Ingredient deep-dive

Ginkgo At 240 mg, And What That Number Was For

Ginkgo biloba is the most-swallowed botanical in this whole category and the one with the steadiest number attached to it. Two hundred and forty milligrams a day turns up in trial after trial, across decades and continents. What is less well known is what those trials were actually testing, and how often the answer came back flat.

By Primal Grow Pro Team · Last updated September 19, 2026 · 10 min read · Ingredient deep-dive

Where the number comes from

Most botanical ingredients have a dosing literature that sprawls. Ginkgo’s does not. The great majority of serious ginkgo research has been conducted on a single standardised leaf extract, at either 120 or 240 milligrams a day, and the higher of those two figures has become the reference amount.

That convergence is unusual and it is worth appreciating before anything critical is said. It means ginkgo trials can be compared with each other, pooled, and argued about on their merits rather than on whether they were testing the same thing. Very few ingredients in this aisle can say that.

The confirmatory trial makes the point most directly by putting the amount in its title, and it ran 240 mg once daily for 24 weeks in 410 outpatients.

What those trials were testing

Here is where the reputation and the research start to separate. The overwhelming majority of ginkgo trials were designed around cognition in older or clinical populations, not around vitality, energy or circulation in healthy men.

Four entries, two positive and two not. Every one of them used a standardised extract at a stated daily amount, which is what makes them comparable at all.

Two of those four are positive and two are not, and the split is not random. The positive results cluster in populations with an existing cognitive impairment, measured on cognitive scales. The flat results appear where a healthy or a general population was studied, or where a physical outcome was measured.

The largest trial, and what it did not find

The Ginkgo Evaluation of Memory study is the biggest thing that has ever happened to this ingredient. Three thousand and sixty-nine adults aged 75 and over, 120 mg twice daily, followed for a median of 6.1 years, with dementia incidence as the outcome.

It found no reduction. The hazard ratio came out at 1.12, with a confidence interval spanning 1.0 in both directions, which is a result compatible with no effect at all.

That is the most rigorous test this ingredient has faced, and it is worth stating at full strength rather than softening. It is also worth being precise about what it tested: whether six years of ginkgo prevented a disease in people over 75. It did not test, and cannot speak to, whether the same extract does anything for a man of fifty who wants to feel sharper at four in the afternoon.

Why a negative prevention trial is not the end of the story

Prevention trials are the hardest kind to pass. They require an effect large enough to shift disease incidence across thousands of people over years, and a great many interventions that produce real, measurable short-term changes fail them.

The 2023 systematic review of the same standardised extract reaches positive conclusions on cognitive and behavioural measures in mild neurocognitive impairment, at the same 240 mg a day. Both results can be true. Ginkgo can fail to prevent a disease over six years and still move a cognitive score over six months.

The circulation claim, tested where it should be easiest

Ginkgo’s other reputation is for blood flow, and this one has been tested in the fairest possible way.

Intermittent claudication is leg pain on walking, caused by narrowed arteries. It is circulation failing in the most literal and most measurable sense, and the outcome, how far somebody can walk before the pain stops them, is about as objective as clinical measurement gets.

The Cochrane review of ginkgo for claudication gathered the trials and concluded there was no evidence of a clinically meaningful benefit on walking distance.

That is the circulation claim tested on its home ground, and it did not deliver. A structure and function statement about supporting circulation is a different and much weaker assertion than treating a circulatory condition, and that distinction is doing real work every time the word “support” appears on a label.

The sexual-function story, in three studies

This is the part of the ginkgo literature most likely to be met in an advertisement, and it is a textbook case of a reputation outliving its evidence.

One open trial with a striking number, and two blinded attempts to reproduce it that did not. Citing the origin without the replications is how a reputation outlives its evidence.

The 1998 study is a real piece of work by real researchers and it reported a striking number. It was also open label with no placebo arm, which in a domain as responsive to expectation as sexual function is a serious limitation rather than a technicality.

Two groups then tried to reproduce it under blinding. The first found no significant difference from placebo at any timepoint, with both arms improving. The second ran triple-blind for twelve weeks at 240 mg daily and found no statistically significant difference either.

Citing the 1998 result without the two failed replications is how an 84% figure ends up in marketing copy a quarter of a century later. Citing all three is the honest version, and the honest version is that this particular claim did not hold up.

The bleeding reputation

Ginkgo is widely described as a blood thinner, and the caution is repeated almost everywhere. It is weaker than its fame.

A secondary analysis inside a randomised, double-blind, placebo-controlled trial examined coagulation and bleeding time in patients taking the standardised extract, and found no effect on either. That is a direct test of the reputation, run inside a controlled trial, and it came back negative.

The genuine caution is narrower. Anyone taking an anticoagulant needs that conversation with the person holding their anticoagulation record, and anyone facing surgery should say what they have been taking. Those are sensible steps rather than evidence of a hazard, and they apply to a great many supplements.

What happens when ginkgo joins a blend

Every number in this article belongs to a trial that gave ginkgo on its own. That is the condition under which all of it was learned, and it is the condition a multi-ingredient capsule does not meet.

Two hundred and forty milligrams is roughly 37 per cent of a size 0 capsule. A formula carrying ginkgo at its research amount has spent over a third of its container on one ingredient before anything else is added, which is a legitimate design choice and one that a label with printed amounts would make visible.

Primal Grow Pro names ginkgo first on both of its ingredient graphics and prints no quantity for it or for anything else. What that means in practice is set out on the ingredients page, which puts the 240 mg figure beside the blank rather than inventing one.

How to read a ginkgo row on any label

• Look for the amount first. 240 mg a day is the reference figure. Anything substantially under it is below what the trials used, and anything over is unusual.
• Look for the extract, not just the plant. Almost all serious ginkgo research used one standardised extract. A label naming only “ginkgo biloba” leaves open what it is standardised to, or whether it is standardised at all.
• Check whether the amount is per day or per capsule. A two-capsule serving at 120 mg each is 240 mg a day. The same 120 mg on a one-a-day product is half of it.
• Read what the product claims ginkgo is for. Cognitive claims have the better evidence base. Circulation claims were tested in legs and did not deliver.
• Be sceptical of an 84% figure. It comes from one open trial from 1998, and the two blinded replications both failed.

Ginkgo is a reasonable ingredient with a real literature, a stable reference amount and a large safety dataset behind it. That is more than most of this aisle can say. What it is not is a solved question, and the number in the title of this article is worth far more to a reader than the adjectives usually printed beside it.

References