Hyaluronic Acid for Dry Eyes: Does an Oral Supplement Help?

Oral hyaluronic acid has been tested for dry eye disease, but the evidence is much thinner than supplement marketing often implies. The key human study is a small randomized trial in which every participant already used topical hyaluronic acid. Oral HA was tested as an add-on—not as a replacement for eye drops.

That makes the conclusion fairly specific: oral HA is an interesting adjunctive strategy with preliminary human evidence, but it is not an established standalone dry-eye treatment.

Why hyaluronic acid is relevant to dry eye

Topical sodium hyaluronate is widely used in lubricating eye drops because HA binds water and has viscoelastic properties that can support the ocular surface. That topical evidence should not be confused with oral supplementation, however. Putting HA directly on the eye and swallowing it are different interventions with different pharmacology.

A 2017 systematic review of topical sodium-hyaluronate artificial tears included multiple randomized studies and found evidence of improvement in selected dry-eye measures. That helps explain why topical HA is familiar in eye care, but it does not prove that oral HA has the same effect.

The main oral HA dry-eye trial

The most relevant human study was published by Kim and colleagues in 2019. It prospectively randomized 54 adults with dry eye disease.

All participants were treated with topical HA. The study group additionally received oral HA. According to the published protocol, the oral intervention supplied 240 mg/day of 390 kDa sodium hyaluronate for three months.

The investigators evaluated several ocular-surface outcomes, including:

• Ocular Surface Disease Index (OSDI);
• tear breakup time (TBUT);
• corneal fluorescein staining (CFS); and
• Schirmer testing.

The oral-plus-topical group showed significant improvements in OSDI, TBUT and corneal staining during follow-up. The authors concluded that combined oral and topical HA improved symptoms and ocular-surface parameters more efficiently than topical HA alone.

Read the study at PubMed.

What the trial does—and does not—prove

The positive signal is worth taking seriously. It was randomized, prospective and used clinically recognizable dry-eye measures.

But there are four major limitations:

1. Small sample: only 54 participants were enrolled.
2. Adjunctive design: everyone received topical HA, so the study did not test oral HA as monotherapy.
3. Single trial: we do not have a large replicated oral-HA dry-eye evidence base.
4. Short duration: the treatment period was three months, not years.

So “oral HA cured dry eye” would be an unjustified claim. “One small randomized study found benefit when oral HA was added to topical HA” is accurate.

Can oral HA replace hyaluronic acid eye drops?

No evidence supports that substitution. The available oral trial specifically layered supplementation on top of topical treatment.

If topical lubricants help you, an oral supplement should not be treated as a reason to stop them. More importantly, dry eye has many potential contributors—meibomian-gland dysfunction, medications, contact-lens use, autoimmune disease, environmental exposure, hormonal factors and other ocular-surface disorders—so management depends on the cause.

How much oral HA was studied?

The Kim study used 240 mg/day, which is higher than the 60–200 mg/day range commonly seen in oral skin trials.

That does not mean 240 mg is the universal “dry-eye dose.” It means that is the dose used in the one randomized oral trial we can directly map to dry-eye outcomes.

For broader dosing evidence, see our oral HA dosage guide.

Does molecular weight matter for dry eye supplements?

The oral intervention in the 2019 trial used sodium hyaluronate around 390 kDa. That is useful formulation information, but one study cannot establish 390 kDa as an optimal molecular weight for dry eye.

Across other oral HA indications, clinical trials span from very low molecular weights up to 1.8 MDa. See our molecular-weight evidence review.

Is oral HA standard treatment for dry eye disease?

No. Oral HA supplementation is not established as a first-line or standard treatment based on the current evidence base.

Topical lubricants, management of eyelid/meibomian-gland disease, environmental modification and other clinician-directed treatments have a much larger role depending on the dry-eye subtype and severity.

When should dry-eye symptoms be medically assessed?

Persistent symptoms deserve evaluation, particularly if they interfere with daily activities or do not respond to simple lubrication. Seek prompt eye-care assessment for:

• eye pain rather than mild irritation;
• marked redness;
• light sensitivity;
• new or worsening vision changes;
• significant discharge;
• eye injury or chemical exposure; or
• severe unilateral symptoms.

Where oral HA fits in the broader evidence

The overall oral HA literature is much stronger for selected skin outcomes than it is for dry eye. A 2025 meta-analysis pooled seven randomized skin trials and found significant effects on hydration, elasticity and wrinkle depth. Joint evidence is smaller and heterogeneous, while dry-eye evidence currently rests mainly on this single adjunctive randomized trial.

You can explore all of those evidence tiers in the Hyaluronic Acid Research Data Center.

Bottom line

Oral hyaluronic acid has a plausible and positive preliminary dry-eye signal, but only as an adjunct in a small randomized study. The trial used 240 mg/day of 390 kDa sodium hyaluronate alongside topical HA.

That is enough to justify further research—not enough to replace established dry-eye care or claim that an oral supplement works as a standalone treatment.