How to Take Chlorella: Dosage, Timing, Duration

Chlorella is a dietary supplement with a fairly wide range of doses used in studies. To get the benefits from it and not encounter stomach discomfort, it is important to correctly choose the amount, the timing of intake, and the length of the course. The editors have prepared a practical guide based on clinical work and experience of use.

Doses in clinical studies

The dosing of chlorella in studies ranges from roughly 2 to 10 g per day. In the randomized study by Kwak et al. (2012), which examined the effect on natural killer cells, participants received 5 g of chlorella per day for 8 weeks.

In the clinical work by Merchant et al. on fibromyalgia and arterial hypertension, patients took about 10 g of chlorella in tablets per day together with a liquid extract — that is, doses in the upper part of the range.

Studies that assessed sports and vascular indicators (Otsuki's group) used multi-component chlorella-based supplements in courses of about 4 weeks, so it is difficult to transfer their dosing directly to ordinary chlorella.

On the market a serving of 2–3 g per day is considered standard and is often recommended on packaging. It is lower than most clinical doses, so it may be insufficient for a targeted effect.

Practical dosing: a gradual start

Because of the fiber and cell wall polysaccharides, chlorella at the start of use often causes bloating and flatulence. So the editors recommend introducing it gradually — the same way as spirulina.

1. Days 1–7:1 g per day (4–5 tablets of 200–250 mg or a corresponding serving of powder);
2. Days 8–14:2–3 g per day, split into 2 intakes;
3. From the third week:3–5 g per day — the target dose for most goals;
4. Upper limit:about 10 g per day — doses that were used in clinical studies under supervision.

Pay attention to the tablet dosage: chlorella often comes in tablets of 200–250 mg, so 5 g will require 20–25 tablets. Powder in this situation is more practical.

For people taking warfarin, any dosing must be coordinated with a doctor, and the dose must be stable each day so as not to disrupt INR control.

For children, pregnant women, and breastfeeding women, self-directed dosing is not recommended: the decision should be made by a doctor.

Timing of intake and relationship to food

Chlorella is best taken with food: this reduces the likelihood of nausea and bloating. No advantages of taking it on an empty stomach have been proven.

It is convenient to split the daily dose into 2–3 intakes — for example, with breakfast, lunch, and dinner. This distribution improves tolerability and allows nutrients to be absorbed more evenly.

Athletes taking chlorella during training camps should tie intakes to their main meals rather than to the workout itself: there is no evidence that taking it before exercise provides an advantage.

As with spirulina, coffee and tea in the same intake may reduce the absorption of iron from chlorella, so it is better to space them at least an hour apart from the supplement.

Course length

Clinical studies of chlorella mostly lasted from 4 to 12 weeks, some a few months. It was over these periods that changes in immune indicators, blood pressure, and aerobic performance were recorded.

Chlorella does not cause dependence or suppression of the body's own systems, so mandatory breaks are not needed. However, the editors advise objectively assessing every 2–3 months whether the supplement provides benefit.

For athletes it is advisable to consider chlorella in courses timed to periods of high load — camps, competition blocks — when immune support is especially relevant. A course should be started a few weeks before such a period, since in studies the effects accumulated gradually.

With long-term use, product quality becomes even more important: a systematic intake of even small amounts of metals or pheophorbides from poor-quality raw material is undesirable.

Choosing a product and common mistakes

The first and most important condition is a broken cell wall. Without it, the absorption of chlorella's nutrients is limited, and the effective dose is actually reduced.

The second is quality control: a certificate of analysis for heavy metals, microbiology, and pheophorbide content, GMP manufacturing. For athletes undergoing doping control — certification free of prohibited substances.

A typical mistake is believing that “more means better” and starting right away at 10 g per day. The result is usually bloating and discomfort, because of which the person quits.

Another mistake is regarding chlorella as a reliable source of vitamin B12 for vegans. Although some products contain active B12 (Watanabe et al., 2002), the content is inconsistent, so a separate B12 supplement remains necessary for vegans.

Editors' conclusions

For most goals the optimal dose of chlorella is 3–5 g per day with food, split into 2–3 intakes, with a gradual increase over 1–2 weeks.

A course should last at least 4–8 weeks; for athletes it is advisable to start ahead of periods of high load.

Choose products with a broken cell wall and laboratory quality control, and when taking warfarin coordinate the dosing with a doctor.

To continue the topic, our articles “Chlorella Side Effects,” “Chlorella Benefits for Athletes: The Evidence Base,” and “How to Take Spirulina: Dosage, Timing, Duration” will help.

References

1. Kwak JH, Baek SH, Woo Y, et al. Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of natural killer cell activity and early inflammatory response (randomized, double-blinded, placebo-controlled trial). Nutr J. 2012;11:53.
2. Merchant RE, Andre CA, Sica DA. Nutritional supplementation with Chlorella pyrenoidosa for mild to moderate hypertension. J Med Food. 2002;5(3):141–152.
3. Merchant RE, Andre CA. A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa in the treatment of fibromyalgia, hypertension, and ulcerative colitis. Altern Ther Health Med. 2001;7(3):79–91.
4. Umemoto S, Otsuki T. Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in young individuals. J Clin Biochem Nutr. 2014;55(2):143–146.
5. Bito T, Okumura E, Fujishima M, Watanabe F. Potential of Chlorella as a dietary supplement to promote human health. Nutrients. 2020;12(9):2524.
6. Watanabe F, Takenaka S, Kittaka-Katsura H, Ebara S, Miyamoto E. Characterization and bioavailability of vitamin B12-compounds from edible algae. J Nutr Sci Vitaminol (Tokyo). 2002;48(5):325–331.
7. Panahi Y, Darvishi B, Jowzi N, Beiraghdar F, Sahebkar A. Chlorella vulgaris: a multifunctional dietary supplement with diverse medicinal properties. Curr Pharm Des. 2016;22(2):164–173.