There is an entire shelf of hair serums now built around not using the one ingredient with the strongest evidence. The labels read like a chemistry paper — Redensyl, AnaGain, Procapil, Capixyl, Baicapil, Kopexil — and the percentage printed on the front of the bottle is doing an enormous amount of work.
I get asked about these constantly, almost always by women who have been shedding for months and do not want to start minoxidil. That is a reasonable position to hold. It deserves a straight answer rather than a marketing one.
So here is what those actives are actually doing, how good the evidence behind them really is, and when a serum is a sensible choice rather than an expensive delay.
The evidence behind the labels
Where the evidence for these ingredients comes from
Start here, because it explains most of what follows. Almost every efficacy figure printed on a hair serum box originates with the company that manufactures the raw ingredient and sells it to the brand. Not the brand. Not a university. Not an independent trial.
These supplier studies share a family resemblance: twenty to sixty participants, eight to twelve weeks, frequently men only, and the active tested inside a combination formula so that no single ingredient can be credited for anything. Several have never been peer reviewed or published anywhere you can read them.
Then there is the endpoint problem. Many of these studies do not count hairs at all. They report the ratio of growing hairs to resting hairs, or a doctor’s five-point impression of a photograph. Both can move impressively while the actual number of hairs on a head barely changes. When a box says “78% increase in hair growth”, that is almost always a ratio, not hairs.
None of this makes the ingredients useless. It means the confidence in the marketing is not earned by the data sitting behind it.
What each active is actually doing
Redensyl. A blend aimed at the stem cells at the base of the follicle, meant to push resting follicles back into a growth phase. The supplier’s own placebo-controlled study — 26 men, 84 days — found roughly 17% less hair loss and about 9% more density. Real, modest, anti-shedding. The famous claim that it is “twice as effective as minoxidil” comes from a ten-day comparison on cells in a dish. Not people. Not scalps.
Pea sprout extract (AnaGain). The best substantiated of the sprout extracts, and the one I would pick if forced to choose. It raises growth factors in the dermal papilla, and in a three-month study resting-phase hair density fell by around 28%. Still supplier-funded, but the mechanism and the numbers are at least consistent with each other.
Procapil. A peptide-and-plant combination targeting blood flow, follicle anchoring and DHT at once. The supporting study involved 18 people. Plausible, thin, best understood as a supporting act rather than a lead.
Capixyl. A red clover peptide containing biochanin A, which inhibits 5-alpha-reductase — the enzyme that converts testosterone to DHT. That is a genuinely relevant mechanism for pattern hair loss. Manufacturer data reports more growing and fewer resting follicles at four months. There is no independent trial.
Baicapil. The headline figure, around a 60% reduction in hair loss, comes from a 61-volunteer trial run internally in 2013 that has never been published or peer reviewed. Treat it as an unverified claim, because that is precisely what it is.
Kopexil, also sold as aminexil. Structurally related to minoxidil, and frequently sold on that resemblance, but it works differently — it limits the scarring and stiffening around the follicle rather than stimulating growth. Placebo-controlled data shows a mild anti-shedding effect. It has never demonstrated regrowth, and it is not a quiet substitute for minoxidil.
Turmeric callus and “stem cell complexes”. These carry the most dramatic claims on the shelf — 89% less hair loss, thousands of new hairs — and they rest on a 20-person study run by the ingredient supplier. When a serum of this type was finally tested independently against two others, it came last.
Bean sprout extract, basil root culture, apple stem cell, and most of the rest. Essentially no independent clinical hair evidence. The apple stem cell data that gets cited is skin research, not hair research. These ingredients exist mainly to lengthen the list on the front of the box.
Caffeine. A real mechanism — it opposes DHT’s suppression of the follicle and penetrates the hair follicle within a couple of minutes. A 2025 systematic review found only nine usable studies covering 684 people between them, mostly in men and mostly in minor journals. A legitimate small adjunct, and no more than that.
Rosemary oil. The best-evidenced botanical by a distance. One hundred people, six months, rosemary oil against 2% minoxidil: both groups improved significantly by month six with no meaningful difference between them, and the minoxidil group itched more. It is one modest trial against the weaker strength of minoxidil, but it is a proper randomised comparison, which is more than any of the sprout extracts can say.
Shedding for months and not sure whether the problem is on your scalp or in your bloodwork? Send me your reports and I will tell you what is actually worth testing first.
What each active is actually doing
| Active | Claimed mechanism | The evidence behind it |
|---|---|---|
| Redensyl | Aimed at the stem cells at the base of the follicle, to push resting follicles back into a growth phase | Supplier’s own placebo-controlled study — 26 men, 84 days. Roughly 17% less hair loss, about 9% more density |
| Pea sprout extract AnaGain |
Raises growth factors in the dermal papilla | The best substantiated of the sprout extracts. In a three-month study, resting-phase hair density fell by around 28% |
| Procapil | Blood flow, follicle anchoring and DHT at once | 18 people. Plausible, thin |
| Capixyl | Red clover peptide containing biochanin A, which inhibits 5-alpha-reductase — the enzyme converting testosterone to DHT | A genuinely relevant mechanism for pattern hair loss |
| Baicapil | Around a 60% reduction in hair loss | A 61-volunteer trial run internally in 2013, never published or peer reviewed |
| Kopexil also sold as aminexil |
Structurally related to minoxidil | Frequently sold on that resemblance — which is not the same as sharing its evidence |
What happens when someone tests these properly
In 2025, an Indian dermatology group ran 45 women with telogen effluvium — diffuse shedding, the kind that follows childbirth, illness, crash dieting or a bad year — across three different serums for 90 days, using trichoscopy and hair-wash counts rather than impressions.
A serum built on Redensyl and aminexil reduced shedding by 26%. One built on turmeric callus and peptides managed 24%. A third serum, from an entirely different category — growth factors rather than cosmetic actives — reduced shedding by 55% and raised density by 65%.
Two things follow from that. The cosmetic actives do work: roughly a quarter less shedding over three months is not nothing when you are watching hair collect in the drain. And they were comfortably beaten in a fair fight.
About the study where a serum “beat minoxidil”
Nearly all the marketing around these ingredients leans on a single 2019 paper: 120 men, a Redensyl-Capixyl-Procapil serum against 5% minoxidil over 24 weeks, and the serum came out ahead.
The trial was open-label — everybody knew what they were using. And every endpoint was subjective: a doctor’s naked-eye score, a patient questionnaire, and a visual grading of photographs. No hair counts. No trichoscopy. Nothing anyone actually measured.
An unblinded trial scored by impression is exactly the design that produces flattering results. Whatever it shows, it cannot carry the claim that is being built on top of it.
What has better evidence than any serum
Topical minoxidil. Still the benchmark, and the only topical with genuine hair-count regrowth in women. In a trial of 381 women over 48 weeks, 5% minoxidil beat placebo on all three primary measures. 2% is the approved strength for women, 5% works better with more side effects, and the once-daily foam avoids the propylene glycol that causes most of the itching.
Microneedling alongside minoxidil. The landmark trial found 91 extra hairs per square centimetre at 12 weeks with microneedling plus minoxidil, against 22 for minoxidil alone; 82% of the microneedling group reported more than 50% improvement, against 4.5% of the minoxidil-only group. Done in men, but repeated in women since. A 0.5–1.5 mm roller or pen, roughly weekly, is the best-evidenced adjunct there is.
Anti-androgens. Spironolactone before menopause; finasteride and dutasteride only under specialist supervision. These are teratogenic — they cause serious foetal harm — and no woman who could become pregnant should be on them without proper contraception and a doctor managing it.
Ketoconazole 2% shampoo, PRP and low-level laser therapy. Modest, real, adjunctive. None of them will carry the whole plan.
Oral supplements with actual trial data, such as saw palmetto and the marine collagen formulas. Supportive rather than substitutive; in one pooled analysis the most popular of them came last among the treatments evaluated in women, well behind topical minoxidil.
What has better evidence than any serum
| Option | What the evidence shows |
|---|---|
| Topical minoxidil | Still the benchmark, and the only topical with genuine hair-count regrowth in women. In a trial of 381 women over 48 weeks, 5% minoxidil beat placebo on all three primary measures |
| Microneedling with minoxidil | The landmark trial found 91 extra hairs per square centimetre at 12 weeks, against 22 for minoxidil alone |
| Anti-androgens | Spironolactone before menopause; finasteride and dutasteride only under specialist supervision. These are teratogenic — no woman who could become pregnant should take them casually |
| Ketoconazole 2%, PRP, low-level laser | Modest, real, adjunctive. None of them will carry the whole plan |
| Oral supplements with trial data | Saw palmetto and the marine collagen formulas — supportive rather than substitutive |
Microneedling + minoxidil vs minoxidil alone
Extra hairs per square centimetre at 12 weeks. No serum on the market has produced a number in this range.
What is worth measuring before you buy anything
This is the part nobody selling a serum has any interest in mentioning. In women, far more hairfall is driven by what is in the bloodwork than by anything you can apply to a scalp.
- Ferritin — the single most useful test. A 2025 case-control study found women with telogen effluvium averaging about 24 ng/mL against 45 in women without it. Most hair clinicians want ferritin above 40–70, which is well above the point where your lab report stops flagging it
- Vitamin D — commonly low, cheaply corrected
- B12, particularly if you are vegetarian or have been on metformin for years
- Thyroid function — an underactive thyroid sheds hair diffusely and is routinely missed
- Androgens and a PCOS assessment if your cycles are irregular or you have unwanted hair growth elsewhere
Correct those, and for a great many women the shedding settles without a bottle of anything.
Read the percentage before you pay for it. When a box says “78% increase in hair growth”, that is almost always a ratio — the proportion of hairs in the growing phase against the resting phase — not 78% more hairs on your head. A shift in that ratio is real, but it is a far smaller thing than the number implies, and it is usually measured over twelve weeks on a few dozen people by the company selling the ingredient.
When a serum is genuinely the right choice
It is a fair option if you are dealing with diffuse shedding after childbirth, illness, stress or a period of undereating — the follicles there are dormant rather than dead, which is exactly the situation these actives are built for. It is also fair if you cannot tolerate minoxidil, or you do not want the initiation shed and the risk of hair appearing on your face.
What to look for on a label: percentages next to the actives, not just names. Pea sprout extract and Redensyl present at a meaningful strength rather than twenty ingredients at trace amounts. No added fragrance if your scalp is at all reactive. A long ingredient list with no numbers beside it tells you nothing at all, and you should treat that silence as an answer.
Give it three months of daily use before you judge it, and six before you decide it has failed.
It is the wrong choice for established pattern hair loss where the crown has visibly thinned — those follicles have miniaturised, and a cosmetic serum will not reverse that. It is also the wrong choice for traction alopecia, which is a mechanical problem. No serum will out-argue how tightly you tie your hair.
What I will not tell you
That one of these serums will regrow a thinned crown. It will not, and no serum on the market has ever demonstrated that it can.
That you can skip minoxidil because a serum beat it in a study. That study did not measure anything.
That a serum is a substitute for finding out why you are shedding. Buying the bottle first and investigating later is how people lose a year, and hair that has been shedding for a year is harder to bring back than hair that has been shedding for three months.
The short version
- Almost all the evidence for cosmetic hair actives comes from the companies that sell them — small, short, unblinded, and often scored by eye rather than counted
- Tested properly, these actives reduce shedding by roughly a quarter over three months. That is real, and it is not regrowth
- The “beats minoxidil” study was open-label with entirely subjective endpoints and no hair counts
- Minoxidil, microneedling and anti-androgens sit far above every serum on the evidence ladder
- Ferritin, vitamin D, B12, thyroid and androgens explain more female hairfall than any bottle does
- A serum is a reasonable choice for diffuse shedding once the bloodwork is corrected, and a poor one for established pattern loss
Before you act on any of this
I am a pharmacist and a nutritionist. I am not your doctor, and this article is general information rather than advice about you specifically. Nothing here is a reason to start, stop or change a prescribed medicine — that decision belongs to the person who prescribed it, working from your history and your bloodwork. Hair loss also has causes that need a dermatologist rather than a shopping list, and if yours is patchy, scarring, sudden or accompanied by scalp pain, that is where you should be going. What this article can do is tell you which questions are worth asking at your next appointment.
Sources
- Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial (Skinmed, 2015)
- A randomized, placebo-controlled trial of 5% and 2% topical minoxidil solutions in female pattern hair loss (JAAD, 2004)
- A randomized evaluator blinded study of the effect of microneedling in androgenetic alopecia (Int J Trichology, 2013)
- Comparative analysis of various hair peptide serums in managing telogen effluvium in females (J Cutan Aesthet Surg, 2025)
- Caffeine as an active ingredient in cosmetic preparations against hair loss: a systematic review (Healthcare, 2025)
