Chlorella Side Effects: What To Expect When Taking Chlorella?

chlorella side effects

Article at a glance:

  • Chlorella, if taken for the first time, should be introduced to the body gradually.
  • There may be mild side effects like bloating, nausea, or gassiness, but these are temporary.
  • People with autoimmune conditions or those taking specific medications should consult their doctors first before taking chlorella supplements.


Like any other dietary supplement, chlorella side effects may be expected when introducing this powerful blue-green alga to your system. However, chlorella side effects may differ from one person to another.

That’s why it’s beneficial to have a good understanding of these potential side effects. You’ll know what to expect — good and bad — when taking chlorella supplements. It may also avert adverse side effects for those taking medication or who have sensitivities.

By safeguarding your health, you’ll be able to focus more on the excellent health benefits associated with chlorella supplementation.


What Happens When You Start Taking Chlorella?


woman flexing her muscles


Chlorella is one of the most nutrient-dense functional foods in the world. This single-celled blue-green alga contains approximately 60% protein, 20% healthy fats, 20% carbs, and 5% dietary fiber.

Chlorella is also packed with vitamins, minerals, essential and non-essential amino acids, and omega fatty acids, including gamma linoleic acid, beta-carotene, and chlorophyll — all beneficial and important for human nutrition.

Chlorella supplementation has been associated with many beneficial effects, including:

  • boosting the immune system
  • promoting heavy metal detox
  • protection against viral infections
  • neutralize damage-causing free radicals
  • vitamin and mineral support
  • lower blood glucose levels
  • reduce high blood pressure
  • lower high cholesterol levels
  • reduce allergic symptoms
  • promote healthy bacteria in the gut
  • fight off brain tumors and tumor growth
  • reduce side effects of cancer treatment i.e., radiation
  • protect against age-related eye diseases
  • inhibit cognitive decline
  • reduce the incidence of iron deficiency anemia
  • improve symptoms of major depressive disorder

Given its nutritional value, chlorella can help support overall health. Intake may also address nutrient deficiencies that might increase the risk of chronic or severe diseases.


Can Chlorella Be Harmful?


As a dietary supplement, chlorella is considered gentle and safe. It is well-tolerated by most healthy adults and is not associated with serious side effects. Like other dietary supplements, taking chlorella for the first time may cause specific side effects.

The most common side effects of chlorella include:

  • gas
  • bloating
  • diarrhea
  • nausea
  • dizziness
  • fatigue
  • cramps
  • allergic reactions
  • joint pain
  • green-colored stool
  • photosensitivity

Thankfully, chlorella side effects are not permanent. This is just how your body reacts to chlorella tablets or chlorella powder. The body may take a few days or up to 10 days to build tolerance, and this is because our bodies react differently to it.


What Are the Downsides of Chlorella?


Chlorella is known to work quickly. However, the downside is that you may also immediately experience some of the side effects of chlorella. Nonetheless, this can be a sign that chlorella supplementation is already working.


Possible Chlorella Side Effects When Detoxifying


One of the health benefits of chlorella is detoxification. Chlorella contains chlorophyll, which is well-known for being a potent detoxifying agent. In addition, chlorella’s cell wall has adhesive properties.

This allows chlorella to bind with heavy metals like lead, cadmium, and other toxins. Once that happens, these heavy metals are flushed from your system.

Chlorella may cause toxic metals in your body to dislodge. When they enter the bloodstream, you may experience chlorella side effects such as headaches, nausea, fatigue, and a metallic taste in the mouth.

The severity of chlorella side effects may depend on how much heavy metals have accumulated in your body. It is also recommended to detox slowly and gradually to reduce the severity or incidence of the side effects of chlorella.

The chlorella detox side effects will start to subside after about 10 days.


Possible Chlorella Side Effects on the Skin


Another potential downside is that chlorella may cause photosensitivity. Your skin may burn or develop rashes following exposure to the sun. As such, wearing sunscreen, hats, and other protective gear is essential whenever you anticipate sun exposure. Stay out of the sun if you can.


What Are the Dangers of Chlorella?


Chlorella is considered safe for the general population. However, it can be dangerous to individuals taking certain medications or having specific allergies or sensitivities.

These can lead to mild interactions for some and moderate interactions for others. That’s why seeking medical advice before incorporating any supplement into your diet is important.


Blood Thinners


Researchers have noted drug interactions between chlorella and blood thinners like warfarin. It is attributed to chlorella’s high vitamin K content, which helps promote blood clotting. This goes against the purpose of warfarin, which is to slow down the blood clotting process. As such, there may be serious chlorella dangers for people suffering from blood clots.




chlorella side effects on people with allergies


Chlorella is a chlorophyte, which is considered a weak allergen. As such, it can trigger allergies in certain individuals. The chlorella dangers can range from milder symptoms such as rashes, itching, and asthma to severe allergic reactions such as anaphylaxis.

Studies also found that children with atopic dermatitis or other allergies (pollen, dander, mites, food) may react negatively to chlorella.


Iodine Allergies


Chlorella is also a rich source of iodine. It is not advisable for those with iodine allergies. Chlorella dangers may include hives, swelling, and tightness of breath.


Mold Allergies


Chlorella as an alga has some similarities to mold. Thus, those with mold allergies may also be sensitive to chlorella.


Acute Tubulointerstitial Nephritis


Does chlorella affect kidney function? According to health and nutrition journal articles, chlorella may help avoid mercury-chloride-caused cellular damage and oxidative stress on the kidneys.

However, there was one reported case of acute tubulointerstitial nephritis, where a young boy developed this condition after ingesting chlorella tablets for at least 3 months. The study concluded that chlorella might be a causative allergen that induced the injury in the kidney.


Who Should Not Take Chlorella?


While chlorella is considered safe for general consumption, some individuals need to exercise extra caution before taking this superfood. If the conditions below apply to you, please make sure to consult a healthcare professional before taking chlorella.


With Autoimmune Disorders


Many people decide to take chlorella because of its ability to stimulate and strengthen the immune system. This may lead to increased flare-ups and other adverse reactions for those with multiple sclerosis, rheumatoid arthritis, lupus, and other autoimmune diseases.




Those who are immunocompromised or have a weak immune system may also react adversely to chlorella supplements. This can cause flare-ups or affect the efficacy of immunosuppressant medications.


Pregnant or Breastfeeding


There is no consensus regarding taking chlorella supplements during pregnancy or while breastfeeding. It will depend on you or the advice of your medical practitioner. However, studies show that it may have beneficial effects on pregnant women.

Chlorella supplements may help decrease dioxin content, which is known to affect infant growth and cause neurodevelopment problems. It may also increase carotene and immunoglobulin A levels in breast milk.

Other studies also found that chlorella pyrenoidosa supplementation may help with gestational hypertension, pregnancy anemia, proteinuria, and edema.

Apart from the typical side effects, taking chlorella tablets orally or chlorella powder with food may cause breast milk to turn green.


Health Concerns Without Clearance


If you have other health concerns, consult your healthcare provider before taking chlorella supplements. Your doctor will give you clearance and advise you on proper dosage and usage, which can affect whether or not you experience chlorella tablet side effects.


Other Detox Programs


If you are already on other detox programs, such as an anti-candida diet, you may want to wait before introducing chlorella supplements to your system. Having both simultaneously can increase the intensity of your chlorella detox side effects.


Frequently Asked Questions


Is It Safe to Take Chlorella Everyday?


Chlorella is suitable as a daily supplement. You can take it every day to support your overall health. You can also opt for short-term supplementation, taking chlorella daily for 2-4 months and then repeating this cycle twice a year.

This may depend on what your body currently needs. No matter your schedule, chlorella supplementation can be a worthy addition to your diet.


What Happens If You Have Too Much Chlorella?


There have been no reported cases of chlorella overdose. Chlorella is considered a safe, gentle, and beneficial dietary supplement. If you stick to the recommended dosage, you can take it as much and as often as you like. Those with nutritional deficiencies may opt to increase the dosage according to their individual needs.

As a precaution, we recommend consulting with your healthcare provider to determine your nutritional needs and how chlorella may help supplement those needs. This may also help reduce the incidence and severity of chlorella side effects.

One of the best things about chlorella is that you have a lot of freedom in choosing how to incorporate this fantastic superfood into your daily regimen. You can take chlorella tablets conveniently or even have fun incorporating chlorella powder or chlorella liquid extracts into different tasty recipes.


Focusing on Chlorella Health Benefits


Experiencing chlorella side effects for the first few days may be a small price to pay, considering all the wonderful health benefits you’ll get in return. Just make sure to take the proper precautions. This includes seeking the advice of your healthcare provider, following the recommended dosage, and only choosing the best quality chlorella supplements available.

Remember that the effectiveness of your chlorella tablets or powder will also depend on how these green algae are cultivated, harvested, and processed. These side effects are rare; even if they happen to you, they’re temporary. Give your body time to adjust, and you’ll soon reap the benefits of this ultimate superfood!




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John Riedl

Simply put that’s why I’ve gone down the health journey of research and creating health brands.

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