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October 31, 2026
Nicotinamide (vitamin B3) is still an experimental add-on treatment for glaucoma and is not approved for it as of October 2026. Small trials lasting a few months found better scores on some retinal tests, but none has shown slower vision loss over years [1,2]. Large trials are still running, high doses can harm the liver, and it must never replace pressure-lowering drops, laser or surgery [3,4].
Key takeaways
In this article
This article is general education, not a treatment plan. It does not recommend a vitamin B3 dose. Do not start high-dose supplements, or stop any glaucoma treatment, without talking to your eye doctor.
Most questions about nicotinamide can wait for a routine glaucoma visit. Some symptoms cannot. Get emergency help for sudden eye pain or sudden vision loss. Call your doctor the same day if you notice signs of liver trouble while taking any supplement.
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Call your doctor the same day
Nicotinamide and niacinamide are two names for the same form of vitamin B3. Niacin, also called nicotinic acid, is a different form. High-dose niacin causes skin flushing and can harm the liver over time. Nicotinamide does not cause flushing, but very high doses can still cause nausea and liver problems [5].
Your body uses vitamin B3 to make NAD (nicotinamide adenine dinucleotide). Cells need NAD to turn food into energy [5].
Adults need about 14 to 16 milligrams (mg) of vitamin B3 a day. The glaucoma trials use 1,500 to 3,000 mg a day. The upper limit for supplements, 35 mg a day, does not apply to people taking it under medical supervision [5].
Other products sold as "NAD boosters," such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), are different compounds. The trials in this article tested nicotinamide, alone or with pyruvate. Their results do not automatically apply to other products.
Glaucoma damages retinal ganglion cells, the nerve cells whose long fibers form the optic nerve. These cells use a lot of energy. In glaucoma-prone mice, NAD levels in the retina fell with age, and oral nicotinamide protected the nerve cells. Whether this works in people is still being tested [15].
In that 2017 mouse study, 93% of eyes given the highest dose did not develop glaucoma [15]. A 2019 study found lower blood nicotinamide levels in people with open-angle glaucoma than in people without it [16].
These findings make the idea plausible. They do not prove that a supplement protects human eyes. Many treatments that work in mice do not work the same way in people.
The energy idea also does not replace the pressure explanation. Researchers are testing nicotinamide as an extra layer of protection on top of pressure-lowering care. Our article on why glaucoma can progress even with normal eye pressure explains this wider view.
Human studies so far are small and short. Three randomized trials found improvements in some retinal function tests or visual field test points over about 2 to 3 months. A six-month study without a placebo group found stable results. None has shown slower glaucoma progression over years [1,2].
| Study | Who took part | Treatment and length | What improved | What did not change |
|---|---|---|---|---|
| Hui and colleagues, Australia, 2020 [17] | 57 people with treated glaucoma; crossover design | Nicotinamide 1.5 g a day for 6 weeks, then 3.0 g a day for 6 weeks, compared with placebo | A retinal electrical signal improved beyond normal test variation in 23% on nicotinamide vs 9% on placebo | Visual field mean deviation showed only a trend; long-term outcomes were not studied |
| De Moraes and colleagues, United States, 2022 [18] | 42 people randomized, 32 finished; treated open-angle glaucoma | Nicotinamide 1.0 to 3.0 g a day plus pyruvate 1.5 to 3.0 g a day, compared with placebo; median 2.2 months | More visual field test points improved (median 15 vs 7) | Mean deviation and visual field index did not differ |
| Ha and colleagues, South Korea, 2026 [19] | 53 people with normal-tension glaucoma on pressure-lowering treatment; crossover design | Nicotinamide 1 g a day for 6 weeks, then 2 g a day for 6 weeks, compared with placebo | Two retinal electrical signals improved more than with placebo | No difference in mean deviation, pattern standard deviation or visual field index |
| Nicola and colleagues, exploratory study, 2026 [20] | People with primary open-angle glaucoma; no placebo group | Niacinamide 500 mg a day for 6 months | Overall stability on visual field, OCT and nerve-signal tests | No significant change in mean deviation |
A visual field test maps how well you see light across your side vision. Mean deviation is its overall summary score. It is one of the main numbers doctors follow to judge whether glaucoma is getting worse.
A 2026 systematic review searched studies through August 2026. It found eight human studies. It concluded that the evidence does not support routine high-dose nicotinamide in clinical practice [1].
A second 2026 review looked only at mean deviation in three phase 2 trials with 152 people. None showed a significant improvement, and the certainty of the evidence was low [2].
The pyruvate trial also cannot tell us which ingredient caused the change, because people took both together [1].
That has not been shown. Better test scores over a few weeks may mean stressed nerve cells are working better for a while. That is different from protecting the optic nerve for years or regrowing lost nerve fibers. Only longer trials that track vision loss over time can answer this question [1].
Researchers use different words for these goals. "Neuroenhancement" means helping surviving cells work better. "Neuroprotection" means slowing future damage. The 2022 pyruvate trial was designed to test short-term enhancement, not long-term protection [18].
Glaucoma damage that has already happened cannot be undone. Treatment aims to stop it from getting worse [21]. Be wary of any product that claims to reverse glaucoma or restore side vision.
As of October 31, 2026, ClinicalTrials.gov lists four larger placebo-controlled trials of nicotinamide for open-angle glaucoma. Each compares nicotinamide with a placebo and tracks visual field change over roughly 20 to 27 months. None has posted results. The earliest estimated primary completion date is December 2026.
Three of these records have not been updated since 2023 or 2024, so the listed status may be out of date. Check each registry page for the latest information.
High-dose nicotinamide is not safe for unsupervised use. At about 3 grams a day, it can cause nausea, vomiting and signs of liver injury. In a US glaucoma trial, one participant developed drug-induced liver injury that was likely related to 3 grams a day. That is why trials check liver blood tests [5,10].
The liver case happened in the NIC-OAG trial listed above. The authors warned that many people take nicotinamide as a supplement without medical supervision [10].
An older safety review found that very high doses can cause liver damage that usually reverses. It advised treating doses above 3 grams a day as a drug with toxic potential and discouraged unsupervised use. It also noted reports of mild insulin resistance, which matters for people with diabetes [23].
In January 2025, the American Glaucoma Society and the American Academy of Ophthalmology issued a joint position statement [3]. As reported, it says [11]:
Tell every clinician and your pharmacist about any supplement you take. This includes products labeled "vitamin B3," "NAD booster" or "eye support."
No. Lowering eye pressure is the only proven way to treat glaucoma. The published randomized trials gave nicotinamide on top of usual glaucoma treatment, so they say nothing about using it alone. Stopping drops or skipping laser or surgery to try a supplement risks permanent vision loss [4,17,18,19].
Prescription glaucoma eye drops, laser and surgery lower eye pressure and help prevent further optic nerve damage [21]. Our guide to glaucoma treatment options explains how they compare.
Glaucoma often has no symptoms until damage is advanced [13]. Feeling fine does not mean the disease is stable. Keep your scheduled pressure checks, OCT scans and visual field tests.
This applies to normal-tension glaucoma too. Everyone in the 2026 normal-tension trial stayed on pressure-lowering treatment [19]. Ask your doctor about your target pressure rather than turning to a supplement.
Make this decision with your glaucoma doctor, not on your own. This article does not recommend a dose. If your glaucoma is getting worse despite treatment, the first step is to review your eye pressure, drop use and test results. Joining a clinical trial is the most closely monitored way to try nicotinamide.
Questions to bring to your next visit:
Food is a different matter from high-dose pills. In a US survey, people who got more niacin from food had lower odds of glaucoma on some measures, but not on others. This kind of study cannot prove cause and effect [24]. For a wider look at supplements, see our guide to eye vitamins and our page on lifestyle habits and eye pressure.
Netra Restoration Therapy (NRT) is offered as adjunctive care, meaning support alongside your eye doctor's treatment. NRT has not been tested in controlled trials for glaucoma. It does not treat, reverse or cure glaucoma, and it never replaces pressure-lowering drops, laser or surgery.
If you use NRT, keep every appointment with your ophthalmologist. Do not delay standard care. Share any supplement plans with your glaucoma team as well. You can read what Netra Restoration Therapy involves and what is known about its effectiveness.
It may improve some retinal function tests in the short term, but it has not been shown to slow glaucoma or save vision over time. Small trials lasting about 2 to 3 months found better electrical signals from the retina and, in one trial with pyruvate, more improved visual field points. Larger trials running in 2026 are testing whether it slows vision loss over about 2 years.
There is no recommended dose of vitamin B3 for glaucoma, and you should not choose one yourself. Research trials use 1.5 to 3 grams a day of nicotinamide with liver blood tests, which is roughly 100 to 200 times the daily nutrition need. Glaucoma specialists advise against 3 grams a day or more outside monitored trials.
Yes. Niacinamide and nicotinamide are two names for the same form of vitamin B3. Niacin, also called nicotinic acid, is a different form with different side effects, such as skin flushing. Products sold as NAD boosters, such as NR or NMN, are also different and were not tested in the main glaucoma trials.
No. Niacin is not being tested for glaucoma, and glaucoma specialists say the two are not interchangeable. High-dose niacin can harm the liver and can cause skin flushing. Do not swap one product for the other.
At about 3 grams a day, nicotinamide can cause nausea, vomiting and liver injury. One participant in a US glaucoma trial developed drug-induced liver injury that was likely related to 3 grams a day. Yellow skin or eyes, dark urine or belly pain while taking it needs a same-day call to your doctor.
As of October 2026, none of the four larger trials listed on ClinicalTrials.gov has posted results. Their estimated primary completion dates run from December 2026 to August 2027. Published results usually come later, so check each registry page for updates.
No study has shown that. Short-term gains on retinal tests may reflect stressed nerve cells working better, not regrowth of lost nerve fibers. Glaucoma treatment can stop damage from getting worse, but it cannot undo vision that is already lost.
No vitamin or supplement has been proven to prevent glaucoma or slow its vision loss. Nicotinamide is being studied, but the evidence is still early. A balanced diet supports general health, and prescribed pressure-lowering treatment remains the proven way to protect your sight.
Sources checked October 31, 2026.
This article provides general education and does not replace an individual eye examination, diagnosis or treatment plan. Sudden eye pain, sudden vision loss, or yellowing of the skin or eyes while taking a supplement needs prompt medical care.
