Hair supplements, graded in marker on what the studies actually show
Page 1 · what the trials support
graded against the table on our grades page
- Nutrafol (whole formula)Three placebo-controlled trials, two in women and one in men, all smallSome
- Viviscal (marine protein formula)Placebo-controlled trials in women (2015) and men (2016)Some
- BiotinA 2017 review found 18 reported cases, all in people with an underlying conditionWeak
- Saw palmettoThe NIH's complementary-health centre calls the evidence too limited to allow conclusionsWeak
- TocotrienolsOne placebo-controlled trial of 38 volunteers, from 2010Weak
- Pumpkin seed oilOne placebo-controlled trial of 76 men, from 2014Weak
- Vitamin DRated low-quality evidence in a 2023 JAMA Dermatology reviewWeak
- IronUseful only when a blood test confirms deficiencyTest first
- Ashwagandha, curcumin, marine collagen on their ownNo trial of each alone in people with hair loss that we foundUntested
Top grade, “Good”: nothing on this page has earned it yet.
We read the trials behind Nutrafol, Viviscal, biotin and saw palmetto, note who paid for them and how many people took part, and grade each one. Nothing we checked earns our top grade yet.
Price check, Nutrafol Men
$79 a month on subscription, $422 for six months prepaid (nutrafol.com, 22 September 2026).
One company-funded trial in men. Our score: 5 out of 10.
Free first steps
A doctor visit, a blood test, over-the-counter minoxidil from any pharmacy. None of them pays us.
From the notebook
All 10 entries →
Does Nutrafol Work? What the Company-Funded Studies Show
Four published studies, three with a placebo group, every one tied to the company. What each measured, how big it was, and what an independent reader can and cannot conclude.
Nutrafol Side Effects, and Who Should Avoid It
Stomach upset in the men's trial, biotin and blood tests, vitamin D stacking, liver-injury reports and medicine interactions: the side-effect record, with a source for every line.
Viviscal vs Nutrafol: Ingredients, Evidence and Cost
A marine-protein tablet against a botanical blend. Both have small placebo-controlled trials paid for or written by their makers; they differ on ingredients, allergens and price by about half.
Biotin for Hair Loss: When It Helps, and the Lab-Test Warning
Biotin's reputation rests on people who were short of it. Here is what the evidence shows for everyone else, why the FDA warns about biotin and blood tests, and how biotin sits inside multi-ingredient hair supplements.
How this notebook works
The direct answer: every grade on this site comes from a published trial, a government fact sheet or a label we read, and each one names its source and the date we read it.
We are not clinicians and nobody here has reviewed these pages as one. What we can do is read the studies closely: how many people took part, whether there was a placebo group, what was measured, and who paid. Those four questions decide most grades. Our Nutrafol review shows the method on the biggest name in the aisle, and our evidence grades for hair growth supplements apply it to every ingredient we cover.
Some links on this site are affiliate links, and they are always marked. The steps we recommend most often, a doctor visit, a blood test and over-the-counter topical minoxidil from any pharmacy, pay us nothing.