Supplement · graded by use, two uses
Hyaluronic Acid (Oral)
Skin hydration, elasticity and wrinkle depth in adults.
This page covers hyaluronic acid taken by mouth. In several 12-week studies, mostly of women aged 30 to 65, skin held more water, was more elastic and had shallower wrinkles than with a dummy pill. Every one of those studies was run by or with a company that makes it. For knee pain, results were mixed, and one study found no benefit. No study measured cartilage. There is no data on its safety in pregnancy.
The B belongs to one of the two uses graded on this record. The other one carries its own letter.
As studied, and the trials
Instrument-measured skin outcomes. Kawada et al. (J Clin Biochem Nutr, 2015; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 25834304): skin hydration trial of two of one manufacturer's hyaluronans, run by its research division. Hsu et al. (Nutrients, 2021; PMID 34203487): 40 adults, 120 mg/day for 12 weeks; wrinkles, stratum corneum water content, water loss and elasticity better than placebo An inactive substitute made to look like the real treatment, so participants cannot tell which one they received.; three authors are the manufacturer's employees. Gao et al. (2023; PMID 38009035): randomized skin-condition trial with four authors employed by a second manufacturer. Dolečková et al. (Sci Rep, 2025; PMID 41422283): 150 adults, 60 or 120 mg/day for 12 weeks; hydration, elasticity, water loss and periorbital wrinkle depth better at 120 mg/day; run by a third manufacturer with six employees as authors. Amin et al. (J Drugs Dermatol, 2025; PMID 40911749): meta-analysis A study that pools the numbers from several trials into one combined estimate. of 7 randomized trials; hydration, elasticity and wrinkle depth improved. Replicated The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away. randomized evidence on instrument-measured surrogates is B; every trial was run by or with a hyaluronic acid manufacturer, which the replication funding rule counts and states beside the letter. Not A: skin hydration and elasticity are surrogate measures, not clinical outcomes or functions.
As studied, and the trials
Mixed and self-reported. Tashiro et al. (ScientificWorldJournal, 2012; PMID 23226979): 60 adults with knee osteoarthritis, 200 mg/day for 12 months with daily quadriceps exercise in both arms; a trend favoring hyaluronic acid overall and significance only in those aged 70 or under at months 2 and 4; the manufacturer's researcher is a co-author. Kalman et al. (Nutr J, 2008; PMID 18208600): 20 adults with knee osteoarthritis, 80 mg/day for 8 weeks; WOMAC pain, the primary endpoint The one outcome a trial names in advance as its main test. Results on other outcomes carry less weight., no different from placebo. Sugiyama et al. (Exp Ther Med, 2024; PMID 38234616): healthy adults with knee discomfort, 111 mg/day for 12 weeks; self-rated discomfort improved, objective mobility tests did not; the manufacturer's employees are authors. A trend, a null primary and a self-rating without objective change: C.
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A letter describes the human evidence, not the product, the manufacturer, or the ingredient's worth.
See the full evidence record →Funding: All four trials this Grade B for Skin hydration, elasticity and wrinkle depth in adults rests on were funded by industry or funders the reports do not identify: Kawada 2015 (PMID 25834304) by a funder the indexed report does not name; Hsu 2021 (PMID 34203487) by a funder the indexed report does not name; Gao 2023 (PMID 38009035) by a funder the indexed report does not name; Dolečková 2025 (PMID 41422283) by the maker of the product it tested. The funder's role in design and analysis is not stated here, because the full trial reports could not be read. The letter is what the trials support under the grading rules; the funding is stated here so it can be weighed alongside it. Investigators: All four trials this Grade B for Skin hydration, elasticity and wrinkle depth in adults rests on were run by investigators employed by, founded by, or belonging to the organization that developed, sells or teaches the intervention (the manufacturer of the hyaluronic acid tested, with its researchers among the authors; the manufacturer of the hyaluronic acid tested, with three employees among the authors; a second hyaluronic acid manufacturer, with four employees among the authors; the manufacturer of the hyaluronic acid tested, with six employees among the authors). The funder may read non-commercial; the people who ran the trials are part of the organization whose intervention they tested, which is stated here so it can be weighed alongside the letter.
Funding: All three trials this Grade C for Knee symptoms in adults with knee osteoarthritis or knee discomfort rests on were funded by industry or funders the reports do not identify: Tashiro 2012 (PMID 23226979) by the maker of the studied product, who donated it; Kalman 2008 (PMID 18208600) by non-government support listed, a funder whose relationship to the question the report does not make clear; Sugiyama 2024 (PMID 38234616) by the maker of the studied product, who donated it. The funder's role in design and analysis is not stated here, because the full trial reports could not be read. The letter is what the trials support under the grading rules; the funding is stated here so it can be weighed alongside it.
Skin hydration, elasticity and wrinkle depth, replicated in maker-run randomized trials and a 7-trial meta-analysis.
Why this gradeThe reasoning, and what the grade does not cover.
Grade B, the record's best use: skin hydration, elasticity and wrinkle depth, instrument-measured surrogates with several positive 12-week randomized trials (Hsu et al., 2021; PMID 34203487; Dolečková et al., 2025; PMID 41422283; Gao et al., 2023; PMID 38009035; Kawada et al., 2015; PMID 25834304) and a positive 7-trial meta-analysis (Amin et al., J Drugs Dermatol, 2025; PMID 40911749). Replicated randomized evidence on a surrogate is B, and the surrogate is what keeps it from A. Every skin trial was run by or with a hyaluronic acid manufacturer; under the replication funding rule those trials count and the funding is stated beside the letter.
KNEE SYMPTOMS CARRY THEIR OWN Ca trend with an age-subgroup signal (Tashiro et al., 2012; PMID 23226979), a null primary (Kalman et al., 2008; PMID 18208600) and a self-rated improvement without objective change (Sugiyama et al., 2024; PMID 38234616). The record was divided from one bundled C in October 2026 by the written rule.
WHAT THIS GRADE DOES NOT COVERcartilage or joint lubrication, which no trial measured; a gut-barrier effect, which no human trial tested; injected hyaluronic acid, a different route; and any skin claim beyond hydration, elasticity and wrinkle depth at 60 to 120 mg/day for 12 weeks.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Trials report an average. This box says whether any trial on this record looked at who the result applies to, and what it found.
For Knee symptoms in adults with knee osteoarthritis or knee discomfort, Grade C · Subgroup tested, effect differedTashiro et al. (ScientificWorldJournal, 2012; PMID 23226979) found a trend favoring hyaluronic acid overall, reaching significance only in participants aged 70 or under, at months 2 and 4. A subgroup result shows who the effect appeared in within these trials. It does not change the letter.
As studied: dose, form, population and duration for every use
A grade describes the intervention that was tested. Where the product on the shelf differs from it, this says so.
How this letter has changed · latest: October 2026 · Upgraded
The headline C bundled a replicated instrument-measured skin result with a mixed self-reported knee result. Graded by use: skin hydration, elasticity and wrinkle depth rest on four randomized trials (PMIDs 25834304, 34203487, 38009035, 41422283) and a 7-trial meta-analysis (Amin et al., 2025; PMID 40911749), replicated randomized evidence on surrogates, B, with every trial manufacturer-run and the funding stated beside the letter under the September rule; knee symptoms rest on a trend (Tashiro et al., 2012; PMID 23226979), a null primary (Kalman et al., 2008; PMID 18208600) and a self-rating (Sugiyama et al., 2024; PMID 38234616), mixed, C. The headline follows the best use to B. Applied the written grade definition under the editor's standing instruction of October 2026 (Arnold Sandlow, D.C.).PMID 18208600 PMID 23226979 PMID 38234616 PMID 40911749
The ref said Tashiro 2012 (PMID 23226979) improved knee osteoarthritis symptoms; both groups improved, hyaluronic acid showed a trend overall and significance only in those aged 70 or under, and the record now says so. Kalman 2008 (PMID 18208600), null on its primary pain endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score., is added. Kawada 2014 (PMID 25014997) is a review and is relabeled as background. The best-use line claimed joint lubrication and cartilage health and gut-barrier support; no trial measured cartilage or lubrication and no human trial tested the gut, so both are removed. Added on skin: Hsu 2021 (PMID 34203487), Dolečková 2025 (PMID 41422283), the largest trial, and Amin 2025 (PMID 40911749), the 7-trial meta-analysis; on knees, Sugiyama 2024 (PMID 38234616), self-rated improvement without objective change. The dose line now states each trial's dose and that one often-cited joint trial used a multi-ingredient preparation. Every trial's manufacturer tie is in the funding block. Letter unchanged; splitting skin from joints is on the decision sheet.PMID 23226979 PMID 18208600 PMID 25014997 PMID 34203487 PMID 41422283 PMID 40911749 PMID 38234616
Ties stated beside the letter. Every trial behind the Grade C was run with a manufacturer's product and a manufacturer's researchers among the authors: one manufacturer in Tashiro 2012 (PMID 23226979) and Kawada 2015 (PMID 25834304), a second in Gao 2023 (PMID 38009035). Kawada 2014 (PMID 25014997) is a review by the first manufacturer's employees, not a trial, and is now described as one. Letter unchanged.PMID 23226979 PMID 25834304 PMID 38009035 PMID 25014997
Every change to a letter on this site is dated and published. The full evidence log →
Commercial disclosure
EBL earns no commission on any supplement it grades. A purchase made through the dispensary link below pays EBL nothing, the practitioner discount goes to you in full. The dispensary is Fullscript, a practitioner dispensary, and many of the professional-grade brands in it are sold mainly through practitioners rather than in health food stores. Grades are assigned by published rubric before any commercial relationship exists and are never influenced by one. Full disclosure.
Grade B reflects replicated randomized evidence on a surrogate endpoint A lab value or measurement used in place of the outcome that matters, such as LDL cholesterol standing in for heart attacks. Moving a surrogate does not always move the outcome.: several 12-week trials and a 7-trial meta-analysis agree on skin hydration, elasticity and wrinkle depth, every one run by or with a hyaluronic acid manufacturer, which is stated beside the letter. Skin hydration is a surrogate measure, not a clinical outcome or a function, so the record cannot reach A. Knee symptoms carry their own C. EBL re-grades when new randomized evidence is published.
Skin trials used 60 to 240 mg/day, most at 120 mg/day for 12 weeks. Joint trials used 80 mg/day (the null trial), 111 mg/day (healthy knees) and 200 mg/day (the 12-month knee osteoarthritis trial); one often-cited joint trial used a multi-ingredient preparation that does not isolate hyaluronic acid.
Oral hyaluronic-acid studies have used multiple molecular-weight preparations, including approximately 300 kDa and 800 kDa products. 'Below 300 kDa' is neither universally required nor proven superior. The molecular weight and dose belong to the specific trial being cited.
The 12-month knee trial gave 200 mg once a day (PMID 23226979) and the skin trials gave 120 mg daily (PMID 34203487, PMID 41422283); the summaries do not state a time of day or whether doses were taken with food.
Checked against the full report for 1 of the 3 cited studies, and the published summary for the rest. What the cited trials did, not a schedule. Every supplement, by trial timing →
How to buy this: quality criteria, not a brand
80–200mg/day (skin trials 120–240mg; joint 80–200mg).
Molecular weight matters. Low-MW vs high-MW HA may behave differently. Oral HA acts indirectly (degraded in the gut to signaling fragments).
Molecular weight disclosed; third-party tested.
No MW stated; marketing that claims HA is “delivered intact” to joints/skin (it isn’t).
The grade and these criteria are set only from human trials. Any purchase link is convenience and does not affect the grade.
Pregnancy, on absence of data. Active malignancy is worth naming honestly: hyaluronic acid is involved in tumor microenvironment biology, which is a theoretical concern with no clinical evidence attached in either direction.
No drug interaction has been identified. Oral hyaluronic acid is largely broken down before absorption, which is both why the interaction profile is empty and why the efficacy evidence is modest.
This entry was on the backlog by accident. The record asserts no drug interaction at all. It says oral hyaluronic acid is largely broken down before absorption, which is both why the interaction profile is empty and why the efficacy evidence is modest. It appeared on the outstanding list because an earlier scan matched the letters of the word iron inside microenvironment, in a sentence about tumor biology. There is no iron claim on this record and never was. The absence check below is recorded for the general question rather than for a claim, since there is no claim. Basis: pharmacological mechanism, not a human study. Searched PubMed in August 2026: 1 query, 45 human results.
Skin hydration, skin elasticity, joint pain scores.
Primary evidenceNine papers, each linked to its PubMed record.
Joints: Tashiro et al. (ScientificWorldJournal, 2012; PMID 23226979): 60 adults with knee osteoarthritis, 200 mg/day for 12 months with daily quadriceps exercise in both arms; symptom scores improved in both groups, with a trend favoring hyaluronic acid overall and significance only in those aged 70 or under at months 2 and 4; the hyaluronic acid was made by a manufacturer whose researcher is a co-author. Kalman et al. (Nutr J, 2008; PMID 18208600): 20 adults with knee osteoarthritis, 80 mg/day of a chicken-comb extract for 8 weeks; WOMAC pain, the primary endpoint, did not differ from placebo (p = 0.94). Sugiyama et al. (Exp Ther Med, 2024; PMID 38234616): healthy adults with knees graded 1 or less, 111 mg/day for 12 weeks; self-rated knee discomfort improved, objective mobility tests did not; the capsules were supplied by their manufacturer, whose employees are authors. Skin: Kawada et al. (J Clin Biochem Nutr, 2015; PMID 25834304): randomized skin-hydration trial of two of the same manufacturer's hyaluronans, run by its research division. Hsu et al. (Nutrients, 2021; PMID 34203487): 40 adults, 120 mg/day for 12 weeks; wrinkles, stratum corneum water content, water loss and elasticity better than placebo; three authors are the manufacturer's employees. Gao et al. (2023; PMID 38009035): randomized skin-condition trial with four authors employed by a second manufacturer. Dolečková et al. (Sci Rep, 2025; PMID 41422283): the largest skin trial, 150 adults, 60 or 120 mg/day for 12 weeks; hydration, elasticity, water loss and periorbital wrinkle depth better at 120 mg/day; run by a third manufacturer, with six of its employees as authors. Amin et al. (J Drugs Dermatol, 2025; PMID 40911749): meta-analysis of 7 randomized trials; hydration, elasticity and wrinkle depth improved, firmness and water loss not, with heterogeneity How much the results of the pooled trials differ from each other. High heterogeneity makes a combined estimate less reliable. noted. Kawada et al. (Nutr J, 2014; PMID 25014997) is a review written by a manufacturer's employees, not a trial, and is background. Grade C: self-reported joint outcomes that are mixed, and instrument-measured skin surrogates that are consistent but manufacturer-run throughout. Funding: every trial behind the letter was run with a manufacturer's product and, in all but the null joint trial, with the manufacturer's researchers among the authors; none states an independent funder.
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These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. The grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
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How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
("hyaluronic acid"[tiab] OR hyaluronan[tiab] OR hyaluronate[tiab]) AND oral[tiab] AND (randomized controlled trial[pt] OR randomized[tiab] OR meta-analysis[pt]) AND humans[mesh]Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →