Hair growth serums: what's in them, and what the evidence says
Redensyl, aminexil, caffeine, adenosine, peptides. Active by active, I go through what the serums on the shelf can do, and where the line runs between cosmetic and medicine.
Two worlds: medicine and cosmetic
On the "hair growth serum" shelf, two worlds mix that are also legally distinct. Topical minoxidil is a MEDICINE: its efficacy was studied and approved as a medicine, and in Hungary it is available without a prescription, from pharmacies. NNGYK database A separate article covers it, with where to buy and prices: minoxidil guide.
Every other serum is a COSMETIC. This is a category fact: a cosmetic cannot treat a disease, and it has no prior regulatory approval. Its claims must be substantiated under the EU cosmetic claims rule Regulation (EU) 655/2013, but a clinical efficacy study is not a requirement for that. There can still be data behind it, you just need to know how much. That is what this article is about: the non-minoxidil actives, one by one.
The ones that also have published, independent studies
Adenosine. The 2025 systematic review found 7 clinical studies, and all pointed in the same direction: less shedding, higher density. The other side of the scale: the meta-analysis of the three poolable studies showed no statistically significant difference on any endpoint, and the strength of the evidence is low, because the studies are small and weakly designed. According to the authors, it may still be worth trying, especially if the medication route is not an option for some reason. Szendzielorz 2025
Caffeine. Its strongest data is an open-label study following 210 men, where the 0.2% caffeine solution was "noninferior" to 5% minoxidil. Dhurat 2017 I wrote up the detailed picture, together with the shampoo format, in the shampoo article.
Rosemary oil. In a 100-person study, there was no significant difference between rosemary oil and 2% minoxidil over 6 months, but scalp itching was more common in the minoxidil arm. Panahi 2015 One study, against 2% (not 5%) minoxidil. A separate page covers dilution and the routine: rosemary oil for hair.
The branded complexes: Redensyl, Procapil, Capixyl, AnaGain
These are development companies' trademarked blends: the main molecules of Redensyl are DHQG and EGCG2 Revalid FAQ; according to the makers' descriptions, Procapil combines a biotinoyl peptide with a plant flavonoid, Capixyl a peptide with red clover extract, and AnaGain is a pea sprout extract. The manufacturers' materials show promising numbers for each of them.
The published literature is more modest. Our own search on these names returned few results, mostly reviews and small, open-label, or developer-affiliated studies; we found no large, independent, double-blind trial for any of them. own search, 2026-08 Bikash 2025 This does not mean they are ineffective. It means the level of evidence is different from that of medicines, and that is worth keeping in mind next to the price tag.
Aminexil, Stemoxydine, Nanoxidil: the big brands' own molecules
Aminexil (in the product names of Vichy Dercos and L’Oréal): the search mostly returns formulation papers and small studies on it. Stemoxydine (in the name of Kérastase Densifique): a few small clinical papers. Nanoxidil (in the DS Labs Spectral products): its name echoes minoxidil, but it is a different molecule, and its published data is minimal, the search returned two hits for it. own search
Because of the name similarity, one thing is worth seeing clearly: none of these is a medicine, and none of them is a "stronger" or "side-effect-free" version of minoxidil. They cannot even be compared to it until there is a comparative study.
Peptides and the other names on the box
Research is lively around the copper peptide (GHK-Cu) and the other short peptides, but in our search the bulk of the literature was mechanism descriptions and reviews; in terms of clinical evidence these also stand on the lower rungs of the ladder. own search A separate article covers the natural agents taken by mouth (saw palmetto, pumpkin seed oil), with numbers and limitations: natural DHT blockers. Vitamins are their own genre: when supplementation helps, and what biotin can really do.
How to read the "clinically proven" label
Five questions you can use to check any serum promise: Who was it tested on, and how many people? For how long? What was it measured against (placebo, nothing, or a medicine)? Who funded it? Was it published in a journal, or does it only live in the manufacturer's materials? If a product page has no answer to these, the "clinically proven" label on its own says little. A manufacturer's study is not a lie, but it is not independent evidence either.
When should you move past serums?
Pattern hair loss is a progressive process, and cosmetic serums stand at the bottom of the ladder. If the shedding follows a pattern (crown, temples, a widening part), the cause is hormonal, and two articles cover that: the male pattern and DHT blockers, including what comes before medication if you're afraid of the side effects. Microneedling, which works on the follicle's environment by a mechanical route, is covered in the 1 mm Dermastamp guide. If the shedding is sudden and even, read the diffuse hair loss article first, because there the search for the cause is the first step.
The bottom line: there is a single medicine on the serum shelf, minoxidil, everything else is a cosmetic. Among the cosmetic actives, adenosine, caffeine, and rosemary have published, low-strength data; behind the branded complexes there are mostly the manufacturers' own studies. It's worth calibrating the price and your expectations to this ladder, and then the decision is truly yours.
Frequently asked questions
Redensyl or minoxidil: which is better?
No comparative study between the two has been published, so there is no measured answer to the "which is better" question. What is fact: minoxidil is approved as a medicine, with a large body of trials; Redensyl is a cosmetic complex, with little and typically maker-affiliated data. own search Whoever decides between the two is really deciding between levels of evidence.
Does the Revalid Regrowth serum work?
According to the manufacturer, the key active of Revalid Regrowth is Redensyl (with the molecules DHQG and EGCG2). Revalid FAQ There are few published, independent studies on this complex; the manufacturer's materials are positive. own search So the evidence gives no individual guarantee, and that is true of the category as a whole, not just this one product.
What do I get at dm or Rossmann?
On the drugstore shelf you'll find cosmetic serums: caffeine, herbal, and peptide ones. A medicine-category product (minoxidil) is only available in pharmacies; the where-to-buy chapter of the minoxidil article covers this, with prices.
Serum or shampoo?
The format that STAYS on the scalp has a theoretical advantage: the active ingredient gets more time. The largest caffeine study was also done with a leave-on solution. I wrote about the shampoo side in the shampoo article.
How long until anything shows?
The hair cycle is slow: studies typically measure in months, and the "results" seen over a shorter time are mostly not about the number of hairs. If a product promises thickening within weeks, that belongs among the warning signs. And if there is no change after half a year, that is information too.
Can I use a serum alongside minoxidil?
There is no meaningful study data on combining cosmetic serums with minoxidil; in practice, many people layer them. What to watch: the load on the scalp (more products, more chance of irritation), and that minoxidil is applied as the label says. When in doubt, a pharmacist or a dermatologist.
Is a rosemary oil serum worth it?
Rosemary has one much-cited study, in which it did not differ from 2% minoxidil, with less itching. Panahi 2015 One study, against a weaker minoxidil concentration, so a cautious plus. Dilution and the routine here: rosemary oil for hair.
Do women need a different serum than men?
At the level of the actives, no, but the cause and pattern of the hair loss can differ, and so can what to do: the women's hair loss article goes through the diffuse and the pattern picture separately, together with the medical work-up.
Sources
Every number and claim on this page comes from the sources below. The studies were not done with our products, and they describe group-level results. This is information, not medical advice.
- Szendzielorz E, Spiewak R. Adenosine as an Active Ingredient in Topical Preparations Against Hair Loss: A Systematic Review and Meta-Analysis. Biomolecules. 2025. PMID 40867538 · 7 clinical studies, uniformly less shedding and higher density; the meta-analysis of the three poolable studies, however, was not statistically significant on any endpoint, and the strength of the evidence is low (small samples, weak design); according to the authors, it may be worth trying, especially if the medication route is not an option.
- Bikash C. Topical Alternatives for Hair Loss: Beyond the Conventional. Int J Trichology. 2025. PMID 40654553 · review of the non-conventional topical agents (branded complexes, plant extracts, peptides).
- Dhurat R, et al. Noninferiority of a Caffeine-Based Topical Liquid 0.2% Versus Minoxidil 5% Solution in Male Androgenetic Alopecia. Skin Pharmacol Physiol. 2017. PMID 29055953 · n=210 men, 6 months, open-label design: the caffeine solution is "noninferior" to minoxidil.
- Panahi Y, et al. Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia. Skinmed. 2015. PMID 25842469 · n=100, 6 months: there was no significant difference in hair count between the rosemary oil arm and the 2% minoxidil arm; scalp itching was more common in the minoxidil arm.
- Our own literature search on the branded serum actives, retrieved 2026-08-07 · Europe PMC: "redensyl" + hair 11 hits · "procapil" + hair 15 · "capixyl" + hair 11 · "anagain" + hair 6 · "aminexil" 32 · "stemoxydine" 6 · "nanoxidil" 2 · "copper peptide/GHK-Cu" + hair 74, mostly mechanism descriptions and reviews. Most of the hits are reviews, small or open-label, several tied to the developer companies; we found no large, independent, double-blind trial for any of the names. The query is reproducible.
- The manufacturer's FAQ page for Revalid. revalid.hu/gyik · "Redensyl consists of two patented molecules: DHQG (dihydroquercetin glucoside) and EGCG2 (epigallocatechin gallate glucoside)."
- NNGYK medicines database. ogyei.gov.hu/gyogyszeradatbazis · the products marketed in Hungary as topical, over-the-counter hair loss medicines are minoxidil solutions (REGAINE, MINOXIDIL MIOWELL, REVICAPIL, BRILLATON).
- Commission Regulation (EU) No 655/2013 laying down common criteria for the justification of claims used in relation to cosmetic products. EUR-Lex 32013R0655 · cosmetic claims must be substantiated (common criteria); the framework of the category, including the fact that there is no medicine-style, prior efficacy approval, is set by the Cosmetics Regulation (EC) No 1223/2009.