Label math
Niacin Flush and the 35 mg Upper Limit: Reading 75 mg
Niacin flush is a warm, red, itchy skin reaction that can start at about 30 to 50 mg of nicotinic acid. Protoflow lists 75 mg of niacin per serving, more than twice the 35 mg adult upper limit for supplements. A flush is unpleasant rather than toxic, but the number is worth knowing before you buy.
Written by the Protoflow label deskUpdated · 4 min read
What is a niacin flush?
A niacin flush is a brief reddening of the face, arms and chest, often with burning, tingling and itching. It happens because nicotinic acid, one form of vitamin B3, widens small blood vessels in the skin.
The NIH fact sheet says it typically starts at about 30 to 50 mg or more, and calls it "an unpleasant, rather than a toxic, side effect" (NIH ODS, Niacin). The label for Protoflow says only "Niacin (Vitamin B3)". It does not say if the form is nicotinic acid or niacinamide, so we cannot tell whether a flush is likely.
- Look: red, warm skin on the face, neck, arms or chest
- Feel: tingling, burning or itching
- Unknown: the form of niacin in Protoflow
Is 75 mg of niacin above the upper limit?
Yes, 75 mg is more than twice the 35 mg upper limit for niacin from supplements in adults (NIH ODS, Niacin). The label shows 469% of the Daily Value, because the Daily Value is only 16 mg.
An upper limit is the highest daily amount that is unlikely to cause harm in most people. It is a ceiling for planning, not a poison line. The limit does not apply to people taking niacin under medical supervision.
The figure is not unusual in this product category. A review of 50 "T booster" products found median vitamin B3 content of 187.5% of the RDA, and some products went over the FDA upper limit (Clemesha et al., World J Mens Health 2020).
| Measure | Amount |
|---|---|
| Adult Daily Value | 16 mg |
| Upper limit (supplements) | 35 mg |
| Protoflow, 2 capsules | 75 mg |
| Protoflow, 1 capsule | 37.5 mg |
Does 75 mg of niacin harm the liver?
No evidence we read links 75 mg to liver harm. Liver injury is tied to pharmacologic doses of 1,000 to 3,000 mg a day taken for months or years, with higher risk from extended-release forms (NIH ODS, Niacin).
That is about 13 to 40 times the Protoflow amount. We still do not call 75 mg risk-free for everyone. Your own medicines, liver health and other supplements change the picture.
Ask your doctor or pharmacist before use if you take a statin or other cholesterol medicine, or have liver disease or gout. Keep taking prescribed medicine. Stomach upset and flushing are covered on our side effects page.
Skip extra niacin, B-complex and multivitamin products while taking Protoflow, or count their B3 first. Doubling up is how a flush becomes likely.
Protoflow: from $1.63 a day60 capsules a bottle · packs of 2, 3 or 6 · 60-day money-back guarantee
See packsHow do you read niacin on a supplement label?
Find the line that says Niacin or Vitamin B3, read the milligrams per serving, then compare it with 35 mg. The serving size matters: on Protoflow it is two capsules, so each capsule holds half.
Check the serving size
Protoflow lists 2 capsules per serving and 30 servings per bottle.
Add up other products
Count B3 from any B-complex, energy drink or multivitamin you also take.
Watch for a flush
If your skin turns red and itchy, stop and ask your doctor or pharmacist. Trouble breathing or swelling of the lips needs urgent care.
The full panel is on our supplement facts page. See also the niacin and vitamin E page.
Order Protoflow
Thinking of trying it? The bigger packs cost less per day.
Prices from the sales page, October 19, 2026 (Protoflow sales page: packs). Two bottles cost $158 plus a small shipping fee. Every pack carries the 60-day money-back guarantee. Check your medicines first.
FAQ
Niacin flush questions
01Does the 35 mg upper limit apply to people on prescription niacin?
No. The NIH fact sheet says the limit does not apply to people taking niacin under medical supervision. It is meant for niacin from supplements and fortified foods taken without a clinician's guidance.
02Why does Protoflow's label not say which form of niacin it uses?
We do not know. The label prints only Niacin (Vitamin B3). Nicotinic acid is the form linked to flushing, so the missing detail matters. Ask the order desk if you want the maker's answer.
03Do other testosterone supplements also go over the niacin limit?
Some do. A 2020 review of 50 such products found median B3 content of 187.5% of the RDA, and 13 products went over the FDA upper limit for zinc, B3 or magnesium. Protoflow is not alone in this.
Who wrote this
Written and reviewed by
Pages built from the Protoflow label, the sales page and linked NIH, FDA, FTC, NHS and peer-reviewed sources.
Last updated . Learn about our editorial standards and how we check reviews. This website is run by Goprotoflow, a licensed U.S. retail desk for Protoflow, not by the manufacturer or by PhytoThrive Labs. We earn money when you buy through our order links.
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