Why Supplement Form Matters: Understanding Bioavailability.

When you pick up a supplement, it’s easy to focus on the numbers. How much iron? How much magnesium? How much folate? But there’s another question worth asking:

What form is it in?

Two supplements can list the same nutrient, even at the same dose, but that doesn’t necessarily mean they’ll behave in exactly the same way once you take them. That’s because the form a nutrient takes can influence how it is absorbed, tolerated and made available for the body to use. This is known as bioavailability- and it’s one of the reasons we believe formulation is about much more than simply putting a long list of nutrients on a label.

So, what exactly is bioavailability?

In simple terms, bioavailability refers to the proportion of a nutrient that is absorbed and becomes available for the body to use. It’s not quite as simple as saying “I took 20mg, so my body got 20mg.” The body has to digest, absorb and process nutrients before they can be used, and the form of a nutrient can be one factor that affects this process. This is why, when comparing supplements, it’s worth looking beyond the nutrient and dose alone.

Same nutrient. Different form.

Take iron. You might see two supplements that both provide iron and assume they’re essentially interchangeable. But one could contain Ferrous Sulfate, while another uses Ferrochel® Ferrous Bisglycinate. Both provide iron, but they are different forms of the mineral. 

Ferrous Bisglycinate is a chelated form of iron in which iron is bound to glycine. Research has found that iron bisglycinate can offer advantages in absorption and gastrointestinal tolerability compared with some conventional iron salts, including ferrous sulfate.

So while the label might simply say “iron”, the form underneath that heading matters.

It’s a little like the difference between the ingredient and the delivery system. The nutrient is important. But how that nutrient is delivered can matter too.

It’s not just about iron

The same principle comes up across nutritional science. Folate is another example. Folic acid and methyl-folate, the active form of folate found in ingredients such as Quatrefolic®, are different forms of folate.

Folic acid needs to undergo conversion in the body before it can enter the folate cycle in its active forms, whereas methyl-folate is already in a form the body can use directly in that pathway.

This doesn't mean one form is automatically right for everyone or that folic acid has no role. It means that the form of a nutrient is an important part of the formulation conversation. And the same thinking applies to other nutrients too - from different forms of magnesium to mineral sources such as Aquamin®.

Why does the form matter?

Because your body doesn't interact with a supplement label. It interacts with the actual chemical form of the nutrient. When we formulate a supplement, there are several questions worth asking:

1. Is this the right nutrient?

2. What does the formula actually need to provide?

3. Is this the right form?

4. Which form is best supported by the available scientific evidence for the intended purpose?

5. Is this the right dose?

These considerations work together. Right nutrient. Correct form. Optimal dose - and that’s the approach we take across the entire Gigi range.

Thoughtful formulation starts with a reason

Every ingredient in our formulas is there for a reason. Not because it’s trending. Not because it makes the ingredient list look impressive. And not simply because we can add it.

We look at the available scientific research and consider the nutrient, the form, the dose and its role within the wider formula. That means the formulation process starts with a question:

What does the body actually need, and how can we provide it thoughtfully?

From the form of iron we use, to the folate, to the mineral sources selected across our formulas, all of these decisions are part of the bigger picture.

Bioavailability isn't the whole story

It’s also important to remember that bioavailability isn't a simple “good or bad” label.

Different nutrients behave differently in the body, and factors such as the nutrient itself, the chemical form, what you take it with and individual differences can all influence absorption and utilisation.

So we don't believe in choosing an ingredient simply because it has a particular form or because it sounds more advanced. We look at the whole body of evidence. That means staying close to the latest scientific research and considering how each ingredient fits into the formula as a whole.

So, what should you look for on a supplement label?

Next time you're comparing two supplements, don't stop at the headline nutrient and dose. Take a closer look.

01 — The nutrient

What exactly is the formula providing?

02 — The form

Which form of that nutrient is being used?

03 — The dose

How much is included per serving?

04 — The reasoning

Is there a clear reason that form and dose were chosen? Because a thoughtful formula isn't simply a collection of nutrients. It's a collection of decisions. And when it comes to women's health, those decisions matter.

At Gigi, we formulate with the belief that what goes into a supplement matters, but so does how it's formulated. Every ingredient is carefully considered, from the nutrient itself to its form and dose, and our formulas are developed in line with the latest scientific research. Because we don't want to give you more ingredients. We want to give you the right ones, in the right forms, at the right doses - for a reason!