AlgaeCal (Basic) contains calcium, magnesium and trace minerals derived from algae with added vitamin D. AlgaeCal Plus also includes added vitamins C and K, boron, and additional magnesium. Testing by in 2011 found AlgaeCal Plus to contain a higher amount of lead (a toxic heavy metal) (5.2 mcg per daily serving of 4 capsules) than many other calcium-containing supplements. Testing in 2017 found less lead, although still higher than acceptable to CL, but also less magnesium than listed on the label.

Studies sponsored by the makers of AlgaeCal found that it increased bone mineral density in healthy men and women, although there were weaknesses to the study design. There do not appear to be any clinical studies comparing the effects of AlgaeCal to other forms of calcium, such as calcium carbonate or calcium citrate nor to other calcium + vitamin D supplements. For more about this, plus evidence for other forms of calcium, see the Calcium Supplements Review >>

CL members have contacted AlgaeCal about CL's findings of lead in its AlgaeCal product and have shared the responses they received with us. These are posted below along with our comments:

(11/17/15): We were recently informed by a CL member that AlgaeCal provided the following information in response to the member's inquiry about lead in AlgaeCal Plus. In its response, AlgaeCal appears to acknowledge the amount of lead found by in 2011, but provides information which we consider misleading regarding how that amount of lead compares to what is found in the U.S. diet by stating:
"There are 5.2 mcg of lead in a daily dosage of 4 capsules of AlgaeCal Plus. It is just like taking a daily serving of other typical plant foods according to the FDA's publication, Total Diet Study Statistics on Elements Results (December 11, 2007): Food Amount of Lead in a 4 Ounce Serving Mixed nuts, roasted 10.2 mcg Brussels sprouts, fresh, boiled 7.9 mcg Sweet potato, fresh, baked 7.2 mcg Spinach, boiled 7.0 mcg Avocado, raw 4.5 mcg. Furthermore, the US Government's Centers For Disease Control publication 'Inorganic Lead Exposure, Metabolism and Intoxication' states that 'typical intakes of lead from food, beverages and inhaled air are in the order of 300 to 500 mcg per day.' "
The most recent Total Diet Study (FDA 2014) shows much lower amounts of lead in foods than AlgaeCal states above. The FDA found no detectable lead in peanuts or Brussels sprouts and, based 3 oz servings, only 1.1 mcg in sweet potatoes (0.013 mcg/gram or mg/kg), 0.3 mcg in spinach (0.004 mcg/g) and 0.085 mcg in avocado (0.001 mcg/g). We could not find the CDC publication referenced by AlgaeCal, but found another CDC publication (ATSDR Public Health Statement for Lead 2007) which states that, based on recent studies, "the average dietary intake of lead was about 1 microgram (a microgram is a millionth of a gram) per kilogram of body weight per day." For an adult weighing 70 kg (154 lbs), this would be 70 mcg -- nowhere near the 300 to 500 mcg stated above. In short, the amount of lead in AlgaeCal Plus is higher than in most foods and calcium supplements and adds significantly to one's intake of lead. (Note: Be aware that in 2018, the FDA lowered the maximum intakes for lead from all sources from 70 mcg per day to 12.5 mcg per day in adults, and from 6 mcg per day to 3 mcg per day in children.)

(6/12/18): AlgaeCal recently provided the following information in response to a CL member's inquiry about lead in AlgaeCal Plus:
"Lead is omnipresent, albeit in very minute amounts, in our environment, and thus our food. There are 0.23 ppm (0.556 mcg) of lead in a daily dosage of 4 capsules of AlgaeCal Plus. There is no extraction process with the raw Algae product, it is merely live harvested from the protected beaches, dried and ground. This is one of the many trace minerals and is far below any problematic amounts — well within international safety standards. The vast majority of environmental lead present is safely excreted from the body every day, save for times of unusually high exposure. A study of lead levels in the USA food supply, found HERE, states that "Data obtained on the lead content of milk, eggs, meat, fish, and shellfish indicate that the mean levels in these unprocessed foods varied from 0.02 to about 0.4 ppm, with the lowest level in milk." To attempt to remove this lead would damage the trace mineral content that makes AlgaeCal so effective for bone health. According to THIS Health Canada informational page, "In adults with a normal diet, 3-15% of ingested lead is absorbed into the blood by the intestine. Less than 5% of absorbed lead stays in the body". So you can see that AlgaeCal is a safe, natural way to increase bone density."
The amount of lead that AlgaeCal now claims to be in its product (0.556 mcg per 4 capsules) would pose little risk. However, it is about half the amount that found in its most recent tests in 2017 of AlgaeCal Plus.

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November 19, 2015

Why take calcium at all? There is no strong evidence that the majority of people are calcium deficient.

The most recent USPSTF statement on Ca++ and fractures is: The USPSTF recommends against daily supplementation with 400 IU or less of vitamin D3 and 1,000 mg or less of calcium for the primary prevention of fractures in noninstitutionalized postmenopausal women.
November 20, 2015

Hi Cory - Information about who may or may not need more calcium, how much calcium you may already be getting from food, and doses of calcium for specific uses is found in the "What to Consider When Using" section of the Calcium Supplements Review:

May 17, 2017

Since I have a small frame, white, and ex smoker, I was diagnosed with osteoporosis at age 61. I also have had surgery for reflux, so I cannot take any oral biophosphates, like Fosamax, for example. I failed the Reclast infusion as well, too many side effects.So there are some of us that DO need calcium supplementation. I try not to take too much as it can be constipating, and I do eat a lot of dairy, spinach, broccoli, etc.
This site cuts to the chase with calcium supplementation, as it's important for people to understand you can have too much of anything, and it can be harmful.

November 18, 2015

You provided information on the lead content in AlgaeCal, a plant-based calcium, but what about other plant-based calcium supplements, like Garden of Life's Vitamin Code Raw Calcium or Nature's Plus Source of Life Garden Calcium (which admittedly contains AlgaeCal)? Have you checked out those products?
November 18, 2015

Hi Sandra - We did not test those products in our most recent review of calcium supplements, although we have tested other plant-based calcium supplements, such as the algae-based calcium supplement Nature's Way Alive! Calcium Bone Formula, in the past.

November 18, 2015

I did take Algae Cal for four months before I became very ill. I would never take it again!!!

August 27, 2015

I have been taking AlgaeCal Plus( 4 capsules per day) along with their product, Strontium Boost. Based on reading your article I am concerned that I may have consumed too much lead along with the calcium. Don't know if I should continue with the product. I do have osteoporosis and wanted to avoid taking prescription drugs. Also, any evidence that plant based calcium contributes to kidney stones?
November 16, 2015

Hi Debbie - There do not appear to be any studies on the effects of plant-based calcium supplements on kidney stone formation or risk.

February 8, 2017

I have friends and my husband on The AlgaeCal program...ALL have better readings on their DEXA tests...2 no longer have osteoporosis...all doctors are amazed and say continue what you are doing! do have to continue maintenence...

June 18, 2018

I have also had remarkable success with AlgaeCal and Strontium Boost. My Dexa Scans have shown continual improvement. With the exception of just one place, I have achieved normal bone density.

March 13, 2019

This confuses me even more! I have taken AlgaeCal for a few years from a company in Florida. My dexa scans have not shown improvement. I am to take three caps a day.

May 5, 2020

I contacted AlgaeCal regarding how much Lead there supplement contains. They replied back and said it contains 1.4 mcg of lead in a daily dose.
On this website it claims:"However, calcium derived from algae is still just calcium carbonate, and it is not a new calcium supplement form."
I contacted AlgaeCal regarding this also and they confirmed that AlgaeCal is "100% plant-based and is not calcium carbonate"
Do you know whether AlgaeCal is a 100% plant-based calcium supplement or whether it is just calcium carbonate?
May 5, 2020

As noted in our Calcium Review (, the calcium in AlgaeCal is from algae and consists of a complex of several forms of calcium, one of which is calcium carbonate.

December 13, 2019

Barb1380 I have taken Algae Cal for at least 6 years. The 2 DEXA tests after I started taking it remained the same, but my last test showed more bone loss.

L. Oriana 17714
April 4, 2019

Add me to the list of those who have reversed their declining DEXA results by adding AlgaeCal and Strontium Boost to my regimen. After 15 years of worsening scores, mine have been going up again. I look forward to the results now!

March 27, 2017

I'm confused by this controversy. I wrote to AlgaeCal and they say the lead content in four capsules is about 0.141ppm or 0.000336 mg. That would be 0.3 mcg. I think we would benefit from some more supporting documentation on both sides, since you've got some pretty negative stuff here.

Also, I've read defenses of strontium but am still quite concerned about their related product, Strontium Boost. Strontium replaces calcium not only in bones, but in nerves, and that's a bad thing. There are claims that it does strengthen bone, rather than just looking good on an X-ray, but it seems risky. A naturally-occurring trace level is fine, but I wouldn't take it on purpose.
March 27, 2017

Hi Fae - If AlgaeCal is saying that the lead level in their product is now what you wrote -- 0.3 mcg in four capsules, that would be much lower than what CL found and what AlgaeCal seems to have admitted to in the past, which was 5.2 mcg (see the Update above).

For information about strontium, see our answer to the question "Do any supplements help prevent or treat osteoporosis" at

March 27, 2017

If I've understood your text correctly, you only have that the 5.2 quote secondhand from a member. What did your lab measure in 2011? Thanks.
April 18, 2017

Hi Fae - Our 2011 tests found the same amount as noted in AlgaeCal's company statement -- 5.2 mcg of lead in 4 capsules.

February 9, 2017

I also have had tremendous success with AlgaeCal and Strontium Boost. I have gone from osteopena to normal based on dexa scans. Since I have been taking AlgaeCal/Strontium boost every time I take a Dexa (and there have been 2-3) my bone density increases. I am 65 years old.

April 24, 2017

I too went from Osteopena to almost normal. I'm not taking the Strontium. Just two Algae Cal capsules.

February 8, 2017

My husband was calcium deficient and took an albion chelated form of calcium from a reputable brand for a year that did not raise his levels according to lab results. The next year he took the same dosage of Garden of Life calcium from algae and his calcium levels were raised to normal. He has been taking this calcium ever since, though now at a decreased dose, and his levels have been good for the past several years now. Both their Living Calcium and Vitamin Code Calcium have helped him.

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