Supplements Buying Guide: How to Read Labels, Doses and Testing Marks
This supplements buying guide is for anyone comparing bottles, tubs and stick packs and trying to work out what is actually on the label. It covers the twelve supplements we carry: two fish oils, vitamin D3, vitamin B12, zinc, a women’s multivitamin, magnesium, an electrolyte mix, two creatine powders, a probiotic and a greens powder. We explain how to read a Supplement Facts panel, how to compare doses and forms, and what third-party marks do and do not tell you.
The short answer: decide with your doctor what you need, then compare the amount per serving, the serving size, the other ingredients and any independent testing mark. After that, the form (capsule, soft gel, liquid or powder) and how it fits your day usually settle the choice. Brand claims on these pages are the manufacturer’s own label wording, not our advice.
Talk to your doctor first: talk to your doctor before starting a new supplement, especially if you are pregnant, nursing, take medication or have a health condition. The FDA advises talking to a doctor, pharmacist or other health care professional before buying or using a dietary supplement, partly because some supplements can interact with medicines or other supplements.
How we chose: our picks are based on published label facts, brand specs and public reviews from named outlets linked on each product page. We have not tested these products ourselves, and the order within each group is not a ranking.
How to choose a supplement
1. Read the Supplement Facts panel
Supplements carry a Supplement Facts panel instead of a Nutrition Facts label. According to the FDA, the panel must list the serving size, the number of servings per container and each dietary ingredient, with the amount per serving for anything that is not part of a proprietary blend. Ingredients that are not declared in the panel appear in a separate “other ingredients” list. The NIH Office of Dietary Supplements adds that the manufacturer suggests the serving size, but your health care provider might decide a different amount suits you better.
A blend without amounts makes comparison harder. For the greens powder in our lineup, Healthline points out that the amounts in the blend are not disclosed.
2. Compare the dose per serving, not per pill
Check how many pills, scoops or teaspoons make one serving before comparing numbers. Nordic Naturals Ultimate Omega lists its omega-3s per two soft gels, while Carlson lists them per teaspoon of liquid. The Thorne B12 and zinc picks list one capsule per serving, with 1,000 mcg of vitamin B12 or 30 mg of zinc. If you take a multivitamin as well, add up what each product gives you. Ritual’s multivitamin, for example, also lists vitamin D3 and vitamin B12, so bring the full list of labels to your doctor.
3. Pick a form you will actually take
Capsules and small soft gels are quick to swallow. Liquid fish oil skips the pills, but Carlson asks you to keep the bottle in the fridge after opening. Powders such as creatine, magnesium and greens mix into water, juice or a smoothie, and electrolyte stick packs are made for a water bottle.
4. Check the other ingredients and allergens
The capsule matters if you avoid animal products: the Ultimate Omega soft gels use fish gelatin, while the Thorne capsules list hypromellose, Culturelle uses a vegetarian capsule and Ritual’s capsules are vegan. Both fish oils contain fish. Look for sweeteners too: LMNT uses stevia leaf extract and Thorne’s magnesium powder uses monk fruit. Free-from claims such as gluten free, dairy free or soy free are listed on each product page as the brand states them.
5. Look for independent testing marks
The NIH Office of Dietary Supplements explains that independent groups, including NSF International and U.S. Pharmacopeia (USP), test products and let those that pass display a seal showing the product was properly made, contains the ingredients on the label and does not contain harmful levels of contaminants, though a seal does not guarantee a product is safe or effective. For athletes, NSF says its Certified for Sport program checks for unsafe levels of contaminants, prohibited substances and masking agents, and confirms the label matches what is in the product. In our lineup, both creatine powders and Thorne’s magnesium carry NSF Certified for Sport, and Ritual carries USP Verified. Marks such as IFOS, Friend of the Sea and Non-GMO Project Verified are separate programs, so check each one’s own site for what it covers.
6. Read brand claims for what they are
Under federal law, the FDA does not have the authority to approve dietary supplements before they are marketed, and it does not approve supplement claims or labeling before use. The FDA also explains that the familiar “not intended to diagnose, treat, cure, or prevent any disease” disclaimer is required when a label makes a claim about how an ingredient affects the body. When we mention a claim in this guide, it is the brand’s own wording, attributed to the brand.
7. Think about storage and routine
Some products need care at home. Carlson asks you to refrigerate the liquid after opening, while Culturelle says its capsules need no refrigeration and should be kept in a cool, dry place. A daily powder works best if you already have a drink you mix every day, and a once-a-day capsule is easy to pair with breakfast.
Our picks
Omega-3 fish oil
Nordic Naturals Ultimate Omega, Lemon lists 1,280 mg of total omega-3s per two soft gels, including 650 mg EPA and 450 mg DHA, from anchovies, sardines, mackerel and herring in a tilapia gelatin soft gel. The label describes it as triglyceride form, third-party purity tested and Friend of the Sea certified, and it suits adults who prefer softgels with a lemon flavor. Healthline credits the short ingredient list and published certificates of analysis, while its testers found the soft gels quite large.
Carlson The Very Finest Fish Oil, Liquid lists 1,600 mg of omega-3s per teaspoon, including 800 mg EPA and 500 mg DHA, from wild-caught, cold-water fish with natural lemon flavor. It is IFOS certified, Non-GMO Project Verified and Friend of the Sea certified, a strong pick for people who would rather take a spoonful than swallow pills. The dietitian tester at Yahoo Health found no fishy smell or taste but a thick, oily texture that lingers, and the bottle must be refrigerated after opening.
Vitamins and minerals
Nordic Naturals Vitamin D3 1000 IU, Orange is a moderate-dose vitamin D3 in mini soft gels. Yahoo Health liked the small, easy-to-swallow soft gels, the orange taste and the brand’s posted third-party test results, while noting it has no vitamin K and that 1,000 IU may be too low for some people. It suits adults whose doctor suggests a modest dose.
Thorne Vitamin B12, Methylcobalamin lists 1,000 mcg of vitamin B12 as methylcobalamin in one capsule, with leucine, microcrystalline cellulose and silicon dioxide in a hypromellose capsule. Thorne lists it as gluten free, dairy free and soy free, and the label directions say one capsule one to three times daily or as your health-care practitioner recommends. Healthline cites its testing and flexible dosing but cautions that the dose may exceed some people’s needs.
Thorne Zinc Picolinate 30 mg is a single-mineral capsule with 30 mg of zinc as zinc picolinate and a short list of other ingredients. Thorne’s label notes that zinc can inhibit copper absorption and that long-term zinc use should include copper in a 15:1 ratio, so it is one to plan with your doctor. Athletes should note that Thorne sells a separate NSF Certified for Sport version.
Ritual Essential for Women 18+ is a once-daily vegan capsule with a short nutrient list, including 2,000 IU of vitamin D3, 400 mcg DFE folate, 8 mcg vitamin B12, 8 mg iron, vitamin K2 and 250 mg DHA from microalgae. It is USP Verified and Non-GMO Project Verified, and it suits adult women who want a focused formula rather than a broad multi or a prenatal. BarBend liked its mint scent but pointed out what it leaves out, such as calcium, vitamin C and zinc. Because it contains iron, keep it out of reach of children.
Magnesium and electrolytes
Thorne Magnesium Bisglycinate is a powder with three ingredients: magnesium bisglycinate (200 mg magnesium per scoop), citric acid and monk fruit concentrate. It is NSF Certified for Sport, and Thorne describes it as a powdered formula that promotes restful sleep and muscle relaxation. The tester at Healthline noticed a very slight citrus taste and said the monk fruit may not suit everyone, and Thorne’s label notes that some people taking magnesium may get gas or bloating.
LMNT Zero Sugar Electrolytes, Citrus Salt comes in stick packs that each list 1,000 mg sodium, 200 mg potassium and 60 mg magnesium with 0 g sugar, flavored with lemon, lime and stevia. A registered dietitian at BarBend found it mixed well and tasted good, but noted the sodium is much higher than competitors and that it lacks third-party testing. It suits heavy sweaters in long workouts; if you have been told to watch your sodium, ask your doctor first.
Creatine
Momentous Creatine Monohydrate, Unflavored has one ingredient, 5 g of creatine monohydrate per scoop, with 90 servings and NSF Certified for Sport status. Momentous lists it as vegan, gluten free and GMO free and describes it as supporting cognitive and muscle performance. The tester at Healthline found it truly unflavored and said it dissolved well, while Yahoo Health found the powder settles quickly.
Thorne Creatine, Unflavored is micronized creatine monohydrate, 5 g per scoop with 90 servings, NSF Certified for Sport and listed as gluten free, dairy free and soy free. It suits athletes who want plain creatine to mix into water, juice or another drink. BarBend called the taste mild but said it settles in the glass and needs stirring.
Probiotic and greens
Culturelle Digestive Daily Probiotic lists 10 billion CFUs of a single strain, Lactobacillus rhamnosus GG, in one vegetarian capsule for ages 12 and up. Culturelle lists it as vegan, gluten free, dairy free, soy free and sugar free, says it needs no refrigeration, and notes minor bloating or gas may occur at first. Yahoo Health noted it contains only one strain, and Healthline pointed out it is not third-party tested.
Amazing Grass Super Greens, Original is a scoop-and-stir powder the brand describes as a blend of 14 organic, non-GMO greens, fruits and vegetables, including wheat grass, barley grass and spirulina, plus 1 billion CFU of probiotics and no added sugar. It is listed as vegan, kosher and certified gluten free. BarBend found it mild and easy to hide in juice or smoothies but stressed it is no replacement for eating vegetables, and Healthline flagged the undisclosed amounts in the blend.
Quick comparison
| Product | Type | One key fact | Good for |
|---|---|---|---|
| Nordic Naturals Ultimate Omega | Fish oil soft gel | 1,280 mg omega-3s per 2 soft gels | Softgel fish oil users |
| Carlson Very Finest Fish Oil | Liquid fish oil | 1,600 mg omega-3s per teaspoon | People who avoid pills |
| Nordic Naturals Vitamin D3 | Vitamin D3 soft gel | 1,000 IU vitamin D3 | A modest daily dose |
| Thorne Vitamin B12 | Vitamin B12 capsule | 1,000 mcg as methylcobalamin | A single B12 capsule |
| Thorne Zinc Picolinate | Zinc capsule | 30 mg zinc per capsule | A single-mineral zinc |
| Ritual Essential for Women 18+ | Multivitamin | USP Verified | A short, vegan multi |
| Thorne Magnesium Bisglycinate | Magnesium powder | 200 mg magnesium per scoop | A drink instead of a pill |
| LMNT Citrus Salt | Electrolyte mix | 1,000 mg sodium, 0 g sugar | Heavy sweaters |
| Momentous Creatine | Creatine powder | NSF Certified for Sport, vegan | Athletes in tested sports |
| Thorne Creatine | Creatine powder | NSF Certified for Sport | Plain creatine in any drink |
| Culturelle Digestive Daily | Probiotic capsule | 10 billion CFUs, one strain | No-fridge daily capsule |
| Amazing Grass Super Greens | Greens powder | No added sugar | Smoothies and juice |
Narrowing it down? See our short lists of third party tested supplements and protein powders and vegan supplements and protein powders.
FAQ
Should I talk to my doctor before taking a supplement?
Yes. Talk to your doctor before starting a new supplement, especially if you are pregnant, nursing, take medication or have a health condition. Bring the labels of everything you already take, so your doctor can see the full picture.
Does the FDA approve supplements before they are sold?
No. The FDA says it does not have the authority to approve dietary supplements before they are marketed. Companies are responsible for making sure their products and labels follow federal law.
What does NSF Certified for Sport mean?
NSF says the program verifies that a product does not contain unsafe levels of contaminants, prohibited substances or masking agents, and that the label matches what is inside. Momentous Creatine, Thorne Creatine and Thorne Magnesium Bisglycinate carry it.
Does a USP Verified or NSF seal mean a supplement is safe?
Not on its own. The NIH Office of Dietary Supplements explains that these seals show a product was properly made, contains what the label lists and has no harmful levels of contaminants, but they do not guarantee that a product is safe or effective.
Which supplements here are vegan?
The brands list Momentous Creatine, Ritual Essential for Women, Culturelle, LMNT and Amazing Grass as vegan or vegan friendly. Both fish oils contain fish, and the Ultimate Omega soft gels use fish gelatin.
Can supplements replace food?
No. The NIH Office of Dietary Supplements notes that supplements cannot take the place of the variety of foods that matter for a healthy diet.
Browse every pick in our vitamins and supplements collection. If you are also comparing shakes, see our protein powders and the protein powder buying guide.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.