Protocols — Verified Supplement Data

By Erin Rose · Updated September 3, 2026 · Methodology · About Us

• Prenatal Supplement Guide: Why Methylfolate Beats Folic Acid (MTHFR)

  Evidence-based prenatal supplement guide: 40% of women can't efficiently convert folic acid, but methylfolate works regardless of MTHFR status, at every stage.

• Vegan & Vegetarian Supplement Protocol: 5 Nutrients You Must Get Right (2026)

  Vegans know they need supplements — most take the wrong forms or wrong doses. B12 is non-negotiable. Here are the 5 critical nutrients with evidence-based doses, vegan-appropriate products, and cost per day.

Compare Methylfolate Products by Cost Per Day

Methylfolate is the one non-negotiable nutrient across our prenatal protocol — here's how the products we track compare on cost per day.

About our data

Every comparison uses clinical evidence from PubMed systematic reviews, product label data from the NIH Dietary Supplement Label Database, and third-party certifications (USP, NSF). Products are ranked by cost per clinically-effective dose. See our methodology and editorial standards.

The same bottles, for three completely different reasons

These protocols look alike on the shopping list and are not alike at all underneath. Resolving every product each one links to back to its supplement category, of the 9 distinct supplements across the 4 protocols, 5 appear in more than one:

Iron is in three of the four, and for three different reasons. After gastric bypass it is malabsorption — the rerouted anatomy sends food past the duodenum, which is where most iron is absorbed, so it is bypassed rather than removed and the absorption simply does not happen. On a vegan diet it is availability: plant iron is non-haem and absorbed several times less efficiently than the haem form in meat. In pregnancy it is demand, because blood volume rises by roughly half. The bottle is the same. The reason, the dose and the monitoring are not.

Each of those mechanisms has a different evidence base, and they are worth reading separately rather than as one rule.

What the evidence says for each

After bypass, absorption is the problem. Work on intestinal mucosa after Roux-en-Y describes an impaired iron–copper metabolic axis — the transport machinery itself is affected, not merely the transit time (PMID 42104175). This is why post-surgical supplementation is lifelong and monitored with blood work rather than judged by how you feel.

On a plant-based diet, availability is the problem. Plant iron is non-haem, and its absorption is both lower and far more sensitive to what else is on the plate — phytates and tea depress it, vitamin C raises it. A review of plant-based diets and iron-deficiency anaemia sets out how much that shifts real intake (PMID 40528105). Unlike malabsorption, this one is partly fixable at the table.

B12 is the one where the vegan case is strongest. A review of serum B12 across vegetarian populations found deficiency prevalence ranging from 0% to 86.5% in adults, 17–39% in pregnant women, and up to 45% in infants — consistently higher in vegans than in other vegetarians, and highest of all in vegans not taking a supplement (PMID 24667752). That enormous range is itself the finding: it depends almost entirely on whether someone supplements, which makes it the one item on a vegan protocol that is not optional.

In pregnancy, demand rises — but read what supplementation actually fixed. The USPSTF evidence review found routine prenatal iron cut maternal iron-deficiency anaemia at term from 19.8% to 8.6% (RR 0.40, 95% CI 0.26–0.61, four trials, n = 2,230). It also found the evidence on downstream health outcomes limited or showing no benefit, and no studies at all on whether screening helps (PMID 39163033). So it reliably corrects the laboratory number; what that correction buys in outcomes is less settled than the routine of prescribing it suggests.

That distinction matters more than the overlap does. Malabsorption calls for higher doses and lifelong blood monitoring, because no amount of dietary change fixes a missing absorption surface. A dietary gap can often be closed by food alone. Increased demand is temporary and ends with the pregnancy. Reading across these protocols and concluding “everyone needs iron, B12 and D” gets the right list for the wrong reason, and the wrong reason produces the wrong dose.

Where the protocols genuinely diverge

The 4 supplements that appear in only one protocol are the ones doing the specific work — methylfolate in the prenatal protocol, vitamin K2 and omega-3 in the vegan one. Those are not interchangeable and not optional within their protocol. If you are following one of these, the shared column tells you what you might already have in the cupboard; the single-protocol column tells you what you actually have to go and buy.

One tension worth raising with your clinician

The prenatal protocol uses methylfolate, and that choice deserves a note rather than a silent default. The reason folate is recommended in pregnancy at all is the neural tube defect evidence — and that evidence base, including the US Preventive Services Task Force recommendation built on it, was established with folic acid (PMID 37526714).

Methylfolate bypasses the MTHFR conversion step, which is a reasonable rationale and the reason it is popular. But it is not the form the trials used, and pregnancy is the single worst place to substitute a form on your own reasoning. Raise it with whoever is managing your care rather than swapping the bottle yourself — the methylfolate guide sets out what is and is not established about the two forms.

Which one applies to you

These are not lifestyle categories. Each one describes a specific physiological situation with its own evidence base, and two of them — post-surgical and prenatal — are situations where supplementation is medically standard rather than optional, and where your clinician should be the one setting the doses. The protocols below give you the reasoning and the arithmetic so you can follow the conversation, not replace it.

Method: derived from the protocol pages themselves rather than a hand-kept list — every product each page links to, resolved to its catalogue category, so it reflects what the protocols actually recommend and moves when they change. Regenerated by data/pipeline/condition_overlap.py protocols. What it cannot tell you: whether a supplement shared by two protocols is shared at the same dose. It is usually not — that is the point of the section above — so check the individual protocol before assuming one bottle covers two situations.