New Health Guide

Vitamin B Complex Supplements Side Effects

Oct 13, 2014

Vitamin B actually refers to a group of vitamins - eight of them, in fact, all water soluble. These include thiamine, riboflavin, pantothenic acid, niacin, biotin, pyridoxine, cyanocobalamin, and folic acid. Each one of these vitamins is essential for good health.

A supplement that contains all of these vitamins is known as a B Complex. Though these are believed to have a very low chance of becoming toxic in the body, too much of them can lead to side effects that can be unpleasant.

Vitamin B Complex Supplements Side Effects

As with any supplement, medication or vitamin, there can be side effects. Even though B complex vitamins are generally good for you, you might experience some of these conditions as a result of different parts of the Complex vitamin or overdose of vitamin b complex. Check the side effects as follows:

  • Black stools
  • Constipation
  • Abdominal pain
  • Vomiting
  • Nausea
  • Frequent urination
  • Changes in urine color
  • Diarrhea
  • Itching
  • Redness of skin

In rare cases, allergic reactions could also happen, including itchiness and rashes, as well as kidney stones. If you experience persisting side effects, call your doctor immediately.

Individual B Vitamins Side Effects

We have broken the side effects down into each part of the Complex vitamin, and included the recommended daily allowance for men, women and children.

1. Vitamin B1 (thiamine) Side Effects

Symptoms: Thiamine side effects are very rare. When they do occur, it's usually an allergic reaction that can be spotted by itchiness, rashes or hives. Overdoses can cause sweating, weakness, nausea, restlessness and fluid retention.

Daily RDA for Vitamin B1

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 years

1-3 years

4-6 years

0.2

0.3

0.5

0.6

Females

9-13 years

14-18 years

19 years and above

Pregnant or lactating

0.9

1

1.2

1.4

Males

9-13 years

14 and above

0.9

1.2

2. Vitamin B2 (Riboflavin) Side Effects

Symptoms: Riboflavin often turns the urine into a yellowish-orange color, but this is not cause for concern. An overdose can lead to frequent urination and diarrhea.

Daily RDA for Vitamin B2

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

0.3

0.4

0.5

0.6

Males

9-13 years

14 and above

0.9

1.3

Females

9-13 years

14-18 years

19 and above

Pregnant or lactating

0.9

1

1.1

1.4/1.6

3. Vitamin B3 (Niacin) Side Effects

Symptoms: Niacin can cause flushing of the skin - it can make you look as though you have sunburn. You might also experience a tingling or burning sensation, sweating or chills. Other side effects include dizziness, upset stomach, nausea, vomiting, heartburn or diarrhea. More serious problems can include blurred vision, abdominal pain, joint pains, swelling, yellowing of the eyes and black stools. If you suffer the more severe side effects, alert your doctor.

Daily RDA for Vitamin B3

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

2

4

6

8

Females

9-13 years

14 years and above

Pregnant or lactating

12

14

18/17

Males

9-13 years

14 years and above

12

16

4. Vitamin B5 (Pantothenic Acid) Side Effects

Symptoms: Allergic side effects with this vitamin are rare. When they do occur, it is often due to overdose, and the most common problem is diarrhea.

Daily RDA for Vitamin B5

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

1.7

1.8

2

3

Males

9-13 years

14 years and above

4

5

Females

9-13 years

14 years and above

Pregnant or lactating

4

5

6/7

5. Vitamin B6 (Pyridoxine) Side Effects

Symptoms: Side effects are rare, but when they do occur, they can include tingling, drowsiness, stomach pain, nausea and vomiting, loss of appetite and headache. Very high doses can cause nerve problems and neurological impairment. Rare side effects include disorientation, numbness and extreme fatigue.

Daily RDA for Vitamin B6

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

0.1

0.4

0.5

0.6

Males

9-13 years

14-18 years

19-50 years

51 years and above

1

1.3

1.3

1.7

Females

9-13 years

14-18 years

19-50 years

51 years and above

Pregnant or lactating

1

1.2

1.3

1.5

1.9/2

6. Vitamin B7 (Biotin) Side Effects

Symptoms: There is no indication that biotin is toxic, even when took much is taken. However, in pregnant women it has been shown to shrink the placenta, which could lead to problems for the fetus, or even miscarriage.

Daily RDA for Vitamin B7

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

5

6

8

12

Females

9-13 years

14-18 years

19-50 years

51 years and older

Pregnant or lactating

20

25

30

30

30/35

Males

9-13 years

14-18 years

19-50 years

51 years or older

20

25

30

30

7. Vitamin B9 (Folic Acid) Side Effects

Symptoms: Folic acid doesn't cause any side effects. Overdose might lead to an increased risk of heart attack, liver cancer or prostate cancer.

Daily RDA for Vitamin B9

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-3 years

4-8 years

65

80

150

200

Males

9-13 years

14 years and above

300

400

Females

9-13 years

14 years and above

Pregnant or lactating

300

400

600/500

8. Vitamin B12 (Cyanocobalamin) Side Effects

Symptoms: Sometimes this vitamin can cause itching, diarrhea and blood clots, though these are usually very rare. The amount taken to indicate overdose has not been established.

Daily RDA for Vitamin B12

Group

Age

RAD(mg/day)

Infants

 

Children

0-6 months

6-12 months

1-10 years

0.4

0.5

0.7-2

Males

11 years and up

2.4

Females

11 years and up

Pregnant or lactating

2.4

2.6/2.8

Precautions for Taking Vitamin B Complex

Before you decide to take a Vitamin B Complex, talk to your doctor to determine whether it is right for you. Always let your doctor know if you are taking other medications, including those over the counter, or other vitamins. Make it clear if you suffer from gout, diabetes, liver problems, stomach ulcers or drug allergies. Finally, if you are pregnant or breastfeeding, always consult a doctor to determine whether Vitamin B complex is safe for you and your baby.