- Gummies contain sugar and can only hold a limited number of ingredients
- Kirkland's own tablets (Daily Multi, 50+ Multi) cover far more
People who can't swallow pills at all (not enough to replace a full multivitamin)
Kirkland Signature Wild Alaskan Fish Oil 1,400 mg
Softgel · 1 softgel · fish oil 1,400 mg (EPA+DHA 230 mg) · 230 count
- Of the 1,400 mg, actual EPA+DHA is 230 mg (about 16%)
- 670 mg of other fatty acids, such as omega-5, 6, 7, 9 and 11
- Contains 300 mcg vitamin A (retinol)
- Made from pollock and salmon, in natural TG form
- The 1,400 mg in the name is the weight of all the oil; EPA+DHA is only 230 mg
- You'd need more than 4 a day to reach 1,000 mg, and vitamin A would rise to 1,200 mcg
- Less processed natural (nTG) oil, USP Verified mark
If omega-3 is your goal, another product with more EPA+DHA is a better choice