Consensus on a good Vitamin C source?

LucH

@jd_au said:

I have serious doubts about the quality of Quali-C, which gave me a blocked nose and made me sound like I had a permanent cold.

It seems as if you were having a Herxheimer reaction, often called a health-crisis.

LetTheRedeemed

@jd_au glad you’re feeling good, it reminds me to get some

jd_au

@LucH I don't think so. My reaction is very much in line with Ray's comments over the years about seeing lots of people have the same allergic reaction to synthetic vitamin c. It stops as soon as one stops the supplement. It's either the crappy corn-based production process or the silica that's in almost all brands. It's important to note that, whilst Quali-C might be better than some other brands, it is still manufactured from corn, which Ray wasn't a fan of.

LetTheRedeemed

@jd_au @luch i wonder how hard it would be to make our own

jd_au

@LetTheRedeemed I wonder. Probably very! It's a shame there are so many awful brands out there. I've done so much research into vitamin C. I know Ray wasn't a fan of mega dosing it, but high doses have helped so many people over the years, in dire straits with their health, when nothing else moved the needle. The last few days I've been holding at 5-6g a day and no adverse effects. Just warm toes, improved energy and lifted mood. Fingers crossed.

LetTheRedeemed

@jd_au what brand are you using?

LucH

@LetTheRedeemed said:

i wonder how hard it would be to make our own

Forget this. See the link (study).
For all other readers, with help of AI (only in the second part). No need to say we have to be suspicious with AI. I agree. Control is required from another source
Additional intolerance causes to vitamin C
When taking HD Vit C powder (e.g. 20 g or more), some people may react to these facts, supposing it’s the right kind (N° CAS and HM appropriate):

L-ascorbic acid has been made from wheat (cross-reaction with gluten). Rare.
L-ascorbic acid has been made from corn. Aspergillus niger mold. Intolerance to fungus trace is possible. Possible but very tiny. How much mercury is left too (Hg). Even 1 ppm is too high (0.00001 %).
Excerpt:
Even if the final molecule is “vitamin C,” people who react to corn may still have issues depending on sourcing, processing, and trace residues.
L-ascorbic acid from a chemical source (from GMO corn or not) or from orange fruit / acerola is the same molecule (if we avoid add-on).

AI says (Gemini)
NB: I’ve re-framed Gemini. Tendency to cut hair into 4 pieces.
• The molecule is identical. Industrially produced L-ascorbic acid is structurally the same as vitamin C from food. The body cannot tell the difference.
• Aspergillus niger is a process tool, not an ingredient. It is used in a fermentation step and removed during purification — calling the final product "made from black mold" / fungus is a misrepresentation.
Corn-sensitive individuals occasionally report reactions, though whether this is from trace residues or another cause is rarely confirmed analytically.
• Real reactions, when they occur, are contaminant-driven. At high doses, trace residues (fungal, corn-derived, or heavy metals) could plausibly trigger sensitivity in susceptible individuals — but this is an impurity issue, not a flaw in ascorbic acid itself.
• The practical answer is sourcing, not avoidance. A rigorous certificate of analysis (heavy metals, residual solvents, microbial content) and non-corn-derived alternatives (tapioca, beet-based) address legitimate concerns without the misleading framing.

LucH says:
Better so expressed. Comment on Quali-C (famous Scottish lable). No need to develop. Just target the security process.
AI says:
Quali-C (DSM, Dalry, Scotland) is the benchmark reference in the industry precisely because of its security process:

Non-corn sourced — uses a different raw material pathway, avoiding the main contamination concern.
Pharmaceutical-grade manufacturing — GMP-certified, with batch traceability from raw input to final powder.
Strict CoA per batch — heavy metals, residual solvents, microbial load, and purity all documented and verifiable.
EU regulatory oversight — subject to European pharmaceutical standards, generally more stringent than those applied to Chinese bulk suppliers dominating the market.
It is the default recommendation precisely because the security chain is auditable end to end.

Additional info (LucH):
How is the vitamin C quali-C from DSM made? (Labo DSM-Firmenich)
Quali-C is a labeled vitamin C (L-ascorbic acid) made in Scotland. Vit C is manufactured via a multi-step fermentation process beginning with glucose derived from non-GMO European wheat and corn. There is a strict traceability.
Production Process Details:
• Raw Material: The process begins with glucose, sourced from non-GMO corn/wheat, which is then fermented to create sorbose.
• Fermentation: The production uses a fermentation process to convert materials into 2-keto-L-gulonic acid (2-KGA), a precursor to vitamin C.
• Refining & Crystallization: This 2-KGA is refined and crystallized through multiple controlled steps to produce high-purity L-ascorbic acid.
• Location: All production occurs at the company's plant in Dalry, Scotland, which has produced vitamin C for over 40 years, ensuring high pharmaceutical-grade standards. [1, 2, 3, 4, 5]
Key Characteristics of Quali-C:
• Sustainability: Quali-C has the lowest carbon footprint for ascorbic acid production, with 65% lower GHG emissions compared to typical Chinese-produced vitamin C.
• Quality Control: The plant in Dalry operates under strict European quality standards, fully automated to ensure traceability.
• Traceability: The raw material can be traced back to its origin, providing assurance regarding the non-GMO, safe, and ethical production. [1, 2, 3, 4]
Note1: Quali-C is produced via a fermentation process, but it is a highly controlled, efficient, and sustainable method rather than the traditional, less refined methods often associated with mass-produced vitamin C.
doi: 10.1128/aem.01212-22 Appl Environ Microbiol. 2022. Qian Zhang , Shuxia Lyu.
In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic two-step fermentation process performed by Gluconobacter oxydans, Bacillus megaterium, and Ketogulonicigenium vulgare.

What about contaminant-driven material?
In USA, vitamin C is often made from corn syrup.
While nearly 90% of vitamin C (ascorbic acid) is produced from genetically modified (GMO) corn starch via fermentation, concerns about contaminant-driven material usually focus on processing agents used to refine the corn and chemical intermediates in the synthesis.
Key issues raised regarding potential contaminants include:
• Manufacturing Chemicals: Industrial production of ascorbic acid often involves acetone (used as a solvent), sulfuric acid, and hydrogen gas. While these are used in the process, they are generally purified out of the final product.
• Heavy Metals: Studies on nutritional supplements have found that Vitamin C can be contaminated with trace heavy metals, such as mercury (Hg) and chromium (Cr), added unintentionally during the production process or storage.
NB (LucH): 1 ppm (0.0001%) of Hg in ascorbic acid powder is not always detectable (control labo) but is however problematical. This accumulated residue impact the enzyme pathway (thyroid).
• GMO Residuals: Because it is derived from genetically modified corn, some concern exists regarding residual GMO bacterial material from the fermentation process, such as Ketogulonicigenium vulgare.
• Glyphosate: Concerns exist about potential trace residues of glyphosate (a herbicide used on GMO crops) in the final ascorbic acid product.
• Benzene Formation: If ascorbic acid is paired with benzoate salts in beverages exposed to heat and light, it can lead to the formation of benzene, a known carcinogen

Contaminant Levels and Safety
A 2023 study found that elemental impurities like cadmium (Cd), lead (Pb), and arsenic (As) were below detection limits in many, but not all, tested supplements.
However, for those concerned with additives or sourcing, options like tapioca-derived vitamin C are available.
Answer from IA (Google):
The concern regarding (1ppm) (0.0001 %) of mercury (Hg) in ascorbic acid is scientifically supported, particularly regarding its accumulation and impact on thyroid health. While 1ppm is a very low concentration, often near the limit of detection (LOD) for standard laboratory, it can present significant health risks due to chronic exposure and accumulation, even if standard testing methods occasionally fail to identify it. [1, 2]

Impact on Thyroid Enzyme Pathways
Mercury has a high affinity for thyroid tissue and interferes with the endocrine system through several mechanisms:
• Deiodinase Antagonism: Mercury inhibits deiodinase enzymes, which are responsible for converting T4 (thyroxine) to the active T3 (triiodothyronine) hormone.
• Selenium Depletion: Mercury binds to selenium, an essential element for thyroid function and antioxidant defense. This interaction reduces selenium availability, disrupting thyroid hormone synthesis and increasing oxidative damage.
• Binding to Thyroid Cells: Mercury can accumulate in thyroid follicles, leading to autoimmune reactions, increased TSH levels, and reduced T3 / T4 levels, potentially causing hypothyroidism.
Detectability in Control Labs
• Detection Challenges: Routine laboratory methods may struggle to consistently detect Hg at low levels (<0.1 ppm) or (<100 ppb) in some food-grade applications), as the detection limits can vary based on the method and sample matrix.
• Trace Analysis: More precise techniques like ICP-MS (Inductively Coupled Plasma Mass Spectrometry) are generally required to reliably detect and quantify low-ppm or ppb levels of heavy metals. [1, 2]

Bioaccumulation Risk in Summary
The presence of 1 ppm Hg is problematic due to its cumulative and detrimental impact on thyroid function, specifically by interfering with iodine incorporation and selenium-dependent enzymes.