Does hyaluronic acid serum help hair grow?

What the lab studies show, and what they don't

Bottom line: lab results suggest HA may act on scalp cells, but they stop well short of showing hair growth in people. Researchers treated human dermal papilla cells, which sit at the base of the hair follicle, with a non-cross-linked HA filler that also contains amino acids. The product restored cell viability after UVB damage and increased VEGF, a growth factor tied to blood vessel formation (in vitro dermal papilla study).

A companion study of the same product on keratinocytes found increased VEGF expression, which the authors read as a possible pro-angiogenic effect (keratinocyte study). The authors frame any future use as conditional on clinical testing. Cell culture cannot tell you whether a living scalp grows more hair.

For background on the ingredient itself, see our hyaluronic acid explainer.

The one hair study used an injection, not a serum

Bottom line: the only clinical hair study we found is small, tested injections, and as far as the abstract shows, lacked a control arm.

Twenty-six volunteers with moderate androgenetic alopecia received six sessions, two weeks apart, of a mechanically stabilized HA complex delivered with a micro-papule technique. Reported results included improved scalp hair thickness, shine and density at 40 and 90 days (scalp injection study).

Three caveats matter. The product also contains vitamins, copper, zinc and amino acids, so HA cannot be credited on its own. The abstract we read shows no blinding and no hair-count method. And an injection in a clinic is a different exposure from a serum you apply at home.

Injected HA carries a risk that serums don't

Bottom line: injected HA has a documented downside, which is one reason injection-based hair protocols need careful vetting.

A case report describes a provisional diagnosis of HA-induced alopecia, based on the clinical picture and timing relative to an injection (case report and literature review). The same team reported no adverse events during its own treatment course. That is reassuring, but it does not cancel out a documented case.

This concerns fillers placed under the skin. Rinse-off and leave-on serums are a different exposure, and we found no long-term safety data for topical HA on the scalp.

What the topical serum trial actually measured

Bottom line: the best-designed topical HA serum trial we found tested skin, not hair.

In a split-face study of 24 women, a cross-linked HA serum was applied to areas after fillers, microneedling or peeling. Treated areas showed statistically significant gains in skin surface topography and hydration compared with untreated areas (split-face serum trial).

That is a useful result for skin. It says nothing about follicles or hair counts, so it cannot be stretched into a hair claim.

How to judge a hair serum claim

Bottom line: measure any hair serum against the bar set for approved treatments, which means controlled trials with objective counts.

A 2025 review of medicalized hair-loss treatments says robust, well-controlled randomized trials with standardized formulations and objective endpoints are still needed to show whether HA helps on its own (2025 review). The dermal papilla paper also notes that only minoxidil and finasteride are FDA-approved for hair loss.

• Look for a randomized controlled trial of the exact product, not just an ingredient or a filler.
• Check for objective endpoints such as phototrichogram hair counts, not only shine or feel.
• Note whether the manufacturer funded the study. Several key studies here used manufacturer-linked products.
• Be skeptical of grows-hair language. We found no AAD, FDA or NIH statement on HA for hair.