“Be sure to take your vitamins!”
This is the message we hear starting in childhood: that supplements are an essential part of a healthy lifestyle.
But despite a widespread belief that they are safe because they are natural, the truth is that some supplements can be quite dangerous. Rather than enhancing health, consuming them in high quantities (or in conjunction with other medications) could result in terrible health outcomes.
Unproven Science, Growing Market
Most consumers are unaware that in the United States, supplements are not tested or approved by the Food and Drug Administration (FDA) before being sold.
Supplement sales continue to grow at an astounding rate, with the US market valued at $37 billion in 2019. By 2024, sales are projected to reach $56.7 billion in the US and a whopping $278 billion worldwide. [Sources: Statistica, PRNewsWire]
Yet the majority of patients who take supplements don’t even need them. In one study, less than 1/4 of people who take dietary supplements are actually shown to have a nutritional deficiency at all. [source: American Osteopathic Association]
While taking additional vitamins can be useful, consuming anything in large quantities, and combining them with prescription medications, can actually make certain conditions worse.
The lack of oversight and accountability puts the public at tremendous risk. An unregulated industry, combined with a massive marketing opportunity, has turned the supplement industry into a “Wild Wild West” full of quackery and unsubstantiated health claims.
Rigorous scientific studies about the safety of supplements for both adults and children is greatly lacking, despite the massive amount of money being spent on research (over $1 billion has been spent by one group alone).
Because of this complete lack of supplement regulation, the public is at risk of experiencing:
- physical side effects from overdosing, toxicity, and poisoning;
- harmful interactions with prescribed medications, and
- financial exploitation by practitioners who sell and promote products within their practices. [source: AMA Journal of Ethics]
(You can read more about this in my guest post, What to Do if Your Doctor Promotes Multi-Level Marketing).
So basically,
- a large percentage of people are buying dietary supplements…
- most of which are unproven to actually improve health…
- and in some cases, this may actually be causing harm.
Evaluating the Risk of Harm
In order to make a risk intelligent decision, we can use a Risk Matrix like the one below:

We can evaluate this situation by establishing a few things. First, we know that using some the degree of severity when using certain dietary supplements could be high (right side of the graphic above). We also know that the likelihood of harm occurring could also be high (top of the graph).
So taking dietary supplements could potentially be a High Risk situation.
We can Mitigate the risk of harm by reducing the effects of damage, and by making sure that it does not occur in the first place.
This is only possible if we increase our awareness of possible side effects or drug interactions. Understanding the possible dangers will result in the ability to make informed decisions about your health and the health of your loved ones.
(As with anything else — please consult your medical professional before making any changes to your medications. This information is only being shared for educational purposes and should not be taken as medical advice.)
Supplement Ingredients Which Can Be Damaging
Not all dietary aids are “safe,” despite the marketing pitch that is presented to consumers. Companies that use the Multi-Level Marketing model are especially good at convincing people who are suffering to spend their money on vitamins and minerals that could have amazing results.
Obviously, some supplements do provide health benefits; but many consumers are unaware of the risks that can occur with use.
At least 35 over-the-counter dietary supplements have been shown to result in dangerous side effects. These include:
Aloe, arnica, bitter orange, black cohosh, caffeine powder, cannabidiol, chaparral, colloidal silver, coltsfoot, comfrey, country mallow, dong quai, ephedra, feverfew, garlic, germander, germanium, ginger, ginkgo, ginseng, goldenseal, greater celandine, green tea, hawthorn, kava, licorice root, lobelia, methylsynephrine, pennyroyal oil, red yeast rice, St. John’s wort, stinging nettle, usnic acid, and yohimbe.
Let’s review the dangerous effects of these dietary supplements one by one. This information comes from CBS News, Consumer Reports, Cleveland Clinic, and National Institutes of Health.
1. Aconite
Also known as
Aconiti tuber, aconitum, angustifolium, monkshood, radix aconti, wolfsbane
Harmful effects
Vomiting, low blood pressure, heart arrhythmia, respiratory paralysis, death
2. Aloe
Also known as
Aloë, Aloe vera, “true aloe,” Aloe Barbadensis, Aloe Indica, Aloe Barbados, Indian Alces, Kumari, Ghirita, Gawarpaltra, Barbados Aloe, Curacao Aloe, Lu Hui
Harmful effects
When taken internally, can cause heart arrhythmia
3. Arnica
Also known as
Arnica montana
Harmful effects
Heart toxicity, increased blood pressure when taken internally
4. Bitter orange
Also known as
aurantii fructus, Citrus aurantium, and zhi shi
Harmful effects
Heart problems, stroke, death
5. Black cohosh
Also known as
Cimicifuga racemose
Harmful effects
Low blood pressure
6. Caffeine powder
Also known as
1,3,7-trimethylxanthine
Harmful effects
Heart arrhythmia, cardiac arrest, seizures, death; risk increases when combined with other stimulants
7. Cannabidiol
Also known as
CBD, CBD oil, Cannabis sativa, hemp, hemp oil
Harmful effects
Dry mouth, low blood pressure, light headedness, drowsiness, liver injury [additional sources: WebMD and Molecules by MPDI]
8. Chaparral
Also known as
creosote bush, greasewood, Larrea divaricate, Larrea tridentate, larreastat
Harmful effects
Liver and kidney problems; not advised for use by the FDA
9. Colloidal silver
Also known as
ionic silver, native silver
Harmful effects
Blue skin discoloration, neurological problems, kidney damage
10. Coltsfoot
Also known as
coughwort, farfarae folium leaf, foalswort, Tussilago farfara
Harmful effects
Liver damage and cancer
11. Comfrey
Also known as
blackwort, bruisewort, common comfrey, slippery root, Symphytum officinale
Harmful effects
Liver damage and cancer; FDA barred comfrey products from US production in 2001
12. Country mallow
Also known as
heartleaf, Sida cordifolia, silky white mallow
Harmful effects
Heart attack, heart arrhythmia, stroke, death
13. Dong quai
Also known as
Angelica China, Angelica sinensis, Angelicae Gigantis Radix, Angélique Chinoise, Angélique de Chine, Chinese Angelica, Dang Gui, Danggui, Danguia, Kinesisk Kvan, Ligustilides, Radix Angelicae Gigantis, Radix Angelicae Sinensis, Tang Kuei, Tan Kue Bai Zhi, Tanggwi, Toki
Harmful effects
Hives, swelling, difficulty breathing, bleeding problems, birth defects, high blood pressure in infants exposed from breastfeeding; estrogen-like hormone sensitivity with higher risk of breast, uterine, ovarian cancer, endometriosis, and uterine fibroids; carcinogenic [additional source: MedlinePlus]
14. Ephedra
Also known as
Ephedra sinica, Ma-Huang
Harmful effects
Irregular heartbeat, high blood pressure, fatal interaction with other cardiac medications
15. Feverfew
Also known as
Tanacetum parthenium
Harmful effects
Interferes with blood clotting if taken internally
16. Garlic
Also known as
Allium sativum
Harmful effects
Increased risk of bleeding when taking blood-thinning medications
17. Germander
Also known as
Teucrium chamaedrys, viscidum
Harmful effects
Liver damage, hepatitis, death
18. Germanium
Also known as
Ge, Ge-132, germanium-132
Harmful effects
Kidney damage and death; warned against by FDA since 1993
19. Ginger
Harmful effects
Heart arrhythmia, blood pressure changes, blood clotting problems, and increased risk of bleeding when taking blood-thinning medications
20. Ginkgo
Also known as
Ginkgo biloba, gingko, maidenhair
Harmful effects
Increased risk of bleeding when taking blood-thinning medications
21. Ginseng
Also known as
Panax ginseng
Harmful effects
Hypertension, increased risk of bleeding when taking blood-thinning medications
22. Goldenseal
Also known as
berberine, Hydrastis canadensis
Harmful effects
Irregular blood pressure, irregular heart rhythm, increased risk of bleeding when taking blood-thinning medications
23. Greater celandine
Also known as
celandine, chelidonii herba, Chelidonium maju. Celidonii herba
Harmful effects
Liver damage
24. Green tea
Also known as
green tea extract powder, green tea extract, Camellia sinensis
Harmful effects
Dizziness, tinnitus, reduced iron absorption, worsens anemia and glaucoma, elevated blood pressure, elevated heart rate, liver damage, death
25. Hawthorn
Also known as
Crataegus species, hawthorn, hawberry, quickthorn, thornapple, May-tree, whitethorn
Harmful effects
Increased risk of bleeding when taking blood-thinning medications
26. Kava
Also known as
awa, Ava pepper, Piper methysticum, kava-kava
Harmful effects
Liver damage, exacerbated Parkinson’s symptoms; exacerbated depression, impaired driving, and death. Warned against by FDA since 1993. Banned in Canada, Germany, and Switzerland.
27. Licorice root
Also known as
Glycyrrhiza glabra, gycyrrhizaglabra
Harmful effects
High blood pressure, heart arrhythmia
28. Lobelia
Also known as
asthma weed, Lobelia inflata, pokeweed, vomit wort, wild tobacco
Harmful effects
Vomiting, confusion, tachycardia, low blood pressure, hypothermia, tremors, seizures, coma, death; warned against by FDA since 1993
29. Methylsynephrine
Also known as
oxilofrine, p-hydroxyephedrine, oxyephedrine, 4-HMP
Harmful effects
Arrhythmia and irregular heart rate, cardiac arrest; worse symptoms when taken with other stimulants
30. Pennyroyal oil
Also known as
Hedeoma pulegioides, Mentha pulegium
Harmful effects
Liver failure, kidney failure, nerve damage, convulsions, death
31. Red yeast rice
Also known as
Monascus purpureus
Harmful effects
Problems with kidneys, liver, and muscles; hair loss; magnifies effect of statin drugs
32. St. John’s wort
Also known as
Hypericum perforatum, Hypericum, Saint John’s wort, Goatweed, Klamath weed, Tipton weed
Harmful effects
Sunlight sensitivity, anxiety, dry mouth, dizziness, fatigue, headache, and sexual dysfunction; can also over-metabolizes antibiotics and weaken the effects of antidepressants, oral contraceptives, cyclosporine [organ transplant anti-rejection medication], digoxin [heart medication], indinavir [HIV medication], irinotecan [cancer treatment medication], anti-seizure medications, and anticoagulants such as warfarin [additional sources: National Center for Complementary and Integrative Health and VeryWellMind]
33. Stinging nettle
Also known as
Urtica dioica
Harmful effects
Amplifies the effect of diuretics, reduces the effect of lithium; can cause unregulated blood pressure, uncontrolled blood sugars, diuretic with possible kidney damage. [additional source: VeryWellHealth]
34. Usnic acid
Also known as
beard moss, tree moss, usnea
Harmful effects
Liver damage
35. Yohimbe
Also known as
Corynanthe johimbi, Corynanthe yohimbe, Johimbi, pausinystalia yohimbe, yohimbine [prescription drug]
Harmful effects
Headaches, high blood pressure, tachycardia, heart problems, liver and kidney problems, panic attacks, seizures, death; warned against by FDA since 1993
Sources used in this article (unless listed elsewhere): CBS News, Consumer Reports, Cleveland Clinic, National Institutes of Health
If you or someone you know has experienced a serious reaction or illness after using any vitamins, minerals, herbs, amino acids, whey protein, creatine, and weight loss pills—please file a report using HHS’s Safety Reporting Portal (USA).
In Canada, you can file a report about adverse reactions with the Regulatory Operations and Enforcement Branch (ROEB) using the side effect form found here.
Find out more about adverse events from dietary supplements, check out what the FDA has to say about it: https://www.fda.gov/food/dietary-supplements/how-report-problem-dietary-supplements
Interested in hearing how you can reverse a toxic workplace? Find out more here.
Grace LaConte is a business consultant, writer, workplace equity strategist, and the founder of LaConte Consulting. Her risk management tools are used around the globe, and she has successfully reversed toxic work environments for clients in the healthcare and non-profit fields. Grace specializes in lactation law compliance & policy development, reducing staff turnover after maternity leave, and creating a participatory work culture.
Find more at laconteconsulting.com, or connect with her on Instagram and Twitter @lacontestrategy.