Researchers tested whether a special form of selenium (a mineral) could help people with depression feel better when added to their regular antidepressant medication. Forty-two adults with major depression took either the selenium supplement or a placebo pill along with sertraline for 12 weeks. The group taking selenium showed greater improvement in depression symptoms and had better antioxidant levels in their blood—meaning their bodies had more natural protection against cellular damage. While results look promising, the study was relatively small and short, so more research is needed before doctors widely recommend this approach.

The Quick Take

  • What they studied: Whether adding nano-selenium (a specially processed form of the mineral selenium) to standard depression medication helps reduce depression symptoms and improve the body’s natural antioxidant defenses
  • Who participated: 42 adults (21 in each group) who had recently been diagnosed with major depression. Participants were randomly assigned to receive either nano-selenium or a placebo pill, both taken alongside sertraline (a common antidepressant) for 12 weeks
  • Key finding: People taking nano-selenium experienced greater improvement in depression symptoms compared to those taking placebo. Their blood also showed higher levels of protective antioxidants (TAC and GPX), which help fight cellular damage
  • What it means for you: Nano-selenium may be a helpful addition to standard depression treatment, but this is early-stage research. Don’t start taking supplements without talking to your doctor first, as this study is too small to make definitive recommendations for everyone

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of research studies. Researchers randomly divided 50 newly diagnosed depression patients into two equal groups. One group received nano-selenium (55 micrograms daily) plus sertraline, while the other group received a placebo (fake pill) plus sertraline. Neither the participants, the researchers giving the treatment, nor the people measuring the results knew who was getting the real supplement—this is called triple-blinding and helps prevent bias.

The study lasted 12 weeks, and researchers measured depression symptoms using a standard questionnaire called the Hamilton Depression Rating Scale. They also took blood samples at the beginning and end to measure three important markers: glutathione peroxidase (an antioxidant enzyme), total antioxidant capacity (overall antioxidant protection), and malondialdehyde (a marker of cellular damage).

Nano-selenium is a newer form of the mineral selenium that’s been specially processed into tiny particles, which may allow the body to absorb and use it more effectively than regular selenium supplements.

Depression is often linked to increased oxidative stress—essentially, an imbalance where harmful molecules called free radicals damage cells faster than the body can repair them. This study matters because it tests whether boosting the body’s natural antioxidant defenses alongside standard medication could improve depression outcomes. The triple-blind design is particularly important because it prevents expectations from influencing results, making the findings more trustworthy.

Strengths: This was a properly randomized, triple-blind, placebo-controlled study, which is the gold standard for testing treatments. The researchers measured objective blood markers, not just patient reports. Weaknesses: The sample size was small (only 42 people completed the study), which limits how much we can generalize the findings. The study only lasted 12 weeks, so we don’t know if benefits continue long-term. Some participants dropped out, which could affect results. The study was conducted in Iran, so results may not apply equally to all populations.

What the Results Show

Compared to the placebo group, people taking nano-selenium experienced significantly greater improvements in depression symptoms. On the depression rating scale, the nano-selenium group improved by an average of 5.09 points more than the placebo group, and this difference was statistically significant (meaning it’s very unlikely to have happened by chance).

The nano-selenium group also showed meaningful improvements in blood antioxidant markers. Their total antioxidant capacity (TAC)—a measure of the body’s overall ability to fight cellular damage—increased significantly more than in the placebo group. Similarly, glutathione peroxidase (GPX), a specific antioxidant enzyme, increased more in the nano-selenium group.

Interestingly, malondialdehyde (MDA), a marker of cellular damage, decreased in both groups over the 12 weeks, suggesting that the standard antidepressant medication alone helps reduce oxidative stress. However, the nano-selenium group didn’t show significantly greater MDA reduction than placebo, meaning the supplement’s main advantage appears to be boosting protective antioxidants rather than reducing damage markers.

The study didn’t report major side effects or safety concerns in either group, suggesting nano-selenium appears to be well-tolerated when combined with sertraline. The fact that both groups improved in depression symptoms confirms that sertraline itself is working, which validates the study design. The nano-selenium group’s additional improvement suggests the supplement provides extra benefit beyond the medication alone.

Previous research has shown that people with depression often have higher oxidative stress and lower antioxidant levels compared to people without depression. Some earlier studies suggested that selenium supplementation might help with depression, but results have been mixed. This study is one of the first to test nano-selenium specifically (the specially processed form) as an add-on to standard antidepressant medication in a rigorous, triple-blind design. The findings align with the theory that boosting antioxidant defenses could complement standard depression treatment.

The study had several important limitations. First, only 42 of the original 50 participants completed it, which reduces the reliability of results. Second, 12 weeks is relatively short—we don’t know if benefits continue, increase, or fade over months or years. Third, the sample size is small, making it harder to apply these findings to larger populations. Fourth, all participants were newly diagnosed with depression and taking sertraline, so results may not apply to people with different depression profiles or taking other medications. Finally, the study was conducted in one country, so cultural and genetic differences might affect how well these results apply elsewhere.

The Bottom Line

Based on this research, nano-selenium shows promise as a potential add-on treatment for depression alongside standard medication (moderate confidence level). However, this is early-stage research, and larger studies are needed before making broad recommendations. If you have depression, continue taking prescribed antidepressants as directed. Talk to your doctor before adding any supplements, including selenium, as they can interact with medications and may not be appropriate for everyone.

This research is most relevant to people with major depression who are starting antidepressant treatment and want to explore additional options. It may be of interest to psychiatrists and mental health professionals looking for complementary approaches. However, people with certain health conditions (like thyroid problems), those taking specific medications, or those with selenium sensitivities should consult their doctor before considering this supplement. This research doesn’t apply to people with other types of depression or those already stable on their current treatment.

In this study, improvements in depression symptoms and antioxidant levels were measured after 12 weeks of daily supplementation. Realistic expectations would be to see potential benefits within 8-12 weeks if nano-selenium works for you, though individual responses vary. It’s important to continue taking prescribed antidepressants during this time, as they typically take 4-6 weeks to show full effects.

Want to Apply This Research?

  • If your doctor approves nano-selenium supplementation, track your daily mood on a 1-10 scale and note depression symptoms (sleep quality, energy level, motivation, concentration) weekly. Compare these to your baseline before starting the supplement to objectively measure changes over 8-12 weeks.
  • Work with your healthcare provider to establish a routine: take nano-selenium at the same time daily (ideally with food for better absorption) alongside your regular antidepressant. Set phone reminders to build consistency, as the study showed benefits after 12 weeks of daily use.
  • Create a simple weekly check-in system tracking: (1) depression symptom severity, (2) energy and motivation levels, (3) sleep quality, and (4) any side effects. Share this data with your doctor at regular appointments to determine if the supplement is helping. If no improvement appears after 8-12 weeks, discuss discontinuing it with your healthcare provider.

This research describes a clinical trial testing nano-selenium as an add-on to depression medication. These findings are preliminary and based on a small study. Do not start, stop, or change any depression medications or supplements without consulting your doctor or mental health professional. Selenium supplements can interact with medications and may not be appropriate for everyone, especially those with thyroid conditions or taking certain drugs. This article is for educational purposes only and should not replace professional medical advice. If you’re experiencing depression, please seek care from a qualified healthcare provider.