Spirulina — a nutrient‑dense blue‑green algae — has long been promoted for its antioxidant and anti‑inflammatory properties. A new randomized, double‑blind, placebo‑controlled clinical trial suggests it may also support better sleep and improved mental health, two pillars of healthy aging and cognitive resilience.

What the Researchers Did

The study enrolled 66 adults with mild to moderately severe depression. Participants were randomly assigned to:

• Spirulina group: 2 g/day (two 1000 mg softgels)
• Placebo group

The trial lasted 8 weeks, with assessments at baseline, week 4, and week 8. Researchers measured:

• Sleep quality (Pittsburgh Sleep Quality Index)
• Sleep hygiene behaviors
• Depression, anxiety, and stress (DASS‑21)
• BMI, pulse, and blood pressure

Sixty‑three participants completed the study with excellent adherence.

Key Findings

1. Spirulina significantly improved sleep quality

Participants taking Spirulina saw their PSQI sleep score improve from 7.03 → 4.97. The placebo group improved only slightly (8.07 → 6.73). The difference at week 8 was statistically significant (p = 0.004).

2. Spirulina reduced sleep latency (time to fall asleep)

Spirulina users fell asleep faster, with sleep latency scores improving to 0.82 ± 0.58 compared to 1.33 ± 0.61 in the placebo group (p = 0.001).

3. Mental health improved more in the Spirulina group

Depression, anxiety, and stress scores steadily decreased across all time points in the Spirulina group. The placebo group improved early but worsened again by week 8.

4. No adverse effects

BMI, blood pressure, and pulse remained stable, and no side effects were reported.

Why This Matters for Adults Over 60

Although the study included adults aged 18–60, the findings are highly relevant for older adults. Sleep disturbances and mood changes become more common with age, and both strongly influence cognitive health.

Spirulina contains tryptophan, a precursor to serotonin — a neurotransmitter involved in sleep regulation, emotional balance, and stress response. Supporting these pathways may help protect long‑term brain function.

Bottom Line

Daily supplementation with 2 g of Spirulina for 8 weeks significantly improved sleep quality, reduced time to fall asleep, and supported better mental health compared to placebo.

While more research is needed in older adults specifically, this study suggests Spirulina may be a safe, natural option for supporting sleep and emotional well‑being — two essential components of cognitive health.

Reference

The study is available here: Effects of Spirulina supplementation on sleep quality, sleep hygiene, and mental health in adults with depression.