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Limited evidenceJoints & skin

Drynaria (Gu Sui Bu)

A fern rhizome used in Chinese medicine for fractures and bone loss. Standardized flavonoid extracts have been tested in Chinese trials with effects on bone turnover markers, but the trials are small, mostly published in Chinese databases, and no fracture outcome has been shown.

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What the science says

  • Bone metabolism markers Limited evidence

    A systematic review and meta-analysis of nine randomized trials of total flavonoids of Rhizoma Drynariae reported higher bone formation markers (osteocalcin, P1NP, alkaline phosphatase) and lower bone resorption marker TRACP compared with control therapies. These are biochemical surrogates, and most included trials were small and from a single country's literature.

  • Postmenopausal osteoporosis Limited evidence

    A randomized trial in elderly women with postmenopausal osteoporosis reported improvements in lipid profile and inflammatory markers with Drynaria fortunei alongside standard care. It was a single small trial with mechanistic rather than clinical endpoints.

  • Fracture healing Limited evidence

    The traditional indication — speeding fracture repair — rests on animal models and clinical impression. No adequately powered randomized trial has measured fracture healing time or refracture rates.

Dosage & safety

Studied doseTraditional decoctions use 9–15 g of dried rhizome per day. The trials used standardized total-flavonoid extracts, whose dosing is not interchangeable with raw powdered rhizome sold in capsules.
SafetyLimited safety data outside traditional use. Reported adverse effects are mainly mild gastrointestinal. Avoid in pregnancy and breastfeeding for lack of data. Because trial products were standardized extracts made to pharmaceutical specification, the quality and content of consumer capsules may differ substantially. It should not replace evaluated treatment for osteoporosis.

How to take it

TimingTiming does not matter.
With food?With food, since mild digestive upset is the main reported effect.
Worth knowingThe trials used standardised total-flavonoid extracts made to pharmaceutical specification, so a capsule of raw powdered rhizome is not the same product at any dose.

Frequently asked questions

Does drynaria help heal broken bones?

Drynaria (Gu Sui Bu) is used in Chinese medicine for fractures, but that indication rests on animal models and clinical impression. No adequately powered randomized trial has measured fracture healing time, so the evidence is limited.

Does drynaria help osteoporosis?

A meta-analysis of nine small randomized trials of drynaria total flavonoids found better bone turnover markers than control therapies, but these are biochemical surrogates and no fracture outcome has been shown. The evidence is limited, and drynaria should not replace evaluated osteoporosis treatment.

How much drynaria should I take?

Traditional drynaria decoctions use 9–15 g of dried rhizome per day. The trials used standardized total-flavonoid extracts, so a capsule of raw powdered rhizome is not the same product at any dose.

Does drynaria have side effects?

Reported side effects of drynaria are mainly mild digestive upset, which taking it with food helps. Safety data outside traditional use are limited, so avoid drynaria in pregnancy and breastfeeding.

Scientific references

Related in Joints & skin

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