THORNE - High Potency Vitamin C - Ascorbic Acid with Calcium, Magnesium & Potassium…
- Vitamin C
- Powder
- Vitamin C
- 8.3 ounces
A buffered, unflavored vitamin C powder for people scaling their own dose, third-party tested and free of the usual allergens.
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How it ranks among the 88 vitamin c we track
4.5★ across 886 Amazon ratings, Bayesian-smoothed toward the category average.
886 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
1,000+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 88 vitamin c we track - how the scorecard works · full vitamin c data report. Confidence: high - strong rating volume and complete data.Last refreshed Aug 4, 2026. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
THORNE's High Potency Vitamin C is an unflavored ascorbic acid powder that adds calcium, magnesium and potassium to reduce the acidity plain vitamin C powders carry. Third-party certified and free of gluten, dairy and soy, it suits anyone who wants a mixable dose rather than a pill count.
8.32 ounces works out to roughly 42 servings by Thorne's own count, and the powder format lets you dial the dose into water, juice or a shake rather than swallowing multiple capsules. The added mineral ascorbates buffer the acid, which is the main reason people pick a buffered powder over plain ascorbic acid tablets.
- 8.32 oz powder, about 42 servings
- Calcium, magnesium and potassium added
- Gluten, dairy and soy free
- Third-party certified
Who it's for
Fits people managing a higher daily vitamin C intake who find capsules cumbersome, or anyone whose stomach reacts to unbuffered ascorbic acid. Not aimed at someone who just wants a once-a-day pill with no measuring involved.
Strengths and trade-offs
Drawn from this product's published specifications.
- Buffered formula eases stomach acidity
- Unflavored, mixes into any drink
- Free of gluten, dairy and soy
- Third-party certified for potency and purity
- Requires measuring rather than a fixed capsule dose
- No flavor means it's less palatable taken alone in water
Performance notes
Ascorbic acid buffered with calcium, magnesium and potassium is gentler on the stomach than unbuffered vitamin C at high doses, since the minerals neutralize some of the acidity before it hits the gut. Being unflavored, it dissolves into whatever liquid you choose without adding sweetness.
Specifications
| Brand | THORNE |
|---|---|
| Model | C155 |
| Form | Powder |
| Supplement Type | Vitamin C |
| Count | 8.3 ounces |
| Flavor | Unflavored |
| Diet | Gluten Free |
| Benefits | Antioxidant Support |
| Allergens | Dairy Free, Fish Free, Shellfish Free, Soy Free |
Other THORNE vitamin c
How it compares
This product against the closest alternatives we track in vitamin c.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| THORNE - High Potency Vitamin C - Ascorbic Acid with Calcium, Magnesium & Potassium…This product | 4.5 / 5 | 886 | 4.3 / 5 |
| Emergen-C 1000mg Vitamin C Powder for Daily Immune Support Caffeine Free Vitamin C…Emergen-C | 4.8 / 5 | 53,857 | 4.7 / 5 |
| Nature's Bounty Vitamin C + Rose HipsNature’s | 4.8 / 5 | 49,343 | 4.7 / 5 |
| Nature Made Extra Strength Vitamin C 1000 mg TabletsNATURE | 4.8 / 5 | 40,190 | 4.7 / 5 |
| Nutricost Vitamin C with Rose Hips 1025mgNutricost | 4.8 / 5 | 23,867 | 4.7 / 5 |
Similar vitamin c from other brands
Questions about the THORNE C155
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
Is THORNE's High Potency Vitamin C powder flavored?
No, it's unflavored, meant to be mixed into water, juice or a shake.
What minerals are added to this vitamin C powder?
Calcium, magnesium and potassium ascorbates are included to buffer the acidity of the ascorbic acid.
Is this product dairy and soy free?
Yes, Thorne lists it as gluten, dairy and soy free.