Last reviewed October 28, 2026 by the Cellovi team.
The short answer
Your immune system runs on nutrients you get from food every day. Four of them have a well-established role in normal immune function: vitamin C, vitamin D, vitamin B6 and zinc. Each one is covered in the NIH Office of Dietary Supplements fact sheets, and each is on the European Union's register of authorized health claims for the normal function of the immune system. Cellovi Immune Support Complex gives you all four in two capsules, plus vitamin E, elderberry and echinacea.*
Our grade: Established. We grade this formula on its vitamins C, D3 and B6 and zinc, each with an established role in normal immune function. Elderberry and echinacea come from traditional herbalism, and we do not grade them.*
What each nutrient does
Vitamin C. It plays a part in both the fast, first-line side of the immune system and the slower, targeted side (Carr and Maggini, 2017). It is also an antioxidant that helps protect cells from oxidative stress (NIH ODS, vitamin C).*
Vitamin D. Best known for its role in bone, it also plays a role in normal immune function. Few foods contain much of it, and the skin makes less in winter (NIH ODS, vitamin D).*
Zinc. It is needed for the work of hundreds of enzymes and plays a role in normal immune function (NIH ODS, zinc). The body has no specialized zinc store, so a steady daily intake matters (Chemek et al., 2023).*
Vitamin B6. It takes part in more than 100 enzyme reactions in the body, and it plays a role in normal immune function (NIH ODS, vitamin B6).*
Vitamin E. An antioxidant that helps protect cells from oxidative stress, alongside vitamin C and zinc.*
The European Food Safety Authority reviewed the human evidence for each of these roles before the European Union authorized them as health claims. You can look each one up in the EU register of health claims.
How much is in a serving
| Nutrient | Per 2 capsules | Recommended for adults | Upper limit for adults, from all sources |
|---|---|---|---|
| Vitamin C | 180 mg | 75 to 90 mg | 2,000 mg |
| Vitamin D3 | 40 mcg (1,600 IU) | 15 to 20 mcg (600 to 800 IU) | 100 mcg (4,000 IU) |
| Zinc | 11 mg | 8 to 11 mg | 40 mg |
| Vitamin B6 | 1.7 mg | 1.3 to 1.7 mg | 100 mg |
| Vitamin E | 15 mg | 15 mg | 1,000 mg |
Source: NIH Office of Dietary Supplements fact sheets, based on the National Academies' intake reports. Each serving also has 500 mg elderberry extract, 200 mg echinacea extract, 100 mg citrus bioflavonoids and 100 mg L-lysine.
Vitamin D adds up. The upper limit counts food, fortified foods and every supplement together. If you also take Vitamin D3 + K2, a multivitamin or another product with vitamin D, count it too, and read our guide to vitamin D on how much vitamin D to take.
Elderberry and echinacea
Both have long histories in traditional herbalism. Elderberry is the dark fruit of the European elder tree, and echinacea is a flowering plant in the daisy family. We include them for that tradition, and our grade does not rest on them. Raw or unripe elderberries and other parts of the elder plant are not safe to eat (NCCIH, European elder; NCCIH, echinacea).
How to take it
- 2 capsules a day, with a meal. Food helps with comfort, and vitamin D is absorbed better with some fat.
- Same time every day. A morning routine is easiest to keep.
- One bottle is 30 days.
Who should check with a doctor first
- Anyone taking prescription medicine, especially medicines that act on the immune system. Talk to your doctor or pharmacist before adding any herbal product (NCCIH).
- Anyone allergic to plants in the daisy family, such as ragweed, chrysanthemums or marigolds: echinacea is closely related, and allergic reactions can be severe.
- Anyone pregnant or breastfeeding, where little is known about elderberry and echinacea.
- Anyone already taking other products with vitamin D or zinc. Long-term zinc above the upper limit can lower copper levels (NIH ODS, zinc).
- Cellovi is made for adults 18 and over.
Mild stomach upset is the most common side effect. Taking the capsules with food usually helps.
Where it fits in your day
Cellovi Immune Support Complex is $0.97 a day, with a 3-month supply option. Two capsules with breakfast make it an easy morning habit. To support your gut as well, see the Gut & Immunity Protocol.*
Common questions
Which nutrients support the immune system?
Vitamin C, vitamin D, vitamin B6 and zinc each have a well-established role in normal immune function. Each one is on the EU register of authorized health claims for the immune system.*
Can I take Immune Support Complex with Vitamin D3 + K2?
Count your total vitamin D first. The 4,000 IU upper limit counts food, fortified foods and every supplement together, so check your total with your doctor if you combine them.
Should I take it with food?
Yes, 2 capsules with a meal. Food helps with comfort, vitamin D is absorbed better with some fat, and zinc on an empty stomach can upset some people.
Is it safe if I have plant allergies?
If you are allergic to plants in the daisy family, such as ragweed, chrysanthemums or marigolds, check with your doctor first: echinacea is closely related, and reactions can be severe.
Sources
- NIH Office of Dietary Supplements. Vitamin C: fact sheet for health professionals.
- NIH Office of Dietary Supplements. Vitamin D: fact sheet for health professionals.
- NIH Office of Dietary Supplements. Zinc: fact sheet for health professionals.
- NIH Office of Dietary Supplements. Vitamin B6: fact sheet for health professionals.
- NIH Office of Dietary Supplements. Vitamin E: fact sheet for health professionals.
- Carr AC, Maggini S. Vitamin C and immune function. Nutrients, 2017.
- Chemek M et al. Improving dietary zinc bioavailability using new food fortification approaches: a promising tool to boost immunity in the light of COVID-19. Biology, 2023.
- European Commission. EU register of nutrition and health claims made on foods.
- National Center for Complementary and Integrative Health. European elder; Echinacea.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.