All the products I order are great
5 out of 5 star rating. 
The Vitamin C Advantage
90mg
Recommended daily allowance of vitamin C for males
75mg
Recommended daily allowance of vitamin C for females
Isotonix Vitamin C contains 500mg of vitamin C per serving — an optimal amount for immune system maintenance.
Vitamin C, One of the World's Most Popular Vitamins
Vitamin C (ascorbic acid) is one of the most powerful antioxidants and immune-supporting nutrients available today. Vitamin C is a hard-working water-soluble antioxidant that protects the body at a cellular level. It combats oxidative stress in the bloodstream and within cells, helps restore and promote antioxidant levels, like vitamin E, and supports immune response and cardiovascular function.
Product Classification
Isotonic
Dairy Free
Gluten-Free
Vegan
No Detectable GMO
Good Manufacturing Practices
Directions for Use
Pour one small capful (3.3g) of Isotonix Vitamin C powder into your favorite cup.
Mix: Add 2 fluid ounces (60ml) of water per capful and stir until fully dissolved.
Enjoy: Drink once daily on an empty stomach for maximum absorption, savoring the refreshing citrus flavor!
Key Ingredients & Benefits
Vitamin C (Ascorbic Acid)*
Provides antioxidant protection
Helps maintain healthy cholesterol levels
Beta Carotene (Vitamin A Precursor)*
Promotes cognitive health
Promotes immune functions
Potassium (Bicarbonate)*
Promotes skeleton, muscle and skin health
Promotes normal regulation of heart functions
Antioxidant Support
Isotonix Vitamin C sets itself apart from other products on the market, providing the maximum absorption of nutrients in the shortest amount of time. Isotonix Vitamin C provides superior delivery of the nutrients your body needs in the most cost-effective way.
Isotonix Delivery System
:05 minutes
Isotonix Liquid Vitamins
- Formulated to survive digestion.
- Delivers concentrated nutrients to the site of absorption.
- Contains no fillers or binders.
- No artificial color or flavors.
:40 minutes
Standard Vitamin Tablet
- Contains lab-created coatings and lubricants.
- Often contains artificial colors, nutrients and flavors.
- Limited absorption of nutrient utilization.
Frequently Asked Questions
Who needs to supplement with Isotonix Vitamin C Formula?
Anyone over 18 can use Isotonix Vitamin C Formula to add vitamin C to their diet because very few of us get the recommended five servings of fruits and vegetables in our daily diets.
Is it possible to take too much Isotonix Vitamin C Formula?
Ascorbic acid is extremely safe, even at relatively high levels (because most of the excess is excreted in the urine). At high doses (over 1000 milligrams/day), some people can experience gastrointestinal side effects, such as stomach cramps, nausea and diarrhea. It is recommended that you take vitamin C supplements in gradual servings throughout the day to achieve maximum benefits.*
How does Isotonix Vitamin C Formula aid in cardiovascular health?
It helps maintain healthy cholesterol and triglyceride levels, promoting healthy arterial walls and helping maintain normal blood pressure. It helps the body maintain vitamin E levels, which has known benefits for the cardiovascular system. Finally, vitamin C supports normal platelet activity.*
What is the best way to store this product?
Keep Isotonix in a dry, cool place. If Isotonix are stored in the kitchen, keep them away from the stove, sink, any heat-generating appliances or window ledges. If you live in a very humid area, you may store Isotonix products in the refrigerator, but not in the fruit and vegetables area.
Isotonix® Vitamin C Research Scope
43%
The percentage of U.S. adults with inadequate vitamin C intake
90%
The amount of dietary vitamin C lost from food when heated
100x
The concentration of vitamin C in the adrenal gland ("stress glands"), highlighting the importance of daily vitamin C intake
*These statements have not been evaluated by the Food and Drug Administration. This product(s) is not intended to diagnose, treat, cure or prevent any disease.
Reviews
Break down of ratings: (40) 5 star ratings. (2) 4 star ratings. (3) 3 star ratings. (1) 2 star ratings. (3) 1 star ratings.
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All the products I order are great
Response from Customer Service on 04/29/2026
Thank you so much for your wonderful review! We're delighted to hear that you've been pleased with all the products, including the Isotonix® Vitamin C, you've ordered. Your support means a lot to us. If you ever have questions or need help, we’re always here for you. Thank you for choosing Isotonix!
questions
3 out of 5 star rating.
It took a lot effort to order the product, which should have been on auto-shipped. It alos took a long time to receive the product
Response from Customer Service on 04/23/2026
Thank you so much for your feedback and for sharing your experience with Isotonix® Vitamin C Powder. We appreciate your questions and are sorry to hear that the order was difficult to place. That is a frustrating situation for anyone, and one I, myself, am far too familiar with.
We would also like to apologize for the delay in receiving your Vitamin C. It is one of our most popular items, and we've had a hard time keeping it in stock recently. I am happy to report that some of the issues contributing to the delay have recently been resolved, and we are expecting a smoother ordering and AutoShip experience going forward.
A Customer Service representative will be reaching out to you directly to further assist and ensure your concerns are addressed. Thank you again for your patience and for bringing this to our attention. If you have any other questions, please don’t hesitate to ask.
I don't like it sweet taste
1 out of 5 star rating.
I can not take much sugar due to my physical condition. For everyone's health, all sugar in the supplements shall be replaced by stevia. The cost between sugar and stevia is not much difference. But for me it's big difference. I won't purchase this supplement any more since too much sugar. It's not healthy for both adults and kids. It's not right to please people with sugar.
Response from Customer Service on 02/26/2026
Thank you for your feedback and for sharing your concerns. We understand the importance of being mindful about sugar intake. The minimal amount of sugar used in Isotonix® products is included to support the isotonic formulation, which helps with nutrient delivery. However, we appreciate your suggestion about using stevia as an alternative, and will share your comments with our product development team for their consideration. Your feedback is valuable to us as we strive to meet the needs and preferences of all our customers. Thank you again for reaching out and for sharing your perspective.
Integral to health
5 out of 5 star rating.
This product is in isotonic form so it gets into my system quickly. I especially like it before bed along with magnesium because it also helps create that serotonin we need to settle down before sleep. I would not consider using anything in a tablet of chewable form as they can be loaded with extra sugars and do not have full impact because of their slow absorption.
Response from Customer Service on 02/26/2026
Thank you so much for your thoughtful review! We're delighted to hear that you appreciate the convenience and fast absorption of Isotonix® Vitamin C, especially as part of your evening routine. Your feedback on the benefits of the isotonic form means a lot to us. Thank you for being a valued member of our community and for choosing Isotonix®!
Part of my morning routin!
5 out of 5 star rating.
I love taking this Vitamin C. Especially in the winter months! Helps me stay healthy and I prefer not taking more pulls. Just drink. Great taste.
Response from Customer Service on 02/13/2026
Thank you so much for your wonderful review! We’re delighted to hear that Isotonix® Vitamin C is a favorite part of your morning routine, especially during the winter months. It’s great to know you enjoy the taste and the convenience of drinking your vitamins. Your feedback means a lot to us—thank you for being a valued member of our community!
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