California Gold Nutrition Immune 4 Review 2026: Worth the Price?

Possible side effects

• The most common complaints are diarrhea, nausea, abdominal cramps, and other digestive upset.

Serious risks

• High intakes may raise urinary oxalate and uric acid, which could contribute to kidney stones, especially in people with renal disorders.
• The best evidence that vitamin C contributes to kidney stones is in patients who already have hyperoxaluria.
• In people with hereditary hemochromatosis, long-term high doses could worsen iron overload and cause tissue damage.
• A few in vitro studies suggested that supplemental oral vitamin C, acting as a pro-oxidant, could cause chromosomal or DNA damage and possibly contribute to cancer.
• In postmenopausal women with diabetes in the Iowa Women's Health Study, supplemental vitamin C of at least 300 mg/day was significantly associated with a higher risk of dying from CVD.

Avoid or ask a doctor first if

• People with hereditary hemochromatosis face a concern about iron overload with chronic high doses.
• The upper limits do not apply to people receiving vitamin C as medical treatment, who should be under a physician's care.
• Infants should get vitamin C only from formula and food.

Medication interactions

• Vitamin C supplements may interact with radiation therapy and with medications, including chemotherapy drugs and statins.
• People taking these medications regularly should talk with their health care providers about vitamin C intake.

Possible side effects

• High zinc intakes can cause nausea, dizziness, headaches, gastric distress, vomiting, and loss of appetite.

Serious risks

• Doses of 50 mg or more taken for weeks can interfere with copper absorption, reduce immune function, and lower HDL cholesterol.
• Very high supplemental doses (142 mg/day) might interfere with magnesium absorption and disrupt magnesium balance.
• According to a few reports, overuse of zinc-containing denture adhesive creams can lead to neurological symptoms and anemia.

Avoid or ask a doctor first if

• The upper limits don't apply to people receiving zinc for medical treatment, who should be under a physician's care.
• Zinc-free denture adhesive formulations are available to prevent the effects linked to zinc-containing creams.

Medication interactions

• Zinc may interact with quinolone antibiotics, tetracycline antibiotics, and penicillamine.
• Some diuretics can lower serum zinc by increasing zinc excretion in urine.
• People taking medications regularly should discuss their zinc status with their health care providers.

Possible side effects

• Early signs of too much selenium are a garlic odor on the breath and a metallic taste in the mouth.
• Hair loss and nail brittleness or loss are the most common clinical signs of chronically high selenium intake.
• Other signs of chronically high intake include skin rash, nausea, diarrhea, fatigue, irritability, and nervous system abnormalities.

Serious risks

• Acute selenium toxicity can cause severe gastrointestinal and neurological symptoms, respiratory distress syndrome, heart attack, kidney failure, cardiac failure, and, in rare cases, death.
• Acute toxicity has resulted from misformulated over-the-counter products containing very large amounts of selenium. In 2008, 201 people had severe adverse reactions to a liquid supplement with 200 times the labeled amount.
• Brazil nuts contain very high amounts of selenium and could cause selenium toxicity if eaten regularly.

Avoid or ask a doctor first if

• The upper limits do not apply to people taking selenium under a physician's care.
• People who take medications regularly should discuss their selenium status with their health care providers.

Medication interactions

• Selenium supplements may interact with medications, and some medications, such as cisplatin, can affect selenium levels in the body.

Possible side effects

• Stomach upset and diarrhea are the most commonly reported side effects of oral bromelain.
• Oral bromelain seems to be well tolerated.

Avoid or ask a doctor first if

• Safety during pregnancy or breastfeeding is not well known.
• People who take any medicine should talk with a health care provider before using bromelain.

Medication interactions

• The source says some herbs and medicines interact in harmful ways, and advises talking with a provider before using bromelain if you take any medicine. It names no specific drugs.

Possible side effects

• High blood calcium from vitamin D toxicity can lead to nausea, vomiting, muscle weakness, and other symptoms.

Serious risks

• Toxicity can cause high blood and urine calcium. In extreme cases it may lead to kidney failure, soft tissue calcification, heart rhythm problems, and death.
• Toxicity is almost always caused by taking too much vitamin D through supplements.

Avoid or ask a doctor first if

• The source says people on regular medications should talk with their health care providers about vitamin D intake and status.

Medication interactions

• Vitamin D supplements may interact with orlistat, statins, steroids, and thiazide diuretics.
• Taking calcium supplements with vitamin D supplements may raise the risk of certain adverse effects.