What to look for when choosing supplements on Fullscript
Fullscript is a practitioner dispensary with thousands of professional-grade products. Even among good brands, the form, dose, and testing behind a product vary a lot. This guide shows you how to compare them the way a naturopathic doctor does.
How to read any supplement label
Two bottles can both say "Magnesium 400 mg" and be completely different products. Here's what to check, in order.
The active form
The name in brackets matters most: magnesium glycinate vs. oxide, folate as methylfolate vs. folic acid. The form decides how well you absorb a nutrient and how it feels to take.
Dose per serving, not per capsule
Check the "Serving size" line. A product listing 400 mg may need 4 capsules to get there. That's often why professional products cost more per bottle but less per effective dose.
The elemental amount
For minerals like magnesium, iron, and zinc, look for the elemental amount, meaning the mineral itself rather than the mineral plus its carrier. "500 mg magnesium glycinate" provides only about 70 mg of magnesium.
"Proprietary blend" = red flag
A blend lists a total weight without the amount of each ingredient. You can't tell whether a herb is present at a studied dose or just a sprinkle for the label.
Other ingredients
Scan for allergens (gluten, soy, dairy, shellfish), artificial colors, added sugars, and unnecessary fillers. Small amounts of capsule-flow agents such as rice flour or cellulose are normal.
Storage & expiration
Probiotics should guarantee CFU through expiration and say whether they need refrigeration. Fish oil oxidizes, so look for freshness testing (TOTOX/peroxide values) and skip anything that smells rancid.
Quality seals: what they actually mean
| Seal / claim | What it tells you |
|---|---|
| NSF Certified | An independent lab confirmed the label matches what's in the bottle, screened for harmful contaminants, and audited the facility. |
| NSF Certified for Sport® | Everything above, plus testing for 270+ substances banned in sport. Useful for athletes and anyone who wants extra assurance. |
| USP Verified | Verifies ingredients, potency, purity, and that the product breaks down properly to be absorbed. |
| Informed Sport / Informed Choice | Tests products for banned substances. Informed Sport tests every batch. |
| cGMP / "Made in a GMP facility" | Legal minimum Current Good Manufacturing Practices are FDA requirements for every supplement maker. This is a baseline, not a quality certification. |
| Certificate of Analysis (COA) | A lab report for a specific batch showing identity, potency, and contaminant results (heavy metals, microbes). Reputable brands will share one on request. |
Fullscript also reviews the brands it carries, which screens out many low-quality products. Form, dose, and fit for you still matter, and the steps above cover those.
Category guide: forms, doses & red flags
Pick a category to see which forms to prefer, what dose range to look for on the label, and when to talk to a practitioner first.
Magnesium
Used for sleep, stress, muscle cramps, PMS, headaches, and constipation. Many adults don't get enough from food.
Forms compared
What dose to look for on the label
100–400 mg of elemental magnesium per day
Supplemental magnesium above 350 mg/day can cause loose stools, so split doses if needed.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- The label lists the compound weight (e.g. '1,000 mg magnesium glycinate') instead of elemental magnesium
- A 'magnesium complex' or blend where oxide is listed first
Check with a practitioner first if…
- Kidney disease
- Taking certain antibiotics (tetracyclines, quinolones) or bisphosphonates. Separate doses by at least 2 hours.
Brands to compare on Fullscript
ThornePure EncapsulationsDesigns for HealthMetagenics
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Vitamin D (D3 + K2)
Supports immunity, mood, bone health, and hormone signaling. Low levels are common, especially in winter and northern latitudes.
Forms compared
What dose to look for on the label
1,000–5,000 IU of D3 per day
The general upper limit is 4,000 IU/day unless your provider recommends more based on a 25(OH)D blood test.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Very high daily doses (10,000 IU+) taken long term without testing
- Stacking several products that each contain vitamin D
Check with a practitioner first if…
- Taking warfarin or another vitamin K antagonist. Avoid K2 unless your prescriber approves.
- History of high calcium, kidney stones, sarcoidosis, or other granulomatous disease
- Taking thiazide diuretics
Brands to compare on Fullscript
ThornePure EncapsulationsDesigns for HealthSeeking HealthNordic Naturals
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Omega-3 fish oil
EPA and DHA support heart, brain, mood, skin, and a healthy inflammatory response. They're also important in pregnancy.
Forms compared
What dose to look for on the label
1,000–2,000 mg of combined EPA + DHA per day
Add the EPA and DHA numbers together. Ignore the total 'fish oil' figure on the front.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- '1,000 mg fish oil' on the front, but only ~300 mg EPA + DHA on the back
- A strong fishy smell or taste, or a rancid flavor, which suggests oxidation
- No mention of third-party testing for purity, heavy metals, and freshness (oxidation/TOTOX)
Check with a practitioner first if…
- Taking blood thinners or antiplatelet drugs, or having surgery soon
- Fish or shellfish allergy
- History of atrial fibrillation (higher doses have been linked to increased risk)
Brands to compare on Fullscript
Nordic NaturalsThorneDesigns for HealthMetagenicsPure Encapsulations
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Probiotics
Support digestion, regularity, immune function, and recovery after antibiotics. Effects are specific to each strain.
Forms compared
What dose to look for on the label
Roughly 1–50 billion CFU per day, depending on the strain
The best dose is the one used in studies of that specific strain.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Lists only genus and species, with no strain ID (the letters and numbers after the name)
- CFU guaranteed only 'at manufacture'
- Unclear storage instructions (refrigerated vs. shelf-stable)
Check with a practitioner first if…
- A weakened immune system, central line, or serious illness
- Suspected SIBO, since some probiotics can worsen bloating
- Taking antifungal medication (relevant for S. boulardii)
Brands to compare on Fullscript
Klaire LabsPure EncapsulationsMetagenicsDesigns for HealthJarrowGarden of LifeSeeking Health
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
B-complex, folate & B12
Support energy, methylation, mood, and red blood cell production. Folate and B12 work as a team.
Forms compared
What dose to look for on the label
Folate 400–1,000 mcg DFE · B12 250–1,000 mcg · B6 usually ≤25 mg per day
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- B6 at 50–100 mg or more, or B6 stacked across several products
- Very high folate without B12, which can mask a B12 deficiency
Check with a practitioner first if…
- Tingling or numbness in hands or feet, a possible sign of B6 toxicity. Stop and get checked.
- Taking methotrexate, anti-seizure medications, or levodopa
- Some people feel anxious or wired on methylated B vitamins. Start low.
Brands to compare on Fullscript
ThornePure EncapsulationsSeeking HealthDesigns for HealthIntegrative Therapeutics
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Multivitamin
A nutritional safety net that fills common gaps. It doesn't replace food or targeted treatment.
Forms compared
What dose to look for on the label
Most nutrients at about 100–300% of the Daily Value
Check the serving size. Many professional multis are 2–6 capsules a day.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- A one-capsule 'complete' multi (there isn't room for meaningful mineral doses)
- Megadoses far above the Daily Value with no clear reason
- Proprietary herbal or 'superfood' blends with undisclosed amounts
Check with a practitioner first if…
- Smokers: avoid high-dose beta-carotene
- Pregnancy: limit preformed vitamin A (retinol). Use a prenatal instead.
- Taking blood thinners (watch vitamin K content)
Brands to compare on Fullscript
ThornePure EncapsulationsDesigns for HealthIntegrative TherapeuticsOrtho Molecular
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Prenatal
Ideally started 3 months before conception to cover folate, iodine, choline, and iron for you and your baby.
Forms compared
What dose to look for on the label
Folate 400–800 mcg · Iodine 150 mcg · Iron ~27 mg · Choline 450 mg (total from diet + supplement) · DHA 200–300 mg
Most prenatals contain little choline, and DHA usually comes as a separate softgel.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- No iodine listed
- Choline missing or under ~100 mg
- Vitamin A as retinol above 10,000 IU
Check with a practitioner first if…
- Thyroid conditions (iodine dosing)
- Personal or family history of neural tube defects (you may need a higher folate dose)
- Iron-sensitive digestion. Ask about gentler iron forms.
Brands to compare on Fullscript
ThornePure EncapsulationsSeeking HealthDesigns for HealthIntegrative TherapeuticsNordic NaturalsGarden of Life
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Iron
Treats iron deficiency, which is common with heavy periods, pregnancy, plant-based diets, and endurance training.
Forms compared
What dose to look for on the label
18–65 mg of elemental iron, daily or every other day
Research suggests alternate-day dosing may improve absorption and tolerance.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Iron in a product you're taking 'just in case' without lab work
- The label shows compound weight rather than elemental iron
Check with a practitioner first if…
- Take only if testing (ferritin, CBC, iron panel) shows you need it. Excess iron is harmful.
- Hemochromatosis or a family history of iron overload
- Taking levothyroxine, certain antibiotics, or antacids. Separate doses.
- Keep out of reach of children. Iron overdose is dangerous.
Brands to compare on Fullscript
ThornePure EncapsulationsDesigns for HealthIntegrative TherapeuticsMetagenics
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Zinc
Supports immunity, skin and acne, wound healing, thyroid function, and hormone production.
Forms compared
What dose to look for on the label
15–30 mg of elemental zinc per day
The adult upper limit is 40 mg/day from all sources.
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Above 40 mg/day for months without added copper
- Intranasal zinc products, which are linked to loss of smell
Check with a practitioner first if…
- Long-term use: zinc depletes copper, which can cause anemia or nerve symptoms
- Taking certain antibiotics or penicillamine. Separate doses.
- Take with food if it makes you nauseous
Brands to compare on Fullscript
ThornePure EncapsulationsDesigns for HealthMetagenicsJarrow
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Adaptogens (ashwagandha, rhodiola)
Herbs that may help the body adapt to stress, support sleep, and steady energy. Quality and standardization matter a lot.
Forms compared
What dose to look for on the label
Ashwagandha extract 300–600 mg/day · Rhodiola extract 200–600 mg/day
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Proprietary blends that hide individual herb amounts
- No standardization percentage listed
Check with a practitioner first if…
- Pregnancy or breastfeeding: avoid ashwagandha
- Thyroid conditions: ashwagandha may raise thyroid hormone levels
- Autoimmune conditions, or taking sedatives or immunosuppressants
- Liver concerns (rare liver injury has been reported with ashwagandha)
- Rhodiola: bipolar disorder, or taking antidepressants or stimulants
Brands to compare on Fullscript
Integrative TherapeuticsPure EncapsulationsThorneDesigns for HealthMetagenicsJarrow
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Estrogen metabolism (DIM, calcium-D-glucarate)
Often used alongside fiber and cruciferous vegetables to support healthy estrogen clearance in estrogen-dominance patterns.
Forms compared
What dose to look for on the label
DIM 100–300 mg/day · Calcium-D-glucarate 500–1,500 mg/day
Typical adult label range, not a personal recommendation. Your ideal dose depends on your labs, health history, and medications.
Label red flags
- Very high DIM doses marketed for 'fat burning' or hormone 'detox'
- Combination products with undisclosed herb amounts
Check with a practitioner first if…
- Pregnancy, breastfeeding, or trying to conceive
- History of hormone-sensitive cancer, or taking tamoxifen or other hormone therapy
- Taking hormonal birth control
- DIM can cause headaches or darker urine in some people
Brands to compare on Fullscript
Designs for HealthPure EncapsulationsIntegrative TherapeuticsThorneMetagenics
These professional brands carry this category on Fullscript. Formulas and availability change, so always check the current label for the form and dose above.
Supplement shopping checklist
Run any product through these questions before you add it to your cart.
- I know why I'm taking this, ideally based on symptoms, labs, or a practitioner's advice.
- The active form is one I'd choose (see the category guide).
- I checked the serving size and know how many capsules give the listed dose.
- Minerals show the elemental amount.
- There's no proprietary blend hiding individual amounts.
- The dose falls within a typical label range and doesn't stack with my other products.
- It's free of my allergens and unnecessary additives.
- It has third-party testing (NSF, USP, Informed Sport) or the brand provides a COA.
- I know how to store it and when it expires.
- I checked for interactions with my medications, pregnancy, or health conditions.
- I've set a date to reassess: is it helping after 8–12 weeks?
Get a personalized protocol and practitioner pricing
Stop guessing in the supplement aisle. We'll match forms and doses to your labs and health goals, then send your plan straight to our Fullscript dispensary at practitioner pricing.