PlainVitamins

IsoStak

by Universal Nutrition · capsule · 60 capsules

  • Off the market since September 2014 (NIH)
  • UPC 0 39442 05169 1
  • DSLD label 3502
  • Serving 1 capsule

IsoStak by Universal Nutrition lists 9 ingredients, 9 with an amount per serving of 1 capsule, such as 3.5 mg of vitamin B6, 10 mg of niacin, 10 mg of zinc and 100 mg of 5-methyl-7-methoxyisoflavone. Its current label entered the NIH Dietary Supplement Label Database on December 23, 2011.

What is in IsoStak?

Each row as the label prints it, per serving of 1 capsule. The capsule beside an amount places it among every product in the NIH database that lists the same ingredient: the bar is the middle half of their amounts, the line in it the median, the whiskers the 10th and 90th percentiles; the green tick is the FDA Daily Value and the red dashed tick the adult upper limit (IOM).

IsoStak: Supplement Facts rows against the market (DSLD label 3502, January 2026 release)
IngredientAmount% DVAmong products listing it
Vitamin B63.5 mg175%Vitamin B6 in IsoStak against 15,277 products3.5 mg per serving; the middle half of products list 2 mg to 20 mg, the median 6 mg.DV 1.7 mgUL 100 mg3.5 mg

62% of 15,277 products listing vitamin B6 give more (median 6 mg). Per day at the most servings: 10.5 mg.

Niacin10 mg50%Niacin in IsoStak against 12,413 products10 mg per serving; the middle half of products list 13.2 mg to 48 mg, the median 20 mg.DV 16 mgUL 35 mg10 mg

77% of 12,413 products listing niacin give more (median 20 mg). Per day at the most servings: 30 mg.

Zinc10 mg67%Zinc in IsoStak against 13,186 products10 mg per serving; the middle half of products list 5 mg to 15 mg, the median 11 mg.DV 11 mgUL 40 mg10 mg

51% of 13,186 products listing zinc give more (median 11 mg). Per day at the most servings: 30 mg.

5-Methyl-7-Methoxyisoflavone100 mg
7-Isopropoxyisoflavone100 mgIpriflavone in IsoStak against 75 products100 mg per serving; the middle half of products list 100 mg to 300 mg, the median 200 mg.100 mg

71% of 75 products listing ipriflavone give more (median 200 mg). Per day at the most servings: 300 mg.

5,7 dihydroxyflavone25 mg
20-hydroxyecdysone25 mg
Isoflavonol(TM)150 mgIsoflavones in IsoStak against 290 products150 mg per serving; the middle half of products list 25 mg to 80 mg, the median 50 mg.150 mg

Higher than 89% of 290 products listing isoflavones (median 50 mg). Per day at the most servings: 450 mg.

Triboxybol(TM)as Steroidal SaponinsTriboxybol(TM) (Form: standardized for 29% Steroidal Saponins)200 mgTribulus in IsoStak against 555 products200 mg per serving; the middle half of products list 100 mg to 750 mg, the median 300 mg.200 mg

61% of 555 products listing tribulus give more (median 300 mg). Per day at the most servings: 600 mg.

Lysophosphatidylcholine10 mg

Source: NIH ODS Dietary Supplement Label Database, label 3502 (entered December 23, 2011), version 9.4.0. See the label on DSLD. Amounts are what the maker printed; DSLD does not test products. Daily Values: the FDA's Daily Value page.

Is that a lot?

Every amount on this label with a position sits within the middle 80% of the products that list the same ingredient.

The NIH database records 3 servings a day from the label's directions; its % Daily Values are for adults and children 4 or more years of age. The directions as printed are further down this page.

The Tolerable Upper Intake Level is the most of a nutrient per day, from food, water and supplements together, that is likely to pose no risk for almost all adults (Institute of Medicine, 2011). It does not apply under medical supervision. This page compares labels; it is not medical advice.

Sources: amounts from the DSLD label; Daily Values from 21 CFR 101.9(c)(8)(iv); adult upper limits from the Institute of Medicine's DRI summary tables (2011). How positions are computed.

Which products have the closest formulas?

The products whose ingredient lists overlap most with IsoStak's, rare ingredients counting for more.

Source: ingredient lists of every product's current label in DSLD (version 9.4.0); similarity weights each shared ingredient by how rare it is.

What does the label say about taking it?

Quoted from the label as DSLD transcribed it: the maker's words, including any claim about what the product does, which the FDA has not evaluated and PlainVitamins does not endorse.

Directions
Recommended Use: Take 1 capsules three times daily with meals. Do not exceed 3 capsules in any 24-hour period.
Warnings
KEEP OUT OF REACH OF CHILDREN.
Not for use by pregnant or nursing women or by any person under 18. If you are at risk for prostate or breast cancer you should not use this product.
Discontinue use if nervousness, tremor, sleeplessness, loss of appetite or nausea occur.
WARNING: Due to the powerful nature of this product, do not exceed recommended dosages. Please consult your physician before using this product, especially if you are under one's care.
Allergens and what it does not contain
Non-Hormonal

Source: label statements in DSLD label 3502.

What else is on the label?

Other ingredients: Tribulus terrestris extract, pueraria lobata, Zinc Aspartate, Niacinamide, Pyridoxine Hydrochloride, Gelatin, Magnesium Stearate, Stearic Acid.

How many labels does IsoStak have?

One label is on file, entered on December 23, 2011.

  1. Label 3502 (current) Entered December 23, 2011 · off the market September 9, 2014 · 60 capsules · UPC 0 39442 05169 1

DSLD also links this label to: Iso-Stak (image difference, same product).

Source: DSLD label entry and market events, version 9.4.0 (labels entered through September 25, 2025).

Who makes it?

The label names Universal Nutrition (manufacturer), New Brunswick, New Jersey. All Universal Nutrition products.

Where next?