How to compare two supplements side by side

To compare two supplements fairly, put them on the same footing and then check five things in order: the serving, the amount of each ingredient per serving, the real price at the same commitment, the refund terms, and whether the claims match the research. Write the answers in a two-column table. Whichever column has fewer blanks and fewer "not stated" cells is the offer you can actually evaluate.

This is the same routine we use on every DoseAudit review, so we will use two real reviews as a worked example: GlucoBerry and Gluco Extend, both sold through ClickBank in the blood sugar category.

Step 1: what is one serving in each product?

Before you compare anything, convert both products to the same unit of time. Most people compare bottle to bottle, but a bottle is not a standard amount. GlucoBerry is 30 capsules, one a day with food. Gluco Extend is also 30 capsules, one a day. Those two match, so a bottle equals 30 days in both cases and the comparison stays simple.

They will not always match. Another product in our library, LeanBiome, is 60 capsules with two a day, so a bottle also lasts 30 days but each daily dose is split in two. A powder might be 30 scoops, a liquid might be 60 servings. The FDA's labeling guide defines one serving as the maximum amount the label recommends per eating occasion, so use the label's serving size and servings per container to set the unit: one day of use.

Step 2: how do the ingredient lists line up?

Now list each ingredient with the amount per daily serving. Copy the numbers exactly as the label prints them. The FDA says the Supplement Facts panel must give the amount of each dietary ingredient, except for those inside a proprietary blend, which are listed with only the blend total. Here is how our two examples compare:

That single row of amounts changes what you can do next. For GlucoBerry you can look up the maqui berry figure and find that our review matched 180 mg to a 2016 trial of 31 prediabetic adults who took that amount for three months. For Gluco Extend there is nothing to look up: our review lists berberine, gymnema and turmeric as ingredients whose studied doses are in the hundreds of milligrams, and the label does not say whether the capsule comes anywhere near those numbers.

A blank is information. It does not prove the dose is low, but it means you cannot verify it, and that is a real difference between two products in the same category.

Step 3: what does each cost at the same commitment?

Compare prices at the same number of bottles, and add shipping. Sales pages lead with a bottle price, but the checkout is the source of truth. Both of these offers show the same three bundle sizes, so we can line them up:

The lesson from this table is the shipping column. On the 3-bottle bundle, GlucoBerry's price is still lower even after the shipping range is added, but the gap narrows from $30 to roughly $10 to $20. Neither offer has a one-bottle trial in our review, and the 2-bottle bundles come with shipping too, so the smallest commitment is $138 for one and $158 for the other. If you would rather test the water with one bottle, that is a real limitation on both. Our page on the best blood sugar offers shows more of the category at a glance.

Step 4: what are the refund terms?

Look for three things: the number of days, who handles the refund, and whether you must return the product or pay shipping. Both examples advertise a 180-day window, three times the 60 days most ClickBank supplements use. In our checks the ClickBank checkout page for Gluco Extend confirmed the 180 days, and GlucoBerry's page describes an "empty bottle" guarantee that applies even if you have used the whole supply, with the request routed to the seller's support. Because ClickBank is the retailer of record, our ClickBank refund guide explains how to go through ClickBank if the seller does not answer.

Put the refund row in your table with the conditions written out. "180 days" and "180 days, empty bottles accepted, contact support with packaging details" are not the same line.

Step 5: do the claims match the research?

This is the row that takes the most time and matters the most. For each ingredient, ask whether the sales page cites a study, whether that study tested the same ingredient at a similar dose, and whether it was in humans. Two examples from our reviews show why the row matters:

• GlucoBerry's Gymnema claim references a study group size that we could not independently confirm on PubMed, and there is no published trial of the finished capsule.
• Gluco Extend's science section lists real papers on glucose and insulin biology, but our review found none that tested the six ingredients in the capsule. A commented-out reference in the page code also points to an article about the oral microbiome and dental disease.

The FTC's guidance is a useful yardstick here: it says health claims need competent and reliable scientific evidence, generally randomized controlled trials in humans, and that a study using a different formulation does not support a claim about your product. So a citation only counts when it matches.

Finish with transparency: is a company named, is an author or doctor named and checkable, and does the page use scarcity tactics such as a fake countdown or a warning that your bottles will be given away? Each of those becomes a yes or no in the table.

What does the side-by-side show?

Averaging the four scores from our review method gives GlucoBerry 6.25 (evidence 5.0, price 5.5, refund 8.0, transparency 6.5) and Gluco Extend 4.5 (evidence 2.0, price 4.5, refund 8.5, transparency 3.0). Both fall in the "Worth a look" band, from 4.5 to 6.9, and neither reaches the 7.0 needed for "Holds up." The table shows why: they tie on refund length, GlucoBerry leads on disclosed doses and price, and Gluco Extend leads on free shipping at three bottles.

A comparison like this does not tell you which one to buy, and neither review says either product treats a condition. If you take medicines for blood sugar, check with your doctor or pharmacist before adding a supplement, because supplements can interact with medicines.

A checklist you can copy

1. Set the unit: one daily serving, in capsules, scoops or mL.
2. List each ingredient with its amount per serving, and mark blanks.
3. Note how many ingredients the page claims versus how many the label names.
4. Price both at the same number of bottles, and add shipping.
5. Write the refund days, who processes it, and what you must return.
6. Open each cited study and check the ingredient, dose and species.
7. Mark whether a company, address and named experts can be verified.
8. Take the differences, not the totals, to your pharmacist.

FAQ

How do I compare supplement prices fairly?

Use the same number of bottles for both and divide by the days they cover. Then add shipping, since it can change the ranking, as it does between the 3-bottle bundles above.

Does a higher dose mean a better supplement?

No. A dose matters only relative to what studies used and what is safe for you. Upper limits exist for some nutrients, so ask a doctor or pharmacist before choosing the bigger number.

What if one label hides its amounts?

Treat it as unverified. You can still compare price, refund and transparency, but you cannot compare doses, which is the most important row.

Can I compare a capsule with a powder or a liquid?

Yes, once both are converted to amount per day. Use the servings per container to work out what a day of each costs and contains.