Benefits
Explosive strength recovery after intense training
In a 5-week Lonza-funded trial in 22 regularly exercising adults, with two deliberately overloaded training weeks, jump rate of force development fell in both groups but returned to about 98% of baseline with 25 mg a day by the final test, versus about 68% with placebo. A second small Lonza trial found it prevented a drop in explosive force in a pulling test after 5 days of intense training.
Perceived recovery during hard training
In the 5-week overreaching trial, perceived recovery scores rose about 16% from week 1 to week 6 with 25 mg a day and fell about 6% with placebo, a significant difference between groups. This is a self-rated outcome from one small trial funded by Lonza, which also supplied the product.
Muscle damage markers after a strenuous training event
In a 14-day Lonza-funded trial in 18 endurance-trained adults, those taking 25 mg a day kept more squat-jump power 24 hours after a strenuous cross-training event and lost less isometric strength over 48 hours than those on placebo. Blood creatine kinase, a muscle damage marker, was 14% higher with placebo. The trial was small and maker-funded.
Immune marker (salivary IgA) during intense training
In a Lonza-funded trial in healthy adults (19 of 22 finished) who took 25 mg a day for 14 days before 5 straight days of intense resistance training, salivary immunoglobulin A, an antibody on the lining of the mouth and airways, fell significantly with placebo but not with the phytoplankton. This is one marker from one small trial; colds and infections were not tracked.
Body-composition and hormonal markers in young men
In a 60-day double-blind trial in 46 healthy young men, percent muscle mass, free testosterone, IGF-1 and erythropoietin rose and percent fat mass fell within both the 25 mg and 200 mg groups, with 25 mg looking most effective. The maker supplied the algae and the study has not been repeated. These are marker changes, not proof of muscle building or hormone boosting.
Antioxidant enzyme gene expression in muscle
In a maker-funded crossover trial, 13 healthy men took 25 mg a day and a placebo for 14 days each. Muscle biopsies after the algae showed higher expression of NRF2, a master switch for antioxidant defenses, and of antioxidant enzyme genes such as glutathione peroxidase 7 and peroxiredoxin 6, than after placebo. Gene expression is a lab marker, not a measured health outcome.
Peak oxygen uptake during cycling
In a maker-funded crossover trial in 13 recreationally active men, peak oxygen uptake rose after 14 days of 25 mg a day compared with before it but not after placebo, although after supplementation the two conditions did not differ significantly and time to exhaustion was no different from placebo. A 30-day trial in 32 amateur soccer players taking 200 mg a day also reported a within-group rise.
Grown in closed photobioreactors (sourcing attribute)
TetraSOD is grown by Fitoplancton Marino in closed outdoor photobioreactors near the Spanish coast and freeze-dried as whole algal biomass, so it contains no animal ingredients. It has been authorized in the EU as a novel food since 2014 and for food supplements since 2017. This is a sourcing and regulatory attribute, not a health benefit.
Mechanism of action
Superoxide dismutase (SOD) and indirect antioxidant action
TetraSOD is grown to be rich in superoxide dismutase (SOD), an enzyme that converts the superoxide radical into hydrogen peroxide. A review by the maker and its academic partners proposes that, once eaten, it works mainly as an indirect antioxidant, switching on the body's own antioxidant defenses through NRF2 and SIRT1 rather than scavenging radicals directly.
Inflammatory cytokines in animal studies
In exercising rats, the phytoplankton lowered the inflammatory signals TNF-alpha and IL-1 beta in muscle and blood and lowered malondialdehyde, a marker of oxidative damage, in muscle. The maker's review describes it as raising anti-inflammatory and lowering pro-inflammatory signals. These are animal findings.
Whole-algae nutrient content
As a whole dried alga it also contains protein, fats, vitamins and minerals, but at 25 mg a day these amounts are nutritionally negligible. The proposed effects are attributed to its enzyme activity and other bioactive compounds rather than to its nutrient content.
Hormonal-marker changes in one trial
In one 60-day trial in young men, erythropoietin, IGF-1 and free testosterone rose within the supplemented groups. How the alga might cause this is unknown, and these marker changes have not been repeated or linked to gains in muscle or performance.
Immune markers under exercise stress
Hard training can temporarily lower salivary IgA, an antibody on mucous surfaces. In one Lonza-funded trial salivary IgA held steady with the phytoplankton but fell with placebo, and the researchers propose that lower oxidative stress and inflammatory cytokines may explain this. The idea rests on one small trial and rat data.
Clinical trials
Randomized, double-blind, placebo-controlled parallel trial of 25 mg a day of marine phytoplankton (Oceanix) during a 5-week resistance program with deliberate overreaching in weeks 2 and 5, run at the Applied Science and Performance Institute in Tampa and funded by Lonza, which supplied the product (Sharp et al. 2021, Int J Sports Med)
22 regularly exercising men and women aged 18 to 45 who completed the study (26 enrolled).
Perceived recovery rose about 16% from week 1 to week 6 with the phytoplankton and fell about 6% with placebo, a significant difference. Peak and mean rate of force development in a jump test fell in both groups after the overreaching weeks; at the final test the phytoplankton group was back to about 98% of baseline while placebo stayed at about 68%. A parallel rat study looked at muscle repair markers.
Randomized, double-blind, placebo-controlled parallel trial of 25 mg a day of Oceanix for 14 days before 5 consecutive days of intense resistance training, with a parallel rat study at 2.55 or 5.1 mg/kg a day; funded by Lonza and separate from the 5-week trial (Sharp et al. 2021, Phys Act Nutr)
22 healthy men and women enrolled in the human trial and 19 completed it; rats in four groups of 7.
The phytoplankton group avoided the significant drop in isometric peak rate of force development seen with placebo. Salivary immunoglobulin A fell significantly after training with placebo but not with the phytoplankton. In exercising rats it lowered TNF-alpha and IL-1 beta in muscle and blood and lowered muscle malondialdehyde.
Double-blind, placebo-controlled trial of 25 mg or 200 mg a day of Tetraselmis chuii or a lactose placebo for 60 days, with tests at baseline, month 1, month 2 and 30 days after stopping; Fitoplancton Marino supplied the algae (García et al. 2022, Int J Environ Res Public Health)
46 healthy young men with an average age of about 20 to 21 (16 placebo, 15 in each dose group).
Within both supplemented groups, percent muscle mass, erythropoietin, IGF-1, free testosterone, white cells, neutrophils and lymphocytes rose significantly, while percent fat mass, platelets, hematocrit and mean corpuscular hemoglobin fell. The authors judged 25 mg a day the most effective dose. These are marker changes from one study and were not linked to performance.
Randomized, double-blind, placebo-controlled parallel trial of 25 mg a day of Oceanix for 14 days, with a strenuous cross-training event on day 12 and testing 24 and 48 hours later, plus a parallel rat study; funded by Lonza (Sharp et al. 2020, Nutrients)
18 endurance-trained adults running about 30 miles a week who completed the study, 9 per group (20 enrolled).
Squat-jump power was 15% lower with placebo than with the phytoplankton 24 hours after the event, isometric strength fell more with placebo (by 12%) from before to 48 hours after, and creatine kinase, a muscle damage marker, was 14% higher with placebo. In rats, muscle antioxidant enzyme capacity rose with dose.
Two randomized, double-blind, placebo-controlled crossover experiments of 25 mg a day of Tetraselmis chuii for 14 days per condition, funded by Fitoplancton Marino, whose staff are co-authors (Cocksedge et al. 2025, Antioxidants (Basel))
Two separate groups of recreationally active healthy men, 13 completing each experiment (15 recruited to each).
Peak oxygen uptake in a cycling test rose after the algae compared with before it (p = 0.013) but not after placebo, with a significant supplement by time interaction; after supplementation the two conditions did not differ significantly (p = 0.11), and time to exhaustion and blood lactate did not differ between algae and placebo. Muscle biopsies showed higher expression of NRF2, SIRT1 and antioxidant enzyme genes such as GPX7, GSR, GSTM3 and PRDX6 after the algae than after placebo.
Double-blind, placebo-controlled trial of 200 mg a day of Tetraselmis chuii or a lactose placebo for 30 days; Fitoplancton Marino supplied the algae (Toro et al. 2020, Int J Environ Res Public Health)
32 amateur soccer players aged about 22, 16 per group.
In the supplemented group, relative maximum oxygen consumption rose by about 6%, heart rate during the treadmill test fell and hemoglobin rose, while hematocrit and mean platelet volume fell. The abstract reports these as changes within the supplemented group rather than as differences from placebo.