Written by Alexa Heathorn, MS, CNS-c, Science Writer. Daily supplementation of 2 g of softgel spirulina for 8 weeks significantly improved sleep quality, reduced sleep latency, and enhanced mental health in adults with mild to moderate depression.

Mental health concerns, particularly depression, are on the rise globally, with significant impacts on both individuals and society. Sleep disturbances often accompany depression, creating a vicious cycle that worsens both conditions¹. Traditional treatments, including pharmaceuticals, frequently lead to undesirable short- and long-term effects, including dependency². As a result, there is growing interest in natural, nutrition-based therapies for the root causes of insomnia and depression². A recent randomized, double-blind, placebo-controlled trial evaluated the effects of Arthrospira platensis (Spirulina) supplementation on sleep quality, sleep latency, mental health, and BMI in adults with moderate depression. The results revealed a promising, low risk intervention to support mood and sleep regulation for this population².

Arthrospira platensis (Spirulina), is a blue-green microalgae that thrives in alkaline freshwater lakes³.  It is rich in proteins, essential amino acids, minerals, essential fatty acids, B vitamins, gamma-linolenic acid and- most relevant to this study- tryptophan^2,3. Tryptophan is a precursor to serotonin, a neurotransmitter crucial for mood and sleep regulation². Previous studies have shown a correlation between low tryptophan or serotonin levels and poor sleep and mood disorders².  A systematic review also reported significant improvements in sleep quality following tryptophan supplementation². However, up until this study, there have been no clinical trials evaluating the impact of spirulina in a population with depression-related sleep disturbances².

The study included 66 adults aged 18-60 with mild to moderate depression and a BMI under <30 kg/m². The participants were randomly assigned to receive either 2 g / spirulina per day (n= 33) or an identical placebo (n=33) for 8 weeks².  BMI, pulse and blood pressure, mental health, sleep quality, and sleep latency were assessed at baseline (Day 0), week 4 (Day 28) and week 8 (Day 56)².

The results were as follows after 8 weeks of supplementation²:

• Sleep Quality: Both the spirulina and placebo group showed improvements, but the spirulina group had a significantly greater increase in scores (7.03 → 4.97) compared to the control group (8.07 → 6.73, p.004).
• Sleep Latency: Both groups improved, with the spirulina group showing a statistically significant greater reduction (1.30 → 0.79) compared to the Placebo (1.64 → 1.33, p=0.003).
• Mental Health: The spirulina group experienced steady, statistically significant improvements over the course of the 8 weeks (Baseline: 19.27 ± 13.09 → Week 4: 14.24 → Week 8: 11.58, p < 0.05). The placebo group showed a smaller change with an initial improvement followed by a rebound (Baseline: 15.43 ± 9.18 → Week 4: 12.57 → Week 8: 12.63).
• BMI, Blood pressure, and heart rate: no significant changes were observed in either group.

Potential limitations of the study include:

• The study was limited to adults aged 18-60 with mild to moderate depression and a BMI under 30 kg/m². As such, the results may not be generalized to individuals outside of this population (e.g, severe depression, chronic conditions, other age groups, higher BMI ranges).
• The 8-week duration was relatively short and may not reflect the long-term or cumulative effects of spirulina supplementation.
• The spirulina supplementation used in this study was delivered in soft gel form, which offers enhanced bioavailability. These results may not translate to other supplement forms, such as powders or traditional capsules, which may have lower absorption rates.

This study provides compelling preliminary evidence that daily supplementation of 2 g of soft gel spirulina for 8 weeks may significantly improve sleep quality, reduce sleep latency, and enhance mental health in adults with mild to moderately severe depression. These improvements were not seen in the placebo group, suggesting a genuine effect beyond placebo. These findings support spirulina as a safe, affordable, and accessible option for supporting mental health and sleep in both clinical and public health settings. Further research is needed to evaluate long-term outcomes, determine optimal dosing, and explore its potential benefits in more diverse populations.

Source: Phansuea, Phenphop, Kittipat Chotchindakun, Yuraporn Sahasakul, Karunpong Phattaramarut, and Panwong Kuntanawat. “Effectiveness of an Arthrospira platensis (Spirulina) Softgel Supplementation on Sleep Quality, Mental Health Status, and Body Mass Index in Mild to Moderately Severe Depression Adults: A Double‐Blinded, Randomized, Placebo‐Controlled Trial.” Food Science & Nutrition 13, no. 3 (2025): e70082.

© 2025 The Author(s). Food Science & Nutrition published by Wiley Periodicals LLC.

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Posted July 15, 2025.

Alexa Heathorn, MS, CNS-c, is a clinical nutritionist specializing in metabolic health, hormonal balance, and gastrointestinal restoration through root-cause functional nutrition. She earned her master’s degree in Nutrition from Bastyr University and is currently a Certified Nutrition Specialist (CNS) candidate. Alexa also works as a research writer and functional health consultant, translating complex science into actionable strategies for practitioners and wellness companies. Learn more at www.bloomedwellness.com.

References:

1. Nutt D, Wilson S, Paterson L. Sleep disorders as core symptoms of depression. Dialogues Clin Neurosci. 2008;10(3):329-36. doi:10.31887/DCNS.2008.10.3/dnutt
2. Phansuea P, Chotchindakun K, Sahasakul Y, Phattaramarut K, Kuntanawat P. Effectiveness of an Arthrospira platensis (Spirulina) Softgel Supplementation on Sleep Quality, Mental Health Status, and Body Mass Index in Mild to Moderately Severe Depression Adults: A Double-Blinded, Randomized, Placebo-Controlled Trial. Food Sci Nutr. Mar 2025;13(3):e70082. doi:10.1002/fsn3.70082
3. Sorrenti V, Castagna DA, Fortinguerra S, Buriani A, Scapagnini G, Willcox DC. Spirulina Microalgae and Brain Health: A Scoping Review of Experimental and Clinical Evidence. Mar Drugs. May 22 2021;19(6)doi:10.3390/md19060293