Calcium fructopyranose borate

MineralCalcium-boronBest with a meal

What is it

Calcium fructopyranose borate (CFB) is a proprietary form of boron in which boron is chelated with calcium and the sugar fructopyranose. It is marketed in men's health and bone health supplements, sometimes branded as a "testosterone-enhancing complex."

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Bone and hormone support

Limited Evidence

Boron supplementation has shown small effects on bone mineral metabolism and free testosterone in short-term studies. Evidence specifically for the CFB form is limited.

How it works

Once ingested, CFB delivers small amounts of bioavailable boron along with calcium. Boron has been studied for possible effects on bone metabolism, vitamin D handling, and steroid hormone profiles, with most evidence relating to modest changes in free testosterone and estradiol at intakes of about 6-10 mg of elemental boron per day. Whether the CFB form has unique advantages over more conventional boron forms is not well documented in independent trials.

Dosage

DSLD does not list a single standardized dose. Most products supply boron in the 3-10 mg/day range. The tolerable upper limit for boron is 20 mg/day in adults.

When and how to take it

Often taken with food once daily.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Calcium fructopyranose borate

Branded form found in some testosterone and joint support products.

Sugar-boron-calcium chelate

Safety

Boron is generally well tolerated within recommended limits. High doses can cause nausea, vomiting, headache, and reproductive toxicity. Long-term safety of CFB specifically has not been extensively studied.

Who should be cautious

Avoid in pregnancy and breastfeeding because of reported reproductive toxicity at high boron intakes. Stay within the 20 mg/day tolerable upper limit. People with hormone-sensitive conditions should consult a clinician.

Interactions

Boron may interact with estrogen-modulating medications and high-dose magnesium. No major drug interactions are well established at typical doses.

Food sources

Raisins and prunes

Amount
Small boron content
%DV
—

Avocado

Amount
Small boron content
%DV
—

Frequently asked questions

Is CFB better than other boron forms?⌄

Manufacturers claim improved bioavailability, but independent comparative trials are limited.

Will it raise testosterone?⌄

Boron supplementation has shown modest effects on free testosterone in some short-term studies. Effects vary and are not dramatic.

References

Calcium fructopyranose borate on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Calcium fructopyranose borate (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.