Benefits
Joint pain and stiffness in knee osteoarthritis
In a multicentre randomized trial in people with knee osteoarthritis, 500 mg a day improved pain and stiffness within the first days to weeks. That trial was small and short, and it was co-authored by people connected to the ingredient's manufacturer. No cited study compared eggshell membrane against glucosamine and chondroitin for how quickly it works.
Knee osteoarthritis support
A 2024 systematic review and meta-analysis pooled 5 randomized trials in people with knee osteoarthritis and found small improvements: total WOMAC score -0.34 (95% confidence interval -0.56 to -0.13, p<0.001) and pain -0.23 (95% CI -0.42 to -0.04, p<0.02). An effect that size is small by the usual conventions, not dramatic relief. In a 2025 network meta-analysis of 39 trials and 4,599 people that compared supplements head to head for knee osteoarthritis, eggshell membrane was not among the top performers; boswellia had the highest probability of being most effective for pain and stiffness, and krill oil and curcumin showed potential for function.
Exercise-induced joint discomfort
One randomized placebo-controlled trial in healthy postmenopausal women found less exercise-related joint pain and stiffness with eggshell membrane than with placebo. That is a single small trial in one specific group, so it does not show how the ingredient behaves in younger or male exercisers, and no cited trial reported results for hips or shoulders separately.
What is actually in it, and at what dose
Eggshell membrane naturally contains collagen (Types I, V, X), elastin, hyaluronic acid, chondroitin sulfate, glucosamine, and dermatan sulfate. The studied dose is 500 mg a day, far less than the multi-gram doses used for glucosamine and chondroitin, which also means the amount of each individual compound is small. No cited study showed that this mixture works better than taking those compounds separately.
Cartilage turnover markers
One cited trial in healthy postmenopausal women also tracked a urinary marker of cartilage turnover (CTX-II) alongside symptoms. A change in a laboratory marker is not the same as protecting a joint, and no cited study showed that eggshell membrane slows, stops or reverses joint disease.
Standardization and branded forms
Most of the published human trials used the NEM branded ingredient, and several were co-authored by people connected to its manufacturer, which is a limitation worth knowing. None of the studies cited here tested BiovaFlex or any other brand, so there is no published comparison between brands, or between branded and generic material.
Egg allergy contraindication
Eggshell membrane comes from eggs. Anyone with an egg allergy should avoid it, including people whose reactions have been mild, because processing does not guarantee that egg protein is gone. This is a food allergen inside a joint supplement, where a shopper would not necessarily expect one, so read the label and ask a healthcare provider if you are unsure.
Mechanism of action
Why the oral tolerance idea does not apply here
The oral tolerance idea, in which small amounts of undenatured type II collagen calm an immune reaction against joint cartilage, comes from research on a different ingredient (UC-II type II collagen). Eggshell membrane's collagen is mainly types I, V and X, and none of the studies cited on this page tested oral tolerance, so this mechanism should not be assumed to apply to eggshell membrane.
Direct GAG and hyaluronic acid supplementation
Eggshell membrane contains glucosamine, chondroitin sulfate and hyaluronic acid, which are building blocks of cartilage and joint fluid. At 500 mg a day the amounts are small, and none of the cited human studies measured absorption, cartilage synthesis or joint fluid, so this is a proposed explanation rather than a demonstrated one.
TGF-β and chondrocyte stimulation
Eggshell membrane contains small amounts of transforming growth factor beta, a signalling protein that affects cartilage cells in laboratory work. Whether any of it survives digestion and reaches a joint has not been shown, and no cited human study demonstrated cartilage repair, so treat this as theory rather than an established effect.
Clinical trials
Randomized, double-blind, placebo-controlled multicentre trial of eggshell membrane (500 mg/day) versus placebo in 67 adults with osteoarthritis of the knee. (Ruff et al. 2009, Clin Rheumatol; PMID 19340512)
67 adults with knee osteoarthritis.
Eggshell membrane reduced knee osteoarthritis pain and stiffness compared with placebo, with improvement appearing within days rather than weeks. The trial was small and short, and it was funded by the ingredient's manufacturer (ESM Technologies), whose staff co-authored it. It did not compare eggshell membrane against glucosamine or chondroitin.
Randomized, double-blind, placebo-controlled trial of eggshell membrane (500 mg/day) in healthy postmenopausal women with exercise-related joint pain. (Ruff et al. 2018, Clin Interv Aging; PMID 29497287)
Healthy postmenopausal women.
Eggshell membrane reduced exercise-related joint pain and stiffness compared with placebo, and the study also tracked a urinary marker of cartilage turnover. It was a small, short trial in one narrow group of participants and was co-authored by people connected to the ingredient's manufacturer, so the result needs independent replication in other populations.