The main ingredient has real numbers behind it — weaker than the prescription drug, and from a study with a design flaw worth knowing about. The second ingredient has an FDA safety communication attached to it that has nothing to do with hair.
Saw palmetto has a real comparison study, and it lost. A trial of 100 men with mild-to-moderate androgenetic alopecia gave half 320 mg saw palmetto and half 1 mg finasteride. After 24 months, 38% of the saw palmetto group and 68% of the finasteride group showed increased hair growth. Crucially, there was no control group — so we can’t tell how much of that 38% was the supplement rather than time, seasonality or expectation.
The biotin issue is separate and more serious. The FDA issued a safety communication in November 2017, updated November 2019, warning that biotin can interfere with laboratory tests — with particular concern about falsely low troponin, the marker used to diagnose heart attacks. Tell any doctor or lab that you take biotin. 💊
- The saw palmetto study, in detail
- Why “no control group” changes everything
- The DHT mechanism, fairly stated
- The biotin problem
- Why troponin specifically
- Does biotin even help hair?
- What is actually approved
- Minoxidil: the OTC option that works
- Finasteride, and its trade-offs
- The thing that matters most: timing
- How to decide
- Frequently asked questions
- Your checklist
The saw palmetto study, in detail
Unusually for a supplement ingredient, saw palmetto has been compared head-to-head against the actual prescription drug. That’s worth taking seriously, and worth reading precisely.
| Element | Detail |
|---|---|
| Participants | 100 male patients, mild-to-moderate androgenetic alopecia |
| Arm 1 | Saw palmetto 320 mg |
| Arm 2 | Finasteride 1 mg |
| Duration | 24 months |
| Saw palmetto result | 38% showed increased hair growth |
| Finasteride result | 68% showed increased hair growth |
| Control group | None |
Two further details from the study are worth knowing. Finasteride was effective in the frontal area of the scalp and on the vertex (the crown), while saw palmetto’s effect was most prominent on the vertex. And the participants had mild-to-moderate loss — this tells you nothing about advanced hair loss.
Taken at face value, the headline is that the supplement produced roughly half the response rate of the prescription drug over two years. That is not nothing. It is also not the comparison the marketing implies.
Why “no control group” changes everything
This is the detail that determines how much weight the 38% can carry, and it’s routinely omitted when the study is cited.
There was no control group. Nobody received a placebo. Which means the study cannot say how effective saw palmetto was compared with placebo — only how it compared with finasteride.
Why that matters so much here:
- Hair loss fluctuates. Shedding varies seasonally and with stress, illness and diet. Two years is long enough for natural variation to look like a result.
- Assessment is difficult. Judging “increased hair growth” is harder than it sounds, and without blinding, expectation influences it.
- People change other things. Someone who starts a hair treatment often also changes shampoo, stops harsh styling, improves their diet, or simply pays more attention.
- The comparison is anchored to a known effect. Finasteride’s 68% is a useful reference precisely because finasteride has been placebo-controlled elsewhere. Saw palmetto’s 38% has no such anchor in this study.
What we can say: saw palmetto performed worse than finasteride over 24 months. What we cannot say from this study: whether saw palmetto beat doing nothing.
The DHT mechanism, fairly stated
The theory behind saw palmetto in hair loss is sound in outline. Androgenetic alopecia is driven substantially by dihydrotestosterone (DHT), produced from testosterone by the enzyme 5-alpha-reductase. Finasteride works by inhibiting that enzyme. Saw palmetto is proposed to do something similar.
The gap between “proposed to inhibit the same enzyme” and “produces the same clinical result” is where the argument lives — and the 38% versus 68% figure is a reasonable summary of that gap. A mechanism being directionally right doesn’t tell you the magnitude, and magnitude is the whole question.
Worth noting: saw palmetto’s better-studied use is for benign prostatic hyperplasia, a different condition with its own mixed evidence base. Studies in prostate symptoms don’t transfer to scalp outcomes.
The biotin problem
Now the part that has nothing to do with whether the product works, and that genuinely matters more.
Biotin (vitamin B7) appears in nearly every hair supplement, usually at doses far above any dietary requirement. The FDA issued a safety communication in November 2017, updated in November 2019, warning that biotin can significantly interfere with certain laboratory tests and cause incorrect results.
Depending on the assay, biotin in a blood sample can cause falsely high or falsely low results. The FDA’s specific concern is a falsely low troponin result.
This is not a reason to panic, and it is a reason to be systematic. Add biotin to your medication list — the one you give at every appointment, in an emergency department, and before any blood test. Most people don’t think of a hair supplement as something worth mentioning, which is exactly the problem.
If you are having blood tests and can pause it, ask your doctor how long to stop beforehand. And if you ever attend hospital with chest pain, say you take biotin — before the blood is drawn if possible, and afterwards if not. It takes four seconds and it lets the lab interpret the result correctly.
Why troponin specifically
Troponin is the blood marker used to diagnose heart attacks. It’s the test that determines whether someone with chest pain is admitted and treated, or reassured and sent home.
A falsely low troponin therefore points in the most dangerous direction: it can make a genuine heart attack look like nothing. That’s why the FDA singled it out, and why the agency has stated it continues to receive adverse event reports indicating biotin interference caused falsely low troponin results.
There is one reported death, and it needs stating carefully. The FDA received a report of a patient death following an incorrect cardiac troponin assessment attributed to biotin interference. The important caveat: in that case biotin interference was not confirmed, and the troponin measurements following the event were made post-mortem. So it is a reported case rather than an established causal chain — and it is still the reason a regulator issued a communication and then updated it two years later.
Biotin also interferes with other assays, including thyroid function tests and hCG. A falsely abnormal thyroid result can lead to unnecessary treatment; the practical answer to all of it is the same: disclose it.
Does biotin even help hair?
Having spent that long on biotin’s risk, the fair question is what you’re getting in exchange.
Biotin deficiency causes hair loss, and correcting a deficiency helps. That much is genuine. But biotin deficiency is rare in people eating an ordinary diet — it’s found in eggs, nuts, seeds, fish, meat and many vegetables, and it’s also produced by gut bacteria.
For someone who is not deficient, there’s little basis for expecting extra biotin to grow hair. So the common situation is: a person with no deficiency takes a high dose of something that won’t help their hair, while acquiring a real risk of a misread blood test.
Biotin’s presence in hair supplements is a good example of a general pattern: an ingredient that genuinely helps a deficiency gets marketed to everyone. The claim isn’t false — biotin really does matter for hair — it’s just aimed at the wrong population. The same logic applies to iron, zinc and vitamin D in this category. The question is never “does this nutrient matter for hair?” but “am I short of it?” — and that’s a blood test, not a purchase.
What is actually approved
For male pattern hair loss, two treatments have regulatory approval in the United States, and it’s a short list for a reason.
| Treatment | Status | Notes |
|---|---|---|
| Topical minoxidil | FDA-approved, over the counter | Available without a prescription; works for many |
| Oral finasteride | FDA-approved, prescription | 68% response over 24 months in the study above |
| Saw palmetto | Dietary supplement | 38% in an uncontrolled comparison |
| Biotin (if not deficient) | No basis to expect benefit | Carries lab interference risk |
| Most other supplement ingredients | Little to no clinical evidence | Marketed on mechanism, not outcome |
Minoxidil: the OTC option that works
If you want something you can buy today without a prescription and that has genuine regulatory approval for this use, this is it.
Practical points people get wrong:
- It takes months. Expect four months minimum before judging, and up to a year for the full picture.
- Early shedding is normal. Many people shed more in the first weeks as follicles cycle. It’s the commonest reason people quit — and quitting then is exactly wrong.
- It’s a maintenance treatment. Stop and the benefit reverses over months. That’s a real commitment to weigh before starting.
- Consistency beats quantity. Twice daily as directed, on a dry scalp, every day.
- Women should use the formulation intended for women and speak to a doctor first, particularly if pregnant or trying to conceive.
Finasteride, and its trade-offs
Finasteride’s 68% is the strongest number in this article, and it comes with genuine considerations that belong in the same sentence.
It is prescription-only for good reasons: it has recognised potential side effects including sexual side effects, it is not for use by women who are or may become pregnant (it can cause abnormalities in a male foetus, and tablets shouldn’t even be handled), and it affects PSA results — which matters for prostate cancer screening and must be disclosed to your doctor.
These are exactly the reasons a prescriber is involved, and they’re also why “a natural alternative with no side effects” is an appealing pitch. The honest framing is that you are trading a documented larger effect plus documented risks for a smaller, less certain effect with fewer documented risks. That’s a real decision — just make it knowing both halves.
Minoxidil 5% Topical
FDA-approved for male pattern hair loss and available without a prescription — the only over-the-counter product in this article with that status
If you’re going to spend money on hair loss, spend it on something with regulatory approval for the purpose. Topical minoxidil is FDA-approved and sold over the counter, which puts it in a different category from every supplement on the shelf beside it. The rules for getting a fair trial out of it: apply it twice daily to a dry scalp, consistently; expect increased shedding in the first weeks and don’t stop when it happens, because that’s follicles cycling rather than the product failing; and give it at least four months, ideally a year, before judging. Understand before you start that it’s a maintenance treatment — benefits reverse over months if you stop. Women should use the formulation intended for women and speak to a doctor first.
- Early shedding is expected — the commonest reason people quit too soon
- Apply to a dry scalp, twice daily, consistently
- Four months minimum before judging; photograph at the start
- It’s maintenance — stopping reverses the benefit over months
- Women: use the women’s formulation and speak to a doctor first
- Not for use in pregnancy without medical advice
The thing that matters most: timing
More important than which product you choose is when you start, and this is the point most articles bury.
Treatments for androgenetic alopecia are far better at keeping the hair you still have than at recovering hair that’s gone. A follicle that has been dormant for years is a much harder target than one that’s currently miniaturising.
Which means the calculation is uncomfortable but simple: time spent trying supplements is time not spent on treatments with better evidence, during the window when they work best. Two years on a supplement isn’t just two years of expense — it’s two years of progression.
If you’re going to try a supplement anyway, set a decision date before you start — six months, photographed at the beginning under consistent lighting — and actually act on it.
How to decide
- Confirm what kind of hair loss it is. Male pattern loss is gradual and follows a recognisable pattern. Sudden, patchy, rapid or painful loss is something else and needs a doctor.
- Get the boring things checked — thyroid function and iron status both cause hair loss and both are correctable.
- Start with what’s approved. Minoxidil is available over the counter; finasteride requires a prescriber who can discuss the trade-offs.
- If you use a supplement, treat it as an addition, not a replacement.
- Set a review date and photograph the starting point.
- Disclose biotin everywhere — every doctor, every blood test, every emergency.
- Don’t wait. The window matters more than the product.
Related reading: our piece on the safety profile of this product, and on hair supplement claims generally.
Frequently asked questions
Does saw palmetto work for hair loss?
There’s one direct comparison worth knowing. A study of 100 men with mild-to-moderate androgenetic alopecia gave half 320 mg saw palmetto and half 1 mg finasteride; after 24 months, 38% of the saw palmetto group and 68% of the finasteride group showed increased hair growth. Finasteride worked on both the front of the scalp and the vertex; saw palmetto’s effect was most prominent on the vertex. The critical limitation: there was no control group, so the study cannot tell us how saw palmetto compared with placebo — only that it did worse than the prescription drug.
Is biotin in hair supplements dangerous?
Not toxic — but it can cause a dangerous misdiagnosis. The FDA issued a safety communication in November 2017, updated in November 2019, warning that biotin can significantly interfere with laboratory tests, producing falsely high or falsely low results depending on the assay. The agency’s specific concern is a falsely low troponin, the marker used to diagnose heart attacks — meaning a real heart attack could be missed. The FDA has said it continues to receive adverse event reports of biotin causing falsely low troponin. Add biotin to your medication list and tell every doctor and lab that you take it.
Has anyone died from biotin interference?
The FDA received a report of a patient death following an incorrect cardiac troponin assessment attributed to biotin interference. It’s important to be precise: in that case biotin interference was not confirmed, and troponin measurements after the event were made post-mortem. So it’s a reported case rather than an established causal chain — and it was significant enough that a regulator issued a safety communication and then updated it two years later. The practical response isn’t alarm, it’s disclosure: tell clinicians you take it.
Will biotin make my hair grow if I’m not deficient?
There’s little basis to expect it. Biotin deficiency genuinely does cause hair loss, and correcting a deficiency helps — but deficiency is rare in people eating an ordinary diet, since biotin is present in eggs, nuts, seeds, fish, meat and many vegetables and is also produced by gut bacteria. So for most people taking a hair supplement, the biotin is doing nothing for their hair while adding a real risk of a misread blood test. The useful question isn’t “does biotin matter for hair” — it’s “am I short of it,” which is a blood test rather than a purchase.
What actually works for male pattern hair loss?
Two treatments have FDA approval for this use. Topical minoxidil is available over the counter — apply twice daily, expect increased shedding early on, and give it at least four months before judging. Oral finasteride is prescription-only and produced a 68% response rate over 24 months in the study above, but carries recognised potential side effects including sexual side effects, must not be used or handled by women who are or may become pregnant, and affects PSA results. Both are maintenance treatments — benefits reverse if you stop.
Should I try a supplement first before seeing a doctor?
We’d argue not, and the reason is timing rather than snobbery. Treatments for androgenetic alopecia are much better at preserving hair you still have than at recovering hair that’s gone, so time spent on a supplement is time the process keeps progressing. It’s also worth ruling out thyroid problems and iron deficiency, both of which cause hair loss and are correctable. And see a doctor promptly regardless if the loss is sudden, patchy, rapid or painful — that isn’t male pattern baldness and needs a diagnosis.
Your checklist
- Know the numbers: saw palmetto 38% vs finasteride 68% over 24 months
- Note that study had no control group
- Add biotin to your medication list
- Tell every doctor and lab that you take biotin
- Say it especially in an emergency department with chest pain
- Ask how long to pause biotin before blood tests
- Remember biotin helps only if you’re deficient — which is rare
- Start with FDA-approved options: minoxidil OTC, finasteride on prescription
- Expect early shedding on minoxidil and don’t quit
- Give any treatment 4–12 months, with photos from day one
- Understand these are maintenance treatments
- Get thyroid and iron checked
- Don’t delay — the treatment window matters more than the product
Medical disclaimer. This article is general information, not medical advice. Tell every doctor, hospital and laboratory that you take biotin, particularly before blood tests and immediately if you attend with chest pain — biotin can cause falsely low troponin results and a missed heart attack diagnosis. See a doctor rather than self-treating for sudden, patchy, rapid or painful hair loss, which is not male pattern baldness. Thyroid disease and iron deficiency both cause hair loss and are correctable — ask for them to be checked. Finasteride is prescription-only; it must not be used or handled by women who are or may become pregnant, and it affects PSA testing. Speak to a doctor before starting minoxidil if you are pregnant, breastfeeding, or have heart problems.
Affiliate disclosure. Some links on this page are affiliate links. As an Amazon Associate we earn from qualifying purchases. We have not recommended the product under review; the product we did recommend is the one with FDA approval for the purpose.
