Last Updated: April 2026 | Reviewed by Dr. Davinder Sidhu, OD
Thealoz Duo, Thealoz Gel, and the Duo Gel are made by Laboratoires Théa in France, and each targets a different problem.
Why Théa makes four drops, not one
The differences are in the active ingredients. Hyabak uses hyaluronic acid, Thealoz Duo layers in trehalose, a bioprotective sugar that shields your corneal cells from dehydration stress. And Thealoz Gel goes further by adding Carbopol 974P, a carbomer that thickens the formulation and extends contact time on the ocular surface.
The science behind these choices was published in a 2017 study in Acta Ophthalmologica by Wozniak that measured tear film thickness with OCT imaging across three gel formulations. A 2021 paper in International Ophthalmology by Cagini looked at recovery in post-cataract patients. A 2018 paper in the Italian Review of Ophthalmology by Spadea tracked 262 patients with corneal abrasions. Théa publishes the data and submits it for peer review, which is rare in the artificial tear category.
They are made by Laboratoires Théa, a Clermont-Ferrand pharma group that has made eye drops since 1994. The question isn't which Thealoz is best. It's which one matches your eyes today, and what you pair it with.
Hyabak: when an HA-only drop is enough
Hyabak is the entry point of Thealoz, and the right call for mild or occasional dryness. Long screen days, dry winters, contact lens wearers. It's the kind of dryness that comes and goes without setting up shop.
The formula is sodium hyaluronate at 0.15% in a saline base, preservative-free and phosphate-free, in a multi-dose bottle. Hyaluronic acid is hygroscopic, it pulls water out of the surrounding environment and holds it on the ocular surface. If your tear film is fundamentally healthy but flagging from the environment or screen time, that mechanism is enough on its own. Adding trehalose or carbomer to the formula when you don't actually need them is overspending and overformulating.
The signs that Hyabak isn't working for you are if the dryness becomes daily and persistent. You're reaching for drops more than three or four times a day. At that point, you'll likely need to switch to Duo.
Hyabak works well with daily contact lens wearers and through allergy season in full swing. At $22.99, it's the lowest-cost entry into the lineup.
Thealoz Duo: What is Trehalose?
Thealoz Duo is the product most Canadian dry eye patients land on first when over-the-counter drops stop working. The formula combines 3% trehalose with 0.15% hyaluronic acid in a preservative-free, phosphate-free saline. One drop holds the tear film stable for up to four hours.
Trehalose is the difference. Trehalose is a disaccharide that some plants and microorganisms produce when they need to survive extreme dehydration. A resurrection plant can lose up to 95% of its water content, sit dormant for months, and can still rehydrate fully when water returns. The mechanism that protects those cells is the same one trehalose uses on a dry corneal surface. It stabilizes the membrane proteins and lipids that hold the tear film together when blinking, so your epithelial cells take less damage in the gaps.
Thealoz Duo is best used for moderate dryness, when your drops aren't lasting or symptoms don't quit by mid-afternoon. If you're post-LASIK or post-cataract and need something more protective than lubricating, Thealoz Duo is best for you.
Where it falls short is night-time and the deep end of severe afternoon dryness. Four hours is plenty for daytime but doesn't carry through till the morning.
Thealoz Gel and Duo Gel: same formula, two delivery methods
Thealoz Gel and the Duo Gel have the same formulation: 3% trehalose, 0.15% hyaluronic acid, and 0.25% Carbopol 974P. Three active ingredients holding the tear film stable for six measurable hours per drop, preservative-free and phosphate-free in both. The formula is the same. It's how you use them that is different.
Thealoz Gel comes in a 15mL Novelia multidose bottle that holds 400 drops, the same compact size as a Thealoz Duo bottle, but it's built for daily, repeat use across morning, afternoon, and bedtime.
The Duo Gel is single-use unit-dose vials, sterile per application, built for travel, post-op recovery windows, anyone with an immune-compromised eye, or anyone who doesn't want a multidose bottle in their bag.
Because the formula is identical, the clinical evidence applies to both products equally. The Wozniak 2017 study ran a 60-patient head-to-head against HYLO Gel and Sustain Gel, measuring tear film thickness at one, two, four, and six hours, and the Thealoz formulation held a significantly thicker film at every interval. The Spadea 2018 paper followed 262 patients with corneal abrasions and found the gel accelerated epithelial healing compared to antibiotic plus occlusive patching. Two studies, two different problems (chronic dryness and acute corneal recovery), one formula.
Most brands premium-price their gel version. HYLO Gel runs around 19¢ a drop and I-Drop Pur Gel around 16¢. Thealoz Gel is 12¢ a drop.
How to use Thealoz with the rest of your routine
Thealoz is the artificial tear layer for your dry eye routine, but not the whole routine. The drops do their job best when they're paired with the right products and treatment plan.
For patients with meibomian gland dysfunction, no drop alone solves the problem. Pair Thealoz Duo or Gel with a lid hygiene product like Blephaclean wipes, ideally backed up by a warm compress. The drops keep the tear film stable, the lid work addresses what's making it unstable in the first place.
Omega-3 supplementation runs on a different timeline. DE3 omega-3 capsules support meibomian gland function over weeks, not minutes, while the drops handle the daily relief. The supplements work on the underlying biology, the drops manage the symptoms.
For contact lens wearers, the routine is simple: Hyabak before insertion, Thealoz Duo after removal, and skip the gels on lens days because the viscosity isn't lens-friendly.
Post-surgery is its own routine. Duo Gel, single-use and sterile, are the cleanest option for the first two weeks after cataract or refractive surgery. Once your surgeon greenlights it, the multidose Gel can replace them.
The Thealoz family is a lineup, not a hierarchy. Hyabak isn't "worse" than Gel, it's made for a different eye and a different day.
All four products are in stock now at mypear.ca, including the new Thealoz Gel.
About the Reviewer
Dr. Davinder Sidhu is an optometrist based in British Columbia with a focus on dry eye management and preservative-free solutions. Learn more at TheGenuwineOD.com or follow him on Instagram and Facebook.
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